Vitamin D supplements could help prevent mobility problems
Vitamin D-deficient older individuals are more likely to struggle with everyday tasks such as dressing or climbing stairs, according to a recent study published in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).
Scientists estimate many as 90 percent of older individuals are vitamin D deficient. The vitamin – typically absorbed from sunlight or on a supplementary basis through diet – plays a key role in bone and muscle health. Vitamin D deficiency can lead to a decline in bone density, muscle weakness, osteoporosis or broken bones.
"Seniors who have low levels of vitamin D are more likely to have mobility limitations and to see their physical functioning decline over time," said the study's lead author, Evelien Sohl, MSc, of VU University Medical Center in Amsterdam, the Netherlands. "Older individuals with these limitations are more likely to be admitted to nursing homes and face a higher risk of mortality."
Using data from an ongoing Dutch cohort study (The Longitudinal Aging Study Amsterdam), the researchers examined among two groups – 762 people between the ages of 65 and 88, and 597 people between the ages of 55 and 65 – over the course of six years. Using blood test results, the subjects were split into groups with the highest, moderate and lowest vitamin D levels. To assess mobility limitations, participants were asked about their ability to perform routine tasks, including sitting down and standing up from a chair or walking outside for 5 minutes without resting.
Among the older group of participants, people with the lowest vitamin D levels were 1.7 times more likely to have at least one functional limitation compared to those with the highest vitamin D levels. In the younger cohort, individuals with low vitamin D levels were twice as likely to have at least one physical limitation.
While the majority of the people in the older cohort's top two vitamin D groups did not report any physical limitations, 70 percent of the people with the lowest vitamin D levels had at least one limitation.
In addition, the study found vitamin D-deficient individuals were more likely to develop additional limitations over time. The older cohort reported more mobility issues after three years, while the younger cohort developed additional limitations over the course of six years.
"The findings indicate low vitamin D levels in older individuals may contribute to the declining ability to perform daily activities and live independently," Sohl said. "Vitamin D supplementation could provide a way to prevent physical decline, but the idea needs to be explored further with additional studies."
Vitamin D Helps Prevent Falls in Seniors
A systematic review of over 50 clinical trials finds that exercise and Vitamin D supplements are the best ways to reduce the risk of falling in people aged 65 and over. The review is published in the December 21, 2011 issue of Annals of Internal Medicine and was commissioned by the US Preventive Services Task Force. A researcher at the Drexel University School of Public Health worked with colleagues at the Kaiser Permanente Center for Health Research, which is part of the Oregon Evidenced-based Practice Center, to conduct the study.
For the review of Vitamin D supplementation researchers evaluated nine clinical trials involving nearly 6,000 participants who received daily oral doses of Vitamin D with or without calcium. The dosage ranged from 10 to 1,000 IU’s per day, in one trial participants received a larger single intramuscular injection of 600,000 IU’s of Vitamin D. The trials lasted from eight weeks to three years. Follow up periods ranged from six to 36 months. Participants who received Vitamin D had a 17 percent reduced risk of falling, compared to participants who did not receive Vitamin D.
Older Adults May Need More Vitamin D to Prevent Mobility Difficulties
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.
"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," said lead author Denise Houston, Ph.D., R.D., a nutrition epidemiologist in the Wake Forest Baptist Department of Geriatrics and Gerontology. Houston researches vitamin D and its effects on physical function.
The study, published online (May, 2012) 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 (Health ABC) study. Mobility limitation and disability are defined as any difficulty or inability to walk several blocks or climb a flight of stairs, respectively.
Of the 3,075 community-dwelling black and white men and women aged 70-79 who were enrolled, data from 2,099 participants was used for this study. Eligible participants reported no difficulty walking one-fourth 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.
"We 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," 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 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. 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 over age 70 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."
