Garcinia cambogia

Geschatte leestijd: 6 minuten Garcinia cambogia is a plant that has attracted attention due to its (presumed) appetite-suppressing and weight-reducing effects of the fruit. In this article, we will check to what extent these claims are confirmed in research.

What is Garcinia Cambogia?

Garcinia cambogia is the Latin name for a tree also called guttegomboom in Dutch and Malabar tamarind. The Latin name owes the tree in part to the French/Dutch botanist Laurent Garcin. In English, the tree is called Garcinia gummi-gutta, but also brindleberry, Malabar tamarind, and kudam puli [2,3]. Garcinia cambogia bears yellow/green fruits somewhat resembling a small pumpkin. The extract of the fruits of Garcinia Cambogia is currently receiving much attention because it could lead to suppressed appetite and weight loss. However, research shows that these preparations could potentially have a toxic effect on the liver, while the effect on weight loss has not been unequivocally demonstrated.

Garcinia Cambogia as Slimming Pills?

Garcinia cambogia is often claimed to be able to suppress appetite and reduce body weight. The pharmaceutical sector has eagerly seized on this by offering extracts and slimming pills based on Garcinia cambogia. I wondered to what extent these claims, extracts, and slimming pills are supported by scientific research. I always tend to be skeptical when another plant pops up that would solve all of humanity’s problems. However, I will try to approach this objectively again. First, I will describe the theory behind the claimed action of Garcinia cambogia. Then I will look at the studies to assess to what extent these claims can be confirmed or refuted.

Hydroxycitric Acid (HCA)

Extracts, powders, and slimming pills based on Garcinia cambogia are supposed to achieve their effect thanks to the active substance in the fruit, especially its peel. The peel consists of 20 to 30 percent hydroxycitric acid (HCA) [3,9]. HCA is a derivative of citric acid. HCA has an inhibitory effect on the enzyme ATP-citrate lyase. ATP-citrate lyase normally contributes to the breakdown of citrate into oxaloacetic acid and acetyl-CoA. Acetyl-CoA is necessary for the synthesis (formation) of new fatty acids. A complicated way to explain that HCA can limit fat production. More HCA → Less acetyl-CoA → Reduced fatty acid synthesis [4,5,6]. In addition to limiting production, HCA has also been shown in animal and laboratory studies to increase the burning of fatty acids [7]. But what does that say about what people can actually expect in practice?

Losing Weight with HCA?

That’s why I delved into a systemic review from 2011 [8]. This review was conducted by researchers who compared the outcomes of multiple randomized clinical trials on the weight-reducing effect of HCA. They hoped to come to a clear conclusion about the effect of HCA on people’s weight. Ultimately, they found 9 relevant studies that met all the criteria for such a comparison. The analysis showed that HCA had a small but statistically significant effect compared to a placebo (average difference of 0.88 kilograms). According to this comparison, HCA could thus make a small contribution to weight loss. The researchers who conducted the analysis therefore conclude that HCA can lead to weight loss in the short term, but that this effect is small. Therefore, according to them, the clinical relevance is doubtful. A year later, Spanish researchers came to the same conclusion. They also pointed out that the studies showing an effect were often small in size and of short duration.

“Garcinia cambogia is less effective for people with certain genetic predispositions for obesity”

Last year, research was also conducted on the effects of Garcinia cambogia on body weight [10]. The study involved 214 people who were overweight or obese. They received 500mg of Garcinia cambogia twice a day. There were some interesting aspects in the way this study was set up. Firstly, the study lasted for 6 months, so it wasn’t just looking at short-term effects. Additionally, they looked at certain variations in genes that have previously been associated with obesity. This allowed researchers to take into account some known innate factors. They looked at variations in genes known to make you eat more, for example, due to lower satiety. But also genes known to be associated with lower fat burning and slower metabolism. On the right, you can see the results.

We first analyzed whether the treatment of people with overweight or obesity with GC and GNN had any effect of weight, metabolic basal rate, fat mass and visceral fat. We found a dramatic, highly significant and sustained reduction of weight at 3 and 6 months compared with the start of the study. This decrease was parallel to a highly significant and significant increase in metabolic basal rate in 3 months 6 months respectively (Fig. ​(Fig.1b).1b). Weight loss was also related to a highly significant reduction of fat mass and visceral fat in 3 and 6 months (Fig. ​(Fig.1c).1c). Weight decrease was independent of sex, age, or suffering from hypertension, DM2, dyslipidemias or their combinations Andrea Maia-Landim, University of Córdoba

‘Obesity Genes’

Weight and fat mass thus significantly decreased while metabolism was increased. In addition, the researchers also observed improvements in blood sugar, the amount of fatty acids in the bloodstream, and cholesterol. As mentioned, the researchers also looked at the effect of certain variations in genes associated with obesity. The results of people with three different types of these variations were compared to the results of people who did not have these variations. On the right, you can see the difference. People with these gene variations (FTO, PLIN, and ADBR3) lost less weight and body fat than others. The researchers did not observe a difference in the effect on metabolism, blood sugar, triglycerides, and cholesterol. They therefore concluded that Garcinia cambogia could be an effective means of weight loss, but that this effect may be smaller in people with the mentioned genetic variations. They therefore recommend first determining whether these variations are present to make a better estimate of the expected outcome. Of the 214 people in the study, 76 were found to have one of the three variations. That was just over a third of the 214 overweight people who participated in the study.

