Will Dr. Oz’s Garcinia cambogia Help You Lose Weight?

Garcinia Cambogia, Malaber Tamarind (Photo credit: shari kadirur)

Every week the supermarket magazine rack trumpets another weight loss miracle.  I cannot believe that we are not all losing weight at a tremendous rate.  Just pick up a magazine, take the supplement and have the pounds drop away.

This week’s current miracle pill was Garcinia cambogia.  I’d written myself almost a decade ago about the possible weight loss effects, but my name isn’t Dr. Oz, and my mug shot on the front of a magazine will not sell a million copies.  Here’s what I said about Garcinia: helps reduce the rate of conversion of carbohydrates to fats, helps
reduce appetite, and will also help the reduction of LDL cholesterol levels.

Pretty wordy stuff, huh?  I should have gone with the Dr. Oz credited:  Lose 8 pounds in a week!  Now that jingle would sell some papers.

I say Dr. Oz credited because these are the same magazines that claim that celebrity X is either divorcing celebrity Y or having their child or maybe both.  Dr. Oz may have mentioned Garcinia. but the show I found was from last November.  He probably mentions one a day and there is a backlog for the weekly mags.

So what is our evidence about Garcinia?  There were some very nice trials almost a decade ago.  Many of them were positive and also funded by the manufacturer, so always take those results with a grain of potassium.

What’s our overall picture?  We’ve had a nice meta-analysis that found, pooling all studies, that Garcinia did help lose weight over placebo.  Before you go leaping out the door (leaping helps with weight loss as long as you don’t break anything) to get Garcinia, the average weight loss “translates to about 1% in body weight loss in HCA group compared with placebo.”  (Full medline article here).  That’s not bad, but it’s short-term (eight weeks on average for the studies) and it’s not spectacular.  In fact, to get the sort of weight loss touted by the magazine covers, you’d need to weigh 800 lbs.  And that weight loss would be over eight weeks not in one week.

Does that mean Garcinia is useless?  No.  It can be a helpful adjunct, especially if you are on a diet and plateauing.  So definitely look into it before giving up.  But don’t expect it to do the work for you.  Body change is a tricky, hormonally based business, and the addition of something like Garcinia is an extra tool.

Here are some more studies on Garcinia, including its possible toxicity.

Crit Rev Food Sci Nutr. 2012;52(7):585-94. doi: 10.1080/10408398.2010.500551.

Evaluation of the safety and efficacy of hydroxycitric acid or Garcinia cambogia extracts in humans.

Márquez F, Babio N, Bulló M, Salas-Salvadó J.

Source

Human Nutrition Unit, Department of Biochemistry and Biotechnology, Faculty of Medicine and Health Sciences, Rovira i Virgili University, Reus, Spain.

Abstract

Several studies have shown that Garcinia cambogia plays an important role in the regulation of endogenous lipid biosynthesis. This effect is specially attributed to (-)-hydroxycitric acid (HCA) inhibiting the enzyme ATP-dependent citrate lyase, which catalyzes the cleavage of citrate to oxaloacetate and acetyl-CoA. Although several studies have found that the administration of G. cambogia extracts is associated with body weight and fat loss in both experimental animals and humans, we should be cautious when interpreting the results as other randomized, placebo-controlled clinical trials have not reported the same outcomes. Furthermore, most studies in humans have been conducted on small samples and mainly in the short term. None of them have shown whether these effects persist beyond 12 weeks of intervention. Therefore, there is still little evidence to support the potential effectiveness and long-term benefits of G. cambogia extracts. With regard to toxicity and safety, it is important to note that except in rare cases, studies conducted in experimental animals have not reported increased mortality or significant toxicity. Furthermore, at the doses usually administered, no differences have been reported in terms of side effects or adverse events (those studied) in humans between individuals treated with G. cambogia and controls.

PMID:22530711

J Med. 2004;35(1-6):33-48.

An overview of the safety and efficacy of a novel, natural(-)-hydroxycitric acid extract (HCA-SX) for weight management.

Preuss HG, Rao CV, Garis R, Bramble JD, Ohia SE, Bagchi M, Bagchi D.

Source

Department of Physiology, Medicine and Pathology Georgetown University Medical Center, Washington, DC 20057, USA.

