Prevention of Supplement-D Deficit
step 3 (25[OH]D3) in animal studies 4,24 and of vitamin D–deficient individuals in human studies. 25,26 In a clinical trial 25 in which middle-aged men and women (n = 15) were placed on a low-boron diet, which was also marginal in magnesium and copper status, for 63 days (0.23 mg B/2000 kcal), 25(OH)D3 rose significantly after boron supplementation (3 mg/d as sodium borate) for an additional 49 days. Levels of 25(OH)D3 rose from an average of 44.9 nM after the 63 days of boron deprivation to 62.4 nM after the 49 days of boron repletion, a 39% increase.
Similar results were seen in an open pilot study of middle-aged individuals (n = 13) predetermined to be vitamin D deficient (serum 25[OH]D3 26 The study took place in Serbia with supplementation beginning in October and concluding by January; in other words, the study occurred during the fall transition to winter, a time when vitamin-D status would be expected to worsen. Yet, with boron supplementation, 25(OH)D3 levels rose significantly, with an average rise of 20%. 27
How does boron exert its hormonal effects? In sum, boron increases the biological half-life and bioavailability of E2 and vitamin D.