Diet or Garcinia Cambogia?

Even if you take into account the genetic variations, you could still be quite impressed by the result. But this result was not achieved by Garcinia cambogia alone! The researchers combined this with a calorie-restricted diet. “Yes, that’s easy,” I hear you say. And rightly so. After all, how can you distinguish between the effect of the diet and the effect of Garcinia? You could do this by giving one half of the group a placebo. In both groups, you would then expect weight loss due to the diet, and any difference could potentially be attributed to Garcinia cambogia. The researchers write that they worked with a placebo group. However, I do not find the results of this control group in the study. So, although the researchers are positive, it is not clear to me what they base this on. I mainly mentioned this study to show that you have to take into account genetic differences when you have certain expectations of a supplement.

Is Garcinia Cambogia Dangerous?

Fortunately, the same difference between theory and practice seems to apply to safety as well. In the last-mentioned study, doses of 500mg of Garcinia Cambogia were given twice a day. This did not cause any negative side effects, and the researchers therefore concluded that it can be used safely. A conclusion that is consistent with other studies. In 2012, the safety of Garcinia cambogia was investigated, again by comparing the outcomes of various studies. The conclusion was that there was no evidence that Garcinia cambogia leads to negative side effects. Even at doses up to 2800mg per day. In cases where side effects were reported, they were combined with other products.

Those products which have been reported to possess adverse effects are either polyherbal or multi-component in nature. To date, there is no case study or report showing the direct adverse effect of HCA. The structure, mechanism of action, long history of the use of Garcinia/HCA and comprehensive scientific evidence had shown “no observed adverse effect level (NOAEL)” at levels up to 2800 mg/day, suggesting its safety for use. Chuah Lo, University Science Malaysia

Conclusion

Researchers also try to explain their different results when it comes to the effect of Garcinia cambogia on body fat and weight. They mention differences in the composition of the supplement itself, but also genetic differences of participants in the study as possible causes of these differences. So, although there is a theoretical basis for the operation of Garcinia cambogia, we cannot yet state with certainty that it can work (for everyone).

References

1. Garcinia gummi-gutta“. Germplasm Resources Information Network(GRIN). Agricultural Research Service (ARS), United States Department of Agriculture (USDA). Retrieved 11 December 2017.
2. ^ Tinworth, Kellie D; Harris, Patricia A; Sillence, Martin N; Noble, Glenys K (2010). “Potential treatments for insulin resistance in the horse: A comparative multi-species review”. The Veterinary Journal. 186 (3): 282–291. doi:10.1016/j.tvjl.2009.08.032. PMID 19783461. Retrieved 6 October 2013.
3. Yamada T, Hida H, Yamada Y (2007). “Chemistry, physiological properties, and microbial production of hydroxycitric acid”. Appl. Microbiol. Biotechnol. 75 (5): 977–82.
4. Inhibition of lipogenesis in rat liver by (-)-hydroxycitrate. Sullivan AC, Hamilton JG, Miller ON, Wheatley VR Arch Biochem Biophys. 1972 May; 150(1):183-90.
5. Effect of (-)-hydroxycitrate upon the accumulation of lipid in the rat. I. Lipogenesis. Sullivan AC, Triscari J, Hamilton JG, Miller ON, Wheatley VR Lipids. 1974 Feb; 9(2):121-8.
6. Citrate and the conversion of carbohydrate into fat. Fatty acid synthesis by a combination of cytoplasm and mitochondria.Watson JA, Lowenstein JM J Biol Chem. 1970 Nov 25; 245(22):5993-6002.
7. Han J, Li L, Wang D, Ma H. (-)-Hydroxycitric acid reduced fat deposition via regulating lipid metabolism-related gene expression in broiler chickens. Lipids Health Dis. 2016;15:37. Published 2016 Feb 24. doi:10.1186/s12944-016-0208-5
8. Onakpoya I, Hung SK, Perry R, Wider B, Ernst E. The Use of Garcinia Extract (Hydroxycitric Acid) as a Weight loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials. J Obes. 2010;2011:509038. doi:10.1155/2011/509038
9. Chuah LO, Ho WY, Beh BK, Yeap SK. Updates on Antiobesity Effect of Garcinia Origin (-)-HCA. Evid Based Complement Alternat Med. 2013;2013:751658. doi:10.1155/2013/751658
10. Maia-Landim A, Ramírez JM, Lancho C, Poblador MS, Lancho JL. Long-term effects of Garcinia cambogia/Glucomannan on weight loss in people with obesity, PLIN4, FTO and Trp64Arg polymorphisms. BMC Complement Altern Med. 2018;18(1):26. Published 2018 Jan 24. doi:10.1186/
11. In vitro and in vivo toxicity of garcinia or hydroxycitric Acid: a review. Chuah LO, Yeap SK, Ho WY, Beh BK, Alitheen NB Evid Based Complement Alternat Med. 2012; 2012():197920.