Vitamin K is Activator X

This is an abstract of an article by Chris Masterjohn titled "On the Trail of the Elusive X-Factor" which was published in Wise Traditions, Volume 8 Number One, Spring 2007, pages 14–32.

Dr. Weston A. Price's research into health and dental defects led to his discovery of a vitamin-like substance found in the traditional diets of the healthy peoples he studied, a substance he called "Activator X." He found that Activator X "played an influential role in the utilization of minerals, protection from tooth decay, growth and development, reproduction, protection against heart disease, and the functioning of the brain."

The author lays out a clear case for the equivalence of Activator X and vitamin K₂, that they are one and the same.

The K vitamins belong to the class of chemicals called quinones. "There are two natural forms of vitamin K: vitamin K₁ and vitamin K₂. Vitamin K₁ ... is found in the green tissues of plants .... When animals consume vitamin K₁, their tissues convert part of it into vitamin K₂ .... The ability to convert K₁ to K₂ varies widely between species and breeds of animals; it has not been determined in humans."

Recent "research is demonstrating that these two substances are not simply different forms of the same vitamin, but are better seen as two different vitamins."

Vitamin K was first identified in the 1930s, the same period when Dr. Price conducted his research. It was originally thought to only play a role in blood clotting. In 1997 it was first understood that vitamin K was active in much more than clotting. The first efforts to measure K₂ in foods were done in 2006. Details of an optimal quantity of dietary K₂ lie in the future.

Considering whether vitamin K₂ is an essential nutrient, the author wrote "there are a number of lines of evidence strongly suggesting that humans require preformed K₂ in the diet to obtain optimal health." Apparently humans "have a finite ability to absorb vitamin K₁ from plant foods," no more than 200 micrograms per day. Additionally, epidemiological and intervention studies show that dietary K₂ is better than K₁ at establishing optimal health.

Natural food sources of vitamin K₂ include raw butter from animals grazing on rapidly growing green grass, organs and fats of grass-fed animals, fish eggs, bones, and fermented foods such as sauerkraut, cheese, and natto. Natto, made from soy beans, contains the highest amount of K₂ ever measured.

The vitamin K₂ content of these selected foods is in micrograms per 100 grams:

The best way to add K₂ to your diet is by eating foods naturally rich in it, including high X factor butter oil. You can also supplement with K₂. There are two forms of vitamin K₂ supplements available: MK-4 and MK-7. "MK-4 is a synthetic product that is believed to be chemically and physiologically identical to the vitamin K₂ found in animal fats .... Although synthetic, it is effective, and there is no known toxicity." MK-7 is a natural extract of natto. No studies have compared the efficacy of these two forms. MK-7 is more expensive than MK-4.

MK-4 supplements are available from Thorne Research and Carlson Laboratories. Thorne's product is liquid, dissolved in medium-chain tryglycerides with mixed tocopherols. Carlson's product is in dry capsules with cellulose and fillers.

MK-7 supplements are available from Jarrow Formulas and Source Naturals. Jarrow's product is in gel caps, and made from genetically unmodified soy beans; other ingredients are evening primrose oil, medium chain triglycerides, beeswax, and lecithin. Source Naturals' product is in gel caps, they do not say whether their soybeans are GMO; other ingredients include dibasic calcium phosphate, stearic acid, colloidal silicon dioxide, modified cellulose gum, and magnesium stearate.