What Every Vegetarian Needs to Know About Iron
True or False: The iron that our bodies require is the same element found in a cast-iron skillet.
This is a real true or false question on my college exam, and it fools a surprising number of my students. Iron is greatly misunderstood as a nutrient, especially when it comes to vegetarian and vegan diets and by those trying to adopt a plant-based diet.
The mineral is found all over the earth and is essential to red blood cells transporting oxygen and nutrients to every cell in our body, connecting us directly to the land we live on. Pretty amazing, right?
But iron deficiency is the most common nutrient deficiency in North America, with symptoms including fatigue, pale skin, weakness and inability to maintain body temperature. And as vegetarians and vegans, we should be paying attention to more than just protein.
When it comes to iron (and especially iron for women), vegans should pay special attention to make sure we’re getting enough — and, along with vitamin b12 and a handful of other hard-to-get nutrients (like the ones featured in Complement Plus), may be one of the important supplements for vegans to consider.
So how much iron do we actually need?
Recently in the U.S., the Dietary Reference Intakes (DRI) gave new recommendations for iron, specifically for vegetarians, that are 1.8 times higher than the general population. This increase is not based on actual research on vegetarians, but simply because the iron in plant foods is not as easily absorbed as the iron in animal products (more on this in just a minute).
As a result, many experts in vegetarian nutrition believe that these recommendations are much higher than needed.
My take on it: if you eat a varied, healthy plant-based diet that includes a balance of grains, legumes, nuts and seeds, and fruits and vegetables — and follow the recommendations below — I don’t believe it is necessary to keep close track of iron intake.
Iron from plants vs. iron from animals
To better understand what we need to do to ensure our bodies are getting enough iron, we first have to accept two facts about iron — painful as they are for vegetarians and vegans to hear:
- There are two types of iron — heme, which is found in animal foods, and non-heme, which is from plants. It is true that heme iron (the kind from animals) is better absorbed than non-heme iron.
- Vegetarians and vegans may have lower iron stores than omnivores.
But don’t fret your vegetarian brain over these issues. We’ll see that in fact it’s not all that difficult to get the iron you need on a plant-based diet.
As for #2, it’s important to note that while vegetarians have lower stores of iron than omnivores, they do not have higher rates of anemia. In the research, many vegetarians’ stores are “low-normal,” but this does not mean less than ideal! Actually, there’s some evidence that says low-normal iron stores are beneficial: improved insulin function and lower rates of heart disease and cancer.
How to get enough iron on a plant-based diet
You can start by making sure that you’re eating foods that contain substantial amounts of iron. Some of the best plant sources of iron include:
- Legumes: lentils, soybeans, tofu, tempeh, lima beans
- Grains: quinoa, fortified cereals, brown rice, oatmeal
- Nuts and seeds: pumpkin, squash, pine, pistacio, sunflower, cashews, unhulled sesame
- Vegetables: tomato sauce, swiss chard, collard greens,
- Other: blackstrap molasses, prune juice
But here’s the key: It’s not how much iron you consume, but how well you absorb it.
So paying attention to make sure you’re absorbing your iron is just as important as making sure you’re taking in enough. And fortunately there is a lot you can do to increase the absorption of non-heme iron!
5 ways vegetarians and vegans can absorb more iron
1. The less you eat, the better it is absorbed.
Seriously! I know people who take one 15 milligram pill a day and think they are covered, but it doesn’t work that way. When consuming higher amounts of iron at one time, the percentage that our bodies absorb is actually lower than when your meal contains only a few milligrams. Plant-based foods may contain less iron than animal foods, but eating smaller amounts throughout the day is a great way to increase absorption.
2. Eat non-heme iron foods with vitamin C foods, and absorption can increase as much as five times.
Five times! Culturally these combinations are already happening: think beans and rice with salsa, falafel with tomatoes and hummus with lemon juice. The iron in beans, grains and seeds is better absorbed when combined with the vitamin-C found in fruits and vegetables. Bonus: some iron sources, like leafy greens, broccoli, and tomato sauce already contain vitamin-C.
3. Avoid coffee and tea when eating high-iron meals.
Coffee (even decaf!) and tea contain tannins that inhibit iron absorption. I recommend avoiding them an hour before or two hours after your meal.
4. Cast-iron skillets increase iron absorption.
The answer to the true or false question is true! Cooking with an old school cast-iron skillet increases the iron in your meal — especially when you cook a vitamin-C containing food in it.
