The blind randomized study, published in the online publication Nutrition Journal (2004, vol. 3, no. 8), investigated the effects of low and high doses of vitamin D on biochemical responses and sense of wellbeing. Researchers from the University of Toronto and Mount Sinai Hospital, in Canada, administered daily a low dose of 15 micrograms of vitamin D or a high dose of 100 micrograms of vitamin D, to 65 outpatients with low vitamin D levels participating in study 1, from December 2001 through November 2002. In study 2, 66 outpatients with low vitamin D levels were given either the low or high doses of vitamin D, from December 2002 to February 2003. In study 1, 37 participants completed a wellbeing questionnaire in December 2001 and February 2002, and in study 2, 51 participants completed a wellbeing questionnaire in December 2002 and February 2003. The researchers analyzed the participants’ blood for serum vitamin D, parathyroid hormone and calcium levels.
The researchers found that vitamin D supplementation significantly raised vitamin D levels in both studies, although it was elevated higher in the participants that received the higher vitamin D dose. In addition, Vitamin D supplementation lowered parathyroid hormone but did not affect calcium levels. Findings also revealed that wellbeing was improved more in those participants who received the higher vitamin D dose in study 1, compared to those who received the lower dose. In study 2, winter wellbeing was improved with both doses of vitamin D.
“This work confirms the safety and efficacy of both 15 and 100mcg/day vitamin D3 in patients who needed additional vitamin D,” the study authors conclude.
REFERENCES:
1. Vieth R et al. Randomized comparison of the effects of the vitamin D3 adequate intake versus 100 mcg (4000 IU) per day on biochemical responses and the wellbeing of patients. Nutrition Journal 2004, 3:8 doi:10.1186/1475-289 1-3-8.
Online: http://www.nutritionj.com/content/3/1/8
