WINSTON-SALEM, N.C. — Older adults who don’t get enough vitamin D — either from diet, supplements or sun exposure — may be at increased risk of developing mobility limitations and disability, according to new research from Wake Forest Baptist Medical Center released Tuesday.
“This is one of the first studies to look at the association of vitamin D and the onset of new mobility limitations or disability in older adults,” stated lead author Denise Houston, a nutrition epidemiologist in the Wake Forest Baptist Department of Geriatrics and Gerontology. Houston researches vitamin D and its effects on physical function.
“We observed about a 30% increased risk of mobility limitations for those older adults who had low levels of vitamin D, and almost a twofold higher risk of mobility disability,” Houston said.
Houston said vitamin D plays an important role in muscle function, so it is plausible that low levels of the vitamin could result in the onset of decreased lower muscle strength and physical performance. Vitamin D also may indirectly affect physical function, as low vitamin D levels have also been associated with diabetes, high blood pressure, cardiovascular disease and lung disease — conditions that are frequent causes of decline in physical function. Houston said people get vitamin D when it is naturally produced in the skin by sun exposure; by eating foods with vitamin D, such as fortified milk, juice and cereals; and by taking vitamin D supplements. “About one-third of older adults have low vitamin D levels,” she said. “It’s difficult to get enough vitamin D through diet alone, and older adults, who may not spend much time outdoors, may need to take a vitamin D supplement.”
Current recommendations call for people older than the age of 70 years to get 800 international units of vitamin D daily in their diet or supplements. Houston pointed out that current dietary recommendations are based solely on vitamin D’s effects on bone health. “Higher amounts of vitamin D may be needed for the preservation of muscle strength and physical function, as well as other health conditions,” she said. “However, clinical trials are needed to determine whether increasing vitamin D levels through diet or supplements has an effect on physical function.”
The study, published online this month in the Journal of Gerontology: Medical Sciences, analyzed the association between vitamin D and onset of mobility limitation and disability over six years of follow-up using data from the National Institute on Aging’s Health, Aging, and Body Composition study.