Higher Vitamin D, Better Golden Years?
Older Adults With Higher Vitamin D Levels Have Improved Mobility, Study Finds
April 26, 2010 (Anaheim, Calif.) -- Vitamin D, already considered a way to help fight colds, cancer, diabetes, heart disease, and other ills, may also keep people mobile in their golden years, according to a new study.
Older adults who had higher blood levels of vitamin D had better physical functioning, says Denise Houston, PhD, RD, assistant professor of internal medicine at Wake Forest University in Winston-Salem, N.C. She presented the findings Sunday at the Experimental Biology 2010 meeting.
"Those with better vitamin D levels started out better and ended up better on physical performance tests," she tells WebMD.
Vitamin D in Older Adults: Study Details
Results have been mixed in previous studies looking at whether vitamin D helps physical functioning in older adults, Houston says. Some studies found no effect of boosting low vitamin D levels in seniors and other studies showed an association.
Vitamin D, important for promoting calcium absorption, maintaining muscle strength, promoting bone growth and repair, and other activities, is produced when ultraviolet rays from the sun strike the skin and spark its synthesis.
It's found naturally in few foods and is added to others. Deficiency is common, especially with age, because the ability to synthesize vitamin D declines. Older adults also have difficulty converting vitamin D to its active hormone form.
In the new study, researchers wanted to see if vitamin D could delay age-related changes in physical functioning.
So Houston and her colleagues evaluated 2,641 older men and women, on average age 75.
The older adults were part of the Health, Aging, and Body Composition (Health ABC) Study that looked at the links between body composition, health conditions, and mobility with age.
For this new analysis, Houston divided the adults into three groups, depending on whether their vitamin D levels as evaluated from blood samples was low, medium, or high.
Those terms were relative, she tells WebMD, as ''two-thirds had vitamin D insufficiency."
For the study, low blood levels of vitamin D were under 50 nanomoles per liter (nmol/L), high blood levels were those 75 or higher, and levels of 50-75 were intermediate.
All the adults were tested to assess physical function, including walking 400 meters (about 1/4 mile) as fast as possible, standing from a chair without using the arms, balance tasks, and other tests of their lower extremity strength and functioning.
The tests were given at the start of the study and repeated two and four years later.