Middle-age men who drink just a glass or two of milk every day are raising their risk of developing Parkinson's disease later in life, reports The BBC News of research from the University of Virginia Health System in Charlottesville and Korea University in Seoul.
It's not known what ingredient in milk is responsible for the increased risk, but the researchers say it does not appear to be calcium. It's possible that the effect is caused by a contaminant in milk. Previous research has shown that milk does not pose the same risk for women.
The study of 7,504 men ages 45 to 68 who were enrolled in the Honolulu Heart Program examined dietary intake over a 30-year period beginning in the late 1960s. Of these men, 128 developed Parkinson's disease. Those who consumed the most milk daily had the highest risk of developing the disease, which was about 2.3 times the risk of the men who did not drink milk.
It's very important to note that even among the heavy milk drinkers, the risk of developing Parkinson's is still very small, about 14.9 cases per 10,000 people who drink more than 16 ounces of milk a day.
Parkinson's disease, a degenerative disease of the nervous system, causes a noticeable trembling of the arms and legs, stiffness and rigidity of the muscles and slowness of movement. It typically affects people who are 50 and older, although 10 percent to 20 percent of patients are diagnosed before their 40th birthday. Perhaps the most famous Parkinson's patient is actor Michael J. Fox, who was diagnosed at age 30. The cause is not known, but those with the disease have a shortage of a dopamine in their brains, a chemical that affects movement.
The study findings were published in the medical journal Neurology.