What is it?
(-)-Hydroxycitric acid (HCA) is a compound found in Garcinia cambogia, a type of fruit. HCA has a chemical structure similar to that of citric acid (the primary acid in citrus fruits).
Where is it found?
HCA is found in only a few plants, with one rich source being the rind of a little pumpkin-shaped fruit called Garcinia cambogia, which is native to Southeast Asia. This fruit (also called Malabar tamarind) is used as a condiment in dishes such as curry.
What do the advocates say?*
The promise of (-)-Hydroxycitric acid (HCA) is based on animal studies that suggest it inhibits fat synthesis and perhaps suppresses appetite. Human studies have not been consistent, however, with one reporting no benefits while another reported improved results when combined with a weight-loss diet.
How much is usually taken by dieters?
HCA, extracted from the rind of the Garcinia cambogia fruit grown in Southeast Asia, has a chemical composition similar to that of citric acid (the primary acid in oranges and other citrus fruits). Preliminary studies in animals suggest that HCA may be a useful weight-loss aid.1 2 HCA has been demonstrated in the laboratory (but not yet in clinical trials with people) to reduce the conversion of carbohydrates into stored fat by inhibiting certain enzyme processes.3 4 Animal research indicates that HCA suppresses appetite and induces weight loss.5 6 7 8 However, a double-blind trial found that people who took 1,500 mg per day of HCA while eating a low-calorie diet for 12 weeks lost no more weight than those taking a placebo.9 A double-blind trial of Garcinia cambogia (2.4 grams of dry extract, containing 50% hydroxycitric acid) found that the extract did not increase energy expenditure; it was therefore concluded that this extract showed little potential for the treatment of obesity at this amount.10 Nonetheless, another double-blind trial found that using the same amount of Garcinia cambogia extract significantly improved the results of a weight-loss diet, even though the amount of food intake was not affected.11
*Dieters and weight-management advocates may claim benefits for hydroxycitric acid based on their personal or professional experience. These are individual opinions and testimonials that may or may not be supported by controlled clinical studies or published scientific articles on hydroxycitric acid. For more complete and detailed information, including references and safety information, see Hydroxycitric Acid as a nutritional supplement.
References
1. Lowenstein JM. Effect of (-)-hydroxycitrate on fatty acid synthesis by rat liver in vivo. J Biol Chem 1971;246:629–32.
2. Triscari J, Sullivan AC. Comparative effects of (-)-hydroxycitrate and (+)-allo-hydroxycitrate on acetyl CoA carboxylase and fatty acid and cholesterol synthesis in vivo. Lipids 1977;12:357–63.
3. Cheema-Dhadli S, Harlperin ML, Leznoff CC. Inhibition of enzymes which interact with citrate by (-)hydroxycitrate and 1,2,3,-tricarboxybenzene. Eur J Biochem 1973;38:98–102.
4. Sullivan AC, Hamilton JG, Miller ON, et al. Inhibition of lipogenesis in rat liver by (-)-hydroxycitrate. Arch Biochem Biophys 1972;150:183–90.
5. Greenwood MRC, Cleary MP, Gruen R, et al. Effect of (-)-hydroxycitrate on development of obesity in the Zucker obese rat. Am J Physiol 1981;240:E72–8.
6. Sullivan AC, Triscari J. Metabolic regulation as a control for lipid disorders. Am J Clin Nutr 1977;30:767–76.
7. Sullivan AC, Triscari J, Hamilton JG, et al. Effect of (-)-hydroxycitrate upon the accumulation of lipid in the rat: I. Lipogenesis. Lipids 1974;9:121–8.
8. Sullivan AC, Triscari J, Hamilton JG, et al. Effect of (-)-hydroxycitrate upon the accumulation of lipid in the rat: II. Appetite. Lipids 1974;9:129–34.
9. Heymsfield SB, Allison DB, Vasselli JR, et al. Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial. JAMA 1998;280:1596–600.
10. Martinet A, Hostettmann K, Schultz Y. Thermogenic effects of commercially available plant preparations aimed at treating human obesity. Phytomedicine 1999;6:231–8.
11. Mattes RD, Bormann L. Effects of (-)-hydroxycitric acid on appetitive variables. Physiol Behav 2000;71:87–94.
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2006-09-07
