Obesity: vitamin D an aid against inflammation

In obese or overweight women, daily vitamin D intake is associated with a reduction in C-reactive protein (CRP), a signal molecule of chronic inflammation. However, this effect is evident only if the vitamin is taken in supplement form. 

This was reported in a study published in the American Journal of Clinical Nutrition and conducted by researchers at the School of Public Health in Seattle, USA.

Vitamin D and inflammation

Inflammation is a natural,protective reaction of the body in response to injury. Chronic one,of longer duration, is due to over-expression or lack of regulation of normal protective mechanisms. The link between inflammation and chronic disease has been confirmed by the identification of typical inflammatory molecules, among them the C-reactive protein that appears to increase the risk of coronary artery disease. Vitamin D exists in two forms: D2 or ergocalciferol, and D3 or cholecalciferol; it plays many roles besides the well-known role of regulating bone metabolism. Receptors that bind the vitamin have been identified in more than 30 types of cells, including fat cells. Vitamin D deficiency also appears to be associated with obesity, as well as exacerbating conditions such as muscle weakness, fractures, autoimmune diseases, and some cancers and diabetes.

CRP decreases in patients taking vitamin D

The study was conducted on 218 overweight or obese women, aged 50 to 75 years, undergoing weight loss through a dietary regimen. One part of them took a daily dose of 50 micrograms of vitamin D3 for one year, another part a placebo. The results of the analysis after the treatment showed that there was no difference between the two groups regarding weight loss, hip circumference and body fat percentage, in spite of previous studies. Instead, CRP was reduced by 46 percent in the women who had taken the supplement correctly and consistently and only 25 percent in those who had received the placebo.

A trial to be deepened with further studies

Supplementation with vitamin D3 in the weight loss phase does not seem to affect the progress of weight loss, but it is able to provide benefits compared with placebo and reduce the signal molecule of inflammation. In this study, however, a portion of the participants did not adhere correctly to the therapy, decreasing the robustness of the observed results. Future studies to test the action of vitamin D should optimize and promote subjects' adherence to the experimental indications. Intakes should be weekly, subjects should fill out a diary, be contacted by telephone, and monitored with more frequent visits.

Source: Caitlin Mason, Liren Xiao, Ikuyo Imayama, Catherine Duggan, Ching-Yun Wang, Larissa Korde, and Anne McTiernan "Vitamin _D3 supplementation during weight loss: a double-blind randomized controlled trial" March 12, 2014, doi: 10.3945/ajcn.113.073734 Am J Clin Nutr May 2014ajcn.073734