Nutrition And Neurologic Disorders

Nutrition And Neurologic Disorders
The brain and nervous system require the full complement of
essential nutrients and energy to develop and maintain their neurons
and supporting cells. A deficiency of any one of these essential
nutrients may impair the structure or functionality of the neurologic
system.

Stroke is the most common life-threatening neurologic disease. Other
neurologic conditions are, epilepsy, chronic headaches, and Alzheimer's
disease.

The brain metabolizes 100 g to 150 g of glucose per day. During starvation, it adapts and uses ketones, derived from the breakdown of body fat stores, for energy and thus spares blood glucose and conserves body protein.

Severe deficiencies of vitamins, especially the B-complex group,
impair nervous system function. Thiamin deficiency causes beriberi
neuropathy as well as a peripheral neuropathy and polyneuritis that
leads to paralysis of the eye muscles, loss of muscular coordination,
and memory loss, especially in long-term alcoholics. Inadequate niacin
intake causes pellagra, with symptoms that include intellectual
impairment and dementia. Deficiency caused by vitamin B12

malabsorption in untreated pernicious anaemia, or as a result of a long
term deficient vegetarian diet, can result in subacute degeneration of
the spinal cord, optic nerves, cerebral white matter, and peripheral
nerves. Severely deficient intakes of other vitamins of the B-complex
group also affect neurologic function. In the early stages, these
symptoms are readily overcome by increased dietary intake of the
appropriate vitamins, but nerve damage in later stages are irreversible.

Deficiencies of other nutrients relate to defects in the nervous
system function. Iodine deficiency during brain development causes
mental retardation and neuromotor abnormalities. Chronic iron
deficiency is associated with deficits in cognitive abilities. Vitamin
E deficiency can cause spinal cord, cerebellar, and peripheral nerve
degeneration with muscle wasting.

Stroke

Stroke is the sudden loss of brain function caused by thrombosis,
embolism, stenosis, atherosclerosis, or haemorrhage from rupture of a
cerebral artery. These events deprive the brain of oxygen and cause
tissue death and irreversible damage to nervous tissue. Symptoms range
from those too trivial for the victim to notice to major sensory
deficits, blindness, paralysis, speech loss, coma, and death.

Persons at greatest risk for stroke are those with hypertension and
diabetes, and those who smoke cigarettes and display impaired cardiac
function due to coronary heart disease, congestive heart failure, or
hypertensive heart disease. These major risk factorsfor stroke are
related to nutritional, dietary, and lifestyle factors.

Moderate sodium intake, high potassium intake, vegetarian diets,
calcium, weight reduction, and alcohol restriction all have been
suggested as factors associated with lowering the risk factor for
stroke in humans.

Headache

Headache is one of the most common complaints evaluated by
neurologists. The foods most frequently implicated contain tyramines
(eg. cheese, red wines), or phenylethylamine (eg. chocolates). The
"Chinese Restaurant Syndrome" is associated with numbness around the
mouth, tingling, flushing of the face, dizziness, and headache. This
syndrome could be attributable to the high quantity of monosodium
glutamate (MSG) used in the prepared foods.

Epilepsy

Low levels of magnesium can cause seizures, and the magnesium-deficient rat is used as a model of experimental epilepsy. [Buck,
D.R., Mahoney, A.W., and Hendricks, D.G.: Preliminary report on the
magnesium deficient rat as a model of epilepsy. Laboratory Animal
Science. 28(6),680-85, 1978.] Magnesium deficiency in humans most often results from kidney disease and is not a significant cause of epilepsy in people.

Vitamin Intake and Drug-Nutrient Interactions

Excessive intake of vitamin A causes reversible intracranial
hypertension, headache, blurred vision, seizures, end encephalopathy.
Excessive pyridoxine has been associated with peripheral nerve
deterioration.

Naturally occurring food-borne toxins also affect the mature nervous
system. Specific dietary constituents, such as heavy and trace metals,
may have adverse effects on the nervous systems of older adults.
Increased amounts of aluminum and calcium have been reported in brains
of patients with Alzheimer's disease.

Some of the drugs used to treat neurologic disease can lead to
vitamin deficiencies by changing the metabolism of vitamins, causing a
secondary impairment of brain function. Dilantin, used to treat
epilepsy, can increase folate requirements and cause vitamin K
deficiency. Hydralazine can cause neuropathy, tranquilizers such as
chlorpromazine and other phenothiazines may cause hyperphagia and
weight gain. Monoamine oxidase inhibitors can cause acute hypertensive
crises, including excruciating headaches or fatal intracranial
haemorrhages, when taken with foods or beverages high in tyramine.
Caffeine, found in foods and drugs, is an active pharmacologically
active agent that can enter the brain because of its lipid solubility.

Nutrition Programs and Services

Food Labels:Evidence related to the role of dietary
factors in stroke and other neurologic diseases supports the need for
sodium labeling of packaged food products.

Food Services:Food service programs should emphasize
diets low in sodium and calories to maintain ideal body weight and to
control obesity and diabetes. [The Surgeon General's Report on Nutrition & Health, 1988.]

Symptoms Of Infections In Your Immune System

Symptoms Of Infections In Your Immune System
The immune system protects the body against infection by producing
specific substances in response to foreign materials called antigens.
Immunity to specific antigens occurs through the cooperative
interactions of two subsets of blood cells, T lymphocytes and B
lymphocytes.

There are several subtypes of T lymphocytes, each with specific
functions. Helper and suppressor T lymphocytes regulate the quantities
of antibodies produced, while killer T lymphocytes respond selectively
to foreign material, search and destroy internally infected, or
malignant body cells.

Severe infections can compromise nutritional status through a
variety of mechanisms: hypermetabolism, appetite depression, decreased
absorption of nutrients, altered nutrient metabolism, increased
nutrient excretion, and internal diversion of nutrients. additional
nutrient losses occur with vomiting, diarrhea, and sweating.

Hypermetabolism

Fever causes metabolic rates to increase. This hypermetabolism
affects all cells in the body. Because this extra energy comes largely
from amino acid metabolism the body stores of muscle protein amino
acids are rapidly depleted. Loss of nutrients also occur during
sweating associated with fever. Controlling the infection reduces fever
and losses of body nutrients.

Severe loss of appetite is a common symptom during most infectious
diseases and often leads to an almost total cessation of food
consumption. Vomiting and diarrhea further reduce the absorption of
nutrients. Antibiotics and other medications also modify intestinal
absorption.

Excess nitrogen is metabolized to urea and excreted in the urine.
Even brief viral infections and brief fevers induced by bacterial
infections can cause sizable losses of nitrogen.

Tissue and plasma concentrations of most vitamins decline during
infections, because of increased metabolism or excretion. The
accelerated metabolism or loss of vitamins during infections may
precipitate recognizable deficiency states.

Food Associated Illnesses

Adverse reactions to food involve immunologic and nonimmunologic
mechanisms. Immunologic reactions are known as food allergies.
Nonimmunologic intolerances include those that are biochemical or
psychologic.

Food allergies are examples of the negative consequences of immune
function on the gastrointestinal tract, skin, lungs, and other organs.
The most common foods to which people are allergic are eggs, milk,
fish, shellfish, chicken, wheat, and nuts. Symptoms include acute
abdominal pain, swelling, nausea,vomiting, rashes, chronic itching,
headache, tension, and fatigue.

The causes of nonimmunologic adverse reactions to foods include food
toxicities, food poisonings, and pharmacologic or metabolic reactions.
Such intolerances occur more frequently than true food allergies and
are related to dose as well as to the concurrent presence of
medications, other diseases, or genetic errors of metabolism.

