Sodium intake and bone health.

Date:

06-Oct-2003

Source

Journal of Nutrition

Related Monographs

Consumer Data: Sodium Osteoporosis
Professional Data: Sodium Osteoporosis

Article

If you are a woman over forty, you may be starting to worry about bone health. Everyone loses bone as they age. By the time a women is told she has osteoporosis, her gradual loss of bone mass has been progressing for years. Men lose bone too, but only about half as fast as women. Medically speaking, osteoporosis is characterized by low bone density and structural deterioration of bone tissue. The soft spongy bone in the wrists, hips, and spine are the most vulnerable to osteoporosis and prone to breakage as a result.

Exactly why and how bone loss accelerates with aging is not completely understood. Many different physiologic changes appear to be involved. Bone cells called "osteoblasts" that rebuild bone seem to falter with aging. Hormones of the thyroid and parathyroid glands control the movement of calcium in and out of bone: calcitonin secreted by the thyroid deposits calcium into bone while PTH from the parathyroids pull calcium out. As we age, calcitonin levels tend to fall coupled with a rise in PTH, tipping the scale toward bone breakdown. Estrogen protects against bone loss and declining estrogen levels after menopause increase bone resorption.

A recent study investigated different intakes of sodium in 186 men and women in regards to bone health. Participants were aged between 23 and 76 years and were assigned to three different 30-day diets with low, medium and high levels of sodium. The DASH diet (Dietary Approaches to Stop Hypertension) was used as the low sodium diet in this study. Researchers analyzed serum levels of calcitonin, PTH, sodium, and calcium at the beginning and end of this trial. After examining the results, this study showed that the DASH diet decreased bone turnover, and the authors concluded that if this diet is continued, the bone mineral status may improve in both men and women.1

References

1. Lin PH, et al. The DASH Diet and Sodium Reduction Improve Markers of Bone Turnover and Calcium Metabolism in Adults. J Nutr. Oct 2003;133:3130-6.