Mr and Mrs Nutritionist

Foods That Hinder Iron Absorption

Structure of heme

The structure of a Heme Molecule, highlighting the iron within the middle.

Are you always tired, and do you feel like you barely make it through the work day without falling asleep at your computer?  If that is the case you may be deficient in iron. Keep reading to find out how to fix this problem and how to avoid those foods that hinder iron absorption.

Introduction to Iron

We all may try to eat a meal that contains every single nutrient under the sun in one sitting, however, is that really the best way of going about it? Nutrients can be fickle sometimes, some nutrients love to be with each other, whereas others don’t get along very well, such as iron and calcium.

Iron is an important mineral because it is needed in order to make a heme molecule (see right), and four heme molecules are need to make hemoglobin.  Hemoglobin is really important because red blood cells traveling through your blood require hemoglobin to transport oxygen all over your body including your brain, fingers, toes, stomach, etc.  Without the iron we would not be able to use the oxygen we breath in and therefore would not exist.  Which is why when people are low in iron they are usually tired and out of breath because their bodies are not able to transport the oxygen around their bodies effectively.  After the red blood cells release the oxygen to their target location in the body they then pick up carbon dioxide which, is a waste product we then breathe out.

Types of Iron

One thing we need to clarify is that there are two types of iron:

  1. Heme iron, which is found exclusively from meat sources.
  2. Non-heme iron, which you can get from plant sources. However, non-heme iron is not as easily absorbed as heme iron.

Sources of Iron

 

Scenario Time

It is steak night at the local restaurant and you order your steak with fries. You finish your meal and the waiter comes and carefully sneaks that dessert menu down and you notice that your favourite ice cream is back on the menu, you order it and you enjoy every bite of that ice cream. As you walk out of the restaurant you may be patting yourself on the back for having a good source of iron (the steak).

Iron absorption in the small intestines

Diagram of the different parts of the small intestines.

Unfortunately, you just wasted your money. The calcium in the ice cream will compete with the iron in the steak, and therefore prevent the iron from being absorbed. Both calcium and iron are absorbed in the beginning part of the small intestines called the duodenum. So, what ends up happening is that the iron will just travel right through your intestines and straight out the other side… tut tut, what a waste of good steak!

In the future, how can we prevent our perfectly good steak from being wasted? Well, try to avoid having dairy products (like the ice cream) when you are having a good source of iron (like the steak), and try to opt for a fruit based dessert such as fruit salad.  If you really want to be able to give yourself a hearty pat on the back try to eat the steak with a glass of orange juice. This is a because the vitamin C in the orange juice (and in most fruits) helps promote the absorption of iron from the gut. Below is a table that highlights some of the foods to avoid or seek when consuming iron rich foods. 

 

 

Drinks That Inhibit Iron Absorption

Another common food item that is often consumed after a meal is tea (typically in Britain) and coffee. Tea and coffee contain compounds that inhibit the absorption of iron from the duodenum in the small intestine by 50%. Red wine was also found to inhibit the absorption of iron from the gut. However, red wine does not contain as much iron inhibiting compound as tea and coffee. However in a balanced diet it did not significantly reduce the body’s ability to absorb iron, so having your glass of red wine with dinner may be something you want to reconsider, especially if you have an already low iron status.

Foods that inhibit and promote iron absorption

Fiber

Fiber comes in two types; insoluble and soluble. Soluble fiber as found in apples, lentils and beans produces a gel like substance that helps the movement of feces through the bowel. Soluble fiber does not effect iron absorption. Whereas, insoluble fiber has a unique ability to absorb toxins in the bowel and form the bulk of feces. Unfortunately, insoluble fiber also manages to hide iron, and therefore decreases iron absorption. Bran fiber is the main type of insoluble fiber that causes this inhibition. Bran fiber is the outermost layer of cereal grain. If you find that you have a low iron status, you should avoid insoluble bran fiber while consuming iron rich foods. Popcorn, brown rice and couscous are all sources of insoluble bran fiber.

Recommendations for Iron Intake

Below are the estimated average requirements (EAR) for iron intake.  The estimated average requirement concept is very confusing at best, even for those in the health field.  These estimated average requirements for iron intake per day, shown below, will be adequate for around 50% of the population, meaning that these numbers below may be too low a recommendation for around half of you reading thi.  Confusing isn’t it?  Our recommendation is to consume these amounts of iron shown below and get your iron levels tested, if you find that you are still low in iron you may be one of those people who has a greater iron requirement and you should consume more.

Iron Recommendations

 

References

Brune, M., Hulten, L., Hallberg, L., Gleerup, A. and Sandburg, A. (1992). Iron Absorption from Bread in Humans: Inhibiting Effects of Cereal Fiber, Phytate and Inositol Phosphates with Different Numbers of Phosphate Groups. Human and Clinical Nutrition, 122(3), pp.442-449.