Sulfites

Approximately 10 percent of people with asthma are sensitive to
ingestion of sulphite, which induces asthma. Foods containing sulfur
dioxide, as a preservative, should be used with caution.

FDA has taken two major steps to protect consumers who are sensitive
to sulfites in food. No longer can these preservatives be used on raw
fruits and vegetables. And processed foods that contain sulfites will
have to say so on the package label.

The allergic-type reactions range from mild to severe, and in some
cases can cause death. "Sulfites" or "sulfating agents" are general
terms used to describe sulfur based substances that have been in
widespread use for many years by the food and drug industries. They
include sulfur dioxide, sodium sulfite, sodium and potassium bisulfite,
and sodium and potassium metabisulfite. Although they have various
permitted uses, their primary function is as a preservative or
antioxidant to prevent or reduce spoilage and discolouration during the
preparation, storage and distribution of many foods.

There is some evidence that some non-asthmatics also can suffer
adverse reactions to sulfites. For example, out of more than 500
reports of sulfite reactions investigated by the FDA, about one-fourth
involved people who had no known history of asthma.

Asthma is also induced by tartrazine, a yellow dye used to color
medicines, soft drinks, and foods. Tartrazine can also cause
hyperactivity in sensitive individuals. It has no nutritional value.
Because of the negative effects associated with tartrazine, foods and
drinks containing it should be avoided. Other substances that cause
adverse reaction or neurologic disorders are monosodium glutamate (MSG)
and the preservative benzoic acid.

Psychologic mechanisms can provoke physical and mental symptoms of
food sensitivity that do not appear to be medicated by the immune
system. In individuals with psychologically induced allergic symptoms
no physiologic or biochemical nonimmunologic mechanisms can be
identified.

Individuals with food intolerances should exclude the offending
foods from their diet. Those with potentially life-threatening
sensitivities should carry an epinephrine-containing syringe and wear a
bracelet identifying the problem.

HIV Infection and AIDS

Acquired immunodeficiency syndrome (AIDS), caused by the human
immunodeficiency virus (HIV), is a disease with multiple pathologies,
most of which are the consequence of a profound immunodeficiency.

Weight loss and deteriorating nutritional status are critical
features of the AIDS disease. Anorexia, nausea and vomiting, fever, and
diarrhea are common features of advanced AIDS, as are malabsorption of
fats, carbohydrates, and protein. Immune abnormalities resulting from
malnutrition seen in AIDS implies that malnutrition might predispose to
AIDS or that nutritional therapy might improve immune status and
prevent AIDS.

Folate levels were measured in HIV-infected patients. For persons
not supplemented with folic or folinic acid and not taking antifolate
drugs, serum and erythrocyte folate was decreased significantly. Folate
deficiency was frequent and observed at all stages of HIV infection. [Boudes, P. et al: The Lancet. 335:1401, 1990.]

Nutrition Programs and Services

Food Labels:Evidence related to diet-immune function
interactions reinforces the need for food manufacturers to include
explicit and complete ingredient statements to protect individuals who
may have severe adverse reactions to foods.

Food Services:Current evidence about the role of dietary
factors in the maintenance of optimal immune function currently has no
special implications for change in policy related to food service
programs. Evidence related to the spread of infections suggests that
food service personnel should receive adequate training in sanitary
food handling and storage procedures.

Food Products:Evidence related to diet-immune function
interactions suggests that food product manufacturers should take
special precautions to use good manufacturing practices to avoid
contamination with ingredients that may produce severe reactions and to
reduce microbial and chemical contamination during production and
storage. Manufacturers should continue to develop new products that are
free of substances likely to induce allergic symptoms in susceptible
individuals. [The Surgeon General's Report on Nutrition & Health, 1988.]

Research Findings On Gastrointestinal Diseases

Research Findings On Gastrointestinal Diseases
The gastrointestinal system extracts essential vitamins and
minerals from diverse plant and animal foods and breaks down the
carbohydrate, protein, and fat molecules to smaller subunits that can
be absorbed. It accomplishes these tasks by means of the various
digestive organs of the body and the enzymes. (See Digestive System.)

The diet must provide, sufficient nutrients and energy to synthesize
the rapidly renewing cells that line the gastrointestinal tract, the
enzymes that digest and transport nutrients across the intestinal
walls, and other hormones that control these processes. Digestive
function can be seriously disrupted by inadequate nutrition.

Diseases of the gastrointestinal tract will unavoidably have
profound effects on nutritional and metabolic processes. Loss of body
weight is often an indication of gastrointestinal disease and a diet
history may reveal obvious nutritional deficiencies associated with the
underlying disease, eating problems, and psychological problems.

Dietary fat, fiber, and alcohol are significant factors associated
with gastrointestinal diseases. Higher intakes of dietary fiber can
prevent or relieve symptoms of constipation and chronic diverticular
disease. Individuals with celiac disease should obtain information on
foods free of wheat gluten. Those with inflammatory bowel disease,
heart-burn, and ulcers should follow diets appropriate to their
conditions.

Diseases of the Mouth

Dental caries result from demineralization of the enamel surface of
the tooth by acids produced from sugars. Initially mineral disappears
from the sub-surface of the tooth and if this process is not addressed
a cavity will develop in which more bacterial growth can occur causing
further dissolution of enamel. Eventually the tooth may be lost.

The presence in the mouth of fermentable sugars is essential for the
development of dental caries. Within minutes of consumption sugars
cause the pH in dental plaque to fall below the critical pH for enamel
dissolution. This fall in pH will occur irrespective of the amount of
sugar consumed or whether it comes from fruit or chocolate. The normal
oral pH of 7.0 will only be restored about 30 minutes after the sugar
has finally been swallowed. Normally the pH will return sooner if the
item is consumed quickly rather than if eaten slowly over a long period
of time.

Acidic foods, such as citrus fruits and cola drinks, lower the mouth
pH and hence produce cariogenic conditions. Finishing a meal with an
alkaline food, such as cheese, milk, or peanuts can help to raise the
pH of the mouth.

Fluoride can increase enamel resistance by the formation of
fluorhydroxyapatite crystals in the tooth which are more resistant to
acid erosion. The maximum benefit from fluoride is obtained if it is
available during tooth formation. Once the tooth has emerged, further
protection can be obtained from topical or dietary fluoride.

Deficiency of certain vitamins may produce inflammation of the gums
and the teeth may become loose from the lack of cement which normally
holds them to the jaw. A lack of vitamin C causes scurvy, a weakening
of periodontal fibers and the teeth may become loose and fall out. The
gums become tender and bleed easily. Treatment is by vitamin therapy
and sources of vitamin C should be included in the diet regularly.

Deficiency of vitamin D causes defective calcification of the
dentine of the teeth and may increase susceptibility to dental caries.
Eruption of the teeth may be delayed in children with rickets. Vitamin
D therapy should be given and good sources of vitamin D taken in the
diet, together with exposure to sunlight where possible.

Disorders of the esophagus

The diaphragm has several openings through which the abdominal
viscera can enter the thorax. The opening for the esophagus, the
hiatus, is loosely attached to the esophagus. In middle age this
attachment weakens and in overweight people additional abdominal weight
puts extra strain on the hiatus which herniates. A low fiber diet which
results in constipation causes straining when the bowels are opened and
weakening of the hiatus. The major symptoms of hiatus hernia are those
of reflux and esophagitis and the sensation of food 'sticking'.

The refluxed contents of the stomach may contain partly digested
foods, acids and enzymes. It is possibly this combination which causes
mucosal damage and esophagitis. Symptoms develop if reflux becomes
frequent and the mucosa of the esophagus becomes sensitive to the
acidic reflux. Fatty foods, chocolate, coffee, alcohol, spicy foods and
citrus juices lower sphincter pressure and may induce reflux.

