Garcinia cambogia is a plant, also known as Garcinia gummi-gutta.
The fruit of the plant looks like a small, green pumpkin and is used in many traditional Asian dishes for its sour flavor.
In the skin of the fruit, there is a large amount of a natural substance called Hydroxycitric Acid (HCA).
This is the active ingredient in Garcinia Cambogia extract… that is, the substance that produces the weight loss effects.
There are actually a whole bunch of studies in rats showing that Garcinia Cambogia consistently leads to significant weight loss.
Bottom Line: Studies in rats show that the active ingredient in Garcinia Cambogia can inhibit a fat producing enzyme called Citrate Lyase and increase serotonin levels, leading to significant weight loss.
The medical literature primarily documents weight loss and lipid-lowering activity for the plant. However, trials supporting its use are limited.
HCA is the primary medicinal component contained in the fruit rinds of G. cambogia . HCA is present as up to 30% by weight in the pericarp of G. cambogia fruit. 6 Xanthones, xanthone derivatives, and polyisoprenylated benzophenones have been isolated. 6 , 7 Some salts used in commercial products are water soluble and bioavailable, and are a good source of calcium (495 mg) and potassium (720 mg). 8 Studies also document interest in production of HCA by using microorganisms.
Uses and Pharmacology
The medical literature primarily documents research on the weight loss and lipid-lowering activity of the plant.
In vitro and animal data
In 2 experiments using the human hepatoma cell line HepG2, overnight exposure to G. cambogia extract caused an upregulation of low-density lipoprotein (LDL) receptor activity and an upregulation of the level of HMG-CoA reductase resulting in decreased cholesterol synthesis. Flavonoids from the plant reduced lipid levels in normal and hypercholesterolemic rats. Reductions were also documented in triglycerides, phospholipids, and free fatty acids. The mechanism of action for the flavonoids may involve: (1) reducing the rate of lipogenesis by reducing the activities of lipogenic enzymes, glucose-6-phosphate dehydrogenase, and isocitrate dehydrogenase; and (2) increasing the rate of degradation of cholesterol leading to higher levels of hepatic and fecal bile acids, as well as neutral sterols in rats treated with the herb. While dexamethasone typically elevates lipid profiles, G. cambogia extract maintained normal lipid levels in rats administered dexamethasone.
In a 4-week randomized, double-blind, placebo-controlled trial, 150 obese patients were treated with a dietary supplement ( G. cambogia extract 55 mg, chitosan 240 mg, and chrome 19 mg) together with a weight reduction regimen. Treatment groups administered the dietary supplement showed statistically significant dose-related reductions in weight, total and LDL cholesterol, and triglycerides, and improvement in high density lipoprotein cholesterol.
The suggested mechanism of action involves HCA-inhibiting lipogenesis, increasing lipid oxidation, and reducing food intake.
A study in obese rats found high doses of HCA-containing G. cambogia (154 mmol HCA/kg diet) effective in suppressing epididymal adipose tissue. This same study also found testicular atrophy and toxicity at dosages of 778 mg HCA/kg body weight/day (102 mmol HCA/kg diet) and higher. Another study in rats administered a high-fat diet and a mixture of G. cambogia extract, soypeptide, and L-carnitine, led to a reduction in body weight and accumulation of visceral fat mass. The mixture also improved blood and hepatic lipid concentrations or the induced dyslipidemia in the rats. Other combination products with G. cambogia are also effective in reducing weight gain and improving dyslipidemia, hyperinsulinemia, hyperleptinemia, and fatty liver in mice. The antiobesity effect involves modulation of several genes associated with visceral adipogenesis. One study in adult, nonobese cats found no effect on fat-free mass or energy expenditure.
Other pharmacologic activity
Some studies found that supplementation with G. cambogia can reduce oxidative damage.
The fruit contains xanthones, which inhibit pre-neoplastic lesions in mammary and colon cancer. The xanthones may also induce apoptosis in mouth, leukemia, breast, gastric, and lung cancer cell lines in vitro.
Glucose metabolism may be improved by lowering serum insulin levels in mice treated with G. cambogia . Leptin is a hormone associated with appetite control. G. cambogia may have leptin-like activity as mice treated with G. cambogia had decreased serum leptin levels and a reduced leptin/white adipose tissue ratio. HCA treatment delayed and reduced intestinal glucose absorption in rats; the treatment causes delayed intestinal absorption of glucose rather than delayed gastric emptying.
HCA promoted lipid oxidation and reduced carbohydrate use in mice at rest and during running. The utilization of respiratory gases was reduced for mice treated with HCA at rest and during exercise. Some studies on herbal coffee supplements with HCA showed an increase in resting energy expenditure to enhance metabolic rates and promote weight and fat loss.
Red blood cell count
A G. cambogia extract caused an increase in the red blood cell (RBC) count in rat tissue. The activity may be (1) associated with the iron in G. cambogia , as iron is an erythropoietic agent; (2) antioxidant activity and may decrease the rate of oxidant-induced hemolysis, which increases the life span of the RBC; or (3) the content of bioflavonoids in the plant, which may increase the level of peripheral testosterone, which can stimulate erythropoiesis in humans.