A cluster of recent reports and scientific papers has put a spotlight on copper, a micronutrient most people think about only in passing. New analyses of large US datasets suggest that modestly higher dietary copper is associated with better cognitive test scores in people aged 60 and over, while long‑running brain autopsy research links higher brain copper with slower cognitive decline and less Alzheimer’s pathology. At the same time, clinicians warn that true copper deficiency — while uncommon — can cause persistent fatigue, numbness and balance problems, and that certain patients (bariatric surgery, malabsorption, heavy zinc use) are at risk. For ordinary readers the takeaway is practical: most people can meet needs with a varied diet that includes shellfish, liver, nuts, seeds, tofu and whole grains, but anyone with unexplained fatigue or neurological symptoms should consult a doctor rather than self‑supplement. (Sources: Telegraph [news summary], Scientific Reports [NHANES analysis], NIH Office of Dietary Supplements, MAP autopsy study.) See links in the text for full sources.
Copper’s role and why the topic matters to Thai readers. Copper is a trace mineral required in very small amounts, but it plays outsized roles in the body: it is a co‑factor for enzymes involved in energy production inside cells, iron metabolism (so iron can be used to make red blood cells), formation of connective tissue and bone, antioxidant defence (superoxide dismutase) and neurotransmitter synthesis that supports cognition and nerve health. The US National Institutes of Health Office of Dietary Supplements (ODS) summarises these functions and lists common copper‑rich foods such as shellfish, organ meats, nuts, seeds, whole grains, soy foods and dark chocolate — many of which are familiar to Thai diets in local form (prawns, mussels, squid, liver dishes, tofu, cashew and peanuts) [ODS fact sheet]. Because Thailand’s cuisine traditionally includes a wide variety of seafood, soy and nuts, outright dietary copper deficiency should be uncommon in the general population — but modern factors such as weight‑loss surgery, inflammatory bowel disease, prolonged high doses of zinc and restrictive diets can create gaps that matter for individual patients. [Telegraph explainer; ODS].
What the new research found. A cross‑sectional analysis published in Scientific Reports used dietary recall data from the US National Health and Nutrition Examination Survey (NHANES, 2011–2014) to examine links between estimated copper intake and objective cognitive test scores in US adults aged 60 and older. The study sample included 2,420 older adults; researchers divided participants into quartiles of copper intake and tested cognition with a battery that included processing speed, verbal fluency and memory tasks. After adjusting for demographic, clinical and dietary confounders (including zinc, iron and saturated fat), higher dietary copper was associated with higher cognitive scores across multiple tests, and a dose–response trend was seen up to a threshold. The authors reported non‑linear (inverse L‑shaped) relationships with suggested inflection points roughly in the range 1.2–1.6 mg/day for different tests — meaning cognitive scores rose with copper intake up to that range but did not continue to climb beyond it. The paper emphasised that the association is complex and cannot establish causation because of its cross‑sectional design [Scientific Reports — Association between dietary copper intake and cognitive function in American older adults].
Complementary human brain data. A separate, long‑running community study from the Rush Memory and Aging Project (MAP) examined copper levels directly in brain tissue from autopsied participants and tracked cognitive decline before death. In that neuropathologic study of 657 autopsied participants, higher copper concentrations in certain brain regions (notably inferior temporal and mid‑frontal cortex) were associated with slower cognitive decline and with lower measures of Alzheimer’s‑type pathology (amyloid and phosphorylated tau tangles). The MAP authors also analysed dietary copper (from food‑frequency questionnaires) and reported that higher dietary copper correlated with slower cognitive decline in some analyses, but importantly they found no simple relationship between average dietary copper and measured brain copper levels — brain copper homeostasis is regulated and not directly predicted by intake. The authors caution that the epidemiological and neuropathologic data support a role for copper homeostasis in brain ageing but do not imply that people should self‑prescribe high‑dose copper supplements [MAP autopsy study — PMC9764421].
How deficiency shows up in clinic. Clinicians and case reviews underline that symptomatic copper deficiency (hypocupremia) exists and can be disabling, though it is relatively rare. Typical features include persistent tiredness and fatigue (often from anemia caused by impaired iron use), numbness or tingling in fingers and toes, difficulty with balance and gait (a myeloneuropathy that can resemble B12 deficiency), fragile bones and an increased susceptibility to infections due to lower white blood cell counts. Risk situations that raise concern for deficiency include prior foregut surgery or gastric bypass (where the duodenum is bypassed), conditions causing small‑intestinal damage such as celiac disease or inflammatory bowel disease, prolonged total parenteral nutrition without adequate copper, excess zinc intake (which competes with copper absorption), and rare genetic disorders such as Menkes disease. Several clinical reviews and case series document hematologic (anemia, neutropenia) and neurologic presentations and the fact that symptoms can be slow to reverse if diagnosis is delayed [case reviews; ODS]. (See sources below.)
Why the data do not mean “take copper pills and beat dementia” — important caveats. The observational and neuropathology studies suggest copper status matters to brain health, but they do not prove that simply increasing intake will prevent or reverse dementia. The NHANES analysis is cross‑sectional — it measures diet and cognition at one point in time and can be confounded by many lifestyle and health factors despite statistical adjustments; people who eat more copper‑rich whole foods may also have other healthful habits. The MAP autopsy analysis shows a stronger biological link between brain copper and slower decline, but crucially dietary copper did not predict brain copper levels in that cohort. Animal experiments and small clinical trials have produced mixed results: some preclinical models indicate benefits from restoring neuronal copper in specific ways (for example via targeted compounds that alter copper handling), while other animal experiments and limited supplement trials in humans have shown no benefit or even adverse effects when copper is administered inappropriately. The Scientific Reports authors and the MAP group both call for randomized controlled trials and mechanistic research before recommending population‑level supplementation [Scientific Reports; MAP; ODS].