Cystic fibrosis

Cystic fibrosis (CF) is a generalized hereditary condition
characterized by chronic pulmonary disease, reduced secretion of water
and bicarbonate, pancreatic enzyme deficiency and abnormally high
concentrations of electrolytes in the sweat.

Progressive malnutrition and poor growth are common features of CF
and need to be addressed by diet therapy. It is important to provide
the CF patient with the optimum diet for the potential for growth to be
fulfilled and resistance to infection maximized.

Energy intake is generally increased by 50% more than the
Recommended Daily Requirement. In order to achieve an adequate energy
intake, effective use should be made of suitable energysupplements such
as glucose polymers and glucose drinks. Fat intake should be normal and
frequent snacks should be encouraged.

Deficiencies of vitamins A, D, E and K are well documented. Daily
supplementation of 8000 IU of vitamin A, 20 mg of vitamin D, and 200 mg
of vitamin E is currently advised. Deficiency of vitamin K has been
noted in patients with liver disease and in young infants with CF. A
supplementation is only necessary if deficiency has been demonstrated.

Lactose Intolerance

Lactose (milk sugar) is digested in the small intestine by the
enzyme lactase. An insufficiency of lactase, in the small intestine,
results in undigested lactose to pass into the large intestine where it
is fermented by bacteria with the production of lactic acid. This
accumulation of lactic acid is characterized by abdominal discomfort,
pain, and diarrhea, the condition known as lactose intolerance.

After the age of 5 the genetic absence of lactase occurs among
remarkably high proportions of Asians (95 percent), Africans (99
percent), American Indians (95 percent), and black Americans (75
percent), as well as among a significant proportion of healthy
Caucasians. The origin of racial lactose intolerance is not entirely
clear. It may be a genetic difference or it may be that the custom of
drinking milk, which is common among Caucasians, results in the
continued production of lactase. Many other races do not take much milk
after infancy, so the enzyme diminishes or disappears completely.

For practical purposes, no differentiation is usually made between
cows milk and goats or sheeps milk. For people who are milk intolerant
a wide range of soya based foods are available.

Nutrition Programs and Services

Food Labels:Evidence related to the role of dietary
factors in gastrointestinal disease suggests that food manufacturers
should include on package labels information about nutrient content of
the food, especially for fat and carbohydrate components (including
fiber).

Food Services:Evidence related to the role of dietary
factors in gastrointestinal diseases suggests that food services should
include provisions for adequate intake of high-fiber and low-fat foods.

Food Products:Evidence related to the role of dietary
factors in gastrointestinal diseases suggests that the public would be
benefit from additional products that are low in fat and calories and
high in fiber. [The Surgeon General's Report on Nutrition & Health, 1988]

Realtionship Between Cancer And Diet

Realtionship Between Cancer And Diet
Cancer, the second leading cause of death in the United States,
is a group of conditions of uncontrolled growth of cells originating
from almost any tissue in the body.

Cancer may arise in any organ in the body, but tumours of the lung,
colon and rectum, breast, skin, and prostate occur most frequently, and
are variably associated with dietary factors.

The relationship between diet and cancer has been a topic of
considerable controversy in research as well as in public policy. It
has been estimated that as many as 35% of all cancer deaths in the
United States are attributable to diet. In 1984, the American Cancer
Society published a set of dietary guidelines that recommended reducing
fat intake to lower the risk of some types of cancer. This
recommendation has been supported by the National Cancer Institute and
the Surgeon General's Report on Nutrition and Health.

The National Cancer Institute initiated a low-fat dietary
intervention program (The Women's Health Trial), to study the effects
of a low-fat diet on the incidence of breast cancer in women at
elevated risk for the disease.

Women in the intervention group reduced their total fat intake to
approximately 20% of total calories over a 12 month period, mainly by
decreasing their fat intake from milk products, red meats, and
fats/oils. In addition the overall quality of the diets improved.

The intervention produced a number of beneficial dietary changes
beyond its primary objective to reduce total fat intake. These dietary
changes are consistent with the dietary guidelines for reducing cancer
risk, developed by the American Cancer Society and the National Cancer
Institute, and included: eating more complex carbohydrates from fruits
and vegetables, eating more foods high in vitamin A and C, weight loss,
drinking less alcohol, and eating less salt-cured, smoked, and
nitrate-cured foods (bacon, baked ham, pork sausages and hot dogs).

Current dietary guidelines recommend that individuals reduce their
fat intake, not only for the prevention of cancer but also to reduce
the risks of other chronic diseases such as coronary heart disease,
hypertension, obesity, and diabetes. In this study the participants
successfully decreased their fat intake to 20% of total calories while
maintaining nutritional adequacy in their diets and without major
changes in the types of foods they were consuming. [Journal of the American Dietetic Association]

It appears that a high vegetable, low-fat, low-calorie diet protects
against rectal cancer. Risk decreases with an increased intake of
carotenoids, vitamin C, and dietary fibre fromvegetables. [Freudenheim, et al]
Records from insurance companies suggested that overweight people were
at higher risk for cancer than normal or underweight people.

Tumours of the upper aerodigestive tract (laryngeal, pharyngeal,
oral, and oesophageal cancers) are alcohol related, and there is
increasing evidence linking alcohol and breast cancer in women. For
oral and oesophageal cancers, one cohort study documented a quadrupled
mortality rate for persons who drink six or more alcoholic beverages a
day, compared with nondrinkers.

Table 2.16

National Cancer Institute Dietary Guidelines.

Reduce fat intake to 30 percent or less of calories.

Increase fibre intake to 20 to 30 grams per day, with an upper intake of 35 grams.

Include a variety of vegetable and fruits in the daily diet.

Avoid obesity.

Consume alcoholic beverages in moderation, if at all.

Minimize consumption of salt-cured, salt-pickled, and smoked foods.

Several mechanisms have been proposed to account for observed
associations between diet, digestive processes, and cancer. These
include:

• Carcinogens in food that are present naturally, that are
  inadvertent contaminants, or that form as products of cooking or
  preservation.



• Diet-induced metabolic activation or deactivation of
  carcinogens. For example, formation of oxygen radicals and lipid
  perioxidation products can be retarded or blocked by normal enzymatic
  processes or by the selenium or beta-carotene present in foods.



• Biological formation of carcinogens, as with conversion of bile
  acids to tumour-promoting chemicals by normal intestinal bacteria. The
  bacteria that accomplish this conversion may be affected by diet.



• Enhancement (eg. by fats) or inhibition (eg. by vitamin A) of promotion.



• Nutrient imbalance may impair immunity and thus may influence
  early rejection of malignant cells or the ability of cells to repair
  damaged DNA.

Role of Vitamin A and Carotenoids in Cancer

A large body of evidence suggests that foods high in Vitamin A and carotenoids

are protective against a variety of cancers. The strongest evidence for
the role of vitamin A in the prevention of human cancer comes from
epidemiologic studies that correlate consumption of
carotenoid-containing vegetables or foods with a high vitamin A index
to protection against cancer of the lung.

An important issue, related to these studies is whether the
protective effects attributed to vitamin A activity, are truly
attributable to vitamin A, or whether they are due to some other factor
that may be present in the foods. For example, a study of lung cancer
among New Jersey white males showed a protective effect for fruits and
vegetables that was greatest for dark yellow-orange and green
vegetables, but no statistically significant effect for retinol,
carotenoids, or vitamin A activity. [Ziegler et al]

Because retinoids are required for normal cell differentiation,
their deficiency leads to improper differentiation of stem cells in epithelial tissue. In animals, retinoids may inhibit initiation and promotion
stages of carcinogeneses. Retinoids may also have a role in reversing
cancerous changes.

