Altered Iron and Selenium Levels Linked to Higher Dementia Risk, Suggests Study
USA: Data from participants in the National Alzheimer’s Coordinating Center showed that lower plasma iron and higher plasma selenium levels were each associated with an increased risk of dementia. The findings suggest that abnormalities in trace-element status may be linked to dementia risk, although the observational nature of the data does not establish a causal relationship.
The study, published in Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring, was conducted by Xin Wang of the University of Michigan, Ann Arbor, Michigan, United States, and colleagues. Researchers examined whether circulating levels of essential trace elements were associated with Alzheimer’s disease (AD) and dementia risk.
Trace elements such as iron, manganese, cobalt, copper, zinc, selenium, and molybdenum are required for several biological processes. However, disturbances in their levels have been proposed to contribute to mechanisms involved in neurodegeneration and AD. Despite this, epidemiological evidence examining multiple essential elements together has remained limited.
The researchers analyzed data from 1,737 participants in the National Alzheimer’s Coordinating Center. Cross-sectional analyses examined existing AD and all-cause dementia, while longitudinal analyses focused on 1,101 participants who were dementia-free at baseline. These participants were followed for a median of approximately 2.05 years.
The investigators evaluated plasma concentrations of seven essential trace elements—manganese, iron, cobalt, copper, zinc, selenium and molybdenum. Statistical models were used to assess the relationship between individual elements and dementia outcomes, as well as the combined influence of the seven-element mixture.
Key Findings:
- A simultaneous one-quartile increase in all seven trace elements was associated with 31% lower odds of prevalent Alzheimer’s disease (OR, 0.69; 95% CI, 0.52–0.91).
- Higher plasma iron levels were associated with a lower risk of developing Alzheimer’s disease, with the highest iron quartile showing a 59% lower risk than the lowest quartile (HR, 0.41).
- Higher plasma selenium levels were associated with increased incident Alzheimer’s disease risk, with the highest quartile having more than twice the risk compared with the lowest quartile (HR, 2.42).
- Higher plasma selenium levels were also associated with an increased risk of all-cause dementia.
The authors cautioned that the findings should be interpreted carefully because the short follow-up period and single-time-point trace-element measurements may not reflect long-term exposure and could allow reverse causation. Measuring total plasma levels rather than specific chemical forms of the elements may also limit interpretation of their biological effects. Residual confounding from diet, supplement use, and environmental exposures could not be ruled out, and the clinically referred and volunteer-based NACC population may limit the generalizability of the findings.
Overall, iron and selenium emerged as potentially modifiable factors associated with dementia risk, but the study does not establish that altering their levels can prevent dementia. The researchers recommended larger prospective studies with longer follow-up and repeated measurements to confirm the associations and assess whether targeted nutritional strategies could help prevent dementia.
Reference:
Wang X, Albin RL, Giordani B, Mukherjee B, Paulson HL, Bakulski KM. Associations between essential trace elements and Alzheimer's disease and related dementias. Alzheimers Dement (Amst). 2026 Aug 26;18(3):e70467. doi: 10.1002/dad2.70467. PMID: 42657258; PMCID: PMC13508569.
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