http://www.lef.org/newsletter/2014/0429_Correcting-low-vitamin-D-levels-results-in-weight-loss-and-reduced-inflammation.htm Tuesday, April 29, 2014. The May 2014 issue of the American Journal of Clinical Nutrition published the results of a trial of vitamin D supplementation in women which found that correction of vitamin D insufficiency resulted in weight loss and a significant reduction in C-reactive protein (CRP), a marker of inflammation. The double-blinded trial included 218 overweight or obese postmenopausal women who had low serum 25-hydroxyvitamin D levels between 10 nanograms per milliliter (ng/mL) and 32 ng/mL. The women were assigned to a twelve-month reduced calorie diet along with 225 minutes per week aerobic activity, combined with a daily placebo or 2,000 international units (IU) vitamin D3. Body measurements and serum insulin, 25-hydroxyvitamin D3 and CRP were assessed before and after treatment. Women who received vitamin D3 had an average increase in serum 25-hydroxyvitamin D of 13.6 ng/mL, while those who received a placebo experienced a decline. Among those whose vitamin D3 became replete at a level of 32 ng/mL or more, weight loss averaged 8.5 kilograms (kg), while those whose levels failed to reach this amount lost an average of 5.6 kg. Vitamin D replete women also experienced a significantly greater reduction in insulin levels, waist circumference and body fat. Among women whose adherence to the vitamin D regimen was high, there was an average decline in C-reactive protein of 1.18 milligrams per liter (mg/L), while the placebo group experienced a reduction of 0.46 mg/L. The finding indicates a significant decrease in inflammation in association with vitamin D supplementation. "Our observation that women randomly assigned to vitamin D supplementation who became replete lost more weight and had greater improvements in body composition compared with women who did not become replete suggests a potential threshold effect and highlights the importance of considering changes in nutrient status rather than only the mean magnitude of change," write authors Caitlin Mason and her associates at Fred Hutchinson Cancer Research Center in Seattle. "Supplementation that does not alter nutrient status may be insufficient to detect an effect; thus, consistent with the argument recently put forward by Heaney, the nutrient response curve should be carefully considered when designing future clinical trials to test nutrient effects." "Careful consideration not only of the participants' baseline status but also of changes in vitamin D status resulting from a given intervention will help future studies continue to elucidate the role of vitamin D in weight loss and other outcomes," they conclude.