Antioxidant chemicals are thought to protect against certain
promoters of carcinogeneses. Foods containing vitamin A have been shown
to protect against the formation of oxygen radicals and lipid
peroxidation, and beta-carotene is a very efficient neutralizer of
oxygen radicals.

Large amounts of retinoids in the blood or tissues, can be toxic and
may cause birth defects and adverse effects on the skin, liver, and
neurologic tissue. Excessive intake of preformed vitamin A or retinoid
supplements should be avoided, especially by pregnant women. However,
increased intake of carotenoids from food alone is unlikely to have any
adverse effects, other than skin discolouration at very large intakes.

Role of Other Dietary Constituents in Cancer

Foods contain both nutritive and nonnutritive components. Most of
the later are present naturally, but some are added during formulation,
processing, and cooking. Studies have shown that some specific
nonnutritive substances can promote tumour development in animals. For
example, aflatoxin, a potent carcinogen derived from mold on grains,
legumes, or nuts is a naturally occurring toxin in these foods.

Experimental and epidemiological data suggest an association between
alcohol consumption and human cancer that is strongest for certain head
and neck cancers. Alcohol intake and smoking act synergistically to
increase the risk for cancer of the mouth, larynx, and oesophagus.

Although alcohol has an effect independent of smoking in increasing
cancer risk, it remains uncertain whether the responsible agent is
alcohol itself or any of the more than 400 other chemicals identified
in alcoholic beverages. The nutrient deficiencies produced in
alcoholics could be associated with impaired immune function,
permitting increased carcinogenesis. A slightly greater risk for breast
cancer in women has been associated with an average of one drink per
day in a cohort study of 89,538 American women. [Willett et al]

Vitamin C functions as a chemical-reducing agent and antioxidant.
Human studies have shown a protective association between foods that
contain vitamin C and cancers of the oesophagus, stomach, and cervix.
Vitamin C blocks the formation of carcinogenic nitrosamines from
nitrates and prevents oxidation of certain other chemicals to active
carcinogenic forms.

An association between protein consumption, especially animal
protein, and the incidence of certain cancers has been observed in
several human epidemiologic studies. Smoked and charred foods acquire
polycyclic aromatic hydrocarbons, some of which are known to be
carcinogenic in animals. These and other potential carcinogenic agents
may be formed within foods during cooking in amounts that may be
related to temperature and duration of cooking at very high
temperatures.

International epidemiologic evidence suggests that populations
consuming diets high in salt-cured, salt-pickled, and smoked foods have
a higher incidence of stomach and oesophageal cancers. oesophageal and
stomach cancers are also associated with poor nutrition. For decades
sodium nitrate has been added to cured meats at levels of about 200
parts per million to prevent botulism. Nitrate can react with secondary
amines to form carcinogenic nitrosamines. Bacteria in the mouth or
intestine, however, reduce nitrate to nitrite in appreciable amounts.

Clearly, a nutritious diet providing adequate amounts of all
nutrients and proper calorie content to achieve desirable weight is
important for general health and for vigourous defence mechanisms
against cancer as well as other diseases.

Nutrition Programs and Services

Food Labels:Evidence related to the role of dietary
factors in cancer suggests that food manufacturers should include on
package labelsinformation about nutritional content of the food,
especially for fat and carbohydrate components (including fiber).

Food Services:Evidence related to the role of dietary
factors in cancer suggests that the public might benefit from increased
availability of foods high in fibre and low in fat.

Food Products: Evidence related to the role of dietary
factors in cancer suggests that foods low or reduced in calories and
fat and high in fibre should be made increasingly available by food
manufacturers. [The Surgeon General]

• Journal of the American Dietetic Association: Research, Page 802 - 809, June 1990.



• Freudenheim,
  J.L., Graham, S., Marshall, J.R., Haughey, B.P., and Wilkinson, G., A
  case study of diet and rectal cancer in western New York , American
  Journal of Epidemiology, 131:612, 1990.


• Ziegler,
  R.G., Mason, T.J., Stemhagen, A., Hoover, R., Schoenberg, J.B.,
  Gridley, G., Virgo, P.W., & Fraumeni, J.F., Carotenoid intake,
  vegetables, and the risk of lung cancer among white men in New Jersey ,
  American Journal of Epidemiology 123:1080, 1986.


• Willett, W.C., and MacMahon, B., Diet and Cancer; an overview , New England Journal of Medicine 310:697, 1984.



• The Surgeon General's Report on Nutrition & Health, 1988.

How Nutrition Can Effect Our Behavior

How Nutrition Can Effect Our Behavior
The disciplines of nutrition and behavior are not usually
considered to be closely related, but there are infact several key
areas of overlap between these fields. Behavior factors determine the
choice of foods in the diet, and any attempt to change dietary patterns
must necessarily involve the central nervous system and may be
associated with mood changes.

That diet influences behavior is an ancient human belief. Primitive
people attributed friendly and unfriendly feelings to plants and
animals and expected these feelings to be transferred to anyone who ate
such foods. In religious teachings, the behavior of mankind was said to
change instantly when Eve ate the apple. Solomon, suffering the pangs
of love, was confronted with apples. The ancient Greeks proposed that
the body is composed of four "humors" - hot, cold, wet, and dry - that
control health, feelings, and behavior. Such ideas have carried forth
to the present day, when many cultures believe in hot/cold or yin/yang
approaches to food and health.

Systematic study of cultural influences on food intake began early
in this century as anthropologists examined the use of food in isolated
cultures and ethnic groups. Even in contemporary times, foods are
endowed with magical powers and are believed to symbolize feelings such
as those of satisfaction and security.

The reduction of behavioral risk factors for chronic disease, an
improvement of the food choices and dietary practices of individuals,
and the development of effective means to do so is the key to diet and
good health.

Behavioral determinants and aspects of eating disorders

Although infants do not begin life with a choice of foods, some of
the most obvious reflexes at birth are those associated with eating.
Infants learn to associate eating with security and relief from
anxiety, tension, and distress. Later, children eat in conformance to
cultural and familial standards. These ingrained meanings attached to
the roles of food in society suggest reasons that food habits can be
changed only with difficulty.

Although the choice of certain foods as opposed to others may
greatly affect nutritional status, food selection includes multiple
environmental, cultural, genetic, social, and sensory variables that
interact in complex ways. One exception appears to be an innate
preference for foods that are sweet. This preference is acquired in
early childhood and continues throughout life.

Selection of foods for nutritional or health reasons is a learned
behavior. Infants have not been shown to have an inborn ability to
select a balanced, nutritious diet. Variety of foods available has an
important effect on food consumption; the more the available foods are
varied, the more of them people will eat.

Behavior change is a key element in reducing the risk for chronic
disease. Eating behaviors are acquired over a lifetime, to change them
requires alterations in habits that must be continued permanently -
beyond any short-term period of intervention.

Dietary advice is often restrictive and viewed as depriving or
unpleasant. It may also be incompatible with cultural or familial
standards. Furthermore, environmental factors such as peer pressure,
advertising of high-calorie foods and alcoholic beverages may strongly
counteract recommended changes.

Despite these difficulties, considerable evidence supports the
effectiveness of nutrition education in changing dietary intake to
reduce risk factors for conditions such as coronary heart disease,
diabetes, hypertension, and neurologic disorders.

Obesity

Obesity is the excessive accumulation of fat in the body. The cause of obesity is quite simple - fat accumulates when more calories are consumed than are expended.

