Iron In Your Diet

By Lilli Link, MD   |  16Comments|

When it comes to getting iron from your diet, think Goldilocks. You don’t want too much and you don’t want too little. Fortunately, getting just the right amount is not that hard, even for people who don’t eat animal foods.

The main reason we need to be sure our bodies have adequate amounts of iron is to avoid anemia. This is a condition of too few red blood cells. Some of the first symptoms of this are fatigue, shortness of breath, rapid heart beat, and dizziness.

To understand why vegans (and their meat-eating friends and family who worry about them) might think they aren’t getting enough iron, it helps to know how iron in plant foods differs from iron in animal foods. Nonheme iron comes from both plant food and animal food. Heme iron is found only in the red blood cells and muscle cells of animal food. Both forms of iron have the same effect on the body, but heme iron is often thought of as the better source of iron because it is absorbed into the body more efficiently than nonheme iron. That means that even if a vegetarian meal has the same amount of iron as a piece of steak, the person eating the steak will absorb more iron than the person eating the vegetarian meal. In addition, meat, fish, and poultry help absorb the nonheme iron from vegetarian foods. But before you determine that nonheme iron is an inferior source of iron, read on.

While the absorption of heme iron is not affected much by other nutrients in the meal, nonheme iron is. So whether you are getting enough iron is not just about the amount of iron you eat, but which other foods you eat with it.

The following foods and nutrients inhibit nonheme iron absorption:
· Phytates, high in whole grains, legumes, nuts, and seeds.
· Polyphenols, high in coffee, tea, red wine, and fruit.
· Soy.
· Eggs.
· Foods high in calcium and calcium supplements.
· Milk protein. (If any of you Crazy Sexy readers are still eating dairy after reading my previous blog post about it, this is one more reason to stop!)

I know! I know! It seems like everything interferes with iron absorption and you might have to admit that your meat-eating friends are right. But don’t succumb just yet because there are plenty of vegan foods and food preparation techniques, listed below, that will increase nonheme iron absorption:
· Eating foods high in ascorbic acid (aka, vitamin C), such as fruits and vegetables, with your meal not only increases absorption, it also diminishes the negative effects of the inhibitors, listed above.
· Soaking and sprouting seeds, beans, and grains reduce the phytates.
· Leavening bread reduces phytates.
· Fermenting food reduces phytates.

But here is the best news about having only nonheme iron in your diet: Our bodies are unlikely to ever get overloaded with iron because the body absorbs more nonheme iron when our iron stores are low and less when our stores are high. (Of note, for the rare person with hemachromatosis, a severe overload of iron, this is probably not an effective way to keep iron stores low.) Heme iron, on the other hand, is absorbed regardless of your body’s iron stores, so you can end up having too much iron in your body.

If you explain all this to your friends and they are still worried about you, reassure them that studies show that although vegetarians generally store less iron in their bodies than meat eaters, the incidence of iron-deficiency anemia is about the same in both groups.

Although being low in iron might seem like a disadvantage, it may turn out that it is healthier for you. Iron is a pro-oxidant, meaning it activates free radicals which can damage DNA and make LDL (bad cholesterol) more damaging to the arteries. That is why some researchers are concerned that high iron levels could increase the risk for heart disease and some cancers. Since we don’t have a special mechanism in our bodies to get rid of iron, it makes sense to avoid taking in too much.

Given all these inhibitors and enhancers of nonheme iron absorption, it’s hard to know exactly how much a person needs in a day. Nevertheless, the Institute of Medicine recommends the following:

For omnivores:
Adult males: 8 mg/day
Adult females who are menstruating (not pregnant): 18 mg/day
Adult females who are post-menopausal: 8 mg/day

For vegetarians and vegans the recommended daily allowance is 1.8 times greater:
Adult males: 14 mg/day
Adult females who are menstruating (not pregnant): 32 mg/day
Adult females who are post-menopausal: 14 mg/day

(Please note that the needs for children vary as they grow.)

Vegan foods generally high in non-heme iron are dark green vegetables, dried fruit, seeds, nuts, and some grains. Here are some examples, along with the iron content of ground beef for comparison.

Food (100 gm; 3.5 oz): Iron content
Spirulina, dried: 28.5 mg
Cashews, raw: 6.7 mg
Sesame seed paste (aka tahini paste): 6.4 mg
Sunflower seeds, raw: 5.3 mg
Almonds, raw: 3.7 mg
Lentil sprouts, raw: 3.2 mg
Dandelion greens, raw: 3.1 mg
Kidney beans, red, cooked: 2.9 mg
Kelp, raw: 2.9 mg
Ground beef, cooked*: 2.8 mg
Spinach, raw: 2.7 mg
Figs, dried: 2.0 mg
Quinoa, cooked: 1.5 mg

*About 50% of the iron is in the form of heme iron which is the more easily absorbed form of iron.

