A Google search of Garcinia will directly lead you to scores of commercial weight management products developed and marketed by 'N' number of companies including the nutraceutical and multilevel marketing ones. Yes, the most promoted effect of Malabar tamarind is its anti-obesity properties. The fruit's anti-obesity effects can be extended to its ability to give relief from associated complications such as oxidative stress, inflammation, insulin resistance and cardiovascular issues. Its anti-ulcer, anti-microbial, anti-diabetic and even anti-cancer benefits have also been reported.
Coming to the primary property, the mechanism by which Garcinia exerts its weight management effect is outrightly described by all the product launchers: the ingredient hydroxycitric acid (HCA), its inhibitory effect on citrate lyase enzyme of lipogenesis pathway, stimulatory effect on serotonin production and increased metabolism of lipids. The exact mechanism of action can be elaborated into a series of body events.
HCA inhibits the extramitochondrial enzyme ATP citrate lyase which cleaves citrate to oxaloacetate and acetyl CoA; the two carbon units taking part in the initial steps of the biosynthetic pathway of fatty acid and cholesterol synthesis. Subsequently, to this metabolic pathway alteration, a signal is sent to the brain to increase the production of serotonin hormone. The hormone results in reduced appetite and easy attaining of satiety. This, in turn, makes the body to utilize more of carbohydrates for energy production. The overall result is the reduction in the building units of fatty acid and cholesterol synthesis pathways leading to downregulated lipogenesis.
How much is clinically proven?
Well, the dietary market is flooded with Garcinia products, but the question still remains: Does Garcinia Cambogia Work? Garcinia Cambogia is a beneficial plant for sure. Clinical clarification is required regarding how much, in whom and how safe. Clinical substantiation of de novo lipogenesis inhibition to a certain degree was obtained in a placebo study conducted on men with high fat with a reduction in fat deposition. A two-week intake of HCA resulted in decreased energy intake and body weight in another group. Weight loss with a decrease in total cholesterol and low density lipoprotein was found when chromium and chitosan were added to the HCA administration.
The most evident positive results were obtained in multiple studies spanning eight weeks with significant reduction in BMI (Body Mas Index), LDL, food intake, triglycerides and upregulation of fat oxidation, high density lipoproteins, lean body mass, and excreted urinary fat metabolites, upon taking a dose of 1500 mg HCA per day for normal subjects (Ramos et al, Thom). 60 day-studies have reported weight loss up to 4.7%. HCA in combination with other weight loss agents has resulted in reducing almost 3.5 kg in 12 weeks with an HCA dosage of 300 mg per day.
There have been studies which indicate that the administration of HCA on empty stomach, almost 30 to 60 minutes before a meal can have significant results, such as the study by Sullivan. A conclusive remark is yet to be derived due to several negative studies which do not report significant changes with respect to weight loss in obese persons on HCA administration as a single agent and in combination.
These studies were also done for 2 weeks, 8 weeks, and even 12 weeks after taking dosages between 500 mg to 4.3 g. Animal studies, though conclusively show the significant weight loss properties of Garcinia. There is probably a gap between the daily intake of HCA and its synergistic combination with other compounds claimed to have weight management properties.
If we look at the commercially available weight loss products, most of them use a formulation of multiple ingredients which are thought to act in combination to bring about the desired result. The advocates of these products advice on taking them before meals and in supplementation with other compounds like chromium.
The natural extract sure has an effect on fat metabolism, but further studies are in demand to standardize the safest and most effective dosage and administration to counter one of the most important causes of non-infectious chronic diseases.