ビタミンKと脳の健康に関する新たな研究(New Research Deepens Understanding of How Vitamin K Affects Brain Health)

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2025-04-07 タフツ大学


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タフツ大学のジャン・メイヤー米国農務省人間栄養研究センター(HNRCA)の研究者らは、ビタミンKの不足が加齢に伴う認知機能の低下に影響を与える可能性を示す研究結果を発表しました。中年期のマウスを用いた実験で、ビタミンK欠乏食を6か月間与えたところ、海馬における神経細胞の増殖が抑制され、炎症が増加することが観察されました。海馬は学習や記憶に重要な脳領域であり、これらの変化は認知機能の低下と関連しています。ビタミンKは、芽キャベツ、ブロッコリー、グリーンピース、ケール、ほうれん草などの緑黄色野菜に豊富に含まれています。研究者らは、ビタミンKが脳機能に保護的な役割を果たす可能性があると指摘し、健康的な食事を通じて十分なビタミンKを摂取することの重要性を強調しています。

 

 

<関連情報>

C57BL/6マウスにおける低ビタミンK摂取は認知、神経新生を障害し、神経炎症を上昇させる Low Vitamin K Intake Impairs Cognition, Neurogenesis, and Elevates Neuroinflammation in C57BL/6 Mice

Tong Zheng, Shannon Marschall, Jasper Weinberg, Xueyan Fu, Andrew Tarr, Barbara Shukitt-Hale, Sarah L Booth
The Journal of Nutrition  Available online: 28 January 2025
DOI:https://doi.org/10.1016/j.tjnut.2025.01.023

Abstract

Background
In addition to its important roles in blood coagulation and bone formation, vitamin K (VK) contributes to brain function. Low dietary VK intake, which is common among older adults, is associated with age-related cognitive impairment.

Objectives
To elucidate the biological mechanisms underlying VK’s effects on cognition, we investigated the effects of low VK (LVK) intake on cognition in C57BL/6 mice.

Methods
Male and female 9-mo-old C57BL/6 mice (n = 60) were fed an LVK diet or a control diet for 6 mo. Behavioral tests were performed on a subset of mice (n = 26) at 15 mo, and brain tissues were collected for follow-up analyses.

Results
Menaquinone-4, the predominant VK form in the brain, was significantly lower in LVK mice compared to controls (15.6 ± 13.3 compared with 189 ± 186 pmol/g, respectively, P < 0.01). LVK mice showed reduced recognition memory in the novel object test by spending a lower percentage of time exploring the novel object compared to controls (47.45% ± 4.17 compared with 58.08% ± 3.03, P = 0.04). They also spent a significantly longer time learning the task of locating the platform in the Morris water maze test. Within the hippocampal dentate gyrus, LVK mice had a significantly lower number of proliferating cells and fewer newly generated immature neurons compared to control mice. Additionally, more activated microglia cells were identified in the LVK mice.

Conclusions
Our data indicate that LVK intake reduced menaquinone-4 concentrations in brain tissues and impaired learning- and memory-related cognitive function. This impairment may be related to the observed reduced hippocampal neurogenesis and elevated neural inflammation.

医療・健康
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