In a recent study, researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University found that curcumin, the active ingredient in turmeric, seems to reduce weight gain and retard the growth of fat tissue in mice that were fed high-fat diets. Their research is published in the May 2009 issue of the Journal of Nutrition.
"Weight gain is the result of the growth and expansion of fat tissue, which cannot happen unless new blood vessels form, a process known as angiogenesis," said senior author Mohsen Meydani, director of the center's Vascular Biology Laboratory, in a press release announcing the findings. "Based on our data, curcumin appears to suppress angiogenic activity in the fat tissue of mice fed high fat diets."
Turmeric, a plant in the ginger family that is native to South Asia, is generally ground into an orange powder and used as an important spice in curries and Middle Eastern dishes. It is also used in dyes and to give color to mustard, with which it shares similar flavors. One of its main components is curcumin, a type of phytochemical — the term for chemicals found in plants — known as a polyphenol. These chemicals appear to help prevent disease, and after eating turmeric, curcumin is easily absorbed by the body.
The research team at Tufts studied mice fed on high-fat diets for three months; while one group got curcumin supplements in its chow, the other group did not. Both groups consumed the same amount of food, which indicates that curcumin does not affect appetite, but mice fed the curcumin-rich diet did not put on as much weight as the rodents that were not fed curcumin.
"Curcumin appeared to be responsible for total lower body fat in the group that received supplementation," said Meydani, also a professor at the Friedman School of Nutrition Science and Policy at Tufts. "In those mice, we observed a suppression of microvessel density in fat tissue, a sign of less blood vessel growth and thus less expansion of fat. We also found lower blood cholesterol levels and fat in the liver of those mice. In general, angiogenesis and an accumulation of lipids in fat cells contribute to fat tissue growth."
The authors note similar findings from experiments with cell cultures, and suggest that curcumin appears to affect the expression of two genes, which contribute to the growth of new blood vessels. But before you go dashing off to the spice rack, the researchers warn that much more research is needed on the impacts of turmeric - and its active ingredient curcumin - on humans.
"It is important to note, we don't know whether these results can be replicated in humans because, to our knowledge, no studies have been done," Meydani said. "The mechanism or mechanisms by which curcumin appears to affect fat tissue must be investigated in a randomized, clinical trial involving humans."
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