Vitamin K: foods, health benefits and side effects!
Vitamin K is a nutrient essential to life, as t participates in many important functions of the body!
Table of Contents
What is Vitamin K?
Vitamin K was discovered in 1929 and characterized as an essential nutrient for blood clotting.
The original discovery was reported in a German scientific journal, where it was called “Koagulations-Vitamin” and from the initial letter “K” comes the name of the Vitamin.
There are two main forms of vitamin K:[1]
- Vitamin K1 (phylloquinone): found in plant foods such as leafy vegetables,
- Vitamin K2 (menaquinone): found in animal foods and fermented foods.
Vitamin K2 can be further divided into several different subtypes. The most important are: MK-4 and MK-7.[2]
More specifically, bacteria in the gut flora can convert K1 into vitamin K2 (menaquinone). Chemically speaking, they elongate the isoprenoid side chain of vitamin K1 to produce a number of forms of vitamin K2, such as the MK-7 to MK-11 homologues of vitamin K2. All forms of K2 except MK-4 can only be produced by bacteria during anaerobic respiration. [2]
It is worth noting that Vitamin K3 (menadione) is a synthetic water-soluble form of Vitamin K which, however, is rarely used therapeutically as it is considered to interfere with the function of glutathione (a powerful antioxidant). [9]
Vitamin K is a fat-soluble vitamin which, unlike the other fat-soluble vitamins (A, D, E), circulates in small amounts in the blood, as it is metabolized very quickly and then excreted.
Vitamin K and foods
Foods with Vitamin K (Vitamin K1) that one will encounter are: [8]
- green leafy vegetables (spinach, garlic, kale)
- certain biologic oils (e.g. soybean oil, rapeseed oil),
- fruits (kiwi, dried figs, avocado, blackberries, grapes, pear, mango, papaya) and nuts.
On the other hand, food-rich sources of Vitamin K2 are: [8]
- Meat (e.g. beef, chicken)
- dairy products,
- fish (salmon, shrimp)
- eggs
- natto
It is worth noting that Vitamin K1 can also be found in animal foods, but in very small quantities.
What causes Vitamin K deficiency?
It is practically impossible for someone following a Mediterranean diet to be deficient in Vitamin K. Theoretically and in very rare cases (mainly due to malabsorption conditions or due to liver disease), we would observe failure to heal wounds and bleeding due to reduced prothrombin levels.
In addition, low levels of Vitamin K are also blamed for the occurrence of osteoporosis and the existence of cardiac problems.
Who is at risk of Vitamin K deficiency?
The people who should take more care of the levels of Vitamin K in the body are:
- people with malabsorption syndrome (Crohn’s disease or active celiac disease)
- People who consume large amounts of alcohol
- People taking medication that interferes with the metabolism or absorption of Vitamin K (bile acid sequestrants, anti-obesity drugs)
- People taking antibiotics for a long time (due to destruction of the intestinal flora)
- Malnourished people
How much Vitamin K do I need?
To determine the required daily dose we would make a division based on age and gender[7]
| Age | Recommended Daily Intake |
| Children 0-6 months old | 2 mcg/day |
| Children 7-12 months old | 2,5 mcg/day |
| Children 1-3 years old | 30 mcg/day |
| Children 4-8 years old | 55 mcg/day |
| Children 9-13 years old | 60 mcg/day |
| Girls 14-18 years old | 75 mcg/day |
| Boys 14-18 years old | 75 mcg/day |
| Women 19 years old and over | 90 mcg/day |
| Men 19 years old and over | 120 mcg/day |
| Women, pregnant or lactating (19-50) | 90 mcg/day |
Vitamin K and properties
Some scientists have suggested that the roles and properties of Vitamins K1 and K2 are quite different and many believe they should be classified as separate Vitamins.
