Zinc copper ratio men: Eom et al., 2026

A cross-sectional study of 966 Korean adults found that higher zinc-to-copper ratios were associated with increased odds of hypertension (OR 1.91 in the highest tertile vs. lowest), with effect sizes consistent whether participants lived near a copper smelter or in a rural control area. Cross-sectional design means we see association, not causation — the study cannot tell us whether altering zinc or copper intake would change blood pressure.

Key takeaways

• Participants in the highest zinc-to-copper ratio tertile had 91% higher odds of hypertension compared to the lowest tertile (OR 1.91; 95% CI: 1.25-2.93).
• Every unit increase in zinc-to-copper ratio was associated with 1.75 mmHg higher systolic blood pressure and 1.47 mmHg higher diastolic blood pressure in adjusted models.
• The association held across multiple statistical approaches — linear regression, logistic regression, Bayesian kernel machine regression, and restricted cubic splines.
• Cross-sectional design is a snapshot in time — it shows correlation but cannot establish that high zinc or low copper *causes* hypertension or that supplementing one or restricting the other would change outcomes.
• The sample size of 966 adults is adequate for detecting associations of this magnitude, and sensitivity analyses excluding medication users yielded similar results.

The study

Eom and colleagues published this cross-sectional analysis in Biological Trace Element Research in 2026 (PubMed). They recruited 966 Korean adults aged 30 and older in 2008, split into two groups: 564 participants living within 4 km of the Janghang copper smelter (high environmental metal exposure) and 402 participants from a rural area approximately 15 km away (low exposure). The researchers measured serum zinc, serum copper, and calculated the zinc-to-copper ratio (ZCR), along with blood lead, blood mercury, urinary cadmium, and urinary arsenic. They also measured blood pressure and collected data on antihypertensive medication use. The primary outcome was prevalent hypertension, defined as systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, or current use of antihypertensive medication. The authors used multivariable linear regression for continuous blood pressure outcomes, logistic regression for hypertension prevalence, Bayesian kernel machine regression to model multi-metal mixtures, and restricted cubic splines to test for nonlinear associations.

How to read this study

What this paper does well: The sample size of 966 adults is robust for a biomarker association study of this type. The authors measured a full panel of environmental heavy metals (lead, mercury, cadmium, arsenic, nickel) and adjusted for them in the models, which is important when evaluating essential metal ratios in populations with differential environmental exposure. The use of multiple statistical approaches — linear regression, logistic regression, Bayesian kernel machine regression, and restricted cubic splines — strengthens confidence that the association is not an artifact of model choice. The sensitivity analysis excluding antihypertensive medication users (OR 1.83; 95% CI: 1.19-2.80) is methodologically sound, as it removes participants whose blood pressure is artificially controlled and might obscure the true association. The authors also calculated an E-value of 1.97, which quantifies how strong an unmeasured confounder would need to be to explain away the observed effect — a useful transparency measure.

What this paper is missing or weak on: Cross-sectional design is the critical limitation. Blood pressure and zinc-to-copper ratio were measured at the same point in time, so we do not know which came first. It is entirely plausible that hypertension or its metabolic context (inflammation, oxidative stress, dietary patterns that accompany cardiovascular risk) *alters* zinc and copper homeostasis rather than the reverse. The paper cannot tell us whether intervening on zinc or copper intake would change blood pressure. There is also no data on dietary zinc or copper intake — only serum levels — so we cannot separate supplementation effects from endogenous regulation. The interaction term between exposure group and ZCR was not statistically significant (p = 0.561), meaning the hypothesis that environmental metal exposure modifies the zinc-copper-hypertension relationship is suggestive at best, not established.

How I weight this paper: I treat this as a flag worth tracking, not a reason to change supplementation behavior. The association is consistent across multiple models and sensitivity analyses, which elevates it above a spurious finding. But cross-sectional data cannot establish causation, and the mechanistic story — does excess zinc drive hypertension? does copper deficiency? does the ratio itself matter independent of absolute levels? — remains speculative. If a prospective cohort study or an RCT manipulating zinc and copper intake replicated this relationship with incident hypertension as the endpoint, I would weight it much more heavily. On its own, this paper suggests that zinc-to-copper ratio is worth measuring in cardiovascular contexts, but it does not tell us what to do with that information yet.

What they found

In fully adjusted linear regression models, each unit increase in zinc-to-copper ratio was associated with a 1.75 mmHg increase in systolic blood pressure (p = 0.002) and a 1.47 mmHg increase in diastolic blood pressure (p < 0.001). When the authors categorized participants into tertiles by ZCR, those in the highest tertile had 91% higher odds of prevalent hypertension compared to the lowest tertile (adjusted OR = 1.91; 95% CI: 1.25-2.93; p = 0.003). The association was directionally consistent in both the exposed group (OR = 1.71; 95% CI: 0.96-3.06; p = 0.069) and the non-exposed control group (OR = 2.29; 95% CI: 1.18-4.45; p = 0.014), though the formal interaction test was not statistically significant (p = 0.561). Sensitivity analyses excluding participants taking antihypertensive medication yielded similar results (OR = 1.83; 95% CI: 1.19-2.80). Bayesian kernel machine regression and restricted cubic spline analyses both supported a positive, approximately linear relationship between ZCR and blood pressure across the observed range. The E-value of 1.97 indicates that an unmeasured confounder would need to be associated with both ZCR and hypertension with a risk ratio of at least 1.97 to fully explain away the observed association.

What it means for the average man

Zinc-to-copper ratio appears to be associated with blood pressure in this Korean population, but the cross-sectional design means we cannot say whether high zinc, low copper, or an imbalanced ratio *causes* hypertension. The practical takeaway is that balance matters more than isolated dosing. Many men supplement zinc without tracking copper, and chronic zinc supplementation can induce copper deficiency — a known cause of anemia, neutropenia, and potentially cardiovascular dysfunction. This paper suggests that tracking the ratio, not just zinc in isolation, may be relevant for cardiovascular health. If you supplement zinc long-term (especially above 30-40 mg daily), testing serum copper or zinc-to-copper ratio periodically is prudent. The ideal ratio is not definitively established, but ratios consistently above 10:1 or 12:1 warrant attention. This is an observational flag, not a dosing protocol.

The caveats

Cross-sectional design is the central limitation — we see correlation, not causation. Reverse causality is plausible: hypertension and its metabolic context (inflammation, oxidative stress, insulin resistance) may alter zinc and copper homeostasis rather than the reverse. The study population is Korean adults with environmental heavy metal exposure, which may limit generalizability to Western populations without occupational or smelter-proximal exposure. Dietary zinc and copper intake were not measured, so we cannot isolate supplementation effects. The interaction term between exposure group and ZCR was not statistically significant, meaning the hypothesis that environmental metals modify the zinc-copper-hypertension relationship is speculative. The E-value of 1.97 indicates limited-to-moderate robustness to unmeasured confounding — not trivial to explain away, but not bulletproof either.

Frequently asked questions