How quercetin works to protect your heart

Good as Gold

We know that quercetin is good for the heart. And as I’ve noted in previous e-Alerts, it’s also an immune booster that helps curb chronic disease.

Now researchers believe they’ve discovered exactly what makes this flavonoid as good as gold.

Anti this and anti that

Flavonoids are compounds that give fruits and vegetables their color. So when we eat an abundant variety of fruits and vegetables, flavonoids provide antioxidant and anti- inflammatory protection.

In the e-Alert “A Cell’s Best Friend” (5/1/03), I told you about a study from the National Public Health Institute in Helsinki, Finland, in which dietary and medical records of more than 10,000 subjects were tracked for nearly 30 years.

Researchers found that subjects who consumed the greatest quantities of flavonoid-rich foods were less likely to suffer from a number of chronic diseases, including heart disease, lung cancer, stroke, asthma, and type 2 diabetes. Furthermore, those who ate foods that provided a wide variety of different types of flavonoids tended to live longer.

Quercetin and kaempferol were the two flavonoids that stood out in the results. Subjects who had high levels of both of these flavonoids in their diets were found to have a 21% lower risk of heart disease than those who consumed small amounts of the two.

Once uPON a protective gene

What do quercetin, oxidation, and genetics have in common?

We’ll start with a gene called PON1. This gene is going to help you live a long life because it helps protect against oxidation of LDL cholesterol. And as I’ve noted in many e-Alerts, the danger in cholesterol isn’t in the numbers, it’s in the oxidation.

Researchers at the Lipid Research Laboratory in the Veterans Affairs Medical Center in Washington, D.C., conducted a study to assess the effect of quercetin on PON1 and oxidation. After four weeks of giving a control group of rats regular feed, while giving another group the same feed with quercetin added, researchers posted these results:

  • Quercetin increased expression of PON1 by 35 percent
  • Quercetin increased PON1 activity in blood by nearly 30 percent
  • Quercetin increased PON1 activity in the liver by nearly 60 percent
  • LDL took three times as long to oxidize in the quercetin group

Quercetin is most abundant in red apples, red grapes, red wine, broccoli, onions, green tea, and citrus fruits. Broccoli and onions are the best sources of kaempferol.

Talk to your doctor before adding quercetin supplements to your daily regimen.

“Quercetin Up-Regulates Paraoxonase 1 Gene Expression with Concomitant Protection Against LDL Oxidation” Biochemical and Biophysical Research Communications, Published online ahead of print 1/12/09,