Vitamin D May Prevent Falls in Seniors
By Darin Ingels, ND, MT (ASCP)
Healthnotes Newswire (December 9, 2004)—Older people with higher blood levels of vitamin D are able to walk and rise from a chair faster than those who have lower vitamin D levels, according to the American Journal of Clinical Nutrition (2004;80:752–8). Better physical functioning may mean fewer falls and a reduced number of hip and spine fractures, which are a frequent cause of serious injury in elderly people.
Vitamin D is necessary for maintaining a normal blood concentration of calcium; it also enhances the absorption of calcium from the intestines. Vitamin D can be manufactured in the body from a precursor molecule that is produced when the skin is exposed to direct sunlight. Only a small amount of sun exposure is required to prevent vitamin D deficiency. People living at high latitudes (such as Sweden, Norway, and Alaska) and those who avoid the sun or cover their bodies when outdoors may be prone to vitamin D deficiency. Deficiency of vitamin D can lead to softening of the bones (osteomalacia) in adults or rickets in children. In addition to these well-known effects of vitamin D, studies have shown that it plays a role promoting muscle strength and balance.
In the new study, 4,100 adults over age 60 were asked to complete two separate tasks to measure physical function. Participants completed an eight-foot walking speed test (eight-foot-walk test) and a timed test of five repetitions of rising from a chair and sitting down (sit-to-stand test). Those who walked at least one mile, swam, jogged, rode a bike, danced, or did garden work in the previous month were considered “active,” while those who did none of these activities were classified as “inactive.” Blood levels of 25-hydroxyvitamin D (the most reliable test for vitamin D nutritional status) were measured in all participants and divided into five quintiles, ranging from lowest to highest.
People with the highest blood levels of vitamin D were able to complete the eight-foot-walk test and sit-to-stand test faster than those with the lowest blood levels of vitamin D. Although active participants were quicker in completing the tests than the inactive group, the difference in performance speed between the two groups decreased as the level of vitamin D increased, which suggests that vitamin D helps improve muscle function, independent of physical activity. Even a modest increase in vitamin D levels was associated with improvement in both tests; however, the best performance was observed in those whose levels were in the highest quintile.
Several studies have shown that higher 25-hydroxyvitamin D levels are associated with better muscle strength, improved muscle function, and fewer falls. In the United States and other countries where vitamin D is added to milk, the prevalence of vitamin D deficiency is low, but is still present in up to 12.6% of elderly women living in the community and in more than half of patients hospitalized on a general medical ward. Although this study did not specifically evaluate the effect of supplementing with vitamin D, previous studies have shown that correcting vitamin D deficiency can increase muscle strength and reduce the risk of falling and breaking a bone.
Vitamin D is produced in the skin upon exposure to sunlight. It is also found in some foods, including fish, liver, and fortified milk. In many countries, fortified milk is the main dietary source of vitamin D.
Darin Ingels, ND, MT (ASCP), received his bachelor’s degree from Purdue University and his Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. Dr. Ingels is the author of The Natural Pharmacist: Lowering Cholesterol (Prima, 1999) and Natural Treatments for High Cholesterol (Prima, 2000). He currently is in private practice at New England Family Health Associates located in Southport, CT, where he specializes in environmental medicine and allergies. Dr. Ingels is a regular contributor to Healthnotes and Healthnotes Newswire.
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