The Vegan and Vegetarian Guide to Iron for Plant-Based Eating
However, there is one big thing plant-based eaters do need to be vigilant about: iron. Specifically, getting enough of it in their day-to-day diet.
“Iron is necessary for many cellular functions, but most notably, iron is key for helping myoglobin and hemoglobin deliver oxygen to body tissues,” says Katherine Pett, M.S., R.D., nutritionist for Conagra Brands and blogger at Nutrition Wonk. (Your cells and tissues need oxygen to convert food into useable energy, so it's safe to say that iron is essential to every part of the body.) “While our bodies efficiently recycle most of our iron stores, some is naturally lost every day from sloughing of skin and the lining of our intestines, sweating, and menstruation," says Pett.
If you don't have enough iron in your body, that can cause iron deficiency anemia, says Amy Gorin, MS, RDN, a plant-based registered dietitian and owner of Plant-Based Eats in Stamford, CT. “Symptoms of anemia include fatigue, pale skin, irritability, low appetite, and feelings of lightheadedness.” Long term, it can lead to increased risk of heart problems and complications in pregnancy. And it's more common in women than in men.
Here's the thing: Iron is traditionally found in animal products, like meat and seafood, making it potentially tricky for vegetarians and vegans to get enough of it. A small 2017 study comparing 30 vegetarian women with 30 non-vegetarian women found that 60 percent of the plant-based dieters were mildly anemic, compared to the 46 percent of non-vegetarian women who were normal or mildly anemic.
However, it's totally possible for plant-based people to get enough iron if they do it right. Here's everything you need to know about vegan iron sources, according to our experts.
There are actually two types of iron, and vegan iron sources are harder to digest
To understand vegetarian iron, you need to know about heme and non-heme iron. “Heme iron comes from animal products such as meat and seafood,” explains Gorin. It’s found in the blood proteins and hemoglobin of these animals—the same places you find it in humans. “Non-heme iron comes from plant-based foods, such as beans, fortified cereal, nuts, and vegetables," she says.
The heme iron found in animal products is more bioavailable, which means your body can absorb and use it more efficiently than non-heme iron. In fact, it’s estimated that iron absorption in meat eaters is 14 to 18 percent, whereas iron absorption for vegetarians in 8 to 12 percent.
“The recommended daily intake for iron accounts for bioavailability by assuming that only a fraction of the iron eaten is absorbed,” says Pett. She says That bioavailability is likely lower for plant-based eaters, than omnivores because their iron sources are purely the non-heme kind.
That's why Gorin says even though it's recommended that women ages 19 to 50 should eat 18 milligrams of iron per day (and 8 milligrams per day once they're over 50), they should be eating more of it if they're vegetarian or vegan. "They should be taking in 1.8 times the amount recommended for meat-eaters,” she says. This comes out to about 32 milligrams per day for women ages 19 to 50, and 14 milligrams per day for women ages 51 and above.
To make up for this discrepancy, it’s important to prioritize non-heme iron sources on a plant-based diet. Below is a list of vegetarian foods with non-heme iron so you can make sure you get your fill.
14 vegan iron sources
- Fortified breakfast cereals
- White beans
- Kidney beans
- Cashew nuts
- Navy beans
Foods that make vegan iron sources harder to absorb
While there's no shortage of non-heme iron sources from plants, it's important to know that what you pair them with can make absorption either easier or more difficult. “Many foods naturally contain phytochemicals that inhibit iron absorption, including drinks like coffee and tea, as well as many sources of plant protein like beans, soy, and whole grains," says Pett. Ironic, because some of these foods (ahem, beans!) are also good sources of iron. "Foods and supplements high in the minerals calcium and zinc can also decrease iron absorption," she adds.
However, you shouldn't just nix a food source because it might affect your ability to absorb iron. “Just because foods have elements that inhibit absorption doesn’t mean they aren’t healthy or even that they can't be good sources of iron. Properly prepared kidney beans and lentils, for example, can provide excellent sources of iron.” You’re still absorbing iron when you eat beans, grains, and fortified cereals, just not quite as much as you would absorb from an animal source. Just make sure you eat enough iron overall—that 32 milligram magic number—and you should be set without stressing too much about the details.
One thing to be wary of is calcium supplementation. “It’s thought that calcium may make both non-heme and heme iron less well utilized by the body,” says Gorin. If you’re taking calcium supplements—which many plant-based eaters do, because of the lack of calcium-rich dairy—make sure you’re not exceeding the recommended daily intake. If you have iron deficiency anemia, it’s likely that your doctor will recommend cutting out your calcium supplement.
How to increase iron absorption from vegetarian sources
Just like some foods and drinks make iron absorption more difficult, others make it easier. Here, Gorin shares a list of ways to increase iron absorption from vegetarian sources:
1. Pair your iron with vitamin C
“Vitamin C can help increase absorption of non-heme iron,” says Gorin. Gorin recommends reaping the benefits by pairing a non-heme iron source with a vitamin C source in the same meal. That could look like fortified breakfast cereal, which provides non-heme iron, with a cup of orange juice, which provides a day’s worth of vitamin C and will help you better absorb the iron in your cereal. Or make a lemon vinaigrette and drizzle it over your spinach salad. Citrus fruit, melon, berries, broccoli, cauliflower, bell peppers, leafy greens, cantaloupe, and tomatoes are all good sources of vitamin C.
2. Drink your tea separately from your meal
Remember how Pett pointed out that tea made absorbing iron harder? That doesn't mean you have to give it up for the sake of your iron intake. Gorin says you can just enjoy your cup before or after you eat. Doing so will actually work in your favor. "Consuming nonheme iron and tea in the same sitting may inhibit the absorption of iron. But if you separate your tea from your meal, this could help your body absorb more of the iron," she says. In fact, a study in The American Journal of Clinical Nutrition found that when subjects consumed an iron-containing porridge an hour apart from tea, this heightened how much nonheme iron was absorbed from the meal.
3. Cook your iron in a cast-iron pan
"You can cook your foods in a cast-iron pan for the foods to absorb some of the iron," Gorin says. "Studies have found that regular use of it helps to increase iron levels." What you cook with matters.
4. Soak your beans
Here's another pro iron-absorbing cooking tip from Gorin: soak your beans. "If you’re cooking beans, research shows that if you soak [them] and then prepare them in a regular pan, this will help the food to retain the most amount of iron," she says. "In the study, cowpeas were cooked in regular pans and pressure cookers with and without previous soaking."
Bottom line: It’s a little harder for plant-based eaters to get sufficient iron, but it’s not impossible
If you’re worried about not getting enough iron, don’t just go out and buy an iron supplement. They sometimes have nasty side effects like constipation, nausea, and other digestive problems, and can interact with certain medications. “It’s a good idea to share major dietary changes with your healthcare provider,” says Pett. “The best way to know if you are getting enough iron is to ask your healthcare provider to check; a blood test can tell determine whether you have adequate iron.”
The non-heme iron found in plants isn’t as easily absorbed as heme iron from animals, which means plant-based eaters need to eat almost twice as much iron as meat-eaters. Luckily, some of the best sources of non-heme iron—beans, legumes, spinach, tofu, tomatoes, and cashews—are already staples on a plant-based diet, so it’s totally possible to eat adequate iron without supplementation. So make like Popeye and go for that extra helping of spinach. Your bod will thank you.
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