Fruit extract’s value as diet aid unproven

The small, tangy fruits of southeast Asia’s Garcinia trees have been used to spice Indian dishes for centuries. The fruits -- especially those of the species Garcinia cambogia -- contain high concentrations of hydroxycitric acid (HCA). Both Garcinia extract and HCA alone are marketed as weight-loss supplements.

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Uses: In traditional Indian medicine, Garcinia fruits are used as a remedy for upset stomachs and other gastrointestinal complaints.

Dose: Supplement makers recommend 250 to 1,000 milligrams a half-hour before each meal. HCA from Garcinia is sold in capsule form; it’s also included as an ingredient in many weight-loss supplements.

Precautions: HCA may be harmful when combined with other weight-loss supplements. Because of the chemical’s potential effects on brain and blood chemistry, people with dementia and diabetes should avoid it. Little is known about its long-term safety or side effects.

Research: Many animal studies have shown that HCA promotes weight loss by stifling appetite and changing the way the body burns carbohydrates and stores fats. Human studies are fewer in number, but those that do exist fail to show any effect on weight loss. A handful of animal studies have shown that Garcinia extracts protect against stomach ulcers, and lab studies show the fruits from some Garcinia trees may stop cancer cells from proliferating, but much more research is needed to confirm any of Garcinia’s -- or HCA’s -- purported effects in people.

Dietary supplement makers are not required by the U.S. government to demonstrate that their products are safe or effective. Ask your healthcare provider for advice on selecting a brand.

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-- Elena Conis