Obesity is often a familial disorder, obese parents tend to produce
obese offspring. Obesity is more common among women than among men, and
its prevalence increases with age but decreases among individuals of
higher socioeconomic status and greater levels of physical activity.

Once obesity is established, food choices and caloric intake are no
longer normal, and personality differences between obese and
normal-weight individuals may be due to results of physiologic changes,
social discrimination, or dieting.

Disparagement of body image affects a larger percentage of obese
persons than nonobese persons who characteristically dislike their own
bodies. Such feelings are closely associated with self-consciousness
and impaired social functioning.

Although weight reduction ought to confer great benefits upon obese
persons and be simple to accomplish, clinical experience has shown
obesity to be remarkably resistant to treatment. The basis of weight
reduction is deceptively simple: Establish an energy deficit by
consuming fewer calories than are expended or expending more calories
than are consumed. Most such treatment is carried out under the
direction of nonmedical groups and counsellors in programs that pose
some hazard and are of uncertain long-term effectiveness.

Treatment measures should be specified and outcomes evaluated;
treatment should be individualized; and treatment effectiveness should
be assessed. Behavioral weight control programs usually include group
participation at weekly meetings for periods of two months or more, and
involve techniques of stimulus control, eating behavior, reward,
self-monitoring, nutrition education and physical activity.

Obese patients who participate in regular peer group meetings
following the completion of formal treatment maintain their weight loss
better than those who do not participate in such meetings.

It is important to make a note about obesity and the numerous
"weight loss formulas" that are currently marketed. These products
range from diet pills to drinks that supposedly will make weight loss
happen without any other dietary changes.

There is not a single, safe formula available that will cause
permanent weight loss without any adverse effects on the health of the
user. The proof of this is the fact that irrespective of the amount of
products that come and go, obesity still exists among about one third
of the population - millions of people. If there was one product that
was successful, obesity would no longer be a problem and the "inventor"
of this product would probably be the richest person in the world.

Do not take any "formula" for weight loss, you are wasting your
time, money, and probably health by doing so. Rather, follow the
dietary guidelines found in this book to achieve a desirable weight and
healthy lifestyle.

Anorexia Nervosa

Anorexia nervosa is a condition characterized by extreme weight
loss, amenorrhoea, and a constellation of psychologic problems that
have been described as "the relentless pursuit of thinness". [Bruch, H., Eating disorders: obesity, anorexia nervosa and the person within. New York. 1979.]

The most common cause of the disease is a single episode with full
recovery, but anorexia nervosa can be episodic or unremitting until it
causes death by starvation.

Unlike many other psychiatric disorders, anorexia nervosa tends to
occur in intact families and is often precipitated by seemingly minor
events during adolescence. Most theories of anorexia nervosa focus on
psychologic trauma or unempathetic and overly domineering mothering as
underlying causes of the disease. Socio-cultural theories suggest that
the disease represents an exaggeration of the current inordinate weight
consciousness of adolescent girls at a time when high-calorie foods are
readily available and fewer calories are expended through exercise.

Typical symptoms of the disease include depression and
obsessive-compulsive behaviors, it is not clear if these psychiatric
problems preceded weight loss or occur as a result of semistarvation.
Depression is often the first visible sign of anorexia nervosa.
Abnormal hormonal patterns characteristic of starvation also occur.

The clinical features of anorexia nervosa are personality
characteristics such as rigidity or perfectionism, fear of obesity
preceding the onset of the disorder, and the symptoms of starvation
accompanying it. Serious body image disturbance is common, manifested
by a lack of recognition of the severe emaciation and a belief that one
is too fat. Individuals are often preoccupied with food, thinking about
it much of the time, and often engaging in bizarre eating rituals. Many
anorectics engage in very extensive physical exercise. The disorder is
also associated with a pervasive sense of personal ineffectiveness.

Anorectics are divided into two types, "restricters" who confine
their eating disorder to restricted food intake, and "bulimics" who
engage in bingeing and subsequent vomiting and purging. Bulimic
anorectics tend to be older, manifest other impulsive behaviors such as
kleptomania, alcohol and drug abuse, and sexual promiscuity.

Anoretics deny their weight-losing behaviors and the existence of
any illness and avoid treatment even when they have become severely
emaciated. Family members often have to insist on medical treatment.
Some anoretic persons effectively hide their weight-losing behaviors
even after they are forced to seek medical assistance.

Most persons with anorexia are resistant to entering treatment
because of their fear of weight gain and are usually brought, by family
members, under protest. Because starvation plays a significant role in
the clinical portrayal of anorexia nervosa, clinicians begin treatment
with a period in hospital designed to restore body weight. Such
treatment that removes the patient from the environment may permit the
use of behavioral rewards for weight gain and provides the opportunity
to work on issues of control. Some medications have been helpful in the
treatment of anorexia nervosa. These include cyproheptadine (an
appetite stimulant), chlorpromazine (sedative, used in the treatment of
psychotic conditions), and antidepressant medication.

Bulimia

Bulimia is an eating disorder characterized by recurrent episodes of
binge eating in which large amounts of food are consumed over a short
period of time. These episodes are usually terminated by abdominal
pain, self-induced vomiting, sleep, or the appearance of another person
on the scene.

Bulimia occurs among persons of normal weight but is present in half
the patients with anorexia nervosa. The severity of binge eating ranges
from occasional episodes of morbid overeating at a party to the severe
form of the disorder, bulimia nervosa, in which the vomiting or purging
follows frequent episodes of binge eating.

There are many similarities between persons with anorexia nervosa
and bulimia. Both occur primarily in young women, although bulimia
occurs in slightly older individuals, both may relate to the current
preoccupation with thinness and dieting.

The symptoms of depression in the majority of bulimic patients and
the presence of biologic markers of depression suggest that bulimia may
represent a variant of mood disorder. Treatment of bulimia is
cognitive-behavioral and pharmacologic. Behavioral treatment include
modification of the behavioral program designed for obese patients and
a combination of cognitive-behavioral and insight-oriented approaches.

Pica

Pica is the intentional and compulsive consumption of non-food
substances. It occurs worldwide and is common among people of either
sex and of all ages and races. Pica is often associated with
nutritional deficiencies or toxicities, and is of special concern among
young children and pregnant women.

Geophagia is the consumption of earth and clay. Amylophagia is the
consumption of starch and paste, and pagophagia is the eating of ice.
The fourth category includes the consumption of ash, chalk, antacids,
paint chips, plaster, wax, and other substances.

People appear to be driven to consume these substances by
nutritional deficiencies, but pica is not necessarily correlated with
poor nutritional status. The nutritional hazards most frequently
associated with pica are lead poisoning and iron deficiency anaemia.

Hypoglycaemia

Hypoglycaemia (low blood
sugar) can occur either after a fast (fasting hypoglycaemia) or several
hours after the consumption of a meal (reactive hypoglycaemia). Many
individuals have symptoms of weakness, confusion, and irritability
after eating sugars or other carbohydrate foods.

True reactive hypoglycaemia is diagnosed when symptoms of sweating,
tremor, anxiety, and irritability occur at the same time as the
documented low blood sugar level. Such a diagnosis may indicate the
early presence of a disease such as diabetes.

Hyperactive behavior

Hyperactivity is a childhood problem often discussed in relation to
nutrition. This condition is characterized by problems of inattention,
excessive motion, impulsivity, learning disabilities, and related
problems of conduct.

Food additives, especially artificial dyes and colours, can cause hyperactivity.

