Tuesday, February 07, 2012

Flavonoids: Gaining Evidence-Backed Reputation For Improving Health

Sue Hughes has a great rundown of flavonoids:
The Flap Over Flavonoids, TheHeart.org, 2 February 2012

Flavonoids are a class of polyphenolic compounds which occur naturally in plants. There are several types of flavonoids. Hughes included this list:
  • Anthocyanidins—In blueberries, red wine, and strawberries.
  • Flavan-3-ols—In apples, black tea, blueberries, chocolate, and red wine.
  • Flavanones—In citrus fruit and juices and herbal tea.
  • Flavones—In celery, garlic, green peppers, and herbal tea.
  • Flavonols—In blueberries, garlic, kale, onions, spinach, tea, broccoli, red wine, and cherry tomatoes.
  • Proanthocyanidins—In apples, black tea, blueberries, chocolate, mixed nuts, peanuts, red wine, strawberries, and walnuts.
  • Isoflavones—In soy products and peanuts.
Flavonoids are gaining an evidence-backed reputation for improving health. They've been associated with lower risks for hypertension, heart attack and stroke. And you don't have to indulge:
"Many of the associations observed were nonlinear, with low risks seen at even modest intakes, suggesting that consumption of even relatively small amounts of flavonoid-rich foods may be beneficial for reducing risk of cardiovascular death."
Dr. Marjorie McCullough, author of this recent study that found fewer deaths from heart disease in those eating the most flavonoids:
Flavonoid Intake And Cardiovascular Disease Mortality In A Prospective Cohort Of US Adults, American Journal of Clinical Nutrition, February 2012

"This complements what we already know to some extent in that most of these foods fall under the category of healthy foods already . . . fruits and vegetables. But flavonoids are not just in fruits and vegetables. They are in nuts and seeds, tea, cocoa, and red wine."

"Yes, I think we can say that we should increase our consumption of these flavonoid-rich foods."
Some other points Hughes made:

Supplements aren't there yet: McCullough: "We don't know for sure which ones are the best, and we might need some of the other ingredients in the foods, too. It's much better to get these compounds from the diet."

Mix it up: "If you always eat an apple every day, try berries or other type of fruits instead. Try new vegetables—kale or broccoli—and introduce more nuts into your diet."

Other parts of the body may benefit: "There is also some suggestion of positive effects on the brain and cancer and other mechanisms beyond vascular."

Supplements lack the synergistic effect: In investigating red wine, Dr. Ramon Estruch said, "We believe it is all the polyphenols together that have the effect. It is not just one. There are maybe 1000 different ones in red wine that seem to have synergistic effect when taken together. ... So drinking red wine will be better than taking a pill, as you can't reproduce exactly what is in the wine."

It goes beyond chocolate and wine: Studies often highlight benefits from red wine or chocolate or tea. But that's because those were what had been studied most, not because other foods lack beneficial flavonoids. And they were studied most because there was flavonoid data on those foods. That's changing.

The best little item to come out of this article is the French and Canadian collaboration: The Phenol Explorer, which lists the polyphenolic content in over 400 foods ... in excruciating detail:

Beer? Coffee? Beans? It's in there.
Photo of oolong tea from Serious Eats.


Dr. Mel said...

There's a new type of tomato, called "Indigo Rose," which has anthocyanidins in the fruits, esp. in the side of the fruit toward the sun, which turns a dark blue. I've seen seeds and/or plants available from Johnny's Seeds in Maine and Territorial Seeds in Oregon. Here's a link to Johnny's: http://www.johnnyseeds.com/p-8711-indigo-rose-og.aspx

Dr. Mel said...

Fascinating--and cheering--post, btw!