A 2014 article was recently forwarded to me by a woman who takes the GDP class. It’s a pretty interesting meta-analysis of a number of articles about vitamin K2, the version found in our bodies and a synthetic yet identical version made in a lab. Analysis showed that Menetetrenone (the synthetic version of K2) modestly increased the amount of bone deposition in the spine, as well as optimum blood-levels of bone-forming calcium, and decreased the numbers of spinal fractures in post-menopausal women.Vitamin K is a fat-soluble vitamin with possible side effects of high intake levels being gastrointestinal tract symptoms such as discomfort of stomach and diarrhea. normal dietary amounts would not cause any issues. A contraindication of menatetrenone supplementation is warfarin (an anticoagulant) use, because vitamin K is a coagulant (blood clotter).
Vitamin K1 is supplied by the diet, especially in green leafy vegetables, while vitamin K2 is synthesized by bacteria in the gut as well as in fermented foods. This indicates the possible need for a healthy biome and gut bacteria, which as you know is nurtured by adequate fiber in the diet. The gut biome is adversely affected by antibiotics, so its possible that the downstream effect of antibiotics can lead to gut bacteria compromise, vitamin K2 decrease to the point of affecting blood levels of Ca++ and therefore bone density. This intestinal source of vitaminK2 is still under investigation, and a number of foods also contain vitamin K2, notably natto as the richest source (fermented soy beans), cheese and curds. Apart from the blood thinning contraindication, menatetrenone (vitamin K2) does not cause any serious side effects regardless of its dose. This indicates to me that doctors should be having conversations with their post-menopausal female patients about perhaps adding Vitamin K2-rich foods to their diets.