Flavonoids are good for us. I found this out when I saw a recent study showing that people who eat a lot of fruit -- particularly berries such as blueberries, raspberries, strawberries -- have a lower risk of developing Parkinson's disease, a malady that most often develops after age 50. (The wife of a friend of mine just got diagnosed, so I've become more aware of the problem.)
In Parkinson's, the nerve cells in the brain that make a chemical called dopamine are slowly destroyed. Without dopamine, nerve cells cannot send messages, leading to a loss of muscle function. Symptoms include tremor or shaking, impaired balance and walking, rigid or stiff muscles, and eventually cognitive problems.
The secret ingredient in fruit is ... flavonoids. That's why I'm talking about them. They are organic chemicals found in plants that inhibit the oxidation of molecules that can ultimately damage cells. I was a poor chemistry student, so I will not try to explain the chemical qualities of flavonoids -- suffice it to say they are the ingredient that gives plants and fruits their vibrant colors, and play a role in protecting plants from insect attacks as well.
The Parkinson's study evaluated some 80,000 women and 50,000 men, reporting on the relationship between the consumption of flavonoids and the onset of Parkinson's. A little over 800 of the people studied came down with Parkinson's. Men who ate more fruit -- berries, apples, oranges -- were 40 percent less likely to develop Parkinson's disease. For women in the study, there was no benefit in consuming non-berry fruits. But scientists found that the subclasses of flavonoids in berries did seem to protect women against the disease.
Study author Xiang Gao of the Harvard School of Public Health concluded that a diet "high in fruits and vegetables could be protective against Parkinson's disease risk."
What else can flavonoids do for us?
There's some evidence they protect against other neurodegenerative diseases such as Alzheimer's and dementia. One Dutch study found that the risk of contracting Alzheimer’s disease among smokers decreased as daily flavonoid intake increased. A study of the elderly in France found that people with the highest flavonoid intake had a 50-percent lower risk of developing dementia than those with the lowest intake. Another study of 1,640 elderly men and women found that those who consumed a lot of flavonoids had better cognitive performance in general, and experienced significantly less age-related decline over a ten-year period than those who ate fewer flavonoids.
Some (not all) studies have shown that high flavonoid intake is associated with reductions in coronary heart disease. Foods that seem to have the most impact are black tea, apples, onions and, in one study, cocoa.
There is "less than convincing evidence" that consumption of flavonoids is associated with lower incidence of cancer. However, several European studies suggested that a high intake of flavonoids, especially tea, was associated with lower rectal cancer in women. And a high intake of flavonoids, especially apples, seemed to lower the risk of lung cancer in men.
Common dietary sources of flavonoids include both black and green tea, dark chocolate, red wine, and many fruits, vegetables and legumes, particularly apricots, apples and all kinds of berries. And perhaps best of all, no adverse effects have been associated with high dietary intakes of flavonoids from plant-based foods.
So I don't know about you, but you know what they say -- an apple a day ...