A study on mice revealed that a low supply of vitamin K reduces its concentration in the brain tissue and alters cognitive functions linked to learning and memory. Researchers have also observed reduced production of new neurons in the hippocampus and high neuronal inflammation. The results were published in The Journal of Nutrition.
Vitamin K is an essential vitamin essential to blood coagulation. It activates proteins that allow blood to coagulate properly. Without vitamin K adequate, even minor injuries can cause excessive bleeding. Vitamin K also contributes to bone health by regulating calcium deposit and supporting bone mineralization.
There are two main forms of this vitamin: vitamin K1 (phylloquinone), found mainly in green leafy vegetables, and vitamin K2 (menaquinone), which includes several subtypes produced by intestinal bacteria and found in fermented foods and animal products. The predominant form of vitamin K in the brain is Ménaquinone-4, a subtype of vitamin K2. The adequate contribution of vitamin K has also been linked to a lower risk of osteoporosis and cardiovascular disease.
The author of the Tong Zheng study and his colleagues noted that previous research has revealed higher concentrations of Menaquinone-4 in the brain of deceased individuals who had a better cognitive function before death. Other studies have combined higher brain levels of Menaquinone-4 with fewer dementia symptoms. In this context, researchers aimed to study how vitamin K deficiency could affect cognitive function in mice.
The study involved C57BL / 6 mice aged sixty 9 months, a consanguinely used consanguine laboratory strain known for its genetic coherence and sensitivity to food and metabolic changes. These characteristics make it an appropriate model for research in nutritional neuroscience.
The mice were randomly assigned to one of the two groups. A group received a control diet containing the recommended quantity of vitamin K1 (1 mg / kg), while the other group received a low vitamin K diet (80 μg / kg). The two regimes were based on a basal mixture deficient in vitamin K and did not include Menadione, a synthetic precursor of vitamin K which is sometimes used in animal diet but is not authorized in human diets due to safety problems.
The mice have been kept on these diets for six months. After this period, a subset of animals underwent two behavioral tests: the Morris water labyrinth (to assess learning and spatial memory) and the new object recognition test (to measure recognition memory). Two weeks after behavioral assessments, mice were euthanized and their brain tissues were analyzed for vitamin K content and neurogenesis markers in the hippocampus.
The researchers reported that more mice died in the weak vitamin K group than in the control group, in particular men, and some have shown signs of visual impairment. Behavioral tests have revealed that mice fed the deficient vitamin-k diet had a lower recognition memory and required more time to learn the space task in the water labyrinth, indicating cognitive deficits.
Examination of the hippocampus showed that the low vitamin K group had significantly fewer proliferating cells and immature neurons compared to the control group, suggesting reduced neurogenesis. In addition, these mice had increased signs of neuroinflammation, including changes in microglial morphology, indicating a change towards a more activated inflammatory state. The analysis of the brain tissues confirmed that the concentrations of Ménaquinone-4 were significantly lower in the vitamin-k deficient group.
“Our data indicate that low consumption of vitamin K has reduced menaquinone-4 concentrations in brain tissues and cognitive function linked to learning and altered memory. This alteration can be linked to the neurogenesis of the reduced hippocampus observed and to a high neural inflammation, “concluded the authors of the study.
The study highlights the effects that vitamin K deficiency has on cognitive functioning and brain physiology. However, it should be noted that it was a study on mice, not on man. While mice and humans share many physiological similarities, they are still very different species. The effects on humans may not be identical.
Paper “Low consumption of vitamin K alters cognition, neurogenesis and raises neuroinflammation in mice C57BL / 6Was written by Tong Zheng, Shannon Marschall, Jasper Weinberg, Xueyan Fu, Andrew Tarr, Barbara Shukitt-Hale and Sarah L Booth.
