Vitamin K1 is often the sole form of vitamin K in dietary supplements. While vitamin K1 has documented benefits for bone health, vitamin K2 (derived from the Asian fermented food natto and other sources) has been shown to be a safer, and possibly more effective, form of vitamin K.
Several studies published over the last two years document the bone health benefits of vitamin K2. Researchers have found that vitamin K2 promotes the production of quality bone tissue through its effects on a bone mineralization protein known as osteocalcin. Osteocalcin is secreted by osteoblasts (cells responsible for bone-building) and plays an important role in calcium incorporation in bones. Two studies published by Jun Iwamoto and colleagues confirm the beneficial effects of vitamin K2 intake on bone health in an animal model of osteoporosis, as well as in reducing the risk of fractures in postmenopausal women.
Apart from bone-health benefits, two exciting papers examined the cardiovascular effects of vitamin K2 intake. A paper published recently by Gerrie-Cor Gast and colleagues assessed the relationship between intake of K1 and K2 and development of poor cardiac health. After examining a cohort of 16,057 women ranging between the ages of 49 and 70, the researchers concluded that vitamin K2 intake was associated with cardiovascular-protective benefits, while there was no such benefit associated with K1.
Interestingly, a study conducted in the Netherlands by Joline Beulens and colleagues looked at the effects of vitamin K1 and K2 intake on coronary arterial calcium retention in 564 postmenopausal women. The average age of the women was 67 with a BMI of 26.7 kg/m2. Using a 77-item food frequency questionnaire, the researchers reported the average intake of vitamin K1 was 217 micrograms/day while the intake for vitamin K2 averaged only 31.6 micrograms/day. The results revealed that higher intakes of vitamin K2 were associated with improved calcium metabolism and homeostasis in coronary arteries, whereas no such association was seen with vitamin K1.
Based on this research, it is clear that vitamin K2 intake has a multitude of health benefits and is the preferential supplemental form of vitamin K, especially for cardiovascular health.
by Irfan Qureshi, ND