In some human studies, researchers observed that dietary supplements with vitamin K2 improved bone and heart health, while vitamin K1 did not produce the desired benefits. Of course, further studies are needed to draw safer conclusions. In a more general context, the actions of Vitamin K are as follows: [3]
Blood clotting
It is also known according to official health claims from the European Food Safety Authority (EFSA), EU regulation no. 432/2012, how Vitamin K contributes to normal blood clotting. This is the case if one considers that the proteins (such as coagulation factor II-prothrombin which is a serine protease) involved in the blood clotting process are dependent on vitamin K.
Bone health
Vitamin K2 plays a key role in the metabolism of calcium, the main mineral found in bones and teeth.
Vitamin K2 activates osteocalcin. Osteocalcin is a gamma-carboxylated protein of the bone matrix and is used as an indicator of bone metabolism and the processes of bone degradation and remodeling. In addition, its production is stimulated by 1,25 dihydroxy-vitamin D. [5]
Vitamin K2 prevents the reduction of bone density in postmenopausal women as well as in older people. It is worth mentioning that for maximum results, the co-administration of Vitamin K with Vitamin D is recommended.
Heart health
Vitamin K acts as a “traffic warden”, one would say. That is, it determines where calcium will be directed through the activation of osteocalcin and the Matrix GLA protein. More specifically, vitamin K is thought to prevent calcium from being deposited in the arteries and “directs” it to the bones. [5]
Calcium buildup in the arteries around the heart is a huge risk factor for heart disease. Anything that can reduce this calcium build-up can also help prevent heart disease.
In a 10-year study, people with the highest intake of vitamin K2 were 52% less likely to develop calcification of the arteries and had a 57% lower risk of dying from heart disease.[4]
Another study of 16,057 women found that participants with the highest intake of vitamin K2 had a much lower risk of heart disease—for every 10 mcg of K2 they consumed per day, their risk of heart disease decreased by 9%. [4]
Contraindications-Interactions
People taking medication that affects blood clottoing should avoid dietary supplements with vitamin K, as they antagonize its action. Generally it is wise to inform your doctor first in case you are on any medication, so as to avoid worse situations, such as bleeding.
They should also avoid supplemental intake of herbs and ingredients such as garlic, cinnamon, Vitamin E, cordyceps, devil’s claw, siberian-panax, ginseng, stinging nettle, ginkgo biloba, feverfew, red clover, and phytoestrogens. [6]
It can be taken by pregnant and lactating women after doctor’s approval.
Vitamin K and side effects
Side effects from taking Vitamin K2 are extremely rare. In some cases, however, itching, erythema, dizziness, nausea and hypotension may be observed. [6]
It is clear that Vitamin K plays a crucial role in the health of the whole organism. Make sure you get a sufficient amount of it either from the diet or from food supplements that you can easily find at Vita4you.gr.
Bibliography
- Vitamin K. The Nutrition Source
- Vitamin K Metabolism
- Vitamins K1 and K2: The Emerging Group of Vitamins Required for Human Health
- Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study
- Vitamin K Deficiency
- vitamin K1
- Vitamin K
- 20 Foods That Are High in Vitamin K
- Vitamin K: Redox-modulation, prevention of mitochondrial dysfunction and anticancer effect
Panagiotis Nevras
Pharmacist, graduate of School of Pharmacy, Aristotle University of Thessaloniki, specializing in Clinical Pharmacology, Pharmacognosy and Pharmaceutical Biotechnology, Gkatzouli Pharmacy head and member of the editorial team of vita4you.gr.
MOREDisclaimer
The content of this blogspot is not and can not be considered as medical advice, diagnosis or treatment. All information is provided to readers solely for informational purposes. There is no intention to substitute this content for personalized medical advice, diagnosis, prognosis or treatment.
According To Vitamin K2 industry analysis, Certain individuals need to be more cautious about their vitamin K levels in the body. This includes those with malabsorption syndromes like Crohn’s disease or active celiac disease, as these conditions can hinder the proper absorption of nutrients, including vitamin K. People who consume large amounts of alcohol should also be mindful, as alcohol can interfere with the metabolism and absorption of vitamin K. Additionally, individuals taking medications that affect vitamin K metabolism or absorption, such as bile acid sequestrants or anti-obesity drugs, should take extra care.