[Nutrition and bone health. Soybean and soy foods, and bone health].

Soybean and various types of soy products, such as natto, tofu, miso, and soy sauce, have long been consumed in Japan. Soybean, a rich source of plant proteins, contains a relatively high amount of calcium as well as being an important source of isoflavones, a group of substances whose chemical structure is similar to that of estrogen. Natto, fermented soybeans, contains vitamin K, which is involved in the activation of osteocalcin.

[Calcium in aging, health, and anti-aging. Significance of calcium supplement for anti-aging].

For prevention of osteoporosis and debilitating bone fractures, poor calcium intake has long been a major public health problem in Japan. However, few randomized controlled studies have been conducted to clarify the relationship between calcium intake and bone mineral density, and the effect of the prevention of bone fractures. Therefore we reviewed the articles about the evidence for calcium intake and bone fracture incidence in European, American and Asian.