The risk of dementia and neurological disorders increases with age. Diet plays an important role and it is assumed that the widespread lack of vitamin K2 is particularly relevant. In order to test this hypothesis, a group of scientists measured levels of vitamin K2 in the brains of deceased seniors. They found significantly fewer cases of cognitive decline, dementia, and Alzheimer’s disease in brains with higher K2 levels. This has something to do with the fact that vitamin K2 counteracts atherosclerosis, accumulation of harmful protein, and brain inflammation. The study is published in the journal Alzheimer’s & Dementia and sheds a whole new light on vitamin K’s potential role in brain health and the importance of getting enough of this nutrient.
The number of seniors with cognitive decline, dementia, and Alzheimer’s disease is on the rise, which makes it increasingly important to understand the underlying pathological mechanisms. It is generally accepted that diet plays a major role, including the intake of vitamin K, a nutrient of which many older are deficient in. It’s important to know that vitamin K occurs as vitamin K1 and vitamin K2, and both forms of the vitamin have different functions.
We primarily get vitamin K1 (phylloquinone) from cabbage and green vegetables such as spinach and avocado, and K1 is important for the blood’s ability to coagulate. Vitamin K1 is converted into vitamin K2 (menaquinone) by gut bacteria. However, the amounts of K2 in the body are limited. The best sources of vitamin K2 are liver, chicken, butter, egg yolk, eel, and fermented foods such as sauerkraut, cheese, and Natto (a Japanese dish).
Vitamin K2 is particularly important for our circulatory system, which is because it activates a protein named matrix GLA, MGP that removes excess calcium from our blood vessels. That way, vitamin K2 counteracts atherosclerosis. Vitamin K2 also helps the body synthesize other proteins and enzymes that are important for heart health.
To date, scientists have only assessed the body’s vitamin K status by looking at the diet and measuring circulating biomarkers such as uncarboxylated MGP (inactive MGP), while less is known about the different forms and their importance for brain health.
Vitamin K2 supports cognitive functions and brain health in different ways
In their new study, the scientists wanted to look closer at vitamin K’s impact on cognitive function and the risk of developing dementia. They measured levels of vitamin K2 and related metabolites in four different brain regions in the brains of 325 deceased seniors, all of whom were already part of the Rush Memory Aging Project (MAP) and had given their consent to further studies.
The scientists measured the type of vitamin K2 called menaquinone-4 (MK4) in the participants’ brains and found that higher levels were related to the following significant changes:
- 17-20 percent lower risk of developing mild cognitive impairment and dementia
- Less build-up of harmful tau protein that normally contributes to the development of Alzheimer’s disease
- Less build-up of another type of harmful proteins (Lewy bodies) that are related to dementia in people with Alzheimer’s disease and Parkinson’s disease.
The new study is published in the journal Alzheimer’s & Dementia. Here, the scientists look closer at vitamin K-dependent metabolites such as MGP, protein S, GAS6, and gamma-glutamyl-carboxylase and their different functions in relation to brain health and cognitive functions.
As mentioned, vitamin K2 (via MGP) is important for circulatory health and the prevention of atherosclerosis, including arterial clogging in the minute blood vessels in the brain that provide oxygen and nutrients to neurons and other cells. The other vitamin K-dependent proteins help remove diseases or worn-out cells that have self-destructed (apoptosis). They also counteract inflammation that can harm healthy tissues such as the brain. In addition, vitamin K2 is important for the body’s metabolism of sphingolipids, which are fats that are found in the neuronal membranes and are important for cognitive functions.
Altogether, vitamin K2 and the metabolites have a host of different functions that are important for our brain health. It is quite easy to increase your intake of vitamin K2 from dietary sources of from supplements, and increased focus on this nutrient can mean a lot for public health and quality of life.
How to get enough vitamin K2
There are no official recommendations for vitamin K2 intake, only for vitamin K1 (75 micrograms/day). The ability to convert vitamin K1 into K2 varies a lot from person to person. Although the jury is still out on the question regarding optimal vitamin K2 intake, more and more studies indicate that comparatively high doses in the range between 75-180 micrograms daily may be beneficial. No side effects have been observed with such doses.
Reasons for lacking vitamin K2
- Unhealthy diets
- Unhealthy gut flora
- Prolonged use of warfarin (vitamin K antagonist used to prevent blood clots), antibiotics, acetylsalicylic acid, and cholesterol-lowering statins
Sarah L. Booth. Association of vitamin K with cognitive decline and neuropathology in community-dwelling older persons. Alzheimer’s & Dementia, 2022
Essa Hariri et al. Vitamin K2 – a neglected player in cardiovascular health: a narrative review. Open Heart. 2021
8 Foods High in Vitamin K2 and Why You Need It (webmd.com)
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