Frequently consuming dairy foods, in particular low-fat milk, is associated with a modest increased risk of developing Parkinson’s disease (PD), according to a new study published in the June 7 online edition of Neurology. However, the results do not demonstrate that dairy products cause Parkinson’s, and the risk of developing the disease for anyone remains low. More research is needed before recommendations can be made about dairy consumption.
Earlier studies have suggested an association between dairy products and increased Parkinson’s risk. But researchers have not been able to discern whether certain dairy foods, or nutrients within them, are responsible for this link. One previous study pointed to the role of pesticide residues in milk. Also, it has not been clear whether the association holds for both women and men.
To help resolve these issues, researchers led by Katherine C. Hughes, Sc.D., at the Harvard T.H. Chan School of Public Health in Boston, MA, investigated the relationship between dairy consumption and Parkinson’s by analyzing data from two studies in which nurses (all women) and health professionals (all men) regularly answered questions about diet and other aspects of health over a period of up to 26 years. The study authors also used a statistical technique called meta-analysis to combine this data with results from four other studies of milk and dairy consumption, and Parkinson’s.
- Among nearly 130,000 men and women who participated, 1,036 participants developed PD over the course of two decades.
- As compared to people who didn’t consume dairy, people who consumed at least three servings of low-fat dairy a day had a 34 percent increased risk of developing Parkinson’s.
- Among types of low-fat dairy, skim and low-fat milk were most associated with risk for Parkinson’s.
- Results were similar in women and men.
- Combining data from several studies, the researchers found that frequent consumption of all types of dairy products appears to be associated with a modest increased risk of Parkinson’s.
What Does It Mean?
This study is the largest analysis of dairy and Parkinson’s to date. At this point, however, no recommendation can be made. In fact, there could be a cost to cutting dairy — milk, yogurt, cheese and other items contain calcium for bone strength, as well as vitamin D and many other beneficial vitamins and minerals.
The study authors call for future research to discover a mechanism for the findings. For example, one possible explanation is that drinking milk reduces a person’s blood levels of urate, a substance that may be protective against PD.