A recent Iranian paper confirmed that vitamin D is an effective antidepressant.
Sepehrmanesh Z, Kolahdooz F, Abedi F, Mazroii N, Assarian A, Asemi Z, Esmaillzadeh A. Vitamin D Supplementation Affects the Beck Depression Inventory, Insulin Resistance, and Biomarkers of Oxidative Stress in Patients with Major Depressive Disorder: A Randomized, Controlled Clinical Trial. J Nutr. 2015 Nov 25. pii: jn218883. [Epub ahead of print]
There has already been a meta-analysis of 7 randomized controlled trials that concluded vitamin D is an effective antidepressant, as effective as the medications marketed by the pharmaceutical companies.
However, this study was unique in that it had a depressed control group that remained deficient throughout the 8 week trial; researchers measured baseline and final vitamin D levels of patients with major depressive disorder to find that 25(OH)D levels increased by 20 ng/ml in the treatment group to a final level of 30 ng/ml. Unfortunately, they used weekly, not daily, vitamin D dosing.
The 40 patients who met the criteria for major depression were randomized to either placebo or 50,000 IU/week for 8 weeks. The Beck Depression Inventory (BDI) was used to measure depression. They also measured conditions not directly caused by depression such as serum insulin, insulin resistance, total plasma antioxidant capacity and serum glutathione (glutathione is the body’s master antioxidant).
Ultimately, 36 subjects completed the trial (18 in each group). Baseline 25(OH)D was 8 ng/ml in the treatment group and 13 ng/ml in the placebo group. At the end of the trial, after adjusting for baseline value, BMI and age, BDI scores were lower in the treatment group (P = 0.04), serum insulin was higher (P=0.03), insulin resistance was improved (P=0.03) and serum glutathione was higher (P=0.02).
One wonders whether the improvements would have been amplified if the baseline 25(OH)D levels of the placebo group was in the single digits (like the treatment group), if adequate daily doses (5,000 – 10,000 IU/day) were used and if final 25(OH)D levels were between 40 – 60 ng/ml.