Author: Morris C, Thorpe J, Ambrosio L and Santin M
Publication: Journal of Nutrition. 2006 May;136(5):1166-70
In Eastern countries such as Japan and China, where the soybean consumption is high, incidence of osteoporosis is lower than in Western countries. It is assumed that isoflavones, such as genistein, is responsible for the protective action in bones. Osteoblasts are bone cells, which are responsible for the production of new bone matrix, consisting mainly of collagen. This collagen matrix is then mineralized with the enzyme alkaline phosphatase. The calcification requires the presence of annexin V ion channels and calcium binding phosphatidylserine. Genistein also reduces the activity of osteoclasts, which are bone cells responsible for the decalcification of bones.
Previous studies have shown that genistein influences osteoblast differentiation, but there have been no studies linking genistein to prevention of bone mass loss. The mechanism by which genistein induces bone formation is still unknown. The aim of this in vitro study was the investigate the effect of genistein on human osteoblasts. The researchers found that genistein resulted in osteoblast with a better organized cytoskeleton and a reduction in cell proliferation. Genistein caused the osteoblasts to release more matrix vesicles, produced more collagen and alkaline phosphatase. These matrix vesicles act as potent calcification centres. Scanning electron microscopy showed that genistein stimulated the production of collagen-rich extracellular matrix around the osteoblasts.
The study concluded that the soybean isoflavone genistein induces bone mass formation through a specific cell activation pathway. This specific property of genistein together with its ability the inhibit macrophages and osteoclast activity indicates that genistein can help to prevent osteoporosis and bone mass loss.