Implications for Public Health Policy

Studies in patients with eating disorders and other chronic disease
conditions emphasize the importance of modification of diet-related
behavior in these conditions. Although evidence linking dietary
caffeine, refined sugars, and food additives to behavioral disorders is
uncertain, their elimination from thediet will not impair nutritional
status and can be recommended to patients on an individual trial basis.

Nutrition Programs and Services

Food Labels:Evidence related to the role of dietary factors in behavioral disorders holds no implication for food labeling policies.

Food Services:Evidence related to the role of dietary
factors in behavioral disorders holds no special implications for
changes in policies related to food programs beyond the dietary
guidelines suggested by Department of Agriculture and the Department of
Health and Human Services. [The Surgeon General's Report on Nutrition & Health, 1988.]

An Overview Of Common Causes Of Anemia

An Overview Of Common Causes Of Anemia
Anemia occurs when the concentration of the pigment
hemoglobin in red blood cells falls below normal. Hemoglobin is
essential for delivering oxygen from the lungs to the body tissues.

Iron deficiency is the most common cause of anemia. Although iron
deficiency is generally the most common cause of anemia, there are
other nutritional, genetic, and environmental causes as well.

Iron was one of the first substances identified as essential in the
human diet. The physiologic function of iron in hemoglobin and its
role in anemia was determined over a two hundred year period from the
1680's.

By World Health Organization criteria, anemia is considered to
exist when the non-pregnant adult female has a haemoglobin level below
11 grams per 100 milliliter of venous blood.

Iron deficiency anaemia refers to anemia that results from iron
deficiency or impaired iron status. Iron dependent physiologic
functions can become impaired before anaemia develops. Although iron
deficiency anemia can occur in all socioeconomic groups, it has
historically been most common among the poor as is still the case today.

Causes of Anemia

Because the synthesis of blood cells requires many cellular and
metabolic processes, a deficiency of any nutrient essential to
hemoglobin production produces adverse effects on these processes.
Good nutrition is fundamental to adequate red blood cell production.
Nutritional anaemia may be due to a dietary deficiency of iron, folate,
vitamin B12, protein, and other vitamins and minerals. Other causes of
anemia include the inherited or acquired inability to use nutrients
required for haemoglobin production.

Nutritional anaemia should be distinguished from deficiencies per se
of iron, folate, or vitamin B12, because an individual may have
manifest any one of these deficiencies without being anaemic. In iron
deficiency disorders immune function and behaviour are not directly
attributable to the anaemia. Similarly, the impaired nerve function of
vitamin B12 deficiency occurs independently of anemia.

The bioavailability of iron is determined by the nature of the diet
and by regulatory mechanisms in the digestion that reflect the body's
physiologic need for iron. Two types of iron are present in food, heme
iron and nonheme iron.

Most of the iron in the diet is present as nonheme iron and consists
primarily of iron salts. The amount finally absorbed is influenced by
other constituents of the diet that either enhance or inhibit, by
decreasing solubility and the absorption of iron.

Iron absorption tends to be poor from meals in which whole grain
products and legumes predominate, but the addition of even small
amounts of foods containing vitamin C (ascorbic acid) substantially
increase the absorption of iron from the entire meal. On the other
hand, tea and coffee, decrease the absorption of nonheme iron.

Heme iron comes from the hemoglobin in meat, poultry, and fish. The
body absorbs a greater percentage of heme iron, and its absorption is
less affected by other dietary constituents.

Iron deficiency causes a substantial reduction in work capacity and
mild anemia can decrease performance in exercise. The major
consequence of this muscle impairment is a lessened capacity for
prolonged exercise or physical endurance. An impaired capacity to
maintain body temperature in a cold environment is another
characteristic of iron deficiency anemia.

Changes in behaviour and impaired intellectual performance may
result from iron deficiency. Even mild iron deficiency significantly
decreases responsiveness, activity, and attentiveness, and increases
body tension, fearfulness and a tendency to fatigue.

Iron deficiency and folate deficiency are more common in women
because of two forms of metabolic stress peculiar to women; the monthly
blood loss in premenopausal women and the drain on maternal nutrient
stores imposed by pregnancy. The fetus will take from the mother
whatever it needs in order to be normal at birth, even if this produces
severe nutrient deficiency in the mother. Nevertheless, a women who has
sufficient iron stores to provide for her increase in hemoglobin mass
during pregnancy, and who breast-feeds for six months will have her
iron needs covered by adequate intake of dietary iron.

Iron deficiency can be prevented by increasing dietary intake,
improving bioavailability from the diet, or decreasing body losses of
iron. Dietary intakes can be improved by increasing the consumption of
iron-rich foods, administering iron supplements, and fortifying certain
food products with iron. Fortification of cereal and grain products is
a relatively inexpensive and effective means of increasing iron intake.
The absorption of iron from fortified cereals can be increased
threefold if the cereals are also fortified with about 5 mg of vitamin
C per mg of iron.

Prevention of nutrition-related anaemia depends on adequate dietary
intake of iron, vitamin B12, and folate as well as the full complement
of other essential nutrients. Folate deficiency anemia usually occurs
among women late in the course of pregnancy, among small premature
infants, and among alcoholics. Strict vegetarians who consume no foods
of animal origin, especially women who are pregnant or nursing, should
take supplemental sources of vitamin B12.

Supplementation has the disadvantage of requiring extra effort and
expense compared with fortified foods. Its effectiveness for a given
individual requires evaluation by a qualified health professional. Iron
supplement use and recommendations to increase dietary intake are
usually not necessary for the general population.

An additional concern is that increased iron intake can harm
individuals who are susceptible to iron overload. Abnormal amounts of
tissue iron accumulate over the years as a result of a genetic defect
in absorption, eventually damaging the liver, heart, pancreas, and
adrenal glands. Excessive iron intake may affect the absorption of
other trace elements.

Nutrition Programs and Services

Food Labels: Evidence related to the role of iron and folate
in anemia suggests that food labels should indicate the content of
these nutrients.

Food Programs: Because groups that benefit from food programs
are those at highest risk for anemia, such programs should continue to
be made available to high-risk groups and should encourage consumption
of foods rich in iron and folate. The current levels of iron
fortification are safe and adequate, and no changes should be
recommended at this time.

• The Surgeon General's Report on Nutrition & Health, 1988

Information On Aging

Information On Aging
Life expectancy at birth is now 75 years, compared with about
47 years at the beginning of the last century. Although it is not
inevitable, health and mobility often change and decline with advancing
age. The increasing life expectancy observed throughout this century
suggests that diet, exercise, and other personal and socioeconomic
factors can help prolong good health for most people.

Nevertheless, the chances are great that an individual in the eighth
or ninth decade of life will be limited in activity and require health
and social services. Many older people (the general term older will
refer to people over age 65) suffer from arthritis, heart disease,
hypertension, hearing loss, diabetes, obesity, gastrointestinal
conditions, liver disease, cancer, and other chronic diseases. Heart
disease, cancer, and stroke account for over three-quarters of the
deaths among older persons and 50 percent of all days of bed
confinement. Such chronic conditions as well as dementia prevent
functional independence and increase the need for dietary and other
long-term care services.

Until the early 1970's, nutrition services for the older population,
with the exception of food stamps, were based almost exclusively in
hospitals and long-term care facilities. In 1973, in response to the
growing population of older people, to rising health care costs, and to
greater interest in preventive health care, the Nutrition Program for
the Elderly was established under the Administration on Aging to expand
food and nutrition services from the hospital to include communities
and homes.

Aging is accompanied by a variety of physiologic, psychologic,
economic, and social changes that may compromise nutritional status.
Older persons have a prevalence of chronic disease, use medications
heavily, and are relatively sedentary.

