路透新聞～澳大利亞的學者研究表明，過量增補維生素Ｄ和鈣並不能夠預防老年男性的骨質疏鬆！他們所進行的爲期18個月的研究表明，經常進行體育鍛煉的個體之骨質密度較每天僅服用1000毫克鈣和800國際單位的維生素D，但無系統性體育鍛煉者高。針對該發現，專家們仍強調適量地補鈣和服用維生素Ｄ仍是降低骨質疏鬆的主要措施之一，但預防骨質疏鬆更爲重要的措施是運動如跑步或舉重等，即適量的運動是預防骨質疏鬆或強筋壯骨最爲主要的措施（注：這與本人的觀點高度一致）。
路透新聞披露，全美受骨質疏鬆影響的人數多達四千萬以上，其中最爲常見的是老年女性，其次約有７％的白人男性和５％的黑人男性患有骨質疏鬆。
美國國立衛生研究院建議，19～70歲的男性每天應該補充鈣1000毫克，補充維生素Ｄ600國際單位；大於70歲的男性每天則應補充更多的鈣（1200毫克/天）和更多的維生素D（800國際單位）。美國國立衛生研究院認爲不吸菸、少喝酒和多運動等是預防骨質疏鬆最主要的措施。
最後需要指出的是，患有骨質疏鬆的個體應在醫生的指導下采取有力的措施預防骨折，如防止跌摔和避免過度負重等。
NEW YORK (Reuters Health) - Taking extra vitamin D and calcium does not seem to prevent bone-thinning in older men, according to Australian researchers.
However, exercise did boost bone mineral density, a proxy for bone strength, their report shows.
Despite the findings, people still need to get enough calcium and vitamin D to reduce the risk of osteoporosis, or bone thinning, said Dr. Mone Zaidi, an osteoporosis researcher at the Mount Sinai School of Medicine in New York, who was not involved in the study.
"It is like the four legs of the stool: vitamin D and calcium, exercise, medications if a person is losing bone, and the fourth leg is telling people how to prevent fractures," Zaidi said.
More than 40 million people in the US are affected by osteoporosis. It is most common in older women, but about seven percent of white men and five percent of black men are affected, according to the American College of Physicians.
In the new study, published in the Journal of Clinical Endocrinology and Metabolism, Robin M. Daly from the University of Melbourne, Australia and colleagues randomly assigned men aged 59 to 70 to an exercise program, drinking milk fortified with calcium and vitamin D, doing both, or doing nothing.
They measured the men bone density before and after the study, which took place over 18 months, but they did not look at fractures.
At the end of the study, men who exercised had higher bone density than those who had supplemented their diet with 1000 milligrams of calcium and 800 international units (IU) of vitamin D per day.
Adding the supplements to the exercise program provided no extra benefit, hinting that the men already had enough vitamin D and calcium in their diets to be able to boost their bone strength through exercise alone.
The recommended daily intake of vitamin D is 600 IU in adults up to age 70, and 800 IU for older people, according to the National Institutes of Health (NIH). A 6-month supply of vitamin D supplements can be bought for less than $10, and many multivitamins contain the recommended daily dose of vitamin D.
As for calcium, the NIH advises 1,000 mg per day for men ages19-70, and then 1,200 mg per day for men older than 70.
To build bone density, weight-bearing exercise is needed, such as running or weight-lifting, according to the NIH.
In animal studies, a lack of vitamin D has been linked to several diseases, such as multiple sclerosis and some types of cancer. However, there is not enough data to say if vitamin D can help treat or prevent these diseases, Zaidi said.
To reduce the risk of bone weakening, the NIH recommends not smoking, drinking less alcohol and exercising more.
Zaidi said that both vitamin D and calcium are extremely important for human health, so people should follow the previous vitamin D and calcium recommendations.
"You have got to have it to build a wall," he said. "Adding more might not strengthen the wall, but you have to take enough to keep the wall strong. Otherwise it might fall apart."
SOURCE: http://bit.ly/i4tDqs The Journal of Clinical Endocrinology and Metabolism, online January 5, 2011.