Salt intake appears to have little impact on bone health in menopausal women

February 25, 2016, Medical College of Georgia at Augusta University

A low-salt diet does not necessarily translate to stronger bones in postmenopausal women, physician-scientists report.

"When we started the study, we thought we were going to be telling everyone again that a low-salt diet is good for your bones," said Dr. Laura D. Carbone, chief of the Section of Rheumatology at the Medical College of Georgia at Augusta University.

"Instead our message is low-sodium intake by itself is not likely to be beneficial to your bones. We definitely don't want to go further than that and say high sodium is good for them," said Carbone, corresponding author of the study in the Journal of Clinical Endocrinology & Metabolism.

The association of high sodium intake and weaker bones seems logical. Sodium and calcium are both stored in the . Sodium increases calcium excretion and low calcium is associated with low bone mineral density, an indicator of fracture risk. While calcium can't really be added to bone after the teen years, it can continue to follow sodium out of the bone and into the urine lifelong.

While current sodium intake guidelines are aimed at cardiovascular health, the National Osteoporosis Foundation also recommends a low-salt diet for bone health. The new surprising results indicate the need for a large, prospective study to really parse whether salt intake is good, bad or indifferent for women's bone, Carbone said.

MCG physician-scientists looked at data on nearly 70,000 followed for 11 years as part of the Women's Health Initiative, or WHI. WHI is a long-term National Institutes of Health-funded study of more than 160,000 postmenopausal women focused on ways to prevent heart disease, breast and colorectal cancer, and osteoporosis. They had fracture data on all the women included in their assessment and bone mineral density studies, an indicator of bone strength, on about 4,400.

They found a bit of a mixed bag that seemed to indicate salt intake was not a major factor in bone health. The study actually showed some association between a higher-salt diet and stronger bones, including higher density throughout the body and fewer hip fractures. When they adjusted for body mass index, or BMI, a measure of fatness, as a known influence of bone strength, they found no association between sodium intake and bone anywhere or with fractures rates. Higher BMI and being black, for examples, are both factors generally associated with stronger bones. Higher BMI also is associated with higher sodium intake.

Menopause and aging also are both associated with weakening bones, times when more bone is resorbed than made. Higher calcium intake is believed to aid bone strength by decreasing the number of osteoclasts, which destroy bone, and increasing bone-making osteoblasts.

Possible explanations for the surprising findings go back to the body's natural mechanisms for keeping adequate blood and oxygen flowing throughout. When sodium intake drops, this renin-angiotensin-aldosterone system gets activated, which, at least in experimental models, has been shown to increase bone resorption.

A prospective study will enable more detailed examination of sodium intake, including periodic measures of sodium levels in the urine on some holidays and weekends, times when tends to increase for most people, Carbone notes. The WHI nutrition data comes largely from the women's self-reports, with a correction factor applied based on the few who did have their urine tested for sodium levels.

The MCG team says that a diet high in calcium—including foods such as milk, yogurt, cheese and some green, leafy vegetables—and staying active are definitely good for the bones at any age.

The National Osteoporosis Foundation recommends limiting the intake of processed and canned foods, which are typically high in salt, as well as the salt you add to food. It recommends limiting salt intake to about 2,400 milligrams daily, which is about the same level as federal nutrition guidelines.

Explore further: Salt and sodium intake remains high in China

Related Stories

Salt and sodium intake remains high in China

February 16, 2016
Yongning Wu, Ph.D., of the China National Centre for Food Safety Risk Assessment, Beijing, China, and colleagues compared salt and sodium consumption in China in 2000 with 2009-2012. The study appears in the February 16 issue ...

Kidney, bladder stones do not increase postmenopausal women's risk of osteoporosis

July 13, 2015
Postmenopausal women with kidney or bladder stones are not at increased risk for osteoporosis, but they do have about a 15 percent increased risk of another painful stone, physician-scientists report.

Excessive salt consumption appears to be bad for your bones

June 17, 2013
A high-salt diet raises a woman's risk of breaking a bone after menopause, no matter what her bone density is, according to a new study that will be presented Saturday at The Endocrine Society's 95th Annual Meeting in San ...

Increasing calcium intake unlikely to boost bone health or prevent fractures, say experts

September 29, 2015
Increasing calcium intake through dietary sources or supplements is unlikely to improve bone health or prevent fractures in older people, conclude two studies published in The BMJ this week. Collectively, these results suggest ...

Potassium salts aid bone health and limit osteoporosis risk, new research finds

January 14, 2015
Latest research from the University of Surrey has found that the potassium salts (bicarbonate and citrate) plentiful in fruit and vegetables, play an important part in improving bone health. For the first time, the results ...

Before you start bone-building meds, try dietary calcium and supplements: study

May 2, 2011
Has a bone density scan placed you at risk for osteoporosis, leading your doctor to prescribe a widely advertised bone-building medication? Not so fast! A University of Illinois study finds that an effective first course ...

Recommended for you

Genetic changes associated with physical activity reported

December 10, 2018
Time spent sitting, sleeping and moving is determined in part by our genes, University of Oxford researchers have shown. In one of the most detailed projects of its kind, the scientists studied the activity of 91,105 UK Biobank ...

Licence to Swill: James Bond's drinking over six decades

December 10, 2018
He may be licensed to kill but fictional British secret service agent James Bond has a severe alcohol use disorder, according to an analysis of his drinking behaviour published in the Medical Journal of Australia's Christmas ...

How to survive on 'Game of Thrones': Switch allegiances

December 9, 2018
Characters in the Game of Thrones TV series are more likely to die if they do not switch allegiance, and are male, according to an article published in the open access journal Injury Epidemiology.

Expert calls for strong, sustainable action to make world roadways safer

December 7, 2018
According to the latest World Health Organization (WHO) report on road safety, more than 1.3 million people die on the world's roadways each year—and millions more are injured or disabled. Yet despite the huge cost to families ...

Hazelnuts improve older adults' micronutrient levels

December 6, 2018
Older adults who added hazelnuts to their diet for a few months significantly improved their levels of two key micronutrients, new research at Oregon State University indicates.

Regular bedtimes and sufficient sleep for children may lead to healthier teens

December 6, 2018
Having a regular, age-appropriate bedtime and getting sufficient sleep from early childhood may be important for healthy body weight in adolescence, according to researchers at Penn State.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.