Many physiologic functions, including the senses of smell and
possibly taste, decrease with age. These changes may result in
decreased appetite as well as impaired utilization of nutrients and
limitations of function.

Dental problems, common in old age,
decrease the ability to chew certain foods. Physical disabilities such
as diminution of vision may make eating less pleasant. The decreases in
basal metabolic rate and physical activity noted with increasing age
reduce nutrient needs, however, the intake of calories and essential
nutrients may be even lower than these needs. Decreased physical
activity also may predispose individuals to the development of
osteoporosis.

Changes such as osteoarthritis can
affect mobility and decrease an older person's ability to purchase and
prepare food. Another possible hinderance to adequate nutrition in the
aged is malabsorption, which can be caused by decrease or absence of
gastric acid secretion and by interaction with medications commonly
prescribed for older persons.

The most common psychologic factor affecting nutrition is depression.
Of all psychiatric diagnoses, depression is most strongly correlated
with increased mortality, regardless of the age of the subjects, and is
most often related to chronic disease and to poverty, which are common
among older persons. Neither institutionalization nor solitary living
necessarily induces depression, but such life changes may be associated
with poor self-esteem, which in turn, can lead to significant changes
in eating patterns.

Older people as a group have a lower economic status than other
adults. Although the percentage of older individuals living below the
poverty level has decreased substantially over the past two decades and
is now less than the percentage of those under 65 living in poverty,
poverty continues to be too high. The decline in income most often
results from retirement from the workforce, the effects of inflation on
fixed incomes, death of wage-earning spouse, or failing health. Income
and health status have been found to be important determinants of life
satisfaction in the older population. Low income is also a major risk
factor for inadequate nutrition in older individuals.

Most older people do not live in institutions, although
institutional food is likely to meet minimal standards for nutrient
content, factors such as lack of choice or limited day-to-day variety
may increase the risk of inadequate consumption. Many residents of
nursing homes consume a therapeutic diet that may further discourage
adequate intake. An important issue for demented institutionalized
individuals is that they may not consume the food, not that the menu is
inadequate.

Clinical and dietary standards for younger adults may not be
appropriate for older persons, yet few data are available on
nutritional requirements or recommended intakes of older adults. The RDA's
for example, were developed from research on the nutrient needs of
younger healthy people. The present standards for adults over the age
50 are, for the most part, identical to those for people aged 23 to 50.
Because these standards fail to consider the great heterogeneity of
adults whose ages may differ by as much as 50 years and because they
were often not developed from actual measurements on older populations,
their appropriateness for older persons is not known.

Energy and Nutrient Status of the Older Population

The national dietary and food consumption surveys conducted during
the 1970's reported lower energy intakes among older persons than among
younger adults. A study of male executives in the Baltimore
Longitudinal Study of Aging found a steady decline in average energy
expenditure from 2700 kcal per day at age 30 to 2100 kcal per day at 80
years of age. The decline in energy expenditure was attributed to
reduced physical activity and to a decline in basal energy metabolism
as a result of a reduction in lean body mass with age.

Although it is difficult to interpret dietary intake studies of
older persons because of methodological problems, existingstudies
almost always reveal decreases in energy intake with age that may also
be influenced by income, race, food preference, and drug use. A
low-calorie diet may not impair health as long as the nutrient density
of the diet is high and can provide adequate amounts of essential
nutrients. However, this issue has not been examined in great detail
because nutrient requirements in older people remain largely unknown.

Consequently, the increasing level of obesity
among older persons, as indicated by higher weight-for-height with age,
requires explanation. Whether the inconsistency between reported low
energy intake and increasing body weight is due to measurement errors,
inappropriate standards, loss of height with age, or lack of physical
activity has not been established.

A 30-day continuous metabolic balance study of seven men and eight
women, over 70 years of age, who consumed the RDA levels of protein and
energy found that about half were unable to maintain nitrogen balance
on this level of protein (0.8 g of protein per kg per day). The results
suggested that higher intakes were required to meet protein
requirements. Because the RDA for protein includes a substantial safety
margin and because clinical measurements have rarely found signs of
protein deficiency among healthy older persons, it is not possible to
conclude from these data that persons with intake below the RDA are
protein deficient or that they would benefit from additional protein
intake.

Older people, especially Caucasian women, lose bone mineral and have
a higher incidence of fractures than younger persons. Metabolic and
absorptive factors as well as low intake may contribute to chronic
negative calcium balance. Reduced efficiency of calcium absorption may
be due to inadequate dietary intake, age related changes in gastric
acidity, and/or interactions of intestinal constituents such as fibre,
bacteria, and other nutrients. Perhaps in some individuals a negative
effect on calcium nutriture may be caused by age-related changes in
hormonal control, abberations in vitamin D metabolism, and imbalances
of protein, phosphorus, alcohol, and electrolytes with calcium.

The RDA for calcium of 800 mg per day may not be sufficient to
maintain calcium balance in populations consuming Western diets.
Calcium intake by older people is often marginal, for example, 43
percent of women in nursing homes failed to get two-thirds of their
calcium requirement. Women living at home consumed even less calcium
than those in nursing homes. Older people may have reduced calcium
intake because they avoid dairy products containing lactose, to which
they are intolerant.

As with people of all ages, the frequency with which anaemia occurs
in the older population and determination of its etiology depend on the
criteria used for diagnosis.

Because iron reserves increase with age, studies that examine only
dietary intake of iron in older people need to be interpreted
cautiously. Low dietary iron intake at one point intime does not
necessarily increase the risk for anaemia because iron may still be
available from body stores and because iron absorption increases when
intake and stores are low. In addition, the type of iron and other
components of a meal such as ascorbic acid also influence the amount
absorbed. Comparison of older subjects who took iron supplements with
those who did not showed no clinically significant differences in the
biochemical measures of iron status.

Vitamin deficiency may be a result of decreased dietary intake,
absorption defects, decreased hepatic avidity for folate in Laennec's
cirrhosis, decreased storage and conversion to active metabolic forms,
or excessive utilization, destruction, or excretion.

No comprehensive study of all vitamins and their related enzyme
systems has been conducted. Most studies have only examined the status
of one or two vitamins. A number of studies have indicated a great risk
for vitamin deficiencies in older persons on the basis of low dietary
intakes, but such deficiencies are not always confirmed by biochemical
or clinical results. In addition, interpretation of biochemical
parameters is hampered by lack of data on normal standards for the
older population. For example, a New Mexico study revealed that more
than one-fourth of the older population consumed less than 75 percent
of the RDA's for folate and vitamins B6 and B12
from diet alone. However, biochemical studies failed to confirm that
these individuals were at risk for developing clinical symptoms
associated with low intakes of these vitamins. Intake of vitamin
supplements may explain part of this apparent discrepancy, although
analysis showed little statistical difference in mean dietary intake
for those individuals taking a specific supplement compared with those
who did not take the supplement.

The body pool of ascorbic acid reaches a maximum of approximately 20
milligrams per kilogram. Women require an intake of 75 mg per day and
men require an intake of 150 mg per day to achieve this ascorbic acid
level in plasma. This finding was supported by a clinical trial that
showed that a daily intake of 60 mg was insufficient to maintain this
plasma concentration.

Vitamin A deficiency does not seem to be a particular problem in
older persons, Although NHANES I and NHANES II (the National Health and
Nutrition Examination Surveys) reported that half the study population
over age 65 had vitamin A intakes at or less than two-thirds of the
RDA, only 0.3 percent of the NHANES older population had low vitamin A
blood levels. Whether vitamin A supplement use can account for the
observed discrepancy is unknown, but similar data suggest that older
individuals can maintain normal vitamin blood levels even with
reportedly low dietary intakes.

