It seems that 2013 has come to an end, and the award for most popular weight loss miracle this year goes to the magical Garcinia cambogia. After being featured on Dr. Oz, this product has popped up on hundreds of sites, forums and in stores across the states. It is harder to find in Canada though, and may of us have been stuck ordering online. I always ask two questions when new products of this nature come to the market (especially via the ‘Oz effect’) - does it work and is it safe? There is no doubt that we love to add supplements to our weight loss protocols – a study done in 2008 found that over 30% of adults have used a supplement to try and enhance weight loss efforts (1). Lets have a quick look at the background of Garcinia cambogia and see what the research really says about it.
Garcinia cambogia, properly known as Garcinia gummi-gutta (you can see why it is marketed using it’s nickname) is a tropic fruit that traditionally culinary roots. It rose to fame quickly this year but is not a new player in the weight loss game - researchers began investigating it's effect over 20 years ago. There are many different constituents of Garcinia that have been identified, but the active component is though to be hydroxy-cytric acid (HCA). This compound makes up 10-30% of the plant, so many of the medicinal extracts are concentrated to contain a certain amount of HCA. The potential impact HCA may have on body weight could be due to an appetite suppressant effect, and it may also change the way our body stores fat. One study in animals has suggested that HCA controls appetite by increasing the amount of serotonin in the brain, a hormone well known for the role it plays in mood and appetite (2). This effect has only been investigated by 1 clinical trial in humans, the results of which did not support an appetite suppressant effect. (3)
The first study done investigating the effect this fruit has on body weight was published in 1998. Either a standardized extract of Garcinia containing 1500mg of HCA or a placebo (inactive supplement) was given to 135 obese participants over 12 weeks, along with a high fiber, low calorie diet. Although both groups lost weight, no difference was seen between the participants taking Garcinia cambogia and those taking the placebo. (4) In a second human trial published in 2000, authors randomized 89 slightly overweight females to receive either a Garcinia supplement containing 1200mg of HCA or placebo in addition to a low calorie diet. After monitoring women for 12 weeks, authors reported that no appetite suppressant effect was seen but the women receiving Garcinia cambogia lost significantly more weight than the women receiving placebo. (3)
Notice how the two trials discussed so far also put participants on a strict low calorie diet? One trial published in 2011 has investigated the effect of Garcinia Cambogia on weight loss without any accompanying calorie restriction. Authors randomized 48 overweight subjects to receive either 2g of Garcinia extract per day or placebo, but authors did not report the amount of active HCA in the supplement. There was no significant weight loss seen in either group after 10 weeks of the trial. (5)
The safety profile of Garcinia in the available short-term trials seems to be acceptable – although headaches and digestive upset were reported in some studies, there was no significant difference from the groups taking placebo. One concern that has emerged as a risk potentially associated with Garcinia is a condition called rhabdomyolsis - a threatening breakdown of muscle tissue. Garcinia may trigger this condition by changing the way muscles store fat and produce heat due to the effect of HCA. Although several case reports exist involving Garcinia and rhabdomyolsis, all the individuals were taking combination products with more than one herb or nutrient involved. This makes it difficult to completely blame Garcinia for these effects. (6) Never the less, caution should be taken by anyone on medication that could also increase their risk of rhabdomyolsis, such as cholesterol lowering statin drugs, or those who have had a history of this condition.
Clearly, the sparse data available in humans does not yet demonstrate the ability of Garcinia cambogia to enhance weight loss. Caution should be taken in some who may be susceptible to rhabdomyolsis, and it is always important to let your medical doctor know when you are taking natural products if unsupervised so they can help screen for negative effects or potential interactions with your medications. If anything, herbal therapies and nutrient support seem to be an adjunct to positive lifestyle changes when it comes to weight loss, not a magic pill that will do the work for you – no matter what images of shrinking belly fat Dr. Oz puts up when promoting the formula. Consider what will be most sustainable before you adopt a low calorie diet, and talk to a naturopathic doctor or dietitian to ensure you are still getting all your required nutrients.
- Dr. Sarah Penney, ND, MSc
Originally writted for acenutrients.com
J. L. Pillitteri et al. Use of dietary supplements for weight loss in the united states: results of a national survey. Obesity. 2008:16(4);790–796.
S.E. Ohia et al. Safety and mechanism of appetite suppressant by a novel hydroxycitric acid extract (HCA-SX). Mol Cell Biochem. 2002: 238(1-2);89-103.
R. D. Mattes. Effects of (-)-hydroxycitric acid on appetite variables. Physiol Behav. 2000:71(1-2);87-94.
S.B. Heymsfield et al. Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial. JAMA. 1998:280(18);1596-600.
J.E. Kim et al. Does Glycine max leaves or Garcinia Cambogia promote weight loss or lower plasma cholesterol in overweight individuals: a randomized control trial.
I.A. Mansi et al. Rhabdomyolysis in Response to Weight-Loss Herbal Medicine. The American Journal of the Medical Sciences. 2004:327(6);356-7.