Speaking of Vitamin D….

Last week's column focused on the link between levels of calcium and vitamin D and breast cancer. Interestingly, in this week's Archives of Internal Medicine (2007;167(11):1159-1165) there's a different look at the effects of inadequate vitamin D. Previous studies have suggested a link between low levels of vitamin D and the risk of high blood pressure and diabetes. In this study, the researchers looked at data from a large-scale study known as the Third National Health and Nutrition Examination Survey (NHANES), which was conducted between 1988 and 1994.

As part of the study, the participants had their blood pressure tested, their weight and height measured, and their blood tested for (among other things) levels of vitamin D. A diagnosis of diabetes was based on fasting blood sugar levels or through the participant reporting that their doctor had told them that they had diabetes.

For those 15,088 men and women over the age of 20 whose profiles included vitamin D levels, the scientists classified the relative levels of vitamin D into four groups. After correlating these levels with the participants' health status, they found that those with the lowest blood levels of vitamin D were more likely to also have various risk factors for heart disease, including obesity, diabetes, high blood pressure, and poor cholesterol scores.

What this means for you

This is an example of how elements of your diet or lifestyle can have wide implications. Low levels of Vitamin D have been directly linked to congestive heart failure, but it also plays indirect roles in the buildup of plaque in the bloodstream, the turnover of bone mass, and even high blood pressure. It also appears to have a role in the regulation of the immune system.

How to get more vitamin D in your diet? Other than foods that are specifically fortified with vitamin D, the single largest source of vitamin D in the human diet is sunshine. It's summer, so get outside! (Just be sure to wear your sunscreen.)

First posted: June 13, 2007