Written by Patrick Massey, M.D., Ph.D. Research from Germany suggests that not only could vitamin D levels predict risk of fatal stroke but that supplementation could prevent stroke.

Can vitamin D prevent stroke and death? A German study shows low vitamin D levels may be associated with a significantly increased risk of stroke-related death.

A stroke happens when the brain cells do not get enough blood. The most common type – an ischemic stroke – occurs when an artery in the brain is blocked by a blood clot. Almost 90 percent of strokes are ischemic. In contrast, hemorrhagic strokes occur when an artery in the brain ruptures.

According to the American Heart Association, about 500,000 people have a new stroke each year. Strokes are the leading cause of long-term disability and the third leading cause of death in the U.S.

Risk factors for stroke include high blood pressure, cardiac disease, a sedentary lifestyle and smoking. Low vitamin D levels may also be a risk factor, but more importantly, may forecast a fatal stroke.

Recent medical research from the Synlab Center of Laboratory Diagnostics in Heidelberg, Germany, concluded people with low vitamin D levels are at increased risk of dying from a stroke when compared to people with higher levels of vitamin D.

For the study, vitamin D levels were measured in more than 6,000 people. The participants were then followed for seven to eight years. During that time, 769 participants died, 42 from strokes. The majority of those who died from stroke were in the group with the lowest vitamin D levels.

The research suggests that not only could vitamin D levels predict risk of fatal stroke but that supplementation could prevent stroke. This is an important clinical finding because the risk of stroke increases with age and very low vitamin D levels are common in the elderly, especially those living in nursing homes.

There is ample clinical research suggesting that vitamin D is important for bone health, reducing cardiovascular disease, preventing cancer and even curtailing the risk of dementia. However, there is scant evidence proving vitamin D will truly prevent disease and it will be decades – or longer – before definitive studies are done.

I am not sure I want to wait that long. Overall, the health benefits of vitamin D are impressive, and toxicity, even with robust doses, is vanishingly rare. I’ll take the chance and add a healthy dose of vitamin D to my daily vitamins.

Although our bodies can make vitamin D with sun exposure, in sun-starved northern latitudes like Chicago, the sun is not strong enough for most of the year.

Good dietary sources of vitamin D are cod liver oil, sardines and a number of other fish. However, most Americans do not eat enough fish to get a healthy dose of vitamin D, and fortified foods like milk and cereal simply do not provide enough of this important vitamin.

Therefore, vitamin D supplements may be the best option.

Posted November 19, 2008.