Researchers may have come up with another reason to eat well. A new study suggests diets rich in fruits, vegetables and dairy foods can prevent the disabilities that often come with age.

The study, which followed 9,404 middle-aged Americans for nine years, found that a healthy diet seemed particularly beneficial among African-American women, who are generally at greater risk than white women of developing physical limitations as they age.

Researchers found that African American women who ate the most fruits and vegetables on a daily basis were about one-third to one-half less likely than those with the lowest intakes to develop problems with activities such as walking, climbing stairs and doing household chores.

High intakes of dairy products such as milk, cheese and yogurt showed an even stronger protective effect.

Similar benefits were found among white women - at least when it came to fruit and vegetable intake - though the protective effect was not as great.

The findings are published in the American Journal of Clinical Nutrition.

Diet is well known to be a factor in a host of diseases, including Heart disease, Diabetes, some cancers and the bone-thinning disease Osteoporosis. But less is known about the role of diet in age-related disability, according to the authors of the new study.

“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,” lead author Dr. Denise Houston said in a statement.

“We know that obesity, lack of physical exercise, alcohol consumption and smoking are modifiable factors for disability, but little is known about the role of diet,” added Houston, a research associate at Wake Forest University Baptist Medical Center in Winston-Salem, North Carolina.

Experts recommend that adults eat two to three servings of low-fat dairy and five to nine servings of fruits and vegetables each day.

The study included 9,404 African-American and white men and women between the ages of 45 and 64 at the outset. At study entry, they completed diet questionnaires that asked how often they ate various foods.

After roughly nine years, 67 percent of the African American women had developed problems with walking, climbing steps, kneeling or other types of lower-limb movement. White men were the least likely to have such problems, with 37 percent reporting lower-limb limitations. African American women also had the highest rates of other types of disabilities, such as difficulty with household chores or basic needs like getting around the house or out of bed.

However, African American women with the highest level of fruits, vegetables and dairy products in their diets were much less likely than their peers to develop any disability.

According to Houston’s team, a healthy diet may ward off physical limitations in a number of ways. The calcium and vitamin D in dairy foods may prevent problems associated with osteoporosis and declines in muscle strength.

Fruits and vegetables are rich in antioxidants, nutrients that counter the potentially cell-damaging effects of oxygen free radicals - substances that are normal byproducts of metabolism and that, over time, can lead to cumulative damage in body tissue.

Exactly why a healthy diet was more protective in African American women than in white women is unclear. The finding, Houston and her colleagues note, could reflect differences in the types of produce or dairy products that African American and white women eat. For example, African Americans have been shown eat more dark green vegetables and get more vitamin A and C than white Americans do.

SOURCE: American Journal of Clinical Nutrition, February 2005.