Even better, a cast-iron skillet purchase puts you in the realm of official serious cook. I bought mine almost 10 years ago for $8 and it is one of my most valued possessions. (Yes, I’m that much of a food nerd that a skillet is one of my most valued possessions!)
5. It pains me to say this, but you may want to avoid spinach as an iron source.
Spinach contains oxalates that block absorption. Sucks, right? There is some disagreement in the research about this, but with all of those other iron-containing plant foods, why not try some new ones?
And for the record, even if you take an iron supplement, you should still follow the advice above. I recommend that if my clients take one, they break it in half and take half in the morning and half at night, always with meals or juice.
Iron doesn’t have to be a problem in a plant-based diet
Follow these principles, eating good sources of iron throughout the day and keeping up with the absorption principles above, and you’ll find that it’s not hard to get enough iron in your diet, even as a vegetarian or vegan.
All of that said, iron is one of the few nutrients where a deficiency both immediately affects your health and is detectable, so if you have any iron-deficiency symptoms I recommend getting blood work with your doctor. It is affordable, reliable and easy to interpret. And iron levels bounce back quickly when using the methods above or supplementation.
I’ll leave you with a fun fact about iron in plant-based diets (well, fun to a food nerd at least):
Some research shows that vegans have higher iron levels than vegetarians.
The difference between vegetarians and vegans is eggs and dairy products, and the latter contain almost no iron. When someone goes from vegetarian to vegan they are replacing dairy products with plant-based ones, all of which contain some iron, therefore increasing the total iron in the diet.
With this information and a little effort you can get all of the iron you need from plants to be a healthy and strong vegetarian!
Vegetarian Foods That Are Loaded With Iron
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Iron is an essential nutrient that plays an important role in many bodily functions.
A diet lacking in iron can result in low energy levels, shortness of breath, headaches, irritability, dizziness or anemia.
Iron can be found in two forms in foods — heme and non-heme. Heme iron is only found in animal products, whereas non-heme iron is only found in plants.
The recommended daily intake (RDI) is based on an average intake of 18 mg per day. However, individual requirements vary based on a person’s gender and life stage.
For instance, men and post-menopausal women generally require around 8 mg of iron per day. This amount increases to 18 mg per day for menstruating women and to 27 mg per day for pregnant women.
And, since non-heme iron tends to be less easily absorbed by our bodies than heme iron, the RDI for vegetarians and vegans is 1.8 times higher than for meat eaters.
Here is a list of some plant foods that are high in iron.
Legumes, including beans, peas and lentils, are great sources of iron.
Listed below are the varieties containing the most iron, from highest to lowest.
1. Tofu, Tempeh, Natto and Soybeans
Soybeans and foods derived from soybeans are packed with iron.
In fact, soybeans contain around 8.8 mg of it per cup, or 49% of the RDI. The same portion of natto, a fermented soybean product, offers 15 mg, or 83% of the RDI.
Similarly, 6 ounces (168 grams) of tofu or tempeh each offer 3–3.6 mg of iron, or up to approximately 20% of the RDI.
In addition to iron, these soy products contain between 10–19 grams of protein per portion and are also a good source of calcium, phosphorus and magnesium.
Lentils are another iron-filled food, providing 6.6 mg per cup cooked, or 37% of the RDI .
Lentils contain a significant amount of protein, complex carbs, fiber, folate and manganese as well. One cup of cooked lentils contains 18 grams of protein and covers around 50% of your recommended daily fiber intake.
3. Other Beans and Peas
Other types of beans contain good amounts of iron as well.
White, lima, red kidney and navy beans closely follow soybeans, offering 4.4–6.6 mg of iron per cup cooked, or 24–37% of the RDI .
However, chickpeas and black-eyed peas have the highest iron content. They provide around 4.6–5.2 mg per cup cooked, or 26–29% of the RDI .
In addition to their iron content, beans and peas are excellent sources of complex carbs, fiber, folate, phosphorus, potassium, manganese and several beneficial plant compounds.
Several studies also link regularly consuming beans and peas to lower blood pressure, cholesterol and blood sugar levels, as well as reductions in belly fat.
SUMMARY:Beans, peas and lentils are rich in iron. These legumes also contain good amounts of protein, fiber, vitamins, minerals and beneficial plant compounds that may reduce your risk of various diseases.
Nuts and seeds serve as two more iron-rich plant sources.
Those who wish to increase their total daily iron intake should add the following varieties to their diet, as they contain the highest amounts.
4. Pumpkin, Sesame, Hemp and Flaxseeds
Pumpkin, sesame, hemp and flaxseeds are the seeds richest in iron, containing around 1.2–4.2 mg per two tablespoons, or 7–23% of the RDI.
