THURSDAY, May 24, 2012 (HealthDay News) -- Japanese-American men who don't eat a diet rich in vitamin D have an increased risk of stroke later in life, according to a new, long-term study.
The study included nearly 7,400 Japanese-American men living in Hawaii. They were between the ages of 45 and 68 in the mid- to late-1960s, when they were first examined and interviewed about their eating habits.
During 34 years of follow-up, 960 of the men suffered strokes. Compared to those with the highest levels of vitamin D in their diet, men who took in the least dietary vitamin D had a 22 percent higher risk of stroke and a 27 percent higher risk of ischemic (blood-clot-related) stroke. No difference existed for hemorrhagic (bleeding) stroke, however.
The study appeared May 24 in the journal Stroke.
"Our study confirms that eating foods rich in vitamin D might be beneficial for stroke prevention," study author Dr. Gotaro Kojima, a geriatric medicine fellow at the John A. Burns School of Medicine at the University of Hawaii in Honolulu, said in a journal news release.
Kojima said, however, it's unclear whether the study findings could be applied to women or to different ethnic groups.
Sunlight generally is the primary source of vitamin D, but synthesizing vitamin D from the sun becomes more difficult as people age, Kojima said, meaning older people need to eat more foods rich in vitamin D or take supplements. Fortified milk, breakfast cereals, fatty fish and egg yolks all are good sources of vitamin D.
The U.S. Office of Dietary Supplements has more about vitamin D.