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Selenium and brain ageing: what the research says
Report author: Fourage · Report written in January 2026 · Article published on 20 October 2026
A literature review on a frequently cited trace element, with data on intake in Spain.
Selenium is an essential trace element: it is part of antioxidant enzymes (selenoproteins). A literature review written in January 2026 by a member of the association looks at the research on its link with cognitive decline.
Hypotheses, not certainties
Some observational studies have found lower selenium levels in people with cognitive disorders. Such associations do not prove cause and effect, and supplementation trials have not shown a preventive effect on dementia. The question remains open.
Intake in Spain
The report gathers data on selenium intake in Spain. Intake depends on soil content and diet (fish, eggs, meat, cereals).
Caution
Too much selenium is toxic; the European Food Safety Authority (EFSA) sets a tolerable upper intake level. Any supplementation should be discussed with a doctor.
- An essential trace element, but toxic at high doses.
- Link with cognitive decline: a debated hypothesis, not proven.
- This article is not medical advice.
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Official sources
Each article is based on a report whose date of writing is shown, and reflects its author’s analysis at that date. General information only: neither legal nor medical advice. The full report can be requested from the association.
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