The May, 2009 issue of the Journal of Nutrition reported the discovery of researchers at Tufts University in Boston of a reduction in the formation of adipose (fat) tissue and the blood vessels that feed it in mice given high fat diets supplemented with curcumin, the major polyphenol in the spice turmeric.
In their introduction to the article, Mohsen Meydani and colleagues at Tufts' Jean Mayer USDA Human Nutrition Research Center on Aging explain that "the growth and expansion of adipose tissues, similar to the growth of cancerous tumors, requires recruitment of new blood vessels or angiogenesis. In adipose tissue, this is mediated by adipose tissue secretion of adipokines, including leptin, adiponectin, resistin, visfatin, tumor necrosis factor-alpha, interleukin-6, interleukin-1, and vascular endothelial growth factor (VEGF). Therefore, in addition to reducing energy intake, the inhibition of angiogenesis in adipose tissue can be a strategy to prevent adipose tissue growth and obesity."
The researchers first investigated the effect of curcumin in cultured human umbilical vein endothelial cells to which adipokines had been added to stimulate angiogenesis. They found that the ability of curcumin to inhibit angiogenesis was partly due to the reduced expression of VEGF-alpha. In another experiment, Dr Meydani's team incubated preadipocytes (immature fat cells) with curcumin and observed significant inhibition of differentiation of the cells into mature adipocytes.
They then divided 18 mice to receive a control diet containing 4 percent fat by weight, a high fat diet containing 22 percent fat, or a high fat diet supplemented with 500 milligrams curcumin per kilogram diet for 12 weeks. At the end of the treatment period, mice that received the high fat diet had gained more weight than those that received the low fat diet; however, the effect was reduced in mice that received curcumin even though the same amount of food was consumed. The authors attribute this reduction to a decrease in total body fat in the curcumin-fed animals. Mice that received curcumin also had lower liver weights than those that received the high fat diet without curcumin. Additionally, curcumin-treated mice experienced a reduction in VEGF, indicating reduced angiogenesis, as well as significantly lower microvessel density in adipose tissue. Furthermore, serum total cholesterol, triglycerides, and free fatty acids were lower in mice that received curcumin compared with both groups of unsupplemented animals.
"In conclusion, dietary curcumin is the major polyphenol found in turmeric with no known toxicity," the authors write. "In addition to several reported pharmacological activities, our results clearly demonstrate that curcumin at cellular and whole organism levels displays remarkable potential health benefits for prevention of obesity and associated metabolic disorders by suppressing angiogenesis in adipose tissue, upregulating adipocyte energy metabolism and apoptosis, and downregulating preadipocyte differentiation. The mechanism(s) by which curcumin modulates these processes need to be further investigated."Related Health Concern: Obesity
Life Extension believes that, in addition to a sensible, balanced diet and exercise, the only way to successfully lose weight is to address the underlying hormonal imbalances that promote weight gain. Ideally, by using bioidentical hormone replacement, dieters can restore their hormonal profile to what it was at the age of 25, an age at which weight gain is less often a problem. In addition, numerous dietary nutrients have been shown to encourage weight loss.
Green tea and green tea extract have shown an ability to increase metabolic rate.
- A study in mice found that the primary polyphenol found in green tea (epigallocatechin gallate, or EGCG) decreased diet-induced obesity by decreasing energy absorption and increasing fat burning (Klaus et al 2005).
- Another study in mice evaluated the effects of caffeine, polyphenols, and L-theanine, the three major components of green tea. Additive benefits were found from green tea polyphenols, caffeine, and theanine on fat accumulation (Zheng et al 2004). Furthermore, another study showed that feeding 4 percent green tea powder to mice resulted in weight loss as well as lower concentrations of total cholesterol in the liver, triglycerides in serum and liver, and fatty acids in serum (Sayama et al 2000).
- A well-known study examined whether or not green tea extract, rich in caffeine and polyphenols, could increase 24-hour energy expenditure and fat oxidation in humans. On separate occasions, subjects were randomly assigned to one of three treatments: green tea extract and caffeine (90 mg EGCG and 50 mg caffeine), caffeine (50 mg), and placebo, which were ingested at breakfast, lunch, and dinner. The results showed that treatment with the green tea extract (which included caffeine) resulted in a significant increase in metabolic rate, as evidenced by a significant increase in 24-hour energy expenditure (Dulloo et al 1999).
- An open-label trial demonstrated that after three months, green tea extract decreased body weight by 4.6 percent and waist circumference by 4.48 percent (Chantre et al 2002).
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