The trial, by researchers at the University of Maastricht in the Netherlands, shows that a supplement could offer equal health benefits in a more convenient form.
Natto, a traditional Japanese food fermented from soybeans, is high in vitamin K2 levels and has been linked to significantly higher bone mineral density and fewer osteoporotic fractures.
The supplement used in the study, made by US health ingredients firm Natural, is a new proprietary extract of natto that provides the vitamin K2 as menaquinone MK-7. Natural markets the ingredient under its Natto K2 brand.
The study showed that the vitamin K2 as MK-7 had a long half-life in the circulation, which may result in a relatively constant level in the blood, unlike vitamins K1 and synthetic vitamin K2, which show a typical rise and fall pattern even if taken twice daily.
In Japan, vitamin K2 is used as a therapeutic treatment for osteoporosis and in the Caucasian population it also has shown a significant benefit in the reduction of heart disease, due to its roles in calcium use and promoting matrix Gla-protein activity, a potent inhibitor of vascular calcification.
Natto K2 is available to US dietary supplement manufacturing and marketing partners as an encapsulated product.