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.
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. Mobility limitation and disability are defined as any difficulty or inability to walk several blocks or climb a flight of stairs, respectively.
Date from 2,0pp men and women aged 70-79 was used for this study. Eligible participants reported no difficulty walking one quarter of a mile, climbing 10 steps, or performing basic, daily living activities, and were free of life-threatening illness.
Vitamin D levels were measured in the blood at the beginning of the study. Occurrence of mobility limitation and disability during follow-up was assessed during annual clinic visits alternating with telephone interviews every six months over six years.
The researchers observed about a 30 percent increased risk of mobility limitations for those older adults who had low levels of vitamin D, and almost a two-fold higher risk of mobility disability.
Vitamin D plays an important role in muscle function, so it is possible that low levels of the vitamin could result in the onset of decreased lower muscle strength and physical performance. Vitamin D may also 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.
People get vitamin D when it is naturally produced in the skin by sun exposure, by eating foods with vitamin D, such as oily fish and fortified milk and juice, and by taking vitamin D supplements.
In the U.S. about one-third of older adults have low vitamin D levels. 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 over age 70 to get 800 International Units of vitamin D daily in their diet or supplements. 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. However, clinical trials are needed to determine whether increasing vitamin D levels through diet or supplements has an effect on physical function.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.