Photo: Helga Weber via Flickr/Creative Commons
Even for the most well-adjusted of us, the temptation to change the way we look can be overpowering. We see idealized images everywhere–nearly always exceedingly thin. In a world where obesity is considered an epidemic, there is certainly a pressure to lose weight. But weight loss is difficult. When diet pills and supplements come swooping in, with bits of science attached, it sounds so good. They promise no diet, no exercise, no hard-work weight loss.
But can they be real?
When someone close to me bought a bunch of Garcinia cambogia tablets, I was intrigued and worried at once. I was assured that “a bunch of doctors and credible people have come out and said that this really works.” Naturally, I wanted to know who these doctors were and one Google search later, the only doctor I came up with is Dr. Oz. Not sure if I have any Oz fans in the audience, but I don’t really want to take anything he says as Gospel.
So, it was on to the research.
It turns out that Garcinia cambogia is a fruit native to southeast Asia and it looks a bit like a yellow pumpkin growing from a tree. It’s rind contains a significant amount of hydroxycitric acid (abbreviated here on out as HCA), and this is the active ingredient that all the hubbub is about. Now, I knew what I was looking for and was ready to check things out.
But first, I had to nail down the claims. According to this *cough*unreliable*cough* article, it’s a fat-blocking, appetite-suppressing, metabolism-boosting, cholesterol-lowering, immune system-strengthening wonder supplement.
First, let’s get the immune system boost out of the way. This argument is based on the concentration of vitamin C in the fruit. However, I was unable to find nutrition data for the Garcinia cambogia to verify anything at all. However, even if it is a good source of vitamin C, that wouldn’t have much effect against the common cold where “the application of vitamin C alone is without clinical effects [1].”
But what about cholesterol? Can Garcinia cambogia and its HCA lower your lipid levels? Erm, maybe? One study cited actually used a different species of the Garcinia genus, but it lowered lipid values in Guinea pigs feed high cholesterol diets [2]. However, a different species working in guinea pigs does not a magic weight-loss supplement make.
How about the meat and potatoes of the claims? Dissolving your fat? Boosting your metabolism? According to this small study (only 10 subjects, so their results come with a grain of salt), taking HCA does not increase your metabolism, measured by energy expenditure and respiratory quotient, in someone on the modern Western diet doing some moderately intense exercise [3]. Regarding fat-blocking: this theory comes from HCA’s ability to inhibit ATP citrate lyase [8], which is used in synthesizing fat from carbohydrates. This sounds really exciting–it stops excess carbs from becoming fat!–but that doesn’t mean we’re getting a free (carby) lunch. Those calories will have to go somewhere and we’ll have to do something with those carbs–like make more glycogen [4].
The claim that is most interesting to me is that Garcinia cambogia increases satiety. Variations on this theme include that it suppresses appetite and curbs emotional eating. Surprisingly enough for me, this may be true. It seems that it increases serotonin, which is involved in stopping cravings and feeling full [5]. However, it is possible to experience serotonin toxicity [6], which is why it’s recommended that those on antidepressants (especially serotonin selective re-uptake inhibitors) don’t use Garcinia cambogia. But there can be other effects of increased serotonin, including irritable bowel syndrome, according to Scientific American [7]. This is especially notable since in some trials, those taking the HCA were twice as likely to complain about GI issues as subjects taking the placebo [8].
Ultimately, after looking over lots of data, the take-away for me has been that Garcinia cambogia is in no way a magical pill–it leads to (at best) boarder-line statistically significant weight loss in clinical trials or meta-analyses [8]. For those in search of more information, I’d like to direct you to this Consumer Reports article [9] and this one from Science-Based Medicine [10].
pretty healthy 