Red Peppers Can Reduce Belly Fat

Plant chemicals known as ”capsinoids,” from non-spicy peppers have been known to play a role in modulating the metabolism and affecting the body weight of animals. This study was conducted to see if capsinoids taken by mouth could help humans in losing weight and fat and improving metabolism. Researchers also attempted to check on any gene changes that allow for such beneficial effects of capsinoids. Results showed that although there were few side effects with capsinoids, there was not a significant loss of weight with the drug. However, capsinoids reduced more fat around the belly compared to a placebo. Also, three genetic traits were identified that predict the efficacy of capsinoids.

Capsaicin, present in chilies, activates certain sensors in the mouth that lead to the perception that they are ”hot.” On the other hand, capsinoids are not pungent and are present in the same plant species that contain capsaicin. Both these agents have been shown to activate metabolism in animal studies. They help reduce body fat as seen in mice. This concept has been tried in a couple of small human studies. The current study was conducted to explore if this same principle held true in obese humans trying to lose weight by adopting a healthy diet and exercise. Additionally, this study attempted to check on specific genetic changes that make capsinoids more effective in helping a person lose weight.

* This study spanned over a 12-week period. Forty men and 40 women who were obese or overweight were randomly assigned to a capsinoid or placebo group.
* One group received capsinoids at a dose of 6 mg per day and the other group received a placebo.
* Throughout the study, body weight, fat around the abdomen and 13 genes were studied. Metabolism and oxidation capacity of body fat was measured only in men because findings in women during different phases of their menstrual cycle would be confusing.

* At the end of the study, no severe intolerance or side effects were noted with the use of capsinoids.
* The average weight loss was 0.9 kg and 0.5 kg in the capsinoid and placebo groups, respectively. This difference was not significant. Fat deposits around the abdomen reduced more with capsinoids than with placebo.
* Those on capsinoids also oxidized the fat in their body better than those on placebo.
* Of the 13 genes studied, changes in 3 of the genes (TRPV1, Val585Ile, and UCP 2 -866 G/A) were found to predict if capsinoids would successfully reduce abdominal fat.

Next steps/shortcomings
The authors agree that this was a short-term study and also only a small number of participants were studied. They agree that metabolic changes could be measured only in men; women had to be excluded, which could have skewed the results. The authors suggest further studies that are conducted over longer periods of time and include more participants to understand the efficacy of capsinoids better.

The authors conclude from this study that “treatment with 6 mg/d capsinoids orally appears to be safe and well tolerated and is associated with loss of abdominal fat.” They also note that capsinoids lead to more oxidation of fat. The results from the study also delineate at least three genetic changes that can tell how people might react to capsinoids. The authors agree that this was a small study and suggest that if future studies could prove that some people with a particular genetic make-up react favorably to capsinoids, it could be used successfully along with lifestyle changes in the obese and overweight.

For More Information:
Effects of Capsinoids on Weight Loss and Metabolism in Humans
American Journal of Clinical Nutrition, December 2008
By Soren Snitker; Yoshiyuki Fujishima
From the University of Maryland School of Medicine, Baltimore, Maryland, and the Ajinomoto Company, Inc., Fort Lee, New Jersey

*FYI Living Lab Reports Are Summaries of the Original Research.
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