Vitamin D2 dangerous while D3 saves lives

Posted on Sun, 1 Jan 12

A large meta-analysis has contrasted the health effects of Vitamin D2 supplements against D3 with an important discovery. Vitamin D2 may be doing more harm than good.

The analysis included 50 randomised trials with 94,148 participants that compared various forms of vitamin D at any dose and duration versus placebo or no intervention. The included studies also reported mortality rates as either primary or secondary outcomes.

Of all the studies in the final analysis 32 used D3 (some 74,000 subjects) and 12 of them used D2 (some 18,000 subjects). It was discovered that supplementing with vitamin D3 resulted in a 6% relative risk reduction in mortality while in contrast vitamin D2 increased risk by 2%. 

The Bottom Line: take D3, not D2

This important finding suggests that vitamin D3 (cholecalciferol) should be the preferred source of vitamin D supplementation. Your body naturally produces vitamin D3 when your skin is exposed to sunlight; vitamin D2 on the other hand is made by irradiating fungus and plant matter.

In many countries vitamin D2 is sold on prescription, while vitamin D3 is available as a dietary supplement. Health authorities need to rethink vitamin D prescriptions.

References:

1. Bjelakovic G, Gluud LL, Nikolova D, Whitfield K, Wetterslev J, Simonetti RG, Bjelakovic M, Gluud C. Vitamin D supplementation for prevention of mortality in adults. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD007470.

2. Murff HJ. Review: cholecalciferol (vitamin D3) reduces mortality in adults; other forms of vitamin D do not. Ann Intern Med. 2011 Nov 15;155(10):JC5-04.