A recent large study has raised an interesting question about something most of us associate simply with oranges and lemons: could vitamin C also have an important role in healthy brain ageing?
Researchers studied 2,044 older adults, with a median age of 69, and measured vitamin C levels in their blood alongside detailed MRI scans of the brain.
They found that people with lower plasma vitamin C levels tended to have lower grey-matter volume and differences in the brain’s default mode network—a network involved in functions such as memory, self-reflection and thinking about the future.
The findings remained significant even after researchers accounted for factors such as age, sex, education, diabetes, high blood pressure, smoking, alcohol consumption and physical activity.
However, there is an important distinction: this study found an association, not proof of cause and effect. We cannot conclude from this study alone that low vitamin C causes the brain to age faster, or that taking high-dose vitamin C supplements will protect us from dementia.
Is this the same vitamin C found in lemons and oranges?
Yes.
Vitamin C, also known as ascorbic acid, is naturally present in citrus fruits such as lemons, oranges and grapefruit. It is also found abundantly in foods such as kiwi, strawberries, peppers, broccoli and Brussels sprouts.
Is vitamin C an antioxidant?
Yes - but vitamin C is not simply another name for an antioxidant.
Vitamin C is one of several antioxidants that help protect our cells against oxidative stress caused by reactive molecules often called free radicals.
The brain is particularly interesting in this respect because it consumes large amounts of oxygen and is metabolically very active. Vitamin C is also involved in several other biological processes, including collagen formation, iron absorption, immune function and some aspects of neurotransmitter biology.
Perhaps the most practical message from this research is not to rush out and buy high-dose supplements, but to remember how important a varied diet rich in fruits and vegetables may be throughout life.
Sometimes something as ordinary as an orange, a kiwi—or a squeeze of lemon—is carrying considerably more biology than we realise.
Reference: Nagaya H. et al., Plasma vitamin C levels are associated with brain structural networks on MRI: A large cohort study, PLOS ONE, June 2026.
On the side note: If you are curious ?
Does more grey matter mean a healthier or more intelligent brain ?
Ans: More grey matter does not automatically mean a healthier or more intelligent brain.
Grey-matter volume can be a useful indicator because significant loss in certain brain regions may occur with ageing, neurodegenerative disease, stroke, or other forms of brain injury. However, overall brain health depends on far more than volume alone. The health of neurons and synapses, the integrity of white-matter connections, blood supply, metabolism, inflammation, and how efficiently different brain networks communicate are all equally important.
- Grey matter = regions rich in neuron cell bodies and local processing.
- White matter = mainly the long myelinated connections linking different brain regions.
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