Image: iStock The discovery of vitamin K as an essential nutrient for blood clotting was first published in a German scientific journal back in the 1920s (where it was termed ‘koagulationsvitamin’). Now, after nearly a century of research, it’s understood to be important for bone health and decreasing our risk of heart problems as well. Although there are several types of vitamin K, the ones we hear about most often are vitamins K1 and K2. While vitamin K1 is typically found in greens, including kale, spinach and broccoli, foods rich in vitamin K2 are rare in a typical western diet. Natto, a traditional Japanese food made with fermented soybeans, is rich in K2. Other dietary sources include dairy products made from the milk of grass-fed cows, but as UK dairy cows are typically grain-fed, our dairy products usually have much lower levels. K2 can also be found in high-fat meats, liver, and other organ tissue, but that’s not much good if you’re vegetarian. Luckily, the body is ab...