By Aylah Clark, ND
Recently we’ve had patients asking about Garcinia cambogia due to a Dr. Oz show that touted its weight loss-promoting properties. Let me start by saying this herb is not a new discovery. Researchers have known about it for many years and it is found in many weight loss supplements. Perhaps this might also tell you that whatever impact it has probably isn’t that big.
I would like to add right off the bat that diet and exercise should (of course!) be the primary route to a healthy weight. If there continues to be difficulty with weight loss, further investigation into certain conditions that create roadblocks to weight loss should be ruled out and a personalized plan should be established. Despite knowing this, you still may be wondering if it can give you a little extra boost. So, can it? Is it even safe?
Does it work?
Postulated mechanisms in which Garcinia cambogia or one of its primary active constituents, hydroxycitric acid (HCA), may aid in weight loss include appetite suppression by increasing serotonin availability, (1) (2) reduction in carbohydrate metabolism by inhibiting certain enzymes (excess carbs would then be expended rather than stored as fat), (3) inhibiting a different enzyme that plays a role in fatty acid, triglyceride, and cholesterol synthesis, (4) and other ways, potentially.
A systematic review and meta-analysis of randomized-controlled trials done in 2011 showed that taking the extract HCA did indeed result in a small amount of additional weight loss compared to placebo in the short term. (5) However, they go on to explain that there are 3 small studies responsible for pushing the result in favor of HCA having an effect—if they were excluded there would be no benefit over placebo. Additionally, the largest and most rigorous study included showed no effect. So, the evidence is not particularly strong.
Did they get the dose right?
The question of whether studies used the right dose comes up a lot, especially when there isn’t a consensus of what an effective dose is (like in this case). To complicate things more, bioavailability of HCA varies by preparation, and some studies use different species of Garcinia that may have different magnitudes of effect. At this point we do not know what the ideal dose would be or how bioavailability may have affected the results.
Like most research there are conflicting study results. This is because there can be methodological errors, ineffective dosing, and other problems that cause differing outcomes. Is it possible that Garcinia cambogia can help you lose weight? Sure, but it probably won’t be much if it does.
Is it safe?
If you’re thinking about trying it anyway, we should at least determine if it is safe. The biggest concern is liver toxicity which is on the radar due to a particular weight loss supplement that contained HCA that was recalled after 23 cases of liver toxicity. Unfortunately, we don’t know if was because of HCA or something else. There have been several cases of acute liver failure since that are believed to be caused by the plant. Most safety concerns that have been raised with Garcinia have been with multi-component formulas where it cannot be teased out as the definitive cause, (4) but ultimately we don’t know quite enough about the liver effects of Garcinia.
From the actual studies, liver failure was not reported. The primary side effects were gastrointestinal in nature. Other symptoms like headaches, nausea, and skin rash have also been reported but because the placebo group reported these just as often, they can’t necessarily be attributed to Garcinia. (5)
In general, studies conclude that Garcinia cambogia is safe for human consumption, (6) but we don’t know if it is safe in the long term. It should not be taken if you are pregnant, breast-feeding, or under the age of 18. It is also not safe for people who have irritable bowel disease (ulcerative colitis or Crohn’s disease) or liver disease.
Another important concern would be supplement quality. Studies have revealed that many supplements on the market may not have what they say they have in them. Some have even been shown to contain house plants! In a 2015 investigation by the New York Attorney General showed that at Walmart only 4% of products tested showed the DNA from the plant(s) listed on the label. (7)
As a caveat to these findings, this study has been scrutinized because plant DNA can be damaged in processing and this study did not confirm their findings with other plant identification techniques like chromatography, but it is still concerning that DNA from plants that should not have been present were also found.
Only reputable companies should be used when consuming supplements, especially herbal formulas, that can ensure the quality (and quantity) of their product.
If you are thinking about taking Garcinia cambogia, consult with a qualified healthcare professional that can take into account your personal health history, is familiar with supplement quality standards, and can help determine if there are medical causes for any weight loss challenges.
- Efficacy of Slim 339 in reducing body weight of overweight and obese human subjects. Toromanyan, E, et al., et al. 12, s.l. : Phytother Res, 2007, Vol. 21, pp. 1177-81.
- . Effect of hydroxycitric acid on weight loss, body mass index and plasma leptin levels in human subjects. Preuss, HG, et al., et al. 5, s.l. : FASEB Journal, 2002, Vol. 16, p. A1020.
- Chemistry, physiological properties, and microbial production of hydroxycitric acid. Yamada, T, Hida, H and Yamada, Y. 5, s.l. : Appl Microbiol Biotechnol, 2007, Vol. 75, pp. 977-82.
- A comprehensive scientific overview of Garcinica cambogia. Semwal, RB, et al., et al. s.l. : Fitoterapia, 2015, Vol. 102, pp. 134-48.
- The Use of Garcinia Extract (Hydroxycitric Acid) as a Weight loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials. Onakpoya, Igho, et al., et al. s.l. : J Obes, 2011. doi: 10.1155/2011/509038.
- Safety assessment of (-)-hydroxycitric acid and Super CitriMax, a novel calcium/potassium salt. Soni, MG, et al., et al. 9, s.l. : Food Chem Toxicol, 2004, Vol. 42, pp. 1513-29.
- O’Connor, Anahad. New York Attorney General Targets Supplements at Major Retailers. New York Times. Feb 3, 2015.