Products derived from these seeds are also worth considering. For instance, two tablespoons of tahini, a paste made from sesame seeds, contain 2.6 mg of iron — which is 14% of the RDI.
Similarly, hummus made from chickpeas and tahini provides you with around 3 mg of iron per half cup, or 17% of the RDI .
Seeds contain good amounts of plant protein, fiber, calcium, magnesium, zinc, selenium, antioxidants and other beneficial plant compounds, too.
They’re also a great source of omega-3 and omega-6 fatty acids. Hemp seeds, in particular, seem to contain these two fats in the ratio considered optimal for human health.
5. Cashews, Pine Nuts and Other Nuts
Nuts and nut butters contain quite a bit of non-heme iron.
This is especially true for almonds, cashews, pine nuts and macadamia nuts, which contain between 1–1.6 mg of iron per ounce, or around 6–9% of the RDI.
Similarly to seeds, nuts are a great source of protein, fiber, good fats, vitamins and minerals, as well as antioxidants and beneficial plant compounds .
Keep in mind that blanching or roasting nuts may damage their nutrients, so favor raw and unblanched varieties .
As for nut butters, it’s best to choose a 100% natural variety to avoid an unnecessary dose of added oils, sugars and salt.
SUMMARY:Nuts and seeds are good sources of non-heme iron, as well as an array of other vitamins, minerals, fiber, healthy fats and beneficial plant compounds. Add a small portion to your menu each day.
Gram per gram, vegetables often have a higher iron content than foods typically associated with high iron, such as meat and eggs.
Though vegetables contain non-heme iron, which is less easily absorbed, they are also generally rich in vitamin C, which helps enhance iron absorption (1).
The following vegetables and vegetable-derived products offer the most iron per serving.
6. Leafy Greens
Leafy greens, such as spinach, kale, swiss chard, collard and beet greens contain between 2.5–6.4 mg of iron per cooked cup, or 14–36% of the RDI.
For example, 100 grams of spinach contains 1.1 times more iron than the same amount of red meat and 2.2 times more than 100 grams of salmon .
This is also 3 times more than 100 grams of boiled eggs and 3.6 times more than the same amount of chicken .
Yet due to their light weight, some can find it difficult to consume 100 grams of raw, leafy greens. In this case, it’s best to consume them cooked.
Other iron-rich veggies that fit in this category include broccoli, cabbage and Brussels sprouts, which contain between 1 and 1.8 mg per cooked cup, or around 6–10% of the RDI .
7. Tomato Paste
At 0.5 mg per cup, raw tomatoes contain very little iron. However, when dried or concentrated, they offer a much greater amount.
For instance, half a cup (118 ml) of tomato paste offers 3.9 mg of iron, or 22% of the RDI, whereas 1 cup (237 ml) of tomato sauce offers 1.9 mg, or 11% of the RDI .
Sun-dried tomatoes are another iron-rich source, providing you with 1.3–2.5 mg per half cup, or up to 14% of the RDI .
Tomatoes are also a great source of vitamin C, which helps increase iron absorption. Moreover, they’re a great source of lycopene, an antioxidant linked to a reduced risk of sunburn .
Potatoes contain significant amounts of iron, mostly concentrated in their skins.
More specifically, one large, unpeeled potato (10.5 ounces or 295 grams) provides 3.2 mg of iron, which is 18% of the RDI. Sweet potatoes contain slightly less — around 2.1 mg for the same quantity, or 12% of the RDI ().
Potatoes are also a great source of fiber. Additionally, one portion can cover up to 46% of your daily vitamin C, B6 and potassium requirements.
Certain varieties of mushrooms are particularly rich in iron.
For instance, one cooked cup of white mushrooms contains around 2.7 mg, or 15% of the RDI.
Oyster mushrooms may offer up to twice as much iron, whereas portobello and shiitake mushrooms contain very little.
10. Palm Hearts
Palm hearts are a tropical vegetable rich in fiber, potassium, manganese, vitamin C and folate.
A lesser-known fact about palm hearts is that they also contain a fair amount of iron — an impressive 4.6 mg per cup, or 26% of the RDI.
This versatile vegetable can be blended into dips, tossed on the grill, incorporated into a stir-fry, added to salads and even baked with your favorite toppings.
SUMMARY:Vegetables often contain significant amounts of iron. Their generally large volume-to-weight ratio explains why eating them cooked may make it easier to meet your daily requirements.