Useful Information On Hydroxycitric Acid
The main active component in the herbal extract of Garcinia
compound is Hydroxycitric acid (HCA). The earliest research, conducted
in the 1970s, into the antiobesity effects of HCA was conducted by
Hoffmann-La Roche Pharmaceuticals. Studies have shown the ability of
HCA to inhibit the actions of citrate cleavage enzyme, suppress fatty
acid synthesis, increase hepatic glycogen synthesis, suppress food
intake, increase energy expenditure, curb appetite, reduce plasmatic
cholesterol levels, and inhibit fat synthesis from excess carbohydrate
calories.
The herb Garcinia
cambogia and its active ingredient, hydroxycitric acid, have been
promoted as an aid to weight loss. Hydroxycitric acid has a chemical
composition similar to citric acid (the primary acid in citrus fruits).
Preliminary research, based on laboratory experiments and animal
research, suggests that HCA may be a useful weight loss aid. A study
analyzing the claims was recently published in the Journal of the
American Medical Association. The carefully designed research found
that Garcinia cambogia failed to produce either significant weight loss
or loss of body fat beyond that produced by a placebo.
Within cells, hydroxycitric acid is a powerful inhibitor of the
citrate cleavage enzyme. This enzyme is critical for producing the
substrate for synthesis of fatty acids. The theory behind sales of the
herb or its purified active ingredient is that hydroxycitric acid taken
orally will get into the body's individual cells where it will block
the enzyme, block fat synthesis and therefore significantly reduce body
fat mass.
The study failed utterly to detect any benefit for weight loss or
fat loss by the herb. Several reasons could be suggested. 1) Neither
Garcinia cambogia nor its active ingredient hydroxycitrate blocks fat
synthesis or aids in weight loss; 2) neither the herb nor its active
ingredient, when taken orally, is absorbed and reaches the cell intact
where it is supposed to exert its influence; 3) the herb or its active
ingredient might work only in people who have lost weight already and
would prevent weight regain; 4) the herb might work if the dose or
timing were different, for example given between meals instead of just
before.
What this study showed was that under the usual conditions in which
people trying to lose weight might use the herbal product, it was of no
benefit. The low-calorie diet plan was what led to weight loss.
Hydroxycitric acid is included in many fat loss supplements claiming
to increase fat burning. It has been promoted heavily as a fat loss
agent with no legitimate science past the superficial rodent studies.
Many of the products even boast of having this ingredient as a major
selling point. Some go as far as to name the product after it -
Hydroxy-this and Hydroxy-that. Well a new study reveals what we have
known all along. Hydroxycitric acid in no way aids in fat metabolism.
This was a very sophisticated study that revealed HCA had no effect on
energy expenditure either during rest or during intense exercise.
There seems to be no such drug/herb that can cause weight loss
without following an appropriate diet, this seems obvious with the
frequency of obesity in the American population. Although there may be
some evidence in using HCA in combination with other medications and
exercise regimens designed to promote weight loss.
Owing to a substantial increase in glucose uptake by working muscle,
glucose homeostasis during sustained aerobic exercise requires a
severalfold increase in hepatic glucose output. As exercise continues
and liver glycogen declines, an increasing proportion of this elevated
glucose output must be provided by gluconeogenesis. Increased
gluconeogenic efficiency in trained individuals is a key adaptation
promoting increased endurance, since failure of hepatic glucose output
to keep pace with muscle uptake rapidly leads to hypoglycaemia and
exhaustion. Pre-administration of (-)-hydroxycitrate, a potent
inhibitor of citrate lyase found in fruits of the genus Garcinia, may
aid endurance during post-absorptive aerobic exercise by promoting
gluconeogenesis. Carnitine and bioactive chromium may potentiate this
benefit. The utility of this technique may be greatest in exercise
regimens designed to promote weight loss.
Excessive exposure of tissues to fatty acids is likely to be the
chief cause of the various dysfunctions that lead to sustained
hyperglycemia in type II diabetes. These dysfunctions are likely to be
substantially reversible if body fat and dietary fat can be greatly
reduced. Disinhibition of hepatic fatty acid oxidation with
hydroxycitrate (HCA) and carnitine has considerable potential as a new
weight-loss strategy, but in diabetics runs the risk of further
enhancing excessive hepatic gluconeogenesis. Since the clinical utility
of metformin in diabetes is probably traceable to inhibition of
gluconeogenesis, its use as an adjunct to HCA/carnitine treatment of
obesity in diabetics deserves evaluation, particularly as metformin
therapy itself tends to reduce body weight. A consideration of relevant
evidence suggests that metformin therapy will not impede the activation
of fatty acid oxidation by HCA/carnitine, and is likely to potentiate
the appetite-suppressant and thermogenic benefits of this strategy.
