A Wake Forest University Baptist Medical Center researcher and colleagues reported that high consumption of dairy products and fruits and vegetables may lower the risk of disability, especially among black women.
The research, in the American Journal of Clinical Nutrition, found that black women who consumed the highest amounts of dairy products and fruits and vegetables - close to the amounts recommended by the 2005 Dietary Guidelines for Americans - had at least a 30 percent lower risk of disability than participants who consumed the lowest amounts of these foods.
And, among all participants, eating more of these foods was associated with lower risk for functional limitations, such as being unable to walk a quarter of a mile or climb 10 steps, that often precede disability.
"In general, there was an association between dairy, fruit and vegetable intake and functional limitations and disability," said Denise Houston, Ph.D., a research associate at Wake Forest Baptist. "Getting the recommended number of servings of dairy, fruits and vegetables should be investigated for its potential to reduce the prevalence of disability in the aging population."
Houston, who completed the study while she was a graduate student at the University of North Carolina at Chapel Hill, said the findings are important because the number of disabled elderly is expected to triple between 1985 and 2050. About half of people over age 65 will become disabled enough to require some nursing home care.
"We know that obesity, lack of physical exercise, alcohol consumption and smoking are modifiable risk factors for disability, but little is known about the role of diet," said Houston, a registered dietitian.
The researchers believe this is the first study to report on an association between disability and eating certain foods. For the project, they evaluated data from the Atherosclerosis Risk in Communities (ARIC) study, which included about 16,000 randomly selected participants in Forsyth County, Jackson, Miss., Hagerstown, Md., and suburban Minneapolis, Minn. People who had chronic disease and were likely to already be disabled were excluded.
Participants, who were between 45 and 64 years old when the study began, were asked to report on their diets over the past year using a 66-item food frequency questionnaire.
Then, an average of nine years later, the researchers surveyed participants on their ability to perform 12 daily activities, such dressing and feeding themselves and walking across a room, known as activities of daily living; being able to cook and manage their money, known as instrumental activities of daily living; and being able to walk a quarter of mile and walk up 10 steps without resting, to measure functional limitations.
The study adjusted for other factors that could have affected the results - such as age, education, smoking, and body mass index - and found that higher amounts of dairy, fruits and vegetables were associated with lower risk of functional limitations. And, among black women, risk of disability was significantly lower.
The median servings for study participants consuming the highest amounts of the foods were two servings of dairy, three servings of fruits and three servings of vegetables. In contrast, median servings for participants consuming the lowest amounts of the foods were less than half a serving of dairy and one or less serving of fruits and vegetables. Current dietary recommendations call for three cups a day of low-fat or fat-free dairy products, two cups (four servings) of fruit and two and a half cups (five servings) of vegetables.
Houston said there are several ways that the foods could affect disability risk. The calcium and vitamin D in dairy foods may decrease the risk of disability associated with osteoporosis and decreased muscle strength. The antioxidants found in fruits and vegetables may reduce the accumulation of oxidative damage in tissues, which could slow disability associated with aging and decrease the risk of chronic diseases that can lead to disability.
Houston's co-researchers were June Stevens, Ph.D., Jianwen Cai, Ph.D., and Pamela Haines, Ph.D., all with the University of North Carolina at Chapel-Hill.
About Wake Forest University Baptist Medical Center: Wake Forest Baptist is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university's School of Medicine. The system comprises 1,282 acute care, psychiatric, rehabilitation and long-term care beds and is consistently ranked as one of "America's Best Hospitals" by U.S. News & World Report.