Hydroxycitric acid

(−)-Hydroxycitric acid is a specific isomer of hydroxycitric acid (HCA) derived from Garcinia cambogia and other Garcinia species. The fruit of these plants, often called assam fruit or assam gelugur, has been used for centuries as a culinary ingredient due to the distinct acidity imparted by the HCA and because it makes meals more filling and satisfying.

HCA has been touted for its positive effects on weight-loss and metabolism for some time. This is most often attributed to its action as an inhibitor of ATP citrate lyase, an enzyme necessary for the production of fat from sugar in the human body. There is extensive research detailing this activity, particularly as it was the prime motivation for a Roche drug development effort decades ago.

More recently additional biological effects have come to light beyond ATP citrate lyase inhibition. Now HCA is recognized as impacting inflammation, blood pressure, blood sugar, satiety, and overall cellular homeostasis. It is becoming clear that the strength of HCA as a dietary ingredient lies in its multiple modes of action (i.e. pleiotropic mechanisms).

As is true of many herbal products and their components, however, the benefits of HCA are dependent largely upon how it is prepared. In fact, HCA presents more challenges than most. For instance, is the HCA present in a form that is soluble in water, absorbable in the intestines, and bioavailable to tissues throughout the body? Careful processing of the ingredient, which can include removing obstructive constituents, is essential for HCA to work as promised. In fact, a critical analysis of HCA clinical trials illustrates that unsuccessful outcomes can typically be attributed to HCA that has been poorly prepared or given in inadequate quantities.

An increasing number of well-designed and appropriately controlled weight management studies in animals and humans have indicated that HCA is both safe and efficacious in weight management. Safety studies in experimental animals at up to 25 times the human equivalency doses did not produce hepatotoxicity or other significant adverse effects.

Selected References

  • Cheng IS, Huang SW, Lu HC, Wu CL, Chu YC, Lee SD, Huang CY, Kuo CH. Oral hydroxycitrate supplementation enhances glycogen synthesis in exercised human skeletal muscle. Br J Nutr. 2011 Aug 9:1-8.
  • Chiang, Y.F.1, Lu, H.C.1, Tasi, T.W.2, Cheng, I.S.1. The Different Influence Of Post-Exercise Carnitine And Hydroxycitrate Supplementation On Glycogen Synthesis In Human Skeletal Muscle. European Database of Sports Science. 15th Annual ECSS-Congress, Antalya 2010.
  • Clouatre D, Preuss HG. Potassium Magnesium Hydroxycitrate at Physiologic Levels Influences Various Metabolic Parameters and Inflammation in Rats. Current Topics in Nutraceutical Research 2008;6(4): 201-210.
  • Clouatre, D., Talpur, N., Talpur, F., Echard, B., Preuss, H. Comparing metabolic and inflammatory parameters among rats consuming different forms of hydroxycitrate. Journal of the American College of Nutrition 2005;24:429 Abstract.
  • Greenway F. Garcinia, Encyclopedia of Dietary Supplements Second Edition Edited by Paul M. Coates. 2010.
  • Hayamizu K, Ishii Y, Kaneko I, Shen M, Sakaguchi H, et al. Effects of Long-term Administration of Garcinia cambogia extract on Visceral Fat Accumulation in Humans: A Placebo-controlled Double Blind Trial. J. Oleo. Sci. 2001;50(10):805-12.
  • Hayamizu K, Ishii Y, Kaneko I, Shen M, et al. Effects of Garcinia cambogia (Hydroxycitric Acid) on Visceral Fat Accumulation: A Double-Blind, Randomized, Placebo-Controlled Trial. Current Therapeutic Research 2003;64(8):551-567.
  • Lim K, Ryu S, Nho HS, Choi SK, Kwon T, Suh H, So J, Tomita K, Okuhara Y, Shigematsu N. (–)-Hydroxycitric acid ingestion increases fat utilization during exercise in untrained women. J Nutr Sci Vitaminol (Tokyo). 2003 Jun;49(3):163-7.
  • Lim K, Ryu S, Ohishi Y, Watanabe I, Tomi H, Suh H, Lee WK, Kwon T. Short-term (-)-hydroxycitrate ingestion increases fat oxidation during exercise in athletes. J Nutr Sci Vitaminol (Tokyo). 2002;48:128–133.
  • Lim K, Ryu S, Suh H, Ishihara K, Fushiki T. (–)-Hydroxycitrate ingestion and endurance exercise performance. J Nutr Sci Vitaminol (Tokyo). 2005 Feb;51(1):1-7.
  • Loe YC, Bergeron N, Rodriguez N, Schwarz JM. Gas chromatography/mass spectrometry method to quantify blood hydroxycitrate concentration. Anal Biochem. 2001 May 1;292(1):148-54.
  • Loe Y, Bergeron N, Phan J, Wen M, Lee J, Schwarz J-M, Time Course of Hydroxycitrate Clearance in Fasting and Fed Humans, FASEB Journal, 15 4:632, Abs. 501.1, 2001.
  • Mattes RD, Bormann L. Effects of (-)-hydroxycitric acid on appetitive variables. Physiol Behav 2000 Oct 1-15;71(1-2):87-94.
  • Onakpoya I, Hung SK, Perry R, Wider B, Ernst E. The Use of Garcinia Extract (Hydroxycitric Acid) as a Weight loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials. J Obes. 2011;2011:509038.
  • Tomita K, Okuhara Y, Shigematsu N, Suh H, Lim K. (-)-Hydroxycitrate ingestion increases fat oxidation during moderate intensity exercise in untrained men. Biosci Biotechnol Biochem. 2003 Sep;67(9):1999-2001.
  • Westerterp-Plantenga MS, Kovacs EM. The effect of (-)-hydroxycitrate on energy intake and satiety in overweight humans. Int J Obes Relat Metab Disord 2002 Jun;26(6):870-2.
 

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