Better vitamin D status could mean better quality of life for seniors
A limited number of studies point to the possibility that optimal intake of vitamin D (the "sunshine" vitamin) might help keep our muscles strong and preserve physical function. Although there are only few longitudinal studies investigating this relationship, their findings have been mixed. To help understand this diet-health association, Dr. Denise Houston from the Sticht Center on Aging at Wake Forest University and her collaborators studied the relationship between vitamin D status and physical function in a group of relatively healthy seniors living in Memphis, TN and Pittsburgh, PA. Their results were presented as part of the scientific program of the American Society for Nutrition, composed of the world's leading nutrition researchers, at the Experimental Biology 2010 meeting in Anaheim.
This study was part of the Health, Aging, and Body Composition (Health ABC) study initially designed to assess the associations among body composition, long-term health conditions, and mobility in older adults. For Houston's segment of the investigation, she studied 2788 seniors (mean age: ~75 years) for 4 years. At the beginning of the study, they assessed vitamin D status by analyzing each person's blood for 25-hydroxyvitamin D, a precursor for activated vitamin D. At baseline and then 2 and 4 years later, the research team then determined whether circulating 25-hydroxyvitamin D was related to the participants' physical function. Specifically, they looked at how quickly each participant could walk a short distance (6 meters) and rise from a chair five times as well as maintain his or her balance in progressively more challenging positions. Each participant was also put through a battery of tests assessing endurance and strength.
When the results were tabulated, participants with the highest levels of 25-hydroxyvitamin D had better physical function. And, although physical function declined over the course of the study, it remained significantly higher among those with the highest vitamin D levels at the beginning of the study compared to those with the lowest vitamin D levels. The scientists were not surprised to learn that, in general, vitamin D consumption was very low in this group of otherwise healthy seniors. In fact, more than 90% of them consumed less vitamin D than currently recommended, and many were relying on dietary supplements.
The good news: higher circulating 25-hydroxyvitamin D is related to better physical function in seniors. But it's impossible to tell from this type of research whether increasing vitamin D intake will actually lead to stronger muscles and preserve physical function. This is partly due to the fact that our bodies can make vitamin D if they get enough sunlight. So, it is possible that the participants with better physical function had higher vitamin D status simply because they were able to go outside more often. Indeed, the ominous "chicken-or-the-egg" question can only be answered by carefully controlled clinical intervention trials. Nonetheless, it is possible that getting more vitamin D from foods (like fortified milk and oily fish) or supplements will help maintain youth and vitality as we enjoy longer lifespans. As Houston points out: "Current dietary recommendations are based primarily on vitamin D's effects on bone health. It is possible that higher amounts of vitamin D are needed for the preservation of muscle strength and physical function as well as other health conditions. However, clinical trials are needed to definitively determine whether increasing 25-hydroxyvitamin D concentrations through diet or supplements has an effect on these non-traditional outcomes."
Vitamin D may help prevent and treat diseases associated with aging
Vitamin D may play a vital role in the prevention and treatment of diseases associated with aging, according to researchers at Loyola University Chicago Marcella Niehoff School of Nursing (MNSON). These findings were published in the latest issue of the Journal of Aging and Gerontology.
Researchers reviewed evidence that suggests an association between vitamin D deficiency and chronic diseases associated with aging such as cognitive decline, depression, osteoporosis, cardiovascular disease, high blood pressure, Type 2 diabetes and cancer.
"Vitamin D deficiency is a common, serious medical condition that significantly affects the health and well-being of older adults," said Sue Penckofer, PhD, RN, study author and full professor, MNSON.
Older adults are at risk for vitamin D deficiency due to diet, reduced time outdoors and poor skin absorption of the nutrient. With the number of people ages 65 and older expected to more than double from 2012 to 2060, the problem will become much more prevalent.
"Better understanding the relationship between vitamin D and chronic diseases in older adults and whether treatment of vitamin D deficiency can prevent or treat these disorders is important given the increasing number of people at risk for these health issues," said Meghan Meehan, FNP-BC '13, study author, MNSON.
The Institute of Medicine generally recommends that adults up to 70 years of age take 600 IU of vitamin D daily and adults over the age of 70 consume 800 IU of the nutrient daily.
Study authors concluded that as the older population continues to grow, universal guidelines for testing and treating vitamin D deficiency are needed. Research to examine the proper dosing of vitamin D supplements necessary to prevent the chronic diseases of aging also would have significant benefit for future generations.