Written by Greg Arnold, DC, CSCS. In a study with mice on a high fat diet and fed quercetin, there was a 17% reduction in blood sugar and 4% reduction in blood pressure over a control group.

Quercetin is a type of plant antioxidant called a flavonol found in a number of foods including teas, onions, apple and buckwheat. It has gained popularity for its potential anti-inflammatory. But most of the research with quercetin has been done in laboratories, so evidence of definite effectiveness in humans is still needed (1).

Now a new study in rats (2) suggests that quercetin may help patients with Metabolic Syndrome. This condition affects over 47 million Americans and is characterized by central obesity (excessive fat tissue in and around the abdomen), increased blood pressure, and insulin resistance (the body can’t properly use insulin or blood sugar) (3). Its $4,000 yearly pharmacy cost per patient has rendered it “the most expensive disease you’ve never heard of” (4).

In the study, researchers put forty 9-week old rats into one of four groups (10 per group). The first two groups were given one of two diets for 16 weeks to induce Metabolic Syndrome:

  • A corn starch-rich diet.
  • A high-carbohydrate, high-fat diet.

The other two groups were also fed one of the two diets for 16 weeks, but were also given quercetin starting in week 8 through week 16.

When looking at abdominal fat, the quercetin-corn-starch mice had 34% less abdominal fat compared to the corn-starch group while the quercetin-high-fat mice had 40% less abdominal fat compared to the high-fat mice.

Regarding blood pressure, the systolic blood pressure (the top number) was 4% lower in the quercetin-corn-starch group compared to the regular corn-starch group and 5% lower in the quercetin-high-fat group compared to the regular high-fat group.

Finally, researchers assessed insulin sensitivity by measuring blood sugar levels and computing a value called “Blood Glucose Area under the Curve”, or AUC (5). While there was only a 4.5% decrease in the quercetin-corn-starch group compared to the corn-starch group, there was a 17% decrease in the quercetin-high-fat group compared to the high-fat group, showing quercetin to have its’ greatest effects on higher-fat diets while still having a noticeable effect on high-carbohydrate diets.

For the researchers, “quercetin treatment attenuated most of the symptoms of metabolic syndrome, with the most likely mechanisms being decreases in oxidative stress and inflammation.”

Source: Quercetin Ameliorates Cardiovascular, Hepatic, and Metabolic Changes in Diet-Induced Metabolic Syndrome in Rats” published online April 25, 2012 in the Journal of Nutrition. Posted September 18, 2012.

© 2012 American Society for Nutrition.

Posted September 18, 2012.

Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY.  You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com

References:

  1. “Quercetin” -see the Memorial Sloan-Kettering Cancer Center.
  2. Panchal SK.  Quercetin Ameliorates Cardiovascular, Hepatic, and Metabolic Changes in Diet-Induced Metabolic Syndrome in Rats.  Jou Nutr 2012; doi: 10.3945/jn.111.157263.
  3. American Heart Association Website: “Metabolic Syndrome”
  4. “Metabolic Syndrome: The Most Expensive Disease You’ve Never Heard Of” – see the Medical News Today website.
  5. Le Floch JP.  Blood Glucose Area Under the Curve: Methodological Aspects. Diabetes Care 1990;l13(2):172-175.