Iron

Iron is the most commonly deficient mineral in the world, and the effects of running low on it are felt in ways that affect daily life more directly than most micronutrient shortfalls. Iron is the core component of hemoglobin, the protein in red blood cells that carries oxygen from the lungs to every tissue in the body. When iron is low, oxygen delivery is compromised. The result is fatigue that sleep doesn’t fix, reduced physical performance, difficulty concentrating, and a general flatness that’s easy to attribute to stress or poor sleep when iron status is actually the issue.

It’s particularly common in menstruating women, who lose iron regularly through blood loss and need significantly more dietary iron than men to compensate. Pregnant women have higher needs still. People who train heavily — particularly runners, whose repetitive foot strike causes some breakdown of red blood cells — are also at higher risk. Vegetarians and vegans need to be intentional about iron because the form of iron in plant foods is significantly less well absorbed than the form in animal foods.

That distinction is worth understanding. Heme iron, found in meat and fish, is absorbed efficiently and isn’t significantly affected by other foods eaten alongside it. Non-heme iron, found in plant foods and fortified products, is less well absorbed and is affected by other dietary factors — vitamin C consumed at the same meal significantly improves its absorption, while calcium and certain compounds in tea and coffee consumed at the same time reduce it. For people relying on plant sources, eating iron-rich foods with a vitamin C source and separating iron-rich meals from coffee and tea makes a real practical difference.

Iron is also one of the minerals where too much over time causes harm — the body has limited ability to excrete excess iron, and chronically high intake from supplements in people who don’t need it accumulates in tissue. Iron supplementation is worth discussing with a doctor rather than self-prescribing.

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Reference Card

Mineral type: Trace mineral Pillar: Nourish

What it does for you

• Core component of hemoglobin — carries oxygen throughout the body
• Supports energy production and physical performance
• Essential for immune function and cognitive performance

Two dietary forms

• Heme iron — from meat and fish; absorbed efficiently regardless of what else is eaten
• Non-heme iron — from plant foods and fortified products; less well absorbed; absorption is significantly affected by other dietary factors

Where to get it

• Heme — beef, lamb, oysters, clams, chicken, turkey, sardines
• Non-heme — lentils, spinach, tofu, chickpeas, pumpkin seeds, fortified cereals, dark chocolate

Considerations

• Eating vitamin C-rich foods alongside non-heme iron sources significantly improves absorption
• Coffee, tea, and calcium consumed at the same meal reduce non-heme iron absorption — spacing them out helps
• Menstruating women, pregnant women, heavy exercisers, and plant-based eaters are at higher risk of deficiency
• Iron supplementation should be based on confirmed deficiency rather than self-prescribed — excess iron accumulates and causes harm

Signs your intake might be low

• Persistent fatigue that sleep doesn’t resolve
• Reduced physical endurance and performance
• Difficulty concentrating
• Feeling cold frequently
• Pale skin or pale inner eyelids

Common myths

• Spinach is a great iron source — spinach contains iron but also compounds that inhibit its absorption significantly; it’s a useful contributor but not as reliable as legumes or fortified foods for non-heme iron
• Iron supplements are safe to take preventatively — iron accumulates in the body and excess over time causes real harm; supplementation should be guided by actual deficiency confirmed through blood work