Obesity: Vitamin D as an Aid Against Inflammation

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

This is reported by 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 and protective response of the body to injury. Chronic inflammation, lasting longer, is caused by overexpression or lack of regulation of normal protective mechanisms. The link between inflammation and chronic diseases has been confirmed by the identification of typical inflammatory molecules, including C-reactive protein, which seems to increase the risk of coronary diseases. Vitamin D exists in two forms: D2 or ergocalciferol, and D3 or cholecalciferol, and plays many roles beyond its well-known function in bone metabolism regulation. Vitamin D receptors have been identified in more than 30 cell types, including adipose cells. Vitamin D deficiency also appears to be associated with obesity, as well as worsening of conditions such as muscle weakness, fractures, autoimmune diseases, and certain types of cancer and diabetes.

CRP Decreases in Patients Taking Vitamin D

The study was conducted on 218 overweight or obese women aged between 50 and 75 years, undergoing weight loss through a dietary regimen. Some took a daily dose of 50 micrograms of vitamin D3 for one year, while others received a placebo. Analysis results after treatment showed no difference between the two groups regarding weight loss, hip circumference, and body fat percentage, despite previous studies. However, CRP was reduced by 46% in women who correctly and consistently took the supplement, and only by 25% in those who received the placebo.

A Trial That Requires Further Studies

Vitamin D3 supplementation during weight loss does not seem to affect the course of the latter but can bring benefits compared to placebo by reducing the marker of inflammation. However, in this study, some participants did not adhere correctly to the therapy, weakening the reliability of the results. Future studies testing vitamin D’s effects should optimize and promote adherence to experimental instructions. Administration should be weekly, subjects should keep a diary, be contacted by phone, 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