Researchers in the Departments of Physiology and Nutritional Sciences at the University of Arizona has uncovered that weight-bearing and resistance exercises combined with calcium citrate supplementation over one year provided significant improvement in bone mineral density (BMD) of postmenopausal women at specific important skeletal sites.

Notably, this benefit was found both in women not on hormone replacement therapy (HRT) and in women on HRT.

"The good news is that this study has identified a powerful combination of improved nutrition and increased physical activity that prevents bone loss," said Timothy Lohman, PhD, professor of physiology at the UA and principal investigator on the study. "The bottom line: when combined with calcium citrate supplementation, weight-bearing and resistance exercises offer a benefit in building bone mineral density."

Study co-investigator Lauve Metcalfe, director of Community Programs and exercise interventionist, UA Department of Physiology, added, "The study focused on a regimen of six specific exercises that help build bone in the hip and spine-two key fracture sites."

The UA investigators have developed a specific exercise regimen that they consider most effective in building bone in typically vulnerable areas. They suggest 20 to 25 minutes of resistance training-two sets of six to eight repetitions-using these six exercises: back extension, leg press, squats, lat pulldown, dumbbell press and seated row. Seven to 10 minutes of cardiovascular weight-bearing activity, such as skipping, jogging and jumping rope, round out the study regimen.

The key to achieving the goal of improved bone health is in the intensity of the weight-bearing workout and the level of the resistance training, says Scott Going, associate professor, UA Department of Nutritional Sciences, and a co-investigator, who helped design the weightlifting program that progressively increases the pounds of weight lifted throughout the year.

Building BMD is extremely important in staving off osteoporosis, the gradual loss of bone density from the skeleton that often results in fractures of the hip, spine and wrist. Signs of advanced osteoporosis include stooped posture, loss of height and bones that break easily.

Fortunately, osteoporosis often can be prevented through adequate calcium intake and exercise throughout life, beginning in childhood when people are young and healthy. Unfortunately, most fail to take those preventive steps: osteoporosis is a major health risk for 28 million Americans-10 million individuals already have osteoporosis and 18 million more have low bone mass, placing them at increased risk for the disease-according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Bone constantly grows through a regular process of breaking down (resorption) and renewing itself (formation) until peak bone mass (maximum bone density and strength) is reached during a person's mid-20s. Typically, from that point on bone loss outpaces formation and if left untreated osteoporosis can occur. Osteoporosis is more likely to develop if optimal bone mass is not reached during the bone building years from childhood to the mid-20s.

This study developed a model for good bone health that was applied both to women already on HRT and women not on HRT. For many years, experts believed that the best way for postmenopausal women to increase or maintain bone density was to go on HRT. While the effect of HRT on bone health is well established, recent independent studies revealed a growing list of side effects from this treatment, challenging some of the major benefits of HRT and leading many women to re-evaluate whether this therapy is right for them. The researchers in this study, funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (NIH), found that weight-bearing and resistance exercises plus adequate calcium intake from food and calcium citrate were effective in improving bone density in women not on HRT as well as in women on HRT.

While foods such as milk, yogurt, kale, broccoli, cooked dried beans and some cheeses are primary sources of calcium, most individuals do not eat enough of these foods to get the amount of calcium needed in their diets. To address this problem, the researchers supplemented the study participants' diets with calcium citrate (supplied as Citracal, Mission Pharmacal), to help bridge the gap between the amount of calcium in their diets and the amount of calcium recommended by nutritional experts.

Getting the right amount of calcium is important at every age and doctors often recommend supplements to ensure adequate intake. Three primary kinds of calcium supplements are available: calcium citrate, calcium carbonate and calcium phosphate. Even with a supplement, vitamin D is necessary for the absorption of calcium into the bones. The sun triggers the production of vitamin D in the body; however many people, especially older persons, do not receive adequate sun exposure. A diet rich in foods fortified with vitamin D, such as milk, will help those who avoid the sun ensure better calcium absorption.

The best treatment for osteoporosis is prevention. With weight-bearing activities and strength-training exercises, tailored to strengthen bone loss-vulnerable sites in the body, and regular adequate calcium intake, postmenopausal women have a way to fight the chronic disease of osteoporosis.