Vitamin D supplementation for prostate health Original paper

Vitamin D receptors are expressed in different types of cells, including prostate cells. Studies have identified an association between vitamin D deficiency and (i) benign prostatic hyperplasia (BPH) and (ii) BPH-related lower urinary tract symptoms.^[1][2] Does supplementation with vitamin D improve prostate health outcomes in older men?

In this 1-year randomized controlled trial, 57 men (average age of 64) with vitamin D deficiency (25(OH)D levels <20 ng/mL) were assigned to supplement with vitamin D or nothing (the control). In the vitamin D group, the participants received an initial intramuscular injection of 200,000 IU of vitamin D. After 3 months, the vitamin D group then supplemented with 25,000 IU of oral vitamin D every 2 weeks for 9 months.

The outcomes assessed were prostate volume, uroflowmetry maximal flow rate, postvoid residual urine volume, testosterone level, BPH symptoms, symptoms of hypogonadism (low testosterone), prostate specific antigen levels, and blood vitamin D levels.

Compared to baseline, prostate volume increased in the control group, whereas there was no change in the vitamin D group. On the other hand, compared to baseline, blood vitamin D levels increased (from 15.5 to 30.9 ng/mL), postvoid residual urine volume decreased (improved), psychological issues associated with hypogonadism improved, and BPH symptoms improved in the vitamin D group only.

When interpreting the results, it’s important to keep in mind that the participants were included solely on the basis of low blood vitamin D levels. On average, they had normal testosterone levels and mild symptoms of hypogonadism, and only 21% had BPH/lower urinary tract symptoms.

This study had a couple of limitations: (i) it did not compare differences between groups (only within each group compared to baseline), and (ii) the researchers did not adjust for multiple comparisons, despite the inclusion of numerous outcomes, which increases the risk of false-positive results.