Vitamin D advice must weigh benefits, risks
Because exposure to ultraviolet light is one pathway for generating vitamin D, the question arises whether a recommendation for vitamin D supplementation should accompany advice about sun avoidance.
Guidance for counseling patients on this issue may follow the concept of “everything in moderation”, Martin A. Weinstock, M.D., Ph.D., told colleagues recently at the 74th Annual meeting of the American Academy of Dermatology in Washington D.C.
“There has been a lot of publicity in the lay press about the harms associated with not getting enough vitamin D, but there are also risks of getting too much,” says Dr. Weinstock, professor, department of dermatology, Brown University, Providence, R.I.
Adequate levels of vitamin D are important for maintaining musculoskeletal health. There have also been studies linking low levels of vitamin D to a variety of diseases, including cancer, cardiovascular disease, autoimmune disease, and infection, although that work is controversial and does not necessarily imply a causal relationship for vitamin D.
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On the other hand, it is well-documented based on outcomes of randomized controlled trials that ingestion of mega doses of vitamin D may adversely affect musculoskeletal health and the kidneys. Some data also suggest excessive vitamin D supplementation increases risks of overall mortality, cancer, and cardiovascular disease, although the evidence on those associations is not definitive, Dr. Weinstock says.