Vitamin D is Shown to Improve Muscle Strength and Balance in Older Adults
Friday, December 2, 2011
Scientists at the University of Western Ontario analyzed 13 studies conducted over a 30-year period to determine the effects of vitamin D on muscle strength, gait, and balance in older adults. Their findings showed that older adults taking daily doses of at least 800 to 1000 International Units (IU) of vitamin D showed improvement in muscle strength and balance.
Why This Study Was Done
Many people are deficient in vitamin D, especially older adults whose bodies have difficulty absorbing and metabolizing it. In older adults, vitamin D deficiency has been associated with falls, fractures, reduced muscle strength, and difficulties with balance and walking (gait). Not enough vitamin D may also affect the central nervous system, including cognitive function and neuromuscular control and coordination.
Based on these age-associated changes, the researchers decided to study the effects of vitamin D supplementation on neuromuscular function in older adults, particularly when high doses of vitamin D were used.
What They Found
The researchers reviewed 714 articles published between January 1980 and November 2010 that included terms such as: elderly, falls, balance, gait, vitamin D, and muscle strength. Using a set of pre-determined criteria that included an evaluation of the strength of the research studies, the researchers identified 13 articles that met the inclusion criteria. Studies that included exercises combined with vitamin D were excluded since the researchers wanted to focus only on the benefits of vitamin D supplementation.
In the 13 articles that the researchers analyzed in detail, the average age of the participants was 78, with a range in ages of 63 to 99. Seven studies evaluated community dwelling older adults; six evaluated those who lived in nursing homes or other long-term care facilities. The number of people in the various studies ranged from 32 to 302, the majority of whom were Caucasian. The 13 studies had a combined total of 2,146 participants, 85% (1,830) of whom were female.
The study participants received various doses of vitamin D including one single dose of 300,000 IU, one monthly dose of 15,000 IU, daily doses below 800 IU, and daily doses of 800 to 1000 IU.
All the studies that used daily doses between 800 and 1000 IU consistently showed beneficial effects on muscle strength and balance, and nine of these studies were considered statistically significant, which means that the results were unlikely to occur by chance (an indicator of the strength or reliability of the research findings). Vitamin D supplementation was not shown to have any effect on gait, though the studies that evaluated gait were not as strong. A single high dose of vitamin D administered weekly or monthly was not as consistent in demonstrating improvements in physical performance as daily doses.
“Now that we know conclusively that the collective scientific literature supports the improvement of muscle strength and balance in older adults taking daily doses of at least 800 to 1000 IU of vitamin D, we understand why Vitamin D prevent falls in older adults. Our findings can help to design better studies to measure the effects of higher daily supplemental doses of vitamin D on muscle, strength, gait, and balance,” said Manuel Montero-Odasso, MD, PhD, a co-investigator of the study.
What You Can Do
In addition to improving muscle strength and balance, Vitamin D is important in maintaining good bone health and studies suggest it is also beneficial in preventing cardiovascular disease, cancer, and osteoporosis,. It is important to get daily vitamin D at any age.
Vitamin D is present in foods such as salmon and milk, but the majority of it comes from sunlight. Ten to fifteen minutes of daily sun exposure without sunscreen will provide an adequate dose. Ironically, the advice to use sunscreen to help prevent skin cancer, is minimizing our ability to obtain enough vitamin D from the sun. And many of us do not eat enough fish and dairy products. So it is important for most older people to take a vitamin D supplement. Your healthcare provider can do a blood test to check the level of Vitamin D in your body, and can recommend the dose that is right for you.
This summary is from the full report titled, Effect of Vitamin D Supplementation on Muscle Strength, Gait, and Balance in Older Adults: A Systematic Review and Meta-Analysis. It is in the December 2011 issue of the Journal of the American Geriatrics Society (JAGS). The report is authored by Susan W. Muir, PhD and Manuel Montero-Odasso, MD, PhD, AGSF.