Evidence suggests that natto intake may help prevent bone loss in postmenopausal women: Japanese population-based osteoporosis study
Based on study:
“Intake of Fermented Soybeans, Natto, Is Associated with Reduced Bone Loss in Postmenopausal Women: Japanese Population-Based Osteoporosis (JPOS) Study”
Yukihiro Ikeda, Masayuki Iki, Akemi Morita, Etsuko Kajita, Sadanobu Kagamimori, Yoshiko Kagawa, and Hideo Yoneshima
The Journal of Nutrition (2006)
136(5):1323-8
May
Summary:
Osteoporosis leads to fractures with minor or inapparent trauma in postmenopausal women. Nutrition could prevent osteoporosis but it remains unclear whether vitamin K plays a preventive role against age-related bone loss. In Japan, natto, a kind of fermented soybean which is rich in vitamin K2 (menaquinone-7), is consumed regularly and commonly because it is thought to reduce the incidence of hip fracture. This study was conducted to evaluate if taking natto regularly affects bone mineral density (BMD) and change in BMD positively in healthy Japanese women aged 20-79 years. Through the findings of this study, regular natto intake may be linked with reduced bone loss in postmenopausal women through the effects of vitamin K2, or menaquinone-7 or bioavailable isoflavones, which are richer in natto than in other soybean products.
Key words:
Bone mineral density, BMD, fermented soybean, menaquinone-7, natto, osteoporosis, postmenopausal, reduced bone loss, vitamin K2
Osteoporosis is a progressive metabolic bone disease. It leads to fractures with minor or inapparent trauma in elderly people, particularly postmenopausal women. Nutrition plays an important role in the prevention of osteoporosis. Studies have indicated the role of calcium, vitamin D, other micronutrients and macronutrients. However, it remains unclear whether vitamin K plays a preventive role against age-related bone loss. There are two groups of vitamin K: phylloquinone and menaquinone. In Japan, natto, a kind of fermented soybean which is rich in menaquinone-7, is consumed regularly and commonly. Natto is thought to reduce the incidence of hip fracture in Japan. It is believed that natto is effective in increasing serum levels of menaquinone-7 and γ-carboxylated osteocalcin as well as maintaining bone stiffness and bone mineral density (BMD) of women in middle age. Therefore, this study was conducted to evaluate if taking natto regularly affects bone mineral density (BMD) and change in BMD positively in healthy Japanese women aged 20-79 years.
There were 944 women who served as the representative cohort of Japanese women free from bone mass abnormalities. BMD was measured at the spine, hip and forearm at baseline and at follow-up 3 years later. On both occasions, dietary natto intake was assessed by a food frequency questionnaire. Additional covariates were also measured.
Results showed that increasing frequent natto intake increased the total hip BMD in postmenopausal women (P for trend = 0.0034). It was also seen that the associations between natto intake and the rates of changes in BMD at the distal third of the radius (P = 0.0002) and at the femoral neck (P < 0.0001) were positive. These associations persisted even after adjusting for covariates such as age, height, weight, calcium intake, tofu and other soybean products (P for trend = 0.0094). Increasing natto intake positively affected the rate of BMD change at the distal radial third in women in their 50s and 60s and at the femoral neck in women who were in their 60s and 70s. There were no associations between intake of tofu or other soybean products and the rate of BMD change after adjusting for covariates.
In conclusion, regular natto intake may be linked with reduced bone loss in postmenopausal women through the effects of vitamin K2 (menaquinone-7) or bioavailable isoflavones, which are richer in natto than in other soybean products.
Reference:
- Ikeda Y, Iki M, Morita A, Kajita E, Kagamimori S, Kagawa Y, et al. Intake of fermented soybeans, natto, is associated with reduced bone loss in postmenopausal women: Japanese Population-Based Osteoporosis (JPOS) Study. The Journal of nutrition. 2006;136(5):1323-8. Epub 2006/04/15.