Abstract

Garcinia cambogia-derived (-)-hydroxycitric acid (HCA) is a safe, natural supplement for weight management. HCA is a competitive inhibitor of ATP citrate lyase, a key enzyme which facilitates the synthesis of fatty acids, cholesterol and triglycerides. Previous studies in our laboratories have demonstrated the superior bioavailability of a novel calcium-potassium salt of HCA derived from Garcinia cambogia (HCA-SX, Super CitriMax). Greater bioavailability of HCA-SX was observed when taken on an empty stomach. HCA-SX was also shown to exhibit concentration-dependent release of serotonin in isolated rat brain cortex, which may explain its appetite suppressive action. Acute oral, acute dermal, primary dermal irritation, primary eye irritation and 90-day chronic toxicity studies, as well as Ames bacterial reverse mutation and mouse lymphoma tests, were assessed to determine the safety of HCA-SX. In the 90-day toxicity study, dose- and time-dependent effects of HCA-SX were assessed on body weight, selected organ weights, hepatic and testicular lipid peroxidation and DNA fragmentation, hematology and clinical chemistry, and histopathology in male and female Sprague-Dawley rats. No remarkable toxicity results were detected, demonstrating the safety of HCA-SX. Furthermore, clinical studies to evaluate the safety and efficacy of HCA-SX over a period of eight weeks were conducted in 60 human volunteers. Subjects were given a 2,000 kcal diet/day, participated in a 30 min walking exercise program 5 days/week and given an oral dose of placebo or 4666.7 mg HCA-SX (providing 2,800 mg HCA) in three equally divided doses 30-60 min before meals, Body weight, BMI, lipid profiles, serum leptin, serotonin and excretion of urinary fat metabolites were determined at 0, 4 and 8 weeks of treatment. At the end of 8 weeks, body weight and BMI decreased by 5.4% and 5.2%, respectively. Food intake, total cholesterol, LDL, triglycerides and serum leptin levels were significantly reduced, while HDL and serotonin levels, and excretion of urinary fat metabolites (a biomarker of fat oxidation) significantly increased. No significant adverse effects were reported. These results demonstrate the safety, bioavailability and efficacy of HCA-SX in weight management.

PMID: 18084863

Mutat Res. 2005 Nov 11;579(1-2):149-62. Epub 2005 Aug 1.

Bioefficacy of a novel calcium-potassium salt of (-)-hydroxycitric acid.

Downs BW, Bagchi M, Subbaraju GV, Shara MA, Preuss HG, Bagchi D.

Source

InterHealth Research Center, Benicia, CA, USA.

Abstract

Obesity is associated with cardiovascular disease, diabetes and certain forms of cancer. Popular strategies on weight loss often fail to address many key factors such as fat mass, muscle density, bone density, water mass, their inter-relationships and impact on energy production, body composition, and overall health and well-being. (-)-Hydroxycitric acid (HCA), a natural plant extract from the dried fruit rind of Garcinia cambogia, has been reported to promote body fat loss in humans without stimulating the central nervous system. The level of effectiveness of G. cambogia extract is typically attributed solely to HCA. However, other components by their presence or absence may significantly contribute to its therapeutic effectiveness. Typically, HCA used in dietary weight loss supplement is bound to calcium, which results in a poorly soluble (<50%) and less bioavailable form. Conversely, the structural characteristics of a novel Ca2+/K+ bound (-)-HCA salt (HCA-SX or Super CitriMax) make it completely water soluble as well as bioavailable. An efficacious dosage of HCA-SX (4500 mg/day t.i.d.) provides a good source of Ca2+ (495 mg, 49.5% of RDI) and K+ (720 mg, 15% of RDI). Ca2+ ions are involved in weight management by increasing lipid metabolism, enhancing thermogenesis, and increasing bone density. K+, on the other hand, increases energy, reduces hypertension, increases muscle strength and regulates arrhythmias. Both Ca and K act as buffers in pH homeostasis. HCA-SX has been shown to increase serotonin availability, reduce appetite, increase fat oxidation, improve blood lipid levels, reduce body weight, and modulate a number of obesity regulatory genes without affecting the mitochondrial and nuclear proteins required for normal biochemical and physiological functions.

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