(January 2018) If you are aware of vitamin K, you probably know it is something we need from food to help with blood clotting (or “K”oagulation). This particular essential nutrient is called K1 to distinguish it from other lesser-known forms of this vitamin. K1 is found in a variety of plants, particularly green leafy vegetables like spinach and kale.
Now there’s a new “K”id on the block called vitamin K2 that’s beginning to receive much attention. While both K1 and K2 activate proteins that bind calcium, they serve entirely different functions. The main function of K2 is to keep calcium in the bones and out of the tissues. In fact, it may be vital for strengthening bones and preventing issues like bone spurs, kidney stones and hardening of the arteries. Calcium build-up in the arteries is a major risk factor for heart disease. Though an essential mineral, calcium can also work against you if other vitamins and minerals are not present.
Indeed, many nutritionists and healthcare practitioners have embraced vitamin K2 as a cornerstone for bone health and the management of calcium in the body. Others consider it the “missing link” in the prevention and treatment of many diseases. In one major study over a 7-10 year period, subjects with the highest K2 were 52% less likely to develop artery calcification, and 57% less likely to die from heart disease, compared to those with the lowest intake. Another study involving over 16,000 women showed that the risk of heart disease was reduced by 9% for every 10 micrograms of K2 consumed daily.
Vitamin K2 is rare in the Western diet. It is found only in animal-based (e.g., fermented, grass-fed dairy) and other fermented foods like natto, a fermented soy product popular in Japan. It is found in certain cheeses and made in small amounts in the human gut by our normal flora. However, the recommended dosage of up to 180 micrograms daily is quite hard to achieve without supplementation. The minimum dosage found on the shelves is 45 micrograms. There is not yet any established daily intake for this nutrient.
Vitamin K2 is increasingly found on the vitamin shelves in various forms. The most common subtypes available are MK4 and MK7. Most practitioners recommend the MK7 form due to its longer duration in the blood. Commercially, it is found alone, or in combination with vitamin D3 and other bone-building supplements.
Vitamin K2 research has only just begun, but human studies thus far extol the benefits for bone strength and arterial health, with a possible benefit for blood pressure. Vitamin K deficiency may also show up in tooth decay, easy bruising, nosebleeds, or heavy periods. A history of digestive problems or antibiotic use may increase the risk. This essential nutrient is important at all stages of life, including for newborn babies and pregnant mothers. Supplementation should be considered, along with magnesium and vitamin D, for optimal calcium function in the body.