Indeed, since metformin has been reported to lower body weight and
improve cardiovascular risk factors in obese non-diabetics, a broader
application of a metformin/HCA/carnitine therapy for obesity can be
contemplated.
The increasing prevalence of obesity combined with the low efficacy
of conventional treatments led us to examine the weight-loss effects of
G cambogia, a natural source of the citrate-lyase enzyme inhibitor HCA.
Our double-blind, randomized controlled trial was designed from the
consumer's perspective: we administered either a placebo or widely
available G cambogia preparation in suggested amounts along with
dietary recommendations typical of that provided in package inserts.
As potential consumers, we may ask why it remains uncertain that HCA
derived from an over-the-counter product reaches its cellular
destination in amounts adequate to actively inhibit citrate cleavage
enzyme. Why are diet plans suggested to consumers that may render
Garcinia's active agent nonabsorbable or inadvertently switch off the
target citrate cleavage enzyme? Critical tests pinpointing each step in
HCA uptake, distribution, and biological effects in humans are long
overdue.
The need now exists to build, piece by piece, a strong series of
human studies that establish if any G cambogia preparations can be
added to the list of safe and effective weight-loss or
weight-gain?prevention agents. Until this scientific foundation is
established, consumers must rely on appropriately designed studies,
such as ours, to judge if herbal weight-loss products such as the
evaluated G cambogia preparation offer effective therapy beyond that of
well-established diet and exercise measures.
The main active component in the herbal extract of Garcinia
compound is Hydroxycitric acid (HCA). The earliest research, conducted
in the 1970s, into the antiobesity effects of HCA was conducted by
Hoffmann-La Roche Pharmaceuticals. Studies have shown the ability of
HCA to inhibit the actions of citrate cleavage enzyme, suppress fatty
acid synthesis, increase hepatic glycogen synthesis, suppress food
intake, increase energy expenditure, curb appetite, reduce plasmatic
cholesterol levels, and inhibit fat synthesis from excess carbohydrate
calories.
The herb Garcinia
cambogia and its active ingredient, hydroxycitric acid, have been
promoted as an aid to weight loss. Hydroxycitric acid has a chemical
composition similar to citric acid (the primary acid in citrus fruits).
Preliminary research, based on laboratory experiments and animal
research, suggests that HCA may be a useful weight loss aid. A study
analyzing the claims was recently published in the Journal of the
American Medical Association. The carefully designed research found
that Garcinia cambogia failed to produce either significant weight loss
or loss of body fat beyond that produced by a placebo.
Within cells, hydroxycitric acid is a powerful inhibitor of the
citrate cleavage enzyme. This enzyme is critical for producing the
substrate for synthesis of fatty acids. The theory behind sales of the
herb or its purified active ingredient is that hydroxycitric acid taken
orally will get into the body's individual cells where it will block
the enzyme, block fat synthesis and therefore significantly reduce body
fat mass.
The study failed utterly to detect any benefit for weight loss or
fat loss by the herb. Several reasons could be suggested. 1) Neither
Garcinia cambogia nor its active ingredient hydroxycitrate blocks fat
synthesis or aids in weight loss; 2) neither the herb nor its active
ingredient, when taken orally, is absorbed and reaches the cell intact
where it is supposed to exert its influence; 3) the herb or its active
ingredient might work only in people who have lost weight already and
would prevent weight regain; 4) the herb might work if the dose or
timing were different, for example given between meals instead of just
before.
What this study showed was that under the usual conditions in which
people trying to lose weight might use the herbal product, it was of no
benefit. The low-calorie diet plan was what led to weight loss.
Hydroxycitric acid is included in many fat loss supplements claiming
to increase fat burning. It has been promoted heavily as a fat loss
agent with no legitimate science past the superficial rodent studies.
Many of the products even boast of having this ingredient as a major
selling point. Some go as far as to name the product after it -
Hydroxy-this and Hydroxy-that. Well a new study reveals what we have
known all along. Hydroxycitric acid in no way aids in fat metabolism.
This was a very sophisticated study that revealed HCA had no effect on
energy expenditure either during rest or during intense exercise.
There seems to be no such drug/herb that can cause weight loss
without following an appropriate diet, this seems obvious with the
frequency of obesity in the American population. Although there may be
some evidence in using HCA in combination with other medications and
exercise regimens designed to promote weight loss.