How much copper is enough — and what is safe? Official nutrient guidance differs slightly by country and agency. The US Dietary Reference Intake lists an RDA of 0.9 mg/day for adults (900 micrograms), while some other sources or national guidelines may report slightly different reference values (the Telegraph piece referenced a UK guideline figure of about 1.2 mg/day). The NHANES study found cognitive gains up to intakes roughly in the 1.2–1.6 mg/day range for some tests, but also showed no additional benefit above those inflection points. The US ODS also lists Tolerable Upper Intake Levels (ULs) — the intake above which adverse effects are more likely — of 10,000 micrograms (10 mg/day) for adults; chronic intakes above the UL can cause gastrointestinal symptoms and, in severe cases, liver damage and neurological problems. In short: aim for a varied diet to meet the RDA, avoid chronic high‑dose self‑prescription, and let clinicians oversee any replacement in people with medical need [ODS; Scientific Reports].
Foods that supply copper — practical, Thailand‑friendly suggestions. The ODS fact sheet lists rich sources such as liver (beef or chicken), oysters and other shellfish, crab, baking chocolate, cashew nuts, sunflower seeds, tofu, chickpeas, whole grains, sweet potato and spinach. Translating that to Thai meals:
- Prawn, mussel or crab‑based dishes (tom yum with prawns, pla muk/stir‑fried squid, hoy krang/stir‑fried crab) provide bioavailable copper. (Shellfish are among the top sources on ODS.)
- Street‑food and home recipes that include liver (stir‑fried liver with basil), chicken giblets in soups, or pork liver in nam tok styles are rich in copper.
- Plant and snack options like roasted cashews or peanuts, sesame seeds, tofu or tempeh, and dark chocolate are copper‑dense and fit vegetarian/vegan patterns.
- Whole‑grain rice (brown rice), wheat products, sweet potato and dark leafy greens (pak choi, spinach) add smaller but useful amounts.
- For school or elder care menus, simple additions — a small portion of shelled seafood twice a week, or a handful of roasted cashews — will cover most needs without supplements.
Action points for Thai readers — what to do now. First, do not self‑diagnose or start high‑dose copper supplements: both deficiency and excess carry risks. If you have chronic fatigue, unexplained anemia that does not respond to iron, new numbness/tingling or balance problems, or you belong to a higher‑risk group (history of gastric bypass/gastrectomy, long‑standing inflammatory bowel disease, long‑term high‑dose zinc use, or TPN), ask your doctor about copper assessment — typically measured as serum copper and ceruloplasmin, though these markers can be affected by inflammation and other factors and need clinical interpretation. If testing confirms deficiency, oral or intravenous copper given under medical supervision reverses hematologic problems quickly, but neurological recovery may be partial depending on delay to treatment. For most healthy adults, dietary change is the first line: aim to include seafood, organ meats or plant sources (nuts, seeds, tofu, whole grains) in regular meals rather than taking generic over‑the‑counter copper tablets. Finally, if you take zinc supplements (for skin, immune or other reasons), do not exceed recommended zinc upper limits chronically without clinical oversight, because high zinc can block copper absorption and provoke deficiency [ODS; case reports].
Wider scientific picture and what to expect next. The new NHANES analysis and complementary neuropathology data have rekindled interest in the role of trace metals in cognitive ageing. Researchers emphasise three research priorities: carefully designed randomized trials or trials of targeted copper‑modulating drugs (not simple elemental copper tablets), better biomarkers that reflect brain copper status, and mechanistic studies that explain when copper is protective and when imbalance may be harmful. The literature is nuanced: meta‑analyses have sometimes found higher serum copper in people with Alzheimer’s disease, creating an apparent tension with studies that report beneficial associations of brain copper with slower decline; part of this may be the difference between free copper, ceruloplasmin‑bound copper, and copper in specific brain compartments, and the influence of inflammation, diet composition (for example saturated fat), and genetics (APOE status) [ODS; MAP]. For now, clinicians and nutritionists favour food‑first strategies and targeted testing in at‑risk individuals rather than population‑wide supplement campaigns.
Selected sources and further reading: the consumer summary in The Telegraph that prompted wider public interest and interviews with clinicians [Telegraph explainer]; the Scientific Reports cross‑sectional analysis of NHANES 2011–2014 that found a positive but non‑linear association between dietary copper and multiple cognitive tests in older US adults [Scientific Reports — Association between dietary copper intake and cognitive function in American older adults]; the Rush Memory and Aging Project neuropathology and brain copper analysis showing higher brain copper associated with slower cognitive decline and less Alzheimer’s pathology [MAP autopsy study — PMC9764421]; the NIH Office of Dietary Supplements Health Professional Fact Sheet with RDAs, food lists and ULs [ODS copper fact sheet]; and clinical case reviews summarising presentations and causes of copper deficiency including anemia and myeloneuropathy [case reviews, e.g., PMC5637704]. Links: Telegraph article (news summary) — The Telegraph; Scientific Reports study — Nature / Scientific Reports; MAP autopsy study — PMC9764421; NIH ODS copper fact sheet — ODS Copper — Health Professional Fact Sheet; clinical review on copper deficiency presentations — PMC5637704.
Bottom line: Copper matters, especially for older adults and people with risk factors that impair absorption. For most Thais a varied diet that includes seafood, tofu, nuts and whole grains will provide adequate copper without pills. If you have persistent fatigue, unexplained anemia, numbness or balance problems, or you are a gastric surgery or long‑term zinc‑user, seek medical assessment rather than trying supplements on your own.