Older women who eat plenty of fruits, vegetables and whole grains may have a lower likelihood of suffering a bone fracture than those who pass on such healthy fare, a new study suggests.
The findings, reported in the American Journal of Clinical Nutrition, do not prove that the foods themselves directly lower fracture risk. But they highlight another potential health reason for people to reach for an apple instead of potato chips.
A number of studies have found that people with higher intakes of specific nutrients, like calcium and vitamin D, may maintain greater bone mass and have a decreased risk of fractures later in life.
But people consume food, not isolated nutrients, noted Dr Lisa Langsetmo of McGill University in Montreal, Canada, the lead researcher on the new study. And little has been known about how overall diet patterns are related to fracture risk.
For their study, Langsetmo and colleagues looked at the relationship between dietary "nutrient density" and the risk of bone fracture among 3,539 postmenopausal women and 1,649 men age 50 and older.
At the start of the study, participants completed detailed diet questionnaires. The researchers used the answers to calculate nutrient-density scores, which reflect a food's concentration of vitamins, minerals and other nutrients - calorie for calorie. A diet high in nutrient density would feature plenty of fruits, vegetables, fiber-rich whole grains, beans and fish, Langsetmo told Reuters Health in an e-mail.
Over the next seven years, 70 men and 372 women in the study sustained fractures unrelated to major accidents.
Lower risk of fractures
In general, the researchers found that for each 40% increase in calories from fruits, vegetables and other nutrient-dense foods, the odds of suffering a fracture over 10 years fell by 14% among women - even accounting for other factors such as body weight, bone density, smoking habits and calcium and vitamin D intake.
There was a similar pattern among men that did not reach statistical significance.
There was no relationship, however, between fracture risk and diets high in calorie-dense foods, including desserts, chips and processed meats.
Benefits of plant-based diet
The findings add more support to the potential benefits of a diet rich in plant-based foods, according to Dr Joel Fuhrman, a family doctor in Flemington, New Jersey who has written numerous books on following a nutrient-dense diet to help prevent or treat bone thinning and other chronic health conditions.
"I am always glad to see better research demonstrating that through more careful food choices, we can have significant control over our health destiny," Fuhrman told Reuters Health in an email.
For bone health, he noted, it may be particularly important to boost consumption of vegetable proteins, from beans, seeds and greens, without eating too much animal-based protein.
That's because some studies have linked diets with a high ratio of animal protein to vegetable protein to greater bone loss over time. One theory is that diets rich in animal protein create a higher "dietary acid load," which may in turn cause the body to excrete more calcium.
Some research, however, has called that theory into question, Langsetmo and her colleagues note in their report.
The current findings do not prove that a nutrient-rich diet prevents fractures. People with such eating habits, Langsetmo pointed out, also tend to be generally more health-conscious than people who shun vegetables - being less likely to smoke, more likely to exercise and more likely to get adequate calcium and vitamin D.
But, she added, the study did measure a number of those factors, and the relationship between diet and fracture risk remained.
Also unclear is exactly how much of a difference diet changes might make in any one person's risk of suffering a fracture later in life.
In an earlier study, Langsetmo's team looked at the same group's fracture rates according to sex and age. They found that, for example, women ages 75 to 79 had a fracture rate of 26 per 1,000 women per year.
Langsetmo said applying the 14% reduction associated with nutrient-dense eating in this study would trim that rate to 22.4 per 1,000.
According to Langsetmo, the take-home message is that a diet already linked to health benefits - including lower risks of heart disease and diabetes - may also be good for bone health.
She also pointed out that while experts advise all adults to strive for at least five servings of fruits and vegetables per day, most older adults do not meet that goal. - (Amy Norton/Reuters Health, November 2010)