If your weight goes up you may need more vitamin D.

Low vitamin D levels are commonly found with obesity. The first study reviewed here investigated the effect of weight loss through diet and exercise on serum levels of vitamin D (Mason, et al. 2011). Vitamin D concentration was measured at the start of the study and 12 months later. The results showed that greater weight loss was associated with increased vitamin D. As weight loss increased vitamin D levels increased. The next study reviewed evaluated vitamin D levels in normal weight, overweight and obese cancer patients (Vashi PG, et al. 2011). The participants were both females and males with different kinds of cancer. The conclusion of the research was that obese cancer patients had significantly lower levels of serum vitamin D when compared with the other groups. If your body mass index is on the high side you need to supplement with more vitamin D, but what is interesting is that your vitamin D level would increase somewhat just by losing some weight.

Mason C, Xiao L, Imayama I, Duggan CR, Bain C, Foster-Schubert KE, Kong A, Campbell KL, Wang CY, Neuhouser ML, Li L, Jeffery RW, Robien K, Alfano CM, Blackburn GL, McTiernan A. Effects of weight loss on serum vitamin D in postmenopausal women. Am J Clin Nutr. 2011 May 25.

Vashi PG, Lammersfeld CA, Braun DP, Gupta D. Serum 25-hydroxyvitamin D is inversely associated with body mass index in cancer. Nutr J. 2011 May 16;10(1):51.