Women, Menopause and Calcium Supplements
Menopause leads to bone loss. When estrogen production decreases, calcium absorption decreases and bone resorption increases. Bone resorption means the process by which osteoclasts, or bone cells, break down bone and releases minerals, resulting in a transfer of calcium from bone fluid to the blood. Bone loss can lead to osteoporosis in which weakened bones may fracture.
National nutrition surveys indicate that nearly half the women in the U.S. consume less than 800 milligrams of calcium daily as compare to the U.S. Recommended Daily Allowance of 1,200 mg daily. Between low dietary intakes and menopause, women in the U.S. do not consume enough calcium to prevent gradual losses in bone calcium content.
Recent studies have found that calcium and vitamin D supplementation can improve bone density or reduce bone loss. Calcium and vitamin D supplementation can also reduce the risk of osteoporotic fractures.
A recently-concluded National Institute of Health study took 36,282 postmenopausal women, aged 50 to 79 years who were enrolled in a Women's Health Initiative clinical trial. Researchers randomly assigned participants to receive 1,000 mg of calcium carbonate with 400 IU of vitamin D3 daily or a placebo. Researchers measured their bone density, and ascertained fractures over an average 7-year period.
Among healthy postmenopausal women, calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density. Calcium and vitamin D supplementation reduced the risk of hip fracture by 29 percent among women with an adherence of 80 percent or more, 21 percent among those 60 years of age or older at enrollment, and 30 percent among those not taking other calcium supplements during the trial.
A meta-analysis identified 29 trials that recruited people aged 50 years or older in which calcium, or calcium in combination with vitamin D, was used to prevent fractures and osteoporotic bone loss. Based on a random-effect data model, the analysis found that in trials that reported fractures, treatment was associated with a 12% risk reduction in fractures of all types. In trials that reported bone-mineral density, treatment was associated with a reduced rate of bone loss of 0.54% at the hip and 1.19% in the spine. For best therapeutic effect, the researchers concluded by recommending minimum doses of 1,200 mg of calcium and 800 IU of vitamin D.
© Advanced Nutritional Research, Inc. August 2009