Vitamin D is a hormone with effects not only on the skeleton, but on most tissues in the body. Lack of vitamin D is associated with coronary heart disease, cancer and immunological diseases, and also with obesity, hypertension and glucose intolerance. However, to see the full effect of vitamin D, one should not only look at single diseases or risk factors, but have a global approach using a combined clinical index. A similar line of thinking can be applied to genetic, proteomic and metabolomic studies on vitamin D. Thus, in the present study 50 subjects will be included and randomized to vitamin D 40.000 IU per week versus placebo for 2 months. Blood and adipose tissue samples will be collected before and after the intervention and analyzed for gene expression. Based on these results the investigators will proceed with the relevant proteomic and metabolomic profile analyses. If successful, this may reveal new aspects of vitamin D's physiology and metabolic effects.