Vegan iron sources: how much you need and where to get it

Vegans get iron from lentils, beans, tofu, leafy greens, seeds and iron-fortified grains, but NIH puts the requirement 1.8 times higher on vegetarian diets. For a woman aged 19 to 50 that’s about 32 mg a day (our arithmetic). A ferritin blood test is the standard check of your iron stores.

The old version of this page told women they need around 18 mg of iron a day and men about 8. Those are NIH’s standard figures, set for diets that include meat. The same fact sheet says the requirement is 1.8 times higher for people who follow vegetarian diets, because heme iron from meat is more bioavailable than the nonheme iron in plant foods. Multiply it out and a vegan woman aged 19 to 50 is looking at about 32 mg a day, more than the 27 mg NIH sets for a pregnant woman on an ordinary diet (our arithmetic). The page was off by nearly half. If you’re working through the nutrients one at a time, our guide to whether vegans need B12 is the other one to read.

How much iron does a vegan need?

NIH’s multiplier is for “people who follow vegetarian diets”; it doesn’t give vegans a separate number. Applied to its adult and teenage RDAs, it looks like this:

Group	NIH RDA	Times 1.8 for a vegetarian diet (our arithmetic)
Men 19 and over	8 mg	14.4 mg
Women 19 to 50	18 mg	32.4 mg
Women 51 and over	8 mg	14.4 mg
Boys 14 to 18	11 mg	19.8 mg
Girls 14 to 18	15 mg	27 mg

The reason for the gap is absorption. NIH puts the bioavailability of iron at about 14% to 18% from mixed diets with substantial amounts of meat and seafood that also include vitamin C, and 5% to 12% from vegetarian diets. Pregnancy is left out of the table on purpose. NIH’s RDA for pregnancy is 27 mg before any adjustment; set that target with your doctor or a registered dietitian rather than with a calculator.

Which foods carry it

Plants and iron-fortified foods contain nonheme iron only. These are USDA’s figures, converted to a normal serving:

Food	Serving	Iron (our arithmetic from USDA per 100 g)
Lentils, boiled	1 cup, 198 g	6.6 mg
Spinach, boiled	1 cup, 180 g	6.4 mg
Chickpeas, boiled	1 cup, 164 g	4.7 mg
Tofu, firm, made with calcium sulfate	1/2 cup, 126 g	3.4 mg
Quinoa, cooked	1 cup, 185 g	2.8 mg
Pumpkin seeds, dried	1 oz, 28 g	2.5 mg
Kale, boiled	1 cup, 118 g	1.0 mg

The old page had lentils at 3.3 mg a cup. That is USDA’s figure per 100 g, and a cooked cup weighs 198 g, so the old page undersold lentils by half.

Now add up all seven in a single day, which means four cups of cooked legumes and greens plus the rest of the table. The total is about 27 mg (our arithmetic), still roughly 5 mg short of the 32.4 mg target for a woman aged 19 to 50. That gap is where fortified grains come in. In the US, flour is fortified with iron, and about half of dietary iron comes from grain products such as bread and cereal, NIH says. The amount varies from box to box, so read the nutrition panel on the cereal you actually buy.

What helps absorption, and what blocks it

Vitamin C (ascorbic acid) helps: NIH lists it as an enhancer of nonheme iron absorption. On the other side, phytate in grains and beans and certain polyphenols in some plant foods reduce absorption, and calcium might reduce it for both kinds of iron.

Drinks taken with the meal have their own effect. In a 1999 study that measured iron absorption from a bread meal using labeled iron, black tea cut absorption by 79% to 94%, peppermint tea by 84%, cocoa by 71% and camomile by 47%; adding milk to tea or coffee made little or no difference. The authors concluded that coffee, like the teas and cocoa, can be a potent inhibitor of iron absorption. Those figures come from single test meals.

From those two sources, our advice is to put something with vitamin C on the plate with the lentils. The tea effect was measured with the meal, so it makes sense to move the tea and coffee to between meals.

Do vegans actually run low?

A 2018 meta-analysis pooled 24 cross-sectional studies and found that adult vegetarians had serum ferritin, the main marker of iron stores, about 29.71 µg/L lower than non-vegetarians. The gap was larger in men, about 61.88 µg/L, than in premenopausal women, about 17.70 µg/L. The authors concluded that vegetarians are more likely to have lower iron stores. The abstract reports vegetarians as one group; it gives no separate figure for vegans.

Lower isn’t automatically too low, and the same paper points out that high iron stores are themselves a risk factor for certain diseases, such as type 2 diabetes. Their advice is that vegetarians and non-vegetarians alike should check their iron status regularly. NIH, for its part, names women with heavy menstrual bleeding and frequent blood donors among the groups at risk of inadequacy, and people with hereditary hemochromatosis among those at risk of too much. Being vegan is one factor among several.

When to test, and what to know before a supplement

NIH calls serum ferritin the most efficient and cost-effective test for diagnosing iron deficiency, and notes that it falls in the first stage of depletion, before anemia shows up; inflammation can affect it, so doctors often use several measures together. If you’re vegan and have never had one, ask for a ferritin test alongside a blood count.

If a doctor does recommend a supplement, a few lines from NIH are worth knowing first:

Doses of 45 mg a day or more may cause stomach side effects such as nausea and constipation, and 45 mg is the adult upper limit.
Iron amino-acid chelates, the family iron bisglycinate belongs to, might have fewer of those side effects than ferrous or ferric salts. If you need a supplement, I’d try iron bisglycinate. It’s easier on my stomach than most, and my body absorbs it better, at least in my experience; the fact sheet says the first might be so and doesn’t say the second.
Iron supplements may interact with medications including levodopa and levothyroxine, and proton pump inhibitors can reduce iron absorption.
Between 1983 and 2000, at least 43 US children died after swallowing high-dose iron supplements. Keep the bottle somewhere small hands can’t reach.

The dose itself is for the doctor who read your results.

The part I’m least sure about is the multiplier. NIH applies 1.8 to vegetarian diets as a whole, and nothing we read for this page gives vegans their own number or says how far a vegan who eats vitamin C with every meal and keeps tea away from dinner can shrink it. For the rest of the list, see our guide to which supplements vegans actually need.