Vitamin D Important for Brain Function, and Often Deficient
Vitamin D plays an important role in many brain functions, including synapse creation, calcium signaling, reduction of free radicals, neurotransmitter production, immune regulation, and brain development. Deficiencies in vitamin D have been linked to depression and schizophrenia. Some research has suggested that vitamin D supplementation can improve depressive symptoms, but there is still debate about a possible role for vitamin D in treating bipolar disorder.
At the 2014 meeting of the International Society for Bipolar Disorders, researcher Baseok Cha discussed the importance of vitamin D supplementation in bipolar patients, who often have deficient or insufficient levels. People receive 50 to 90% of their vitamin D from sunlight, and the rest from diet and supplements. Too much sunscreen can be a problem if it prevents a person from receiving enough vitamin D from sunlight.
The type of vitamin in supplements, D3, is converted to 25 hydroxy vitamin D in the liver, and then to 1,25 hydroxy vitamin D in the kidney. Levels of 25 hydroxy vitamin D below 20 indicate deficiency while levels between 20 and 29 indicate insufficiency. Low levels of 25 hydroxy vitamin D3 in newborns is a risk factor for schizophrenia, and vitamin D supplementation reduces this risk. Fish oils increase vitamin D, and it is possible that some of the therapeutic effects of omega-3 fatty acids in depression relate to vitamin D.
Two out of four recent studies of vitamin D supplementation have been positive, the last by Khoraminya et al. in the Australia and New Zealand Journal of Psychiatry in 2013, in which daily doses of 1,500 IU were used. Cha et al. found significantly lower levels of 25 hydroxy vitamin D in a Korean study of 21 patients with schizophrenia, 86 patients with bipolar disorder, and 42 patients with depression (mean levels about 15 µg/ml) compared to 31 controls (mean levels about 20 µg/ml).
