Eating potassium-rich foods such as bananas, tomatoes and orange juice can help prevent osteoporosis for postmenopausal women by decreasing calcium losses, according to a UCSF study.
In postmenopausal women the consumption of excessive salt has been shown to increase the level of bone minerals excreted through urine, although salt does not seem to effect younger women or men in a similar fashion, said study author Deborah Sellmeyer, MD, UCSF assistant adjunct professor of endocrinology and metabolism. While the benefits of dietary calcium and vitamin D for preserving bone density have long been established, the UCSF study is the first to examine the role of potassium in preventing bone density loss exacerbated by a high-salt diet.
Osteoporosis affects an estimated 44 million Americans, mostly women. It causes bones to become fragile and more likely to fracture. The National Osteoporosis Foundation estimates that 55 percent of Americans aged 50 and older are at risk for the largely preventable disease. "For women at risk of osteoporosis, eating more fruits and vegetables is a simple way to help prevent the adverse effects of a typical American high salt diet," said Sellmeyer.
Although no studies have directly measured the level of dietary salt necessary to adversely affect bone mineral excretion, Americans eat twice as much salt (sodium chloride) as they should, according to the National Institutes of Health (NIH). The NIH recommends consumption of no more than 6 grams, or about 1 1/2 teaspoons, of salt daily for cardiac health.
In the UCSF study, 60 healthy postmenopausal women were placed on a low salt diet (two grams / day) for an initial three weeks while their level of excreted calcium was measured. The level of excreted NTX, a bone protein, was also measured. A higher NTX level indicates that more bone is being broken down, or reabsorbed, leaving women at increased risk for fractures.