Sunlight provides a valuable, although potentially harmful, source of vitamin D. It also may affect the way the body processes medication. Research performed at the Karolinska Institutet in Sweden has determined that the amount of sunlight a person gets may be directly related to levels of drugs in the blood.

The study, published in the journal Drug Metabolism and Disposition, noted that the uptake of tacrolimus and sirolimus, two drugs used to prevent the rejection of donated organs, varies depending on the time of year.

These results were derived from the medical information of more than 70,000 hospital patients. Researchers theorized that the effect may be due to levels for vitamin D in the blood, since the nutrient activates an enzyme in the liver responsible for the breakdown of foreign compounds.

Health authorities had already established the role that vitamin D plays in liver health. The team concluded that further investigation may be warranted into the interplay between vitamin D and good health.

Most healthcare experts do not recommend excess sun exposure. Instead, individuals who want to ensure that they have adequate levels of the nutrient all year round may take .