Fruits and vegetables contain many nutrients and minerals that play an important role in helping us maintain good health. Take flavonoids, for example. These are a group of natural compounds found in many foods, including citrus fruits, berries, red wine, and even dark chocolate.
Flavonoids act as antioxidants, helping to prevent or delay cell damage that can lead to diseases, such as cancer. They also reduce inflammation in the body, which is common in many chronic diseases, including neurodegenerative ones such as Alzheimer’s or Parkinson’s disease.
Research shows that flavonoids are good for our brain healthwith studies showing that diets rich in fruits and vegetables can slow cognitive decline Y lower risk of dementia. And now, a recent study has suggested that people with Parkinson’s disease who eat diets rich in flavonoids can live longer than those who don’t.
To conduct their study, a team of researchers analyzed data from 121,700 registered nurses and 51,529 male health professionals. They chose to look at these two groups because many aspects of their lifestyles that could influence their disease risk would be similar, such as activity levels, education, and years of employment. Information on their diets has been collected every two to four years, beginning in 1975 for women and 1986 for men. Data from these groups have been used in many other high quality nutrition studies.
At the time this new study was conducted, 599 of the women and 652 of the men had been diagnosed with Parkinson’s disease. From the foods these women and men reported consuming, it was possible to calculate their flavonoid intake.
Men with Parkinson’s disease who consumed the most flavonoids as part of their diet were found to have a 47% lower risk of dying from any cause compared to men who consumed the fewest flavonoids in their diet. But for women, the amount of flavonoids they consumed in their diet had no effect on the risk of death from all causes. So the tentative conclusion of this study is that flavonoids may reduce the risk of death in men with Parkinson’s disease, although not in women. It is currently not known why men saw a greater benefit.
Cherry picking?
As with any such observational nutrition study, where the researchers simply observe the results without trying to intervene in the group (such as having half the group eat a specific diet), it is not possible to prove a causal link. In the case of the current study, a causal link would mean that eating more flavonoids directly reduces the risk of death in men with Parkinson’s disease.
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A main reason for not being able to prove causality is that other dietary and lifestyle factors may also have contributed to the extended lifespan. The authors compensated for this to some extent by making statistical adjustments for other potentially beneficial nutrients, such as beta-carotene and the antioxidant vitamins C and E, and for potentially harmful lifestyle factors, such as smoking, being overweight, and not getting enough exercise.
But this still does not take into account many other dietary, Lifestyle Y genetic factors that could contribute to a person’s risk. An example is exposure to herbicides and pesticides.
One factor that influenced the study results was the type of flavonoids they looked at. There are many different types of flavonoids, and in this study two groups, known as anthocyanins and flavan-3-ols, were found to be most strongly associated with life extension. Anthocyanins give berries and red wine their red and purple colors, and flavan-3-ols are found in high levels in green tea.
But it is not known how these flavonoids may benefit the brain. As with other degenerative brain disorders, the progression of Parkinson’s disease is likely to involve oxidative stress (when too many highly reactive molecules, called free radicals, are produced for antioxidant defenses to handle) and brain swelling. Many flavonoids, including anthocyanins and flavan-3-ols, have been shown in experimental studies have antioxidant and anti-inflammatory properties.
Other mechanisms may also be involved. Flavonoids may have a positive effect on the gut microbiome, which may decrease inflammation that contributes to Parkinson’s. Also, as Parkinson’s disease progresses, many neurological pathways as the dopamine pathway are affected. Dopamine plays a vital role in regulating the movement of the body. But the possible role of flavonoids in improving the functioning of these pathways is unknown.
Although this study examined the risk of death in people who already had Parkinson’s disease, other studies have also shown that flavonoid-rich diets reduce the risk of developing Parkinson’s disease. The benefit was also shown to be greater in men, although again it is not clear why.
While there are many factors that could have influenced the results of this latest study, there is still a good body of evidence suggesting that diets rich in flavonoids may help protect against many degenerative brain disorders – including Parkinson’s disease. And fortunately for us, flavonoids are found in many fruits and vegetables that we can easily buy in our supermarket.