Feltrin, C., Batista de Morais, M., de Cássia Freitas, K., Beninga de Morais, T., Fagundes Neto, U. and Silvério Amancio, O. (2009). Effect of Soluble Fiber Pectin on Growth and Intestinal Iron Absorption in Rats During Recovery from Iron Deficiency Anemia. Biological Trace Element Research, 129(1-3), pp.221-228.

Fidler, M., Davidsson, L., Zeder, C. and Hurrell, R. (2004). Erythorbic acid is a potent enhancer of nonheme-iron absorption. American Journal of Clinical Nutrition, 79(1), pp.99-102.

Hurrell, R., Reddy, M. and Cook, J. (1999). Inhibition of Non-Haem Iron Absorption in Man by Polyphenolic Containing Beverages. British Journal of Nutrition, 81, pp.289-295.

Lynch, S. (2000). The effect of calcium on iron absorption. Nutrition Research Reviews, 13(02), p.141.

Malone, H., Kevany, J., Scott, J., O’Broin, S. and O’Connor, G. (1986). Ascorbic acid supplementation : Its effects on body iron stores and white blood cells. Irish Journal of Medical Science, 155(3), pp.74-79.

Defra, (2014). Nutrient Intakes. [online] Available at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/384775/familyfood-method-rni-11dec14.pdf [Accessed 13 Feb. 2016].

14 Comments

  1. Steph

    This was a very informational article. I also liked that you included your references so we can go check them out for further information. I learned so much from reading this article. For example, I did not know that calcium such as in ice cream and milk will inhibit iron absorption. Thank you for this fabulous article.

    Reply
    1. Kyle McGrady (Post author)

      Thank you for the comment, we are glad that you learnt something. Please check back in the future for more nutrient interaction posts.

      Reply
  2. eva

    Iron intake is an important information I have learned thanks to your very informative website. It pays to read all these as it is part of our everyday life. Eating the right amount of iron is essential.

    Reply
    1. Kyle McGrady (Post author)

      Thank you for your comment, We hope you enjoyed reading our post.

      Reply
  3. Dan

    I have been educated.
    A number of words and phrases in this piece that I’ve heard hundreds of times but didn’t understand the significance.
    Just one point I’m a little confused on. Are you saying alcohol will reduce iron absorption? Although I have to admit, whatever your answer I’m afraid I can’t eat steak without red wine.
    Thanks

    Reply
  4. Kyle McGrady (Post author)

    Thank you Dan for your comment, and this is a very good question.

    The compound that causes a decrease in alcohol is called tannins. Not all alcohol have tannins like; vodka and gin. Unfortunately, all the good ones like whisky, scotch and beer all contain tannins.

    thanks again for the comment and question.

    Reply
  5. Leahrae

    This is GREAT information. As a person that is continually low in iron, I think this information was very useful and helpful to me. Thank you!

    Reply
    1. Kyle McGrady (Post author)

      Thank you for the comment. It makes us happy to read such positive comments and encourages future posts.

      Reply
  6. Debra

    Wonderful post and very informational. I learned that I should work more on eating real meat for protein and that many of the things I already eat promote a better absorption of iron. My fault it seems is the Whole grain fiber. which bring up a question. Whole grain fiber is supposed to be good for you (as opposed to processed of course), so is it still ok to eat it , just not at the same time as the iron rich foods?

    Reply
    1. Kyle McGrady (Post author)

      Hi Debra
      Thank you for the post. This is a very important question you raise…
      When digested food hangs for too long in the gut it increases the chances of developing bowel cancer as the toxins in the gut are excreted, reabsorbed, excreted, reabsorbed until the waste is removed from the body as feces. Whole grain fiber is very good for you as it gets things moving in the gut and prevents those toxins from being reabsorbed, but unfortunately it also hides the digested iron. It just best to not to mix iron and fiber.

      Reply
  7. Robin Hudson

    This is a very well-written, informative article! I think most people forget about vitamins needing to be absorbed to be effective. I”m
    sad about tea and coffee and red wine too! This could explain a few things. Your lists were also nice additions. It would be nice to not only have the chart of recommended iron intake levels, but also a short list of the top foods we could eat for iron.

    I went through your site and it is awesome. Love your “About Us” page and your journey to here! I’m a fan!

    Reply
    1. Kyle McGrady (Post author)

      Hi Robin
      Thank you for the comment and the feedback. Yes in hindsight a chart with a list of heme and non heme iron would have been useful. We will look to add it in, in the next few days.

      Thanks again, Kyle

      Reply
  8. Uwais Aboo

    I am a tea and coffee drinker, well mostly tea. Does all tea inhibit iron absorption, or is drinking green tea and aloe tea still ‘ok’? Or I also need to cut down on that?

    Reply
    1. Maggie

      Hi Uwais

      it depends on how much you consume. Having 2-3 cups a day would be fine as the mg of Polyphenols within tea are low. It was just something to think about. Green tea also effects iron absorption as well but i can not find any literature on the effects aloe tea on iron absorption. i will look into more detail and i will notify you.

      thank you for your comment.

      Reply

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