Previous studies have revealed a generally lowered vitamin D status
in older people, chronically ill individuals, and those living in
institutions with little or no exposure to sunlight. Because the
vitamin D endocrine system is the major regulator of intestinal calcium
absorption, a reduced vitamin D status might promote a negative calcium
balance in older people.

Two studies in the United States have found dietary intake of
vitamin D to be approximately 50 percent of the RDA for older subjects.
However, ultraviolet light induced endogenous production of vitamin D
is the main external factor in maintaining adequate vitamin D status.
Because sunlight exposure activates vitamin D precursors in the skin,
it has been recommended that older people obtain at least minimal
sunlight exposure (10 to 15 minutes) two or three times a week.
Increased sun exposure may help compensate for aging skin's decreased
capacity to produce these precursors. Supplements may be necessary to
compensate for inadequate sunlight exposure due to seasonal variation
in northern latitudes. Moderation of sun exposure should be recommended
because overexposure to the sun is a strong risk factor for skin cancer.

There is no evidence that older individuals are deficient either in
dietary intake or tissue levels of vitamin E. Despite statements that
megadose vitamin E supplements retard the aging process and prevent
atherosclerosis and cancer, its use to treat or prevent other
conditions has not been established.

Nutritional Supplements

It has been estimated that 37 percent of American adults consume a
daily multivitamin preparation, fuelling a $2 billion per year
industry. NHANES II indicated that the persons most likely to take
supplemental nutrients are less likely to need them, and those most in
need of them are least likely to take them. In older persons, vitamin
use has increased dramatically in the past decade. Whether such
supplements improve the health of these people cannot be determined
from existing data, but it is clear that excessive supplementation may
be harmful. High doses of the fat-soluble vitamins A and D are toxic.

Drug-Nutrient Interactions

Although older Americans constitute about 12 percent of the
population, they use about 25 percent of all prescription drugs. This
is not surprising because many chronic diseases associated with aging
are managed with prescription drugs. Over half of the older people take
at least one medication daily and many take six or more a day for
multiple diseases. Cardiovascular drugs (eg. diuretics) are most widely
used by the aging population, followed by drugs to treat arthritis,
neurologic disorders, and respiratory and gastrointestinal conditions.

Many unwanted drug-nutrient interactions in older persons have been
documented. This population requires special consideration because
aging per se changes the absorption, disposition, and
elimination of drugs. The older person with multiple diseases is at
risk for additional drug-nutrient interactions linked to separate drug
therapies for primary and secondary health problems. Even
over-the-counter antacids, laxatives, analgesics,and vitamin and
mineral supplements may result in unwanted drug-nutrient side effects
in the older person.

Effects of Nutritional Deficiencies on the Older Population

Severe malnutrition - protein, calorie, vitamin, or mineral - is
associated with increased mortality, and the relationship of
malnutrition to mortality in older persons is of current interest.
Among severely ill or injured hospital patients of any age,
protein-energy malnutrition greatly increases the risk for
postoperative complications and overall mortality. This association
between nutritional status and survival does not prove a casual
relationship because poor nutritional status may be the result of the
illness or the injury and not its cause.

Several researchers have tried to correlate blood levels of vitamin
C and mortality in an aging population. Among patients admitted to an
acute care geriatric unit, those with low ascorbate levels had a
significantly higher mortality.

Considerable evidence documents an age-related decline in immune
competence. Certain of these changes resemble those induced by
malnutrition. Thus, malnutrition is clearly related to impaired immune
function in older people, and improved dietary intake can at least
partially correct these impairments.

If nutritional deficiencies are related to impaired immune function
in older people, correcting the deficiencies should improve this
function. Among hospitalized patients, intensive nutritional support
does increase immunocompetence. Among older people, dietary supplements
have been associated with improved antibody responses to viral
vaccines, and several studies have reported improved immune function as
a result of zinc supplementation. The possible role of zinc deficiency
in loss of immune function in older people has received considerable
attention.

Whether mental functions necessarily decline with age is
questionable, and whether dietary factors can influence mental status
in older people is also uncertain. Although large population studies
have reported gradual decreases in many mental functions with age,
healthy, active older subjects do not display significant decrements.
This discrepancy suggests that the reported decrements in mental
function are not inevitable age-associated events, rather, such changes
are secondary to the various diseases and physical conditions that
frequently accompany aging.

Alzheimer's Disease

The prevalence of this disease increases with age, while only 5 to 8
percent of people age 65 and over are affected, 35 percent of those
over age 85 are affected. The cost of institutional care alone for
Alzheimer's disease patients is estimated to exceed $40 billion per
year in direct costs and up to $80 billion per year if indirect cost
are considered.

The causes of Alzheimer's disease have not been established, but
potential risk factors include age, family history of Alzheimer's
disease, and head injuries. Whether nutritional factors can alter the
risk for this condition is not known. High concentrations of aluminum
have been found in the neurofibrilla-containing neurons of deceased
patients, suggesting a relationship between aluminum and Alzheimer's
disease.

Because Alzheimer's disease is a neurodegenerative syndrome
involving cell loss and dysfunction, and because there is evidence that
nutrient variables can affect brain metabolism, it might be speculated
that neuro-toxins acquired through the food chain may be involved in
brain cell death.

Implications for Public Health Policy

Aging is accompanied by a variety of physiologic, psychologic,
economic, and social changes that may compromise nutritional status.
However, ways in which the aging process affects energy balance,
specific nutrient requirements, and nutrient status remain to be fully
elucidated. Older adults may not necessarily have the same nutritional
requirements as younger adults, yet current estimates of the nutrient
requirements of older persons are based almost entirely on values
extrapolated from data from studies of younger adults. The ways in
which nutritional status might influence changes in tissue and organ
function change with age and may influence the relationships between
dietary components and the occurrence of chronic diseases in old age.
Until more appropriate age-specific RDA's are established, the current RDA's should continue to be used as standards for nutrient intake of healthy older people.

Older people should consume sufficient nutrients and energy and
maintain levels of physical activity that maintain desirable body
weight and may prevent or delay the onset of chronic disease. Because
it is often difficult to maintain adequate nutrient intake on
low-calorie diets, older people should be advised to maintain at least
moderate levels of physical activity so as to increase caloric needs.
Because many chronic diseases common to older people may originate
earlier in life, dietary guidance to prevent them should be provided
throughout life.

Older people who do not or cannot consume adequate levels of
nutrients from food sources and those with dietary, biochemical, or
clinical evidence of inadequate intake should receive advice on the
proper type and dosage of nutrient supplements. Such supplements may be
appropriate for some older persons, but self prescribed
supplementation, especially in large doses, may be harmful and should
be discouraged. Older people who suffer from diet-related chronic
diseases should receive dietary counselling from credentialed health
professionals, and those who take medications should be given
professional advice on diets that minimize food-drug interactions.

Nutrition Programs and Services

Food Labels:Evidence related to the role of diet in the
aged currently holds no special implications for change in policy
related to food labeling, although the size of the type on the label is
a factor for most older consumers. Information provided on the food
labels should be scientifically sound, understandable, and
nonmisleading.

Food Services:Food services, especially those receiving
Government funds, should be required to pay attention to meeting the
caloric and nutrient needs of older clients. Nutritional assessment and
guidance should be done at hospital admission or enrolment in or
discharge from institutional or community-based services for older
adults.

Food Products:Evidence suggests that older people would
benefit from food products that provide a high proportion of available
nutrients to calories, that have taste appeal, and that are easy to
prepare.

• The Surgeon General's Report on Nutrition & Health, 1988