Garcinia cambogia

Garcinia cambogia is a small fruit that contains the active ingredient hydroxycitric acid (HCA); the abbreviation (-)HCA is also used. One of the main theories of how garcinia and HCA work is through the inhibition in cells of citrate lyase, which is needed for the conversion of carbohydrates to fat. Prevention of carbohydrate conversion to fat is thought to induce the body to oxidize the excess carbohydrates, leading to fully loaded glycogen stores, which in turn may play a part in suppressing the appetite. Preclinical studies have confirmed body weight loss in rats fed HCA, and HCA’s activity of suppressing the appetite and reducing food intake was confirmed. Clinically, however, HCA has failed to perform well. This may be the result of citrate lyase being important only in very high carbohydrate diets, a type of diet that most studies do not prescribe, along with other variables (a high-fiber diet can bind to HCA and block it).

The theory behind the use of HCA and Garcinia cambogia seems to be sound, but clinical studies have still to prove under which conditions HCA is best used. To date, many of the herbal supplements containing HCA are probably not effective because they lack the correct conditions of use.

Appetite Suppression

In a randomized, placebo-controlled, single-blind, crossover study, 24 overweight men and women were administered HCA for 2 weeks. After 2 weeks of treatment, the study subjects’ 24-hour energy intakes (Els), appetite profiles, hedonics, moods, and possible changes in dietary restraint were assessed in a laboratory restaurant. Els were decreased by 15-30%, and body weight tended to decrease during the HCA treatment period without changes in other factors. It was concluded that El was reduced with HCA treatment, while satiety remained the same (Westerterp-Plantenga and Kovacs, 2002).

In a double-blind, placebo-controlled, randomized, crossover study, the effects of the ingestion of HCA alone and combined with medium-chain triglycerides on satiety and food intake was investigated. Twenty-one normal to moderately obese subjects participated in the study, which consisted of three 2-week intervention periods separated by washouts of 2 or 6 weeks. A significant loss in body weight was found in all groups, but no differences were found among the groups. The 24-hour El and appetite-related parameters were similar for all treatments. Neither HCA alone nor HCA combined with medium-chain triglycerides produced changes in food intake or satiety (Kovacs et al., 2001a).

In a double-blind, placebo-controlled, randomized, crossover study, the effects of the ingestion of HCA alone and combined with medium-chain triglycerides on satiety, fat oxidation, energy expenditure, and body weight was investigated. Eleven males participated in the study, which consisted of three intervention periods separated by washout periods of 4 weeks. Body weight was significantly reduced in all three groups but was not found to be different among the groups. Likewise, the appetite parameters and energy expenditures were not different among treatments. Neither HCA alone nor HCA combined with medium-chain triglycerides resulted in increased satiety, fat oxidation, 24-hour El, or body weight loss compared with placebo (Kovacs et al., 2001b).

Mattes and Bormann (2000) studied the effect of HCA in promoting weight loss through appetite suppression. In a double-blind, placebo-controlled study, 89 mildly overweight women were prescribed 5,020-kj diets for 12 weeks, and either 400 mg of Gardnia cambogia (2.4 g/ day of garcinia and 1.2 g/day of HCA) or a placebo 30-60 minutes before meals. Weight and body composition was measured every other week for 12 weeks. Both groups showed a loss in body weight, with the treatment group showing significantly greater reduction. The HCA, however, had no effect on appetite-related variables.

Weight Loss

Preuss et al. (2002) studied the efficacy of Garcinia cambogia derived HCA (HCA-SX from Super CitriMax) in suppressing appetite and inhibiting fat synthesis in a study involving 48 moderately obese adults. Both the HCA group (2,800 mg/day) and the placebo group were treated 30 minutes before meals for 8 weeks. A diet of approximately 2,000 kcal and a walking program supervised by a trainer were prescribed to both groups. Losses of body weight of 3.3% (after 4 weeks) and 4.8% (after 8 weeks) were observed in the treatment group. Triglyceride, LDL, and total cholesterol levels were all reduced in the treatment groups as well. The authors concluded that HCA-SX could be useful in weight management.

To test the theory that HCA increases fatty acid oxidation by reducing the malonyl-coenzyme A concentrations, 10 cyclists were studied after ingestion of an HCA supplement or placebo. The cyclists ingested either 3.1 mL/kg body weight of an HCA solution or a placebo 45 and 15 minutes before exercise and 30 and 60 minutes after the start of exercise. During rest and after 2 hours of exercise at 50% of their maximal work output, the cyclists were measured for their total fat and carbohydrate oxidation rates. Blood samples were collected at rest and during 15-minute intervals of exercise. No significant changes were found in total fat and carbohydrate oxidation rates between the groups. Even when ingested in large quantities, HCA did not increase total fat oxidation in vivo in endurance-trained athletes (van Loon et al., 2000).

In a double-blind, placebo-controlled, randomized, crossover study, HCA was tested for effects on metabolic parameters in humans. With or without moderately intense exercise over four laboratory visits, energy expenditure, respiratory quotient (following an overnight fast), and blood samples (for glucose, insulin, flucagon, lactate, and R hydroxybu-yrate) were measured. Treatment with HCA did not affect energy expenditure either with the exercise or at rest. Blood parameters did not differ significantly between treatments through the course of the study, and respiratory quotient was not significantly lowered at rest or during exercise compared with a placebo. The authors concluded that the hypothesis that HCA could affect the fat oxidation in fasting or moderately exercising humans with a typical Western diet was not supported (Kriketos et al., 1999).

In a randomized, double-blind, placebo-controlled clinical study, HCA was tested for its efficacy in lowering body weight and fat mass loss in overweight humans. Over the course of 12 weeks, participants were given either 1,500 mg/day of HCA or placebo and prescribed a high-fiber, low-energy diet. Every other week, body weight was measured, and fat mass measurements were taken at 0 and 12 weeks. No significant weight loss or fat mass loss was observed in this study by treatment of HCA compared with placebo (Heymsfleld et al., 1998).

Roman et al. (1996) investigated the efficacy of Garcinia cambogia in promoting weight loss, and reducing cholesterolemia and triglycer-idemia in overweight subjects. In a randomized, placebo-controlled design, 40 participants were given either an extract of Garcinia cambogia (500 mg) or placebo before each meal for 8 weeks. The treatment group showed a significant reduction in the amount of overweight and in cholesterol and triglycerides compared with the placebo group.
Garcinia cambogia products vary in their amounts of standardized HCA, but it is rare to find any product claiming less than 50% HCA. Two to three divided doses of Garcinia cambogia, 750-1,500 mg each, may be taken before mealtime (30-60 minutes).

No serious side effects have been noted. The acute LD50 of HCA-SX is more than 5,000 mg/kg (orally in rats), and no gross toxicological pathology was found on autopsy, indicating the safety of this product (Ohia et al., 2002).

There have been safety concerns with ephedra-containing supplements, and HCA is a common component combined with ephedra formulations designed for bodybuilding and weight loss.

Bell et al. (2000) examined the effect of reducing the dosage of combined ephedrine and caffeine administration in athletes on limiting the negative side effects of vomiting and nausea (experienced by 25% of subjects) reported in earlier studies. They found that 4-5 mg of caffeine per kilogram combined with 0.8-1 mg of ephedrine per kilogram resulted in the maintenance of ergogenic effect while reducing the negative side effects. The lowest-dose combination caused no incidence of vomiting or nausea.

Author Bio: Georgiy Kharchenko with American Weight Loss Group LLC: Fitness Trainer, Ephedra Products, Natural Weight Loss Pills, Phentramin D Tablets

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