About vitamin D, vitamin K2 and the complexities of intraspecific competition
The intraspecific struggle is always the most severe. Representatives of the same species need the same resources: territory, sexual partners, food supply, or clients on Instagram. Even when the wolf is chasing hares, the hares are not fighting with the wolf, but with each other - the one who runs faster than the competitor wins.
Identifying a deficiency and prescribing vitamin D is a simple matter, so there are more than enough thoughtful Instagram doctors who treat the causes, and not the symptoms. Answers that are simple and comfortable for people always sell well. But the resources of the food base are limited, so thoughtful doctors have to constantly flaunt new sacred knowledge from closed telegram channels in order to stand out from competitors. Because of this, non-standard test references, tricky ways of taking drugs [Vigantol mix, but do not shake up] or designer combinations of already known dietary supplements appear.
The hype has become popular that vitamin D cannot be taken without vitamin K2. They argue that without vitamin K, vitamin D is poorly absorbed, does not reveal its effects on bone tissue and the risk of toxic manifestations is higher. With regard to the effect on bone tissue, it is still possible to dream up the intersection points: vitamin K is necessary for the carboxylation of osteocalcin, which is involved in the mineralization of bone tissue. How vitamin D and vitamin K affect each other's absorption - my imagination and artisan knowledge were not enough.
I am a simple person: the question arises - I am opening the latest guides, Williams endocrinology or UpToDate.
I have not found any mention of vitamin K in any decent guide on vitamin D. On 2 thousand pages of 2020 Williams endocrinology, vitamin K is mentioned 3 times in the context of the synthesis of coagulation factors and osteocalcin. UpToDate experts write that they do not recommend routine vitamin K prescription for the prevention of chronic diseases and bone health. The connection with vitamin D is not written at all.
As a doctor-artisan, I consider this question closed for myself.
But to give credit to thoughtful doctors looking for a cause, I will mention a couple of studies on the topic. Indeed, there are retrospective studies showing that patients who consumed a lot of vitamin K have less pronounced coronary artery calcification. But there are no prospective studies that prove causation. And there are Japanese studies in which vitamin K intake has a positive effect on bone density and fracture risk. However, subsequent studies have not confirmed this.
Therefore, no revolutions took place. There is no reason to revise vitamin D practice. Just a round of intraspecific competition, where fantasies of sacred knowledge are used instead of bright feathers or fast legs.