Tissues throughout the body contain vitamin D receptors, which means the nutrient influences many organs, says Bess Dawson-Hughes, MD, director of the bone metabolism laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University and professor of medicine at Tufts University School of Medicine in Boston.
Below are some of vitamin D’s most important roles.
Bone Density and Fracture Protection
As the body ages, it continually replaces small areas of old bone with new bone, helping keep the skeleton strong, Dawson-Hughes says. Vitamin D supports the absorption of calcium, which is essential for forming that new bone. Without this ongoing renewal, bones would become far weaker with age and much more likely to fracture, she says.
Along with calcium, vitamin D helps lower the risk of osteoporosis in older adults, a condition that causes bones to become thin and fragile.
Muscle Strength and Fall Reduction
“If you are deficient or insufficient in vitamin D, you are going to be weaker, and muscle strength is one of the strongest risk factors for falls,” Dawson-Hughes says.
Low vitamin D can also affect balance, another major contributor to falls, she says.
Immune Function and Inflammation
Vitamin D helps support the immune system and regulate inflammation, Dawson-Hughes says. It helps infection-fighting cells function more effectively and keeps the body from turning on itself.
Brain Health
Vitamin D has antioxidant properties and is active in brain tissue. It may also help prevent and treat mood disorders. Lower vitamin D levels have been associated with more symptoms of depression and anxiety.
Some studies have also linked vitamin D with improved memory and thinking.
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