A grade of “D” for Vitamin D: supplements unlikely to help physical or mental health

The belief in vitamin D’s ability to improve mood and conditions such as depression might be false, according to a recent review by university doctors. Students currently using supplements of vitamin D to improve wellness might have to look for alternate solutions.

The review found that vitamin D did not improve mental wellbeing of people without diagnosed depression. In individuals with diagnosed depression, vitamin D had conflicting, poor-quality evidence of helping.

Besides depression, the review found that vitamin D did not help with respiratory infections, cancer, multiple sclerosis, and rheumatoid arthritis. It also found that people are not significantly helped or harmed by supplementing vitamin D into their diets and that regular testing for vitamin D deficiency is unnecessary.

Studies that support the benefits of vitamin D are observational and can only detect associations between taking vitamin D and health benefits, but do not have the scope to identify cause-effect relationships, Dr. Michael Allan, the review’s lead author, said.

Students who take vitamin D supplements may be taking them to improve depressive symptoms or increase their general mood, but this treatment is likely ineffective. There is better evidence that mental wellbeing, sleep quality, and mood can improve with physical activity, Dr. Allan, a professor in the Faculty of Medicine, said.

“The chances that someone between the ages of 20 and 50 is going to see any benefit from taking vitamin D regularly are very slim,” Dr. Allan said.

The review did find that vitamin D was slightly helpful in some cases — in individuals over age 50 who take vitamin D and calcium every day for a decade, roughly one in 50 fractures can be prevented. Vitamin D was also found to slightly reduce falls in the elderly and to reduce mortality.

Canadians often assume they don’t receive enough vitamin D, but most people in North America and Edmonton likely receive a healthy amount of vitamin D from their diets. The assumption that certain supplements carry health benefits isn’t exclusive to vitamin D — people usually take various vitamin supplements because they are associated with health. In reality, vitamins will only affect consumers’ wallets, Dr. Allan said.

“There’s a natural appeal to vitamins because they’re seen as harmless,” Dr. Allan said. “(If) we need them naturally maybe if we take a lot, we’ll be even better off. It’s a logic misstep.”

For non-pregnant adults under age 70, Health Canada’s recommended dietary allowance of vitamin D per day is 600 IU, with a tolerable upper intake is 4,000 IU. A typical vitamin D tablet of 2,000 IU gives more than three times what a person needs in a day.

The message for students, according to Dr. Allan, is to be active, eat well, and save money that would have been spent on vitamin D.

“What people really need to ask is, ‘Is this actually making me feel better?’” Dr. Allan said. “When we look at science where we randomize people, the research doesn’t seem to support (improved wellbeing) very well.”

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