“We know from our previous studies that by losing weight, people can reduce their overall levels of inflammation, and there is some evidence suggesting that taking vitamin D supplements can have a similar effect if one has insufficient levels of the nutrient,” said lead and corresponding author Catherine Duggan, Ph.D., a principal staff scientist in the Public Health Sciences Division at Fred Hutch. However, it has not been known whether combining the two — weight loss and vitamin D — would further boost this effect. “It’s the first study to test whether adding vitamin D augments the considerable effect of weight loss on inflammatory biomarkers,” she said.