Higher vitamin C levels linked to greater gray matter volume and stronger default mode network connectivity (which is associated with attention and autobiographical memory) in a study of 2,044 adults over 64, suggesting a potential role in preserving cognitive function during aging

>“Our study demonstrates that higher plasma vitamin C levels are associated with better preserved structural connectivity of the default mode network (DMN), a key brain network involved in cognitive function. This finding generates the exciting hypothesis that a diet rich in vitamin C might play a supportive role in maintaining brain health and mitigating age-related cognitive decline in older adults,” Dr Tomohiro Shintaku at Hirosaki University, Japan said.
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>“It truly highlights the potential impact of our everyday dietary habits on our brain structures.”
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>For the study, published in the journal PLOS One, researchers at Hirosaki University, Japan analysed magnetic resonance imaging (MRI) scans and plasma vitamin C levels of 2,044 Japanese adults over the age of 64.
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>They measured each participant’s gray and white brain matter and evaluated connectivity in the default mode network, which is associated with attention and autobiographical memory.
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>After accounting for factors such as age, activity levels and education level, researchers found that participants with lower plasma vitamin C levels tended to have lower gray matter volume, as well as lower connectivity within the default mode network.
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>These findings suggest vitamin C could support cognitive function and counteract cognitive decline. But the findings only showed an association between vitamin C levels and brain health and not cause and effect.
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[Plasma vitamin C levels are associated with brain structural networks on MRI: A large cohort study | PLOS One](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0348504)

How does a diet with high vitamin c look like in the context of the study?

This is purely anecdotal, but I recently started supplementing vitamin C after I started having scurvy symptoms (I apparently have a vitamin C malabsorption issue that went undiagnosed and my diet is pretty poor, not poor enough to cause scurvy in a normal person but very much enough to do it in me), and aside from scurvy subsiding almost immediately, ADHD meds started working (I’ve been on methylphenidate for a moment and it did very little, now it helps me massively), I was able to retain information accurately while studying again to the point that I’ll be going back to college soon, and I’m reading a whole book a week again after not doing it since middle school

Edit: oh I forgot, my IQ had gone down by 22 points between 15 years old and 21, and I did feel a lot stupider