Vitamin D supplements 'do not reduce depression'

Past studies have suggested that vitamin D deficiency may lead to depression. In response, other studies propose that increasing vitamin D levels with supplements may reduce depressive symptoms. But new research, published in the journal Psychosomatic Medicine, has found no evidence that vitamin D supplements reduce depression.

The research team, led by Dr. Jonathan A. Schaffer of the Columbia University Medical Center (CUMC) in New York, NY, conducted a systematic review of clinical trials that looked at how vitamin D supplementation affected depression.

The team identified seven trials involving 3,191 participants that looked at the effects of vitamin D supplementation against depression and compared this with no vitamin D supplementation.

The investigators say that almost all trials were "characterized by methodological limitations" and only two studies included participants who had clinical depression at study baseline.

The researchers found that vitamin D supplementation itself had no overall impact on depression.

However, further investigation revealed that for patients with clinical depression, particularly those who were taking standard antidepressant medication, vitamin D supplementation may help reduce depressive symptoms.

But Dr. Schaffer says that before this association can be confirmed, new trials that monitor the effects of vitamin D supplements in these patients need to be conducted.

For now, the researchers say vitamin D supplementation may only be beneficial for individuals with vitamin D deficiency.

Dr. Schaffer adds:

"Although tempting, adding vitamin D supplements to the armamentarium of remedies for depression appears premature based on the evidence available at this time."

He hopes that this research will encourage other investigators to create new trials that will determine whether vitamin D supplements can help reduce depression once and for all.

Vitamin D supplements: to take or not to take?

As well as hailing vitamin D supplements for their potential to reduce depression, past research has suggested they can improve breast cancer survival rates, as well as reduce the risk of heart attack, stroke and cancer.