Quick answer
NIH says research on copper and Alzheimer's disease is mixed: some studies link higher blood copper with lower risk, others link high amounts with higher risk. One 12-month trial of 8 mg a day found no difference in thinking scores. More research is needed. Ask your doctor about copper supplements if memory is a worry.1,2
Key facts
- NIH says some research links higher blood copper with lower risk of Alzheimer's disease, while other research suggests high amounts might raise it, and more research is needed.1
- In a trial of 68 people with mild Alzheimer's disease, 8 mg of copper a day for 12 months made no significant difference to cognition.2
- Meta-analyses found higher serum copper in people with Alzheimer's disease than in controls, which cannot show that copper caused it.2
- A 2013 expert conference suggested that people at increased risk of Alzheimer's disease choose multivitamins with no copper or iron.2
- NIH says copper accumulation in damaged brain regions might not reflect overall body copper status or intakes.2
What does NIH say about copper and dementia?
NIH's consumer sheet says that studies on copper and Alzheimer's disease conflict. Some research shows that people with higher copper levels in their blood have a lower risk, other research suggests that high amounts might increase risk, and it is not yet known whether low or high copper levels affect the chance of developing the disease. It adds that research is needed on whether supplements containing copper could affect risk or symptoms.1
The health professional sheet reaches the same place. It points out that low copper levels and low activity of copper-dependent enzymes have been reported in the brains of people with the disease, while high copper levels have been found there too, and that these brain findings may not reflect how much copper a person eats.2
What have studies of copper and memory found?
In a study of 3,718 community-dwelling adults aged 65 and older, copper intake overall was not associated with cognitive decline. In the 604 people (16.2%) who ate more saturated and trans fat, the highest copper intake, a median of 2.75 mg a day, went with faster decline than the lowest, a median of 0.88 mg a day.2
Meta-analyses of 10 and of 26 studies found that people with Alzheimer's disease tended to have higher serum copper than healthy adults. A separate analysis of 1,112 adults older than 60 found no difference in serum copper between patients and healthy controls. Studies that compare blood levels at one point cannot show whether copper played a part or is a result of the illness.2
Have copper supplements been tested?
Very little clinical evidence exists. NIH describes one trial in which 68 people aged 50 to 80 with mild Alzheimer's disease took 8 mg of copper a day or placebo for 12 months. It found no significant difference in cognition between the groups.2
NIH says experts at a 2013 conference on nutrition and the brain suggested that people at increased risk of Alzheimer's disease who use multivitamins choose ones without copper or iron, because excess intakes could contribute to cognitive problems in some patients. NIH adds that much more research is needed, so this is a precaution under study, not a settled finding.2
How much copper is too much in general?
The upper limit is 10,000 mcg a day for adults from food, drinks and supplements, and it was set from amounts linked to liver damage, not memory. Long-term high intakes can also cause abdominal pain, cramps, nausea, diarrhea and vomiting, and NIH says copper toxicity is rare in healthy people.1,2
Who should ask a doctor about copper and memory?
- Anyone with Alzheimer's disease, mild cognitive impairment or a family history who is thinking about a supplement with copper.2
- Anyone with memory changes, who should see a doctor whatever they take.2
- Anyone using a multivitamin that lists copper alongside iron.2
- Anyone with Wilson's disease or liver disease.1
Ask your doctor, and bring the Supplement Facts panel of each product you take.
Questions people ask
Is copper linked to dementia?
NIH says studies are mixed and more research is needed. Some link higher blood copper with lower risk of Alzheimer's disease and others link high amounts with higher risk.1
Does low copper cause dementia?
NIH reports low copper and low copper-enzyme activity in the brains of people with Alzheimer's disease, but also high copper there, and says it is not known whether low or high copper affects risk.1,2
Should people at risk of dementia avoid copper supplements?
NIH says experts at a 2013 conference suggested choosing multivitamins without copper or iron, but that much more research is needed. Ask your doctor.2
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Sources
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.