牛乳・乳製品と骨：総説

Milk, Daily products and Bone health. Effect of milks and daily products on bone health.

　従来，日本では骨粗鬆症や骨折予防の栄養指導は，食事からのカルシウム摂取の改善に主眼をおいて実施され，その中でも牛乳・乳製品の摂取が推奨されてきた。しかし，日本人を対象として骨密度の増加や骨折の発生に対する牛乳・乳製品の摂取効果を明らかにするための無作為化割付比較試験はほとんど行われていない。そこで牛乳・乳製品の摂取と骨密度や骨折に関するエビデンスをレビューした結果，中高年期の骨量減少やその後の骨折を抑制する効果は強くなかった。しかし，週に１回以下の牛乳摂取のような極端に低い摂取状況は大腿骨頸部骨折のリスクを上げる可能性が高いことや，日本人のカルシウム摂取量は低いことから，骨の健康のためには従来通り，成人や高齢者に牛乳・乳製品の摂取を増やすことを勧めることが必要である。

　In Japan, nutrition education programs to prevent osteoporosis and osteoporotic fractures have focused primarily on increasing dietary calcium intake and recommended the consumption of milk and dairy products. However, the effect of milk and dairy product consumption on bone density loss or fracture incidence in Japanese has rarely been evaluated in randomized controlled studies. In the present study, we reviewed the literature investigating the consumption of milk and dairy products in relation to bone density and fracture risk. The results showed that milk and dairy product consumption had only a modest effect in the prevention of midlife bone loss and subsequent fractures. However, given that infrequent（once weekly or less）consumption of milk may be associated with an increased risk of femoral neck fracture, and that Japanese generally have a lower calcium intake, it is still necessary to encourage elderly and younger adults to increase their consumption of milk and dairy products to promote bone health.