Hopefully I’ve reassured you that, with a little forethought, you can get sufficient iron on a vegan diet. It is also possible on a vegetarian diet, though a bit more difficult because eggs and dairy interfere with iron absorption. However, there are certain situations in which it might be more challenging to get sufficient iron from food alone. In addition to the extra iron that menstruating women need, there are others who may not be able to get enough iron with diet alone:
· Pregnant women;
· People on dialysis;
· People with gastrointestinal disorders that affect iron absorption;
· People who engage in regular, intense exercise.

Anyone concerned that they aren’t getting enough (or are getting too much) iron should see their doctor about getting a simple blood test to check for anemia and to check their iron level.

Please note that if you are anemic and iron-deficient, your doctor may check your stool and urine for blood (even if you can’t see any blood). If all is well and you simply aren’t able to absorb enough iron from your diet to maintain a normal red blood cell count, talk to your doctor about whether you should take a low-dose iron supplement. And don’t forget to drink it down with fresh fruit or vegetable juice, which contains ascorbic acid, to help absorb it.

So the next time someone asks, “Don’t you need to eat meat for the iron?,” tell them that meat is not only unnecessary, but with its abundance of iron, may actually be a wolf in sheep’s clothing. And that’s no fairy tale!

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16 responses to Iron In Your Diet
  1. Thank you, Lilli, for bringing this up!

    I have been thinking I might be iron deficient for a few weeks now, and trying to add more iron rich foods into my vegan diet. I have two questions:

    1) I have done a lot of research on this, and discovered that bc spinach contains a lot of oxalic acid, which binds to and limits the absorption of iron, spinach is actually not a good source of iron! Would eating it with a source of vitamin C correct, or lessen this?

    And 2) How effective are iron supplements? Considering they are created in a lab and not natural? Is our body able to healthfully absorb the iron in them?

    Thanks so much!

  2. REALLY informative! thank you!!

  3. Erinn, this is an excellent question. You are correct that spinach does contain a lot of oxalic acid and there has been concern that it interferes with iron absorption. A study in 2008 compared iron absorption in women who ate spinach versus women who ate kale (which has almost no oxalic acid). The results showed a 24% decrease in iron absorption in the spinach group. The authors of the study describe this difference as “minor,” and I agree. If you want to read more about it, go to: http://www.ncbi.nlm.nih.gov/pubmed/17440529 . Eating the spinach with vitamin C-containing foods should help lessen this effect.

    Of course, it is better to get iron from food than from a supplement – nature pretty much always creates a good balance of nutrients, whereas the lab rarely does. Iron supplements are very effective at increasing your iron level and sometimes are necessary. But don’t take them unless you know you need them. If you are concerned that you are iron deficient, the blood test is the best way to figure it out.

    Jenny, thanks for the kind words!


  4. Thank you for this great information.

  5. Thank you! Great article!!!

  6. So informative! Thank you!

    I have been thinking that I might not be getting enough iron. I have been vegan since Feb. 1st, so I thought I should be fine with all of the whole grains and veggies. I decided to try taking an iron supplement in addition to my multi-vitamin. I have been taking Floradix Iron+Herbs Liquid Supplement.

    It recommends 20 ml a day, but I have just been taking 10 ml since I am getting iron from my multi-vitamin and food. I like the product so far, and it seems to have good reviews.

    Do you know anything about this product?

    Thanks so much!

  7. Great post- iron is so important. It’s also good for concentration and memory.

  8. Thanks – this is a great and timely post as I have been questioning my iron levels recently. Thank you as well for the answer to Erinn’s question: mine were both similar :)

  9. Hi Cami,

    I also have heard good things about Floradix Iron + Herbs and I like that it is a low dose of iron. But I feel pretty strongly that you shouldn’t assume you need more iron, especially if you are already taking a multivitamin with iron. If you are NOT menstruating, it’s even more important that you don’t take extra iron unless you know you need it.


  10. Do you send weekly or monthly newsletters to our email?

  11. hello:
    i am a pregnant woman and i was just told that i have anemia and need to take an iron supplement. i tried taking a sustained-release tablet and i cannot tolerate it at all…i am overwhelmed by nausea within an hour of taking my dose. do you think i can bring my iron levels up without supplementation if i just focus on changing my diet according to your recommendations? i hate the supplements but my dr. says that i’m at risk…and so is my baby…if i don’t increase my hemoglobin levels of iron…

  12. Hi Emma,
    Making the dietary changes I suggest should help, but often do not raise your iron levels adequately. There are lower dose iron supplements that may be more tolerable for you. But I agree with your doctor that it is REALLY important to get enough iron and NOT be anemic when you are pregnant.

  13. Fantastic tips and I agree iron is extremely important for the diet. Unfortunately it’s something I hadn’t thought about enough really, but now my foods do contain more of it there has definitely been a boost in natural energy levels. Mark

  14. Hi Lilli – what happens if too much iron is consumed though? I eat quite a lot of high iron foods anyway but also take supplements which contain it. Will this cause much of a problem long term?

  15. I’ve been a vegetarian for 21 years and never have been iron deficient. People always ask me this question and I’m glad to see it spelled out why. DO NOT worry about this at all.

  16. yhur website sucks balls !!!!!!!!!!