点击显示 收起
June 14, 2006 -- Eating lots of fruits and vegetables might strengthen bones, according to a study in The American Journal of Clinical Nutrition.
But most people fall short of the recommended five or more daily servings of fruits and vegetables, the study also shows.
The study comes from research scientist Celia Prynne, PhD, and colleagues at MRC Human Nutrition Research, located in Cambridge, England. Data included 237 adolescents, 120 young women, and 143 senior citizens.
Participants got bone densitybone density scans and kept food diaries for seven days. Prynne's team found that adolescents and older women with higher intake of fruits and vegetables had denser bones than those who skimped on fruits and vegetables.
How Many Servings?
The researchers took a close look at participants' food diaries. They focused on consumption of fruits and vegetables. They added nuts to the fruit category and didn't count potatoes with the vegetables.
Prynne's team notes that the World Health Organization recommended in 1990 that people eat at least five daily servings of fruits and vegetables. But in Prynne's study, only a quarter of adolescents, 38% of young women, and 50% of the older adults met that goal.
Women in the oldest age group were most likely to meet the five-a-day serving goal.
"A recommendation to increase fruit and vegetable intakes, particularly in young people, would be expedient, because indications are that intakes in this age group are generally very low," the researchers write.
What's a Serving?
"One serving of fruits and vegetables should fit within the palm of your hand -- it's a lot smaller than most people think," states the U.S. government's "Eat 5 to 9 a Day for Better Health" web site.
That web site offers these examples of a serving of fruit or vegetable:
Let's say you have a glass of 100% orange juice and a banana as part of your breakfast, a salad with your lunch, an apple as a snack, and a side of vegetables with dinner. Congratulations! You've hit the five-a-day goal.
Other Influences
Diet isn't the only factor that can affect bone densitybone density. For instance, smoking can weaken bones, while weight-bearing physical activity can strengthen bones.
Prynne and colleagues took those factors into account. The results didn't change. People who ate lots of fruits and vegetables might have better diets in general, which could help bolster bones, the researchers also note.
The findings were strongest for adolescents and older women, but people in other age groups still have plenty of reason to eat fruits and vegetables.
"Bone mineral status is only one aspect of health in which greater fruit and vegetable intakes may have long-term beneficial consequences," Prynne's team writes.
Second Opinion
The journal also includes an editorial by nutritionnutrition expert Susan Lanham-New, PhD, of England's University of Surrey.
Lanham-New calls for studies that directly test whether eating fruits and vegetables strengthen bones. Prynne's study didn't do that; it also didn't track participants' bone density and eating habits over time.
If eating more fruits and vegetables strengthens bones, it may be challenging to get people to act on that finding. "Persuading Western populations to increase their fruit and vegetable consumption remains our biggest challenge," Lanham-New writes.
SOURCES: Prynne, C. The American Journal of Clinical Nutrition, June 2006; vol 83: pp 1420-1428. 5aday.gov: "What's a Serving?" Lanham-New, S. The American Journal of Clinical Nutrition, June 2006; vol 83: pp 1254-1255.