Our bodies need vitamin D. Research has linked a deficiency of this vitamin to increased risk of heart disease, diabetes, dementia, cancer, and osteoporosis. Unfortunately, it’s hard to get enough vitamin D from its two main sources: sunlight and fortified foods. That’s why it’s among the few supplements most doctors recommend.
Here’s even more reason to get your daily dose: According to a new Finnish study of more than 2,600 middle-aged men, those with the lowest vitamin D levels were 113 times more likely to suffer chronic headaches. Bolstering the connection, headaches were more frequent from October to May, when Finland’s total sunlight is very low and deficiency is even more widespread.
“The link was quite strong and didn’t change much after we took into account several other factors that might explain it,” says lead researcher Jyrki Virtanen. For example, his team controlled for drinking and smoking habits, physical activity, medications, and blood pressure, all of which could influence head pain. “It seems that the association was specific to low serum vitamin D levels,” he adds. The men in the lowest group had about 11 nanograms of vitamin D per milliliter of blood; anything below 20 ng/mL is considered insufficient for good health.
One possible reason for the headache–low vitamin D connection involves inflammation. As the researchers state in their paper, vitamin D suppresses certain inflammatory compounds while enhancing expression of anti-inflammatory genes. So in theory, with enough vitamin D in your system, your body may be better able to stamp out pain-inducing inflammation. “Also, there are vitamin D receptors in the sensory neurons involved in pain, so [being deficient] may have some direct effects on these neurons,” Virtanen says.
To prompt your body to generate all the vitamin D it needs, you’d have to stand under direct sunlight for 10 to 30 minutes a day with most of your skin showing and not slathered with sunscreen. Since that rarely happens, even during summer, experts say most American men are lacking vitamin D. The nutrient doesn’t occur naturally in very many foods, and even cereal, milk, eggs, and other commonly fortified products often don’t supply enough. If you suspect your levels are low, ask your doctor for a vitamin D test and consider a daily supplement that supplies at least 2,000 IU. Some experts suggest 5,000 IU or more.