The double role of vitamin K2
Are you leggy but calcified? Then you're not alone!
Osteoporosis and atherosclerosis are two health problems that often co-exist in the older population. Initially, these have been seen as independent age-related diseases. However, an increasing number of studies are showing that these health problems may actually be linked. Perhaps osteoporosis is not due to a lack of calcium, but that calcium has ended up in the wrong place? And what can we do about it?
There are many nutrients that affect these processes. Examples include vitamins A, D and K2 and the minerals magnesium and boron.
This article focuses on the role of vitamin K2.
The article is based on the study "The Dual Role of Vitamin K2 in "Bone-Vascular Crosstalk": Opposite Effects on Bone Loss and Vascular Calcification", published in the journal Nutrients in 2021.
What is osteoporosis/osteoporosis?
Did you know that Norway is the world leader in osteoporosis? At the same time, we are also one of the most milk-drinking nations in the world. Where is the logic in that? It probably lies in the fact that we don't lack calcium, but that we lack the auxiliary substances to get calcium where it needs to go.
Osteoporosis is the most common skeletal disease affecting older men and women. The disease is caused by an imbalance between bone formation and bone breakdown. This in turn results in loss of bone mass and lower quality of bone mass.
Many women experience what we call "primary osteoporosis" after the menopause. The reduction in oestrogen levels is associated with an inflammatory condition, which in turn leads to increased degradation of the bones. Secondary osteoporosis occurs in both women and men, but the mechanisms are not fully understood.
What is atherosclerosis?
Atherosclerosis is defined as the deposition of minerals in the vessel wall. Risk factors for atherosclerosis are ageing, high blood pressure, diabetes and chronic kidney disease. Atherosclerosis is an important risk factor for other cardiovascular diseases, such as stroke.
Previously, atherosclerosis was thought to be an uncontrolled process caused solely by abnormal precipitation of calcium. Today, researchers believe that it is an active, regulated event that is closely linked to bone formation and bone metabolism.
What is vitamin K2?
Vitamin K was discovered in the 1930s by the Danish chemist Hendrik Dam, who was studying cholesterol. He observed that chickens fed a low-fat diet had an increased tendency to bleed. Vitamin K is fat-soluble, so it follows the fat in the food. A low-fat diet can therefore provide little vitamin K. Through further experiments, Dam managed to identify the coagulation vitamin (abbreviated vitamin K).
We often talk about vitamin K1 and vitamin K2, which are two subgroups of this vitamin family.
Vitamin K2 is also a family of fat-soluble compounds that we call "Menaquinones (MK)". Vitamin K1 is called phylloquinones. Menaquinones have recently received special attention because they play an important role in maintaining the calcium balance in the body. Vitamin K2 deficiency in particular is related to what is known as the "calcium paradox". This phenomenon is characterized by low calcium in the skeleton (osteoporosis) and high calcium in the walls of the blood vessels (atherosclerosis).
Both vitamin K1 and K2 activate proteins that in turn affect calcium metabolism. However, they act on slightly different proteins. While vitamin K1 activates proteins in the liver that are important for the coagulation process, vitamin K2 activates proteins, such as osteocalcin, that are important for the cells that build calcium into the skeleton. By activating these proteins, vitamin K2 regulates the 'calcium paradox' by reducing calcium deposition in the vessel walls and increasing it in the bone tissue.
Several studies show that the bone loss in osteoporosis can increase the risk of atherosclerosis and cardiovascular disease and vice versa. Cardiovascular disease increases the risk of bone fractures.
Most of the production of vitamin K2 in the human body takes place in the gut, where it is synthesized by intestinal bacteria of the genera Bacteroides, Lactococcus and Escherichia Coli. However, the amount of vitamin K2 from the intestinal bacteria is poorly absorbed and is not able to reach high enough concentration to exercise the physiological functions that we write here. Therefore, we also need vitamin K2 through food/supplements. Examples of foods that contain vitamin K2 are animal foods (meat and egg yolk), bacterially fermented cheese and the traditional Japanese dish called Natto, i.e. fermented soybeans. In SanOmega Premium , we have added MK7.
Characterized by low-grade inflammation
Both bone loss and atherosclerosis are characterized by chronic low-grade inflammation and oxidative stress. Studies have shown that vitamin K2, in addition to implementing calcium into the skeleton, also reduces the activity of inflammatory cells. Nutrients such as the omega-3 fatty acid EPA and the minerals magnesium and boron also play an important role in inflammatory reactions.
https://pubmed.ncbi.nlm.nih.gov/33917175/