Owing to a substantial increase in glucose uptake by working muscle,
glucose homeostasis during sustained aerobic exercise requires a
severalfold increase in hepatic glucose output. As exercise continues
and liver glycogen declines, an increasing proportion of this elevated
glucose output must be provided by gluconeogenesis. Increased
gluconeogenic efficiency in trained individuals is a key adaptation
promoting increased endurance, since failure of hepatic glucose output
to keep pace with muscle uptake rapidly leads to hypoglycaemia and
exhaustion. Pre-administration of (-)-hydroxycitrate, a potent
inhibitor of citrate lyase found in fruits of the genus Garcinia, may
aid endurance during post-absorptive aerobic exercise by promoting
gluconeogenesis. Carnitine and bioactive chromium may potentiate this
benefit. The utility of this technique may be greatest in exercise
regimens designed to promote weight loss.
Excessive exposure of tissues to fatty acids is likely to be the
chief cause of the various dysfunctions that lead to sustained
hyperglycemia in type II diabetes. These dysfunctions are likely to be
substantially reversible if body fat and dietary fat can be greatly
reduced. Disinhibition of hepatic fatty acid oxidation with
hydroxycitrate (HCA) and carnitine has considerable potential as a new
weight-loss strategy, but in diabetics runs the risk of further
enhancing excessive hepatic gluconeogenesis. Since the clinical utility
of metformin in diabetes is probably traceable to inhibition of
gluconeogenesis, its use as an adjunct to HCA/carnitine treatment of
obesity in diabetics deserves evaluation, particularly as metformin
therapy itself tends to reduce body weight. A consideration of relevant
evidence suggests that metformin therapy will not impede the activation
of fatty acid oxidation by HCA/carnitine, and is likely to potentiate
the appetite-suppressant and thermogenic benefits of this strategy.
Indeed, since metformin has been reported to lower body weight and
improve cardiovascular risk factors in obese non-diabetics, a broader
application of a metformin/HCA/carnitine therapy for obesity can be
contemplated.
The increasing prevalence of obesity combined with the low efficacy
of conventional treatments led us to examine the weight-loss effects of
G cambogia, a natural source of the citrate-lyase enzyme inhibitor HCA.
Our double-blind, randomized controlled trial was designed from the
consumer's perspective: we administered either a placebo or widely
available G cambogia preparation in suggested amounts along with
dietary recommendations typical of that provided in package inserts.
As potential consumers, we may ask why it remains uncertain that HCA
derived from an over-the-counter product reaches its cellular
destination in amounts adequate to actively inhibit citrate cleavage
enzyme. Why are diet plans suggested to consumers that may render
Garcinia's active agent nonabsorbable or inadvertently switch off the
target citrate cleavage enzyme? Critical tests pinpointing each step in
HCA uptake, distribution, and biological effects in humans are long
overdue.
The need now exists to build, piece by piece, a strong series of
human studies that establish if any G cambogia preparations can be
added to the list of safe and effective weight-loss or
weight-gain?prevention agents. Until this scientific foundation is
established, consumers must rely on appropriately designed studies,
such as ours, to judge if herbal weight-loss products such as the
evaluated G cambogia preparation offer effective therapy beyond that of
well-established diet and exercise measures.
- Ramos RR, Saenz FJ, Alarcon A. Extract of Garcinia cambogia
in the control of obesity [in Spanish]. Invest Med Intern.
1996;22:97-100. - Rothacker DQ, Waitman BE. Effectiveness of
a Garcinia cambogia and natural caffeine combination in weight loss: a
double-blind placebo-controlled pilot study. Int J Obes. 1997;21(suppl
2):53. - Garcinia Cambogia (hydroxycitric Acid) For Weight Loss. J Am Med Assoc 1998; 280(18):1596-1600.
- Kriketos
AD, Thompson HR, Greene H, Hill JO. Hydroxycitric acid does not affect
energy expenditure and substrate oxidation in adult males in a
post-absorptive state. Int J Obes Relat Metab Disord 1999
Aug;23(8):867-73 - McCarty MF. Inhibition of citrate lyase may aid aerobic endurance. Med Hypotheses 1995 Sep;45(3):247-54
- McCarty
MF. Utility of metformin as an adjunct to hydroxycitrate/carnitine for
reducing body fat in diabetics. Med Hypotheses 1998 Nov;51(5):399-403 - Steven
B. Heymsfield, MD. David B. Allison, PhD. Joseph R. Vasselli, PhD. Et
al. Garcinia cambogia for Weight Loss. Luke's?Roosevelt Hospital
Center, New York, NY
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