Iron

Iron is important for maintaining healthy blood.

Iron is important for healthy brain development and growth in children, and for the normal production and function of various cells and hormones. It is possible to obtain enough iron in a vegetarian/vegan diet with careful planning.

Iron-deficiency anemia is the most common nutritional deficiency worldwide, causing extreme fatigue and lightheadedness. It affects all ages, with children, women who are pregnant or menstruating, and people receiving kidney dialysis among those at highest risk. Iron is a major component of hemoglobin, a type of protein in red blood cells that carries oxygen from your lungs to all parts of the body. Without enough iron, there aren’t enough red blood cells to transport oxygen, which leads to fatigue. Iron is also part of myoglobin, a protein that carries and stores oxygen specifically in muscle tissues.

Iron from food comes in two forms: heme and non-heme. Heme is found only in animal flesh like meat, poultry, and seafood. Non-heme iron is found in plant foods like whole grains, nuts, seeds, legumes, and leafy greens. Iron is stored in the body as ferritin (in the liver, spleen, muscle tissue, and bone marrow) and is delivered throughout the body by transferrin (a protein in blood that binds to iron). Heme iron is better absorbed by the body than non-heme iron. Vitamin C and heme iron taken at the same meal can improve the absorption of non-heme iron. Bran fiber, large amounts of calcium particularly from supplements, and plant substances like phytates and tannins can inhibit the absorption of non-heme iron.

An iron deficiency is seen most commonly in children, women who are menstruating or pregnant, and those eating a diet lacking in iron. Vegetarians may develop IDA if they do not include adequate non-heme iron foods in the diet. Because non-heme iron is not well-absorbed, either greater quantities of these foods my be required or careful attention is needed in how they are eaten to improve absorption (consuming with vitamin C-rich foods while avoiding eating with calcium-rich foods, calcium supplements, or tea).

Some Food Sources of Iron

FORTIFIED BREAKFAT CEREALSBEANSDARK CHOCOLATELENTILS
ENRICHED RICE OR BREADSPINACHPOTATO WITH SKINNUTS, SEEDS

Recommended Daily Allowance (RDA)

Recommended Daily Allowances vary for gender, age, pregnancy, and lactation.

AgeRDA ironPREGNANCYlactation
Male 14-1811 mg
Female 14-1815 mg27 mg10 mg
Male 1950 +8 mg
Female 19-5018 mg27 mg9 mg
Female 51 +8 mg

Toxicity is rare because the body regulates iron absorption and will absorb less if iron stores are adequate. Excessive iron occurs most often from taking high-dosage supplements when not needed or from having a genetic condition that stores too much iron. The maximum daily intake unlikely to cause harmful effects is 40 mg for children 14 and under and 45 mg for all adults over 14.

Source: Harvard School of Public Health

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