Quercetin Shows Promise against Metabolic Syndrome

Quercetin, a compound found in fruits and vegetables, may protect against the detrimental effects of a high-fat diet, including the build-up of abdominal fat, a new study suggests.

The effects of the flavanol are most likely related to its activity against oxidative stress and inflammation, researchers reported in the Journal of Nutrition.

"Quercetin supplementation attenuated the changes in expression of markers for oxidative stress and inflammation in the liver and the heart," wrote the researchers, led by Lindsay Brown from the University of Southern Queensland in Australia.

"Thus quercetin can be considered as a nutraceutical with potential [against] metabolic syndrome; clinical trials of this relatively safe natural compound should be undertaken."

Metabolic syndrome (MetS) is a condition characterized by central obesity, hypertension and disturbed glucose and insulin metabolism. The syndrome has been linked to increased risks of both type 2 diabetes and cardiovascular disease (CVD).

An estimated 32% of Americans are affected by MetS, while 15% of Europeans are estimated to be affected. Obesity is established to be the main risk factor for MetS.

Quercetin is an antioxidant flavonoid found in fruits and vegetables. Potential health benefits include lowering of inflammatory markers, cholesterol reduction and improving blood pressure.

However, many of these potential benefits are the result of in vitro or animal studies and data from human studies is rare.

One such human study by researchers from the University of Utah did indicate that a daily 730 mg supplement of quercetin led to significant reductions in blood pressure. The study, said to be the first to report the blood pressure-lowering activity of this flavanol, was published in the Journal of Nutrition (137:2405-2411, 2007).

The current study involved four groups of lab mice: One group received a corn starch-rich diet for 16 weeks; one group received a high-carbohydrate, high-fat diet for 16 weeks; the third group was fed a corn starch-rich diet for eight weeks and then the same diet fortified with quercetin (0.8 grams per kg of food); and the final group was fed the high-carb, high-fat diet for eight weeks and then the same diet fortified with quercetin (0.8 g/kg).

Results showed that animals consuming the high-carbohydrate, high-fat diet gained more weight and body fat, had unhealthy blood lipid profiles and glucose concentrations, exhibited increased blood pressure and developed fattier livers, compared to the corn starch-fed animals.

Addition of quercetin to the high-carbohydrate, high-fat diet, however, reversed most of these negative outcomes.

"Quercetin was effective against the symptoms of metabolic syndrome in a diet-induced rat model. The trafficking of fat away from the abdomen did not lower body weight and blood lipids, while the cardiovascular and liver complications of metabolic syndrome were attenuated," the researchers concluded.

Journal of Nutrition; Published online ahead of print.

I copied this off off Swansons today. Thought it was worth reading since CS added Quercetin to his supplement regime awhile back. I just added it in a month or so ago myself, although my dosage is 650mg per day. Might want to up that.