Weight loss combined with vitamin D supplementation has a greater effect on reducing chronic inflammation than weight loss alone in postmenopausal women, according to research in Cancer Prevention Research.
In a prospective, double blind analysis of a broad set of inflammatory markers during a 1-year period, researchers found that participants who lost 5% to 10% of their body weight and took vitamin D supplements saw the greatest reduction in interleukin-6 when compared with women assigned a weight-loss regimen and placebo.
“Weight loss has a significant impact on levels of inflammatory biomarkers,” Catherine Duggan, PhD, director of collaborative data services at Fred Hutchinson Cancer Research Center in Seattle, told Endocrine Today. “This study demonstrates that vitamin D supplementation appears to have an effect on levels of IL-6 over and above that of weight loss alone.”
Duggan and colleagues analyzed data from 218 postmenopausal women with overweight or obesity aged 50 to 75 years and levels of serum 25-hydroxyvitamin D between 10 ng/mL and 32 ng/mL (mean age, 59.6 years; mean BMI, 32.4 kg/m²; 86.2% white). Researchers randomly assigned 109 women to 12 months of 2,000 IU per day of vitamin D supplementation plus a lifestyle-based weight-loss program with a goal of 10% weight loss; 109 women in the control arm were randomly assigned a daily placebo and the same lifestyle-based weight-loss program.
Researchers measured serum levels of tumor necrosis factor-alpha (TNF-a), IL-6, IL-1 beta, IL-8 and IL-10, as well as BMI and total body and trunk fat measured by DXA. Researchers stratified mean changes in serum levels by study arm; participants also were stratified by degree of weight loss (< 5%; 5% to 10%; and > 10% of baseline weight lost) and compared with participants who gained weight or experienced no change in weight.
Researchers found that participants in the vitamin D arm who lost 5% to 10% of their baseline body weight reduced IL-6 levels by 37.3%; participants who experienced weight loss in the placebo arm reduced IL-6 levels by 17.2% (P = .004). Researchers found similar results among participants who lost more than 10% of their baseline body weight.
Researchers saw no effects on TNF-a, IL-10, IL-8, the composite score, adiponectin or leptin when stratified by weight loss.
“Overweight individuals should be encouraged to lose weight in order to reduce long-term effects of chronic inflammation, which has been linked to a number of adverse clinical outcomes,” Duggan said. “They should also speak to their doctor about testing their vitamin D levels and supplementing with appropriate levels of vitamin D where necessary.”
Further studies examining the relationship between weight loss, vitamin D supplementation and inflammation are needed, she said.
“As a first step, these results need to be verified in other studies, and effects examined among other racial/ethnic groups, and in men,” Duggan said. – by Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.