When people think about iron and genetics, they usually think about overload: the HFE gene and haemochromatosis, where the body stores too much iron. But iron has another, far more common genetic story that gets much less attention: the genes that tip you toward deficiency. A 2026 systematic review of iron-related gene variants makes the case that your DNA helps decide whether you run low, even when your diet looks fine on paper.
What the research found
Reviewing the common variants that influence iron status, researchers found that every iron-linked SNP they identified affected iron parameters, and that the TMPRSS6 gene showed the strongest correlation of all. Several variants were tied to a higher risk of iron deficiency, suggesting that some people may benefit from a more iron-aware diet, or supplementation, purely because of how their genes regulate iron uptake.
The biology, briefly
Your body controls iron mainly through a hormone called hepcidin, which decides how much iron you absorb from food. TMPRSS6 is one of the master regulators of that system. Certain variants nudge hepcidin in a direction that limits absorption, so you can eat a reasonable amount of iron and still struggle to keep your stores up. This is very different from a simple "eat more spinach" problem; it is a regulation problem written into your genes.
Who this matters for most
- Women of reproductive age, whose monthly losses already push iron demand higher.
- Endurance athletes, who lose iron through training and have higher turnover.
- People eating mostly plant-based, where iron is present but less easily absorbed.
For these groups, an unlucky combination of genetics and lifestyle can show up as stubborn fatigue, poor exercise recovery or low mood, long before a routine test flags anything dramatic.
The genes your DNA report reads
Your Fuel Your DNA report analyses iron-handling genes, most notably HFE (the overload side of the story), and the science above puts genes like TMPRSS6 and the iron-transport genes firmly on the map for the deficiency side. Together they explain why two people with similar diets can sit at opposite ends of the iron spectrum.
What to do with this
- Pair iron with vitamin C. Vitamin C sharply improves absorption of plant (non-haem) iron; a squeeze of lemon or some peppers alongside lentils goes a long way.
- Mind the blockers. Tea, coffee and calcium-rich foods at the same meal reduce iron absorption; separate them by an hour or two.
- Test before you supplement. Iron is one nutrient where more is not automatically better; confirm low ferritin with your doctor before taking high-dose iron.
- Know your setting. If your genes lean toward poor absorption, a consistent, iron-aware diet matters more for you than for the average person.
Important: this article is educational and is not medical advice. Never start high-dose iron supplements without a blood test and your doctor's guidance, iron overload can be harmful. Genetic tendencies are not diagnoses.
See where your iron genes sit
The Fuel Your DNA Complete report reads 40+ genes, including iron-handling variants, and turns them into clear, personalised nutrition guidance based on your own DNA. No new test required, just the raw file you already have. Get your Complete report → or try the free DNA intolerance test first.