Vitamin K: From Blood Clotting to Healthy Aging

That we don’t bleed when we get injured, or that tissues regenerate when damaged by an external agent, are two of the main functions of vitamin K. Although less well known than vitamin C or D, it may hold the secret to a healthy lifestyle. . aging.

vitamins are not boring

Now it may seem to us that the study of vitamins is a boring business, but a hundred years ago they were on the crest of a scientific wave. The name “vitamin” was proposed by the biochemist Casimir Funk in 1912. He used it to refer to the main substances in the diet in small amounts to maintain health.

From the isolation of thiamine (vitamin B1) in 1910 to the isolation of folic acid in 1941, the study of these substances has been a very active field in chemistry and physiology. Nobel Prizes in 1929, 1930, 1934, 1937, 1938 and 1943 were awarded for identifying and describing the functions of various vitamins.

In particular, the history of vitamin K (1943 Nobel Prize winner) is closely related to coagulation. The name comes from the Danish for “coagulation” and from the previously proposed vitamin J (flavin), now renamed vitamin B2. It was discovered by finding in the diet a substance with an antihemorrhagic effect, that is, preventing bleeding.

Soon after, the presence of substances in poor feed was discovered that had the opposite effect on cattle: the animals began to bleed spontaneously.

When these prohemorrhagic compounds were isolated, their structure was found to be similar to that of vitamin K. This led to their medical use as the first oral anticoagulants to prevent blood clots. This is what we call an antivitamin K, such as acenocoumarol (the popular Syntrom®), which works by competing with vitamin K.

How does vitamin K work?

Although the effect of this vitamin on coagulation has been known since the 1950s and antivitamin K has been used, it wasn’t until the 1970s that we really began to understand how it works.

Vitamin K is needed to change the structure of certain amino acids that make up several proteins (less than twenty), which we call “vitamin K-dependent proteins.” Prothrombin, which is the central regulator of the coagulation cascade, occupies a prominent place among them.

The modification that vitamin K interferes with is irreversible and leads to the formation of a new amino acid called gamma-carboxyglutamic acid. This amino acid is able to trap calcium ions like tweezers. The combination of the protein with calcium allows it to perform specific functions, including binding to the outside of cell membranes or to certain cellular receptors, depending on the calcium concentration.

Mammals are not the only animals that use vitamin K. Having gone a little further in evolution, the mollusk Textile cone it uses vitamin K dependent neurotoxins to hunt its prey. And although the shell in the photo seems harmless, be careful, because more than thirty fatal poisonings have been described from its bites.

Vitamin K dependent tissue repair systems

It came as a surprise to those of us working in this field when, in the 1990s, a new vitamin K-dependent protein, very similar to blood clotting proteins, was isolated that was able to activate a family of cellular receptors associated with these proteins. growth hormones. This protein, GAS6, and its coagulation-regulating partner, protein S, are able to help immune system cells repair damaged tissues.

Its mechanism of action is explained in two strokes. What they do to regulate inflammation is to help eliminate cells that are in the process of irreversible death and regenerate new cells. Our research has shown that, in addition, they cause fibrosis in organs such as the liver, a very important process in response to chemical and nutritional damage such as alcohol, certain diets or toxic substances.

Damage to the cells that make up our organs, accumulated over the years of life, is part of the aging process. Thus, over the years, the importance of repair systems, such as those represented by these vitamin K-dependent proteins, increases.

To support healthy aging, various scientists have suggested increasing vitamin K intake in the elderly. It can prevent vascular calcification, improve bone health, and strengthen tissue repair systems.

In fact, vitamin K deficiency in humans is very rare and occurs mainly in newborns, since vitamin K practically does not cross the placental barrier. Therefore, at birth, the deficiency is replenished with a dose of vitamin K to prevent possible bleeding, which is rare, but with devastating consequences. In Europe, it has been done for more than 50 years to almost all newborns.

More spinach, kale and chard

In adults, vitamin K deficiency occurs only when intestinal absorption is impaired. This is due to the fact that the intestinal flora itself produces vitamin K precursors, so a varied diet is enough to cover the daily need for this trace element.

However, for these new aging-related functions, such as reducing osteoporosis and vascular calcification, increasing vitamin K intake by eating vitamin K-rich foods (spinach, chard, kale, and green leafy vegetables in general) may improve health. .

And while much remains to be explored, it seems that we will add to these benefits the maintenance of repair systems and the regulation of inflammation.

Pablo Garcia de Frutos, Director of the Hemostasis and Immunity Group, Biomedical Research Institute of Barcelona (IIBB – CSIC)

This article was originally published on The Conversation. Read the original.