Cadmium
Cadmium is a toxic metal that builds up in the kidney and stays there for decades, and for most people the biggest source they can control is tobacco smoke. In observational studies higher levels go with more heart disease, stroke and faster biological ageing, but a 2026 formal grading rated that evidence weaker than the headline numbers suggest, and its link with faster biological ageing may be mostly smoking itself.
Don't smoke, and avoid second-hand smoke. Beyond that, vary your grains rather than relying on rice, and go easy on organ meats and shellfish.
What it is and where it comes from
Cadmium is a heavy metal that reaches people through tobacco smoke, polluted air and contaminated soil, and from soil into food: organ meats, shellfish, leafy greens and rice are the main dietary sources. Tobacco is the single biggest controllable one.
It is a persistent toxin. Its half-life in the kidney is 10–30 years, so what you take in now stays with you for a long time and no cleanse removes it. The only real lever is not taking it in.
The heart and stroke link: probably real, less certain than it looks
A 2018 meta-analysis of 37 studies and about 350,000 people found roughly a third higher cardiovascular-disease risk and 70% higher stroke risk in the most exposed.[1] In US national survey data, people at the high end of urinary cadmium (the 80th percentile) had about 74% higher cardiovascular mortality than those at the low end (the 20th percentile), and about two and a half times the heart-disease mortality.[2]
All of this is observational. A 2026 umbrella review that formally graded the credibility of 35 meta-analyses of heavy metals rated the cadmium–cardiovascular link only "weak" and the cadmium–stroke link "suggestive."[3]
Faster ageing on epigenetic clocks, mostly in smokers
Epigenetic clocks are blood tests that estimate biological age from chemical tags on DNA. In a 2025 analysis of 2,346 US adults aged 50–84, each standard-deviation rise in blood cadmium went with about 1.23 years of extra ageing on GrimAge and 1.27 on GrimAge2, two clocks built to predict time to death.[4]
Read that with its caveat. The link was essentially confined to current and former smokers — around 1.3 extra years in current smokers and 2.0 in former smokers, and nothing in people who had never smoked — which is what you would expect if tobacco is doing most of the work. GrimAge also has a smoking estimate built into it, a methylation stand-in for pack-years, so it is primed to respond to tobacco-linked exposures like cadmium.[5]
Single measurements say little about any one person. In 1,693 US adults, adding 78 measured chemicals together did not predict biological-age acceleration any better than demographics, diabetes and body-mass index alone.[6]
What to do
- Don't smoke, and avoid second-hand smoke — the biggest cadmium cut available, and the one that comes with every other benefit of quitting.
- Vary your grains rather than eating rice every day.
- Go easy on organ meats and shellfish.
- Skip chelation and detox products; chelation is for diagnosed metal poisoning, under a physician.
How cadmium fits with other household and dietary toxins is on Environmental toxins.
Further reading
- Chowdhury R et al. Environmental toxic metal contaminants and risk of cardiovascular disease: systematic review and meta-analysis. BMJ 2018.[7]
- Tellez-Plaza M et al. Cadmium exposure and all-cause and cardiovascular mortality in the U.S. general population. Environ Health Perspect 2012.[8]
- Lee H et al. Heavy metal exposure and all health outcomes: An umbrella review of meta-analyses. J Hazard Mater 2026.[9]
- Khodasevich D et al. Exposome-wide association study of environmental chemical exposures and epigenetic aging in the national health and nutrition examination survey. Aging (Albany NY) 2025.[10]