by Dr. Andrea Hilborn, ND
This article originally appeared in the Kingston Whig-Standard
Dr. Oz’s sterling reputation has helped him promote a number of weight loss supplements, but now his reputation is taking on some tarnish. In his own words, referring to the weight loss supplements he has promoted, “Oftentimes they don’t have the scientific muster to present as fact.”
Over the next four columns, I’ll first talk about two weight loss supplement scams, then two weight loss supplement stars. Weight loss supplement scams don’t work and may cause harm. Weight loss supplement stars won’t cause you to start dropping pounds magically, but they may correct problems that can prevent weight loss.
One of Dr. Oz’s darlings is Garcinia cambogia, a plant, or an extract from it called hydroxycitric acid. The evidence about Garcinia is a good illustration of how Dr. Oz can make the claims he does.
There are different levels of reliability when it comes to applying medical evidence. Some studies show a way in which the supplement might work — a mechanism of action. These studies can indicate which supplements are worthy of further investigation. Good evidence for what is applicable to people comes from randomized controlled trials (RCTs) conducted on humans. The best possible evidence comes from reviewing a whole bunch of randomized controlled trials.
Garcinia has some interesting evidence showing that it might have a mechanism of action that could cause it to be helpful with weight loss. This is the evidence that Dr. Oz focuses on.
However, the three most recent RCTs show that Garcinia does not boost weight loss or impact body mass index.
One RCT had people take 800 mg of Garcinia three times per day or placebo, as well as make changes to their diet for 60 days. The scientists kept track of many different parameters. At the end of the 60 days, they found no difference in weight, body mass index, waist-hip ratio, percentage of fat mass, resting metabolic rate, respiratory coefficient, total cholesterol, HDL cholesterol, LDL cholesterol, leptin blood levels and insulin blood levels. They was a small decrease in triglyceride levels of the people who took Garcinia. Underwhelming, right?
Another RCT involved 86 overweight people and lasted ten weeks. The experimental group took two grams of Garcinia per day. All participants continued with their normal eating habits. At the end of the study, there was no difference between the Garcinia group and the placebo group in terms of their body weight or body composition.
The third most recent RCT looked at the extract of Garcinia, hydroxycitric acid. One thousand milligrams hydroxycitric acid where given to the experimental group, and the placebo group were given inactive pills. After 12 weeks, there was no significant difference in body weight or body mass index.
So, the stuff does not appear to be very effective when taken by real live people. But maybe it’s harmless if people take it and feel like they are getting a benefit.
Is Garcinia safe? When taken in the amounts commonly recommended, Garcinia is probably safe. However, there have been some alarming reports and longterm studies do not exist.
Garcinia has been found to increase serotonin levels, so there is a risk that it could cause serotonin toxicity.
At high doses, Garcinia may cause the liver to develop scar tissue and the testicles of men to shrink.
One woman who took a combination product containing Garcinia experienced breakdown of her muscle tissue. Yikes! Fortunately, the muscle breakdown stopped when she stopped taking her weight loss supplement.
Overall, I would give Garcinia and hydroxycitric acid a pass. Stay tuned for another weight loss supplement scam in two weeks’ time.