Study in mouse cells affirms that antioxidants in food suppress formation of fats associated with metabolic syndrome, obesity, diabetes, and heart disease
by Craig Weatherby
Scientists in Taiwan may have discovered how diets rich in plant foods—especially blueberries and chili peppers—reduce the risk of metabolic syndrome, obesity, diabetes, and heart disease.
Their study focuses on flavonoid-type antioxidants and the major subgroup known as polyphenols: the antioxidants abundant in berries, cocoa, tea, whole grains, and colorful fruits and vegetables.
Flavonoids and phenols appear to reduce risk factors associated with cardiovascular disease, cancer, obesity, senility, and other disorders: especially ones associated with chronic inflammation, which flavonoids oppose.
(Organic produce is especially helpful: see “Organic Produce and Milk Offer Abundant Antioxidants.”)
The anti-cancer effects of flavonoids are less well proven than their heart-health effects, but evidence on that score continues to accumulate (See “Antioxidant Food Factors Support Breast Cancer Survival” and “Food-Borne Antioxidants May Curb Breast Cancer”).
The Taiwanese researchers studied how 15 phenolic acids and six flavonoids affected adipocytes (fat cells) from mice (Hsu CL, Yen GC 2007).
Their results showed that fat cells exposed to certain antioxidants had lower levels of an enzyme—glycerol-3-phosphate dehydrogenase (GPDH)—that forms triglycerides from glycerol.
As a probable consequence of suppressing expression of this enzyme, the fat cells exposed to flavonoids showed lower levels of triglycerides.
High blood levels of triglycerides are a major feature of metabolic syndrome, and raise the risk of heart disease and diabetes.
And the winning antioxidants are…
Among the six flavonoids and 15 phenolic flavonoids tested, o-coumaric acid and rutin were most effective at reducing production of triglycerides inside cells, dropping fat levels by 61.3 and 83 percent, respectively.
Blueberries and chili peppers are leading sources of o-coumaric acid (Zadernowski R et al 2005).
Rutin is most abundant in buckwheat—which, despite its name is a fruit, not a grain—grapes, and other fruits and fruit rinds, especially citrus fruits (Kreft I et al 2006). Rutin is often included in vitamin C supplements with added flavonoids.
These two compounds also increased expression of adiponectin, a hormone secreted by abdominal fat cells.
Abdominal fat secretes various hormones that exert strong effects on appetite, inflammation, and metabolism, and influence whether fats and carbohydrates in foods are burned or stored as belly fat.
Among the various belly-fat-generated hormones, only adiponectin discourages insulin resistance, inflammation, and atherosclerosis. People suffering from obesity, insulin resistance, and atherosclerosis have substantially below-normal levels of adiponectin.
As the Taiwanese team said, their findings suggest that diets high in antioxidant-rich plant foods could suppress development of metabolic syndrome, obesity, diabetes, and heart disease.
In addition, higher dietary ratios of omega-3 to omega-6 fats also increases production of fat-fighting adiponectin (see “Omega-6/Omega-3 Imbalance Pushes Heart/Diabetes Perils”).
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