The common response from many well meaning people when the topic of iron and deficiency is raised in the same sentence is:
“You need more red meat”.
Or in Outback Australia “Get a steak in ya”.
Yes, red meat does contain iron but there is a nuance involved in this quick fix prescription that is not clear to many people.
Firstly, there are two forms of dietary iron; haem and non-haem. Heam iron is derived from myoglobin, a muscle protein and haemoglobin, a blood protein. So as you can guess, haem iron is only found in animal flesh which has both myoglobin and haemoglobin (muscle and blood).
Which is why meat is associated with iron. But meat is not the only source of dietary iron and we actually get more dietary iron from non-haem iron which is derived from a wide variety of foods such as vegetables, nuts, legumes and meat. In fact, even in affluent nations where high quantities of meat are consumed, haem iron only accounts for 15% of the diet; the rest from non-haem iron sources.
This is typically the part where a nice table showing foods high in non-haem iron would be helpful but unfortunately iron is not that simple.
Eating foods high in iron is only one part of the mission in regard to increasing iron levels within the body. Absorption of iron (Heam or non-haem) food can be less than 1% to 50% of foods, but the typical range is 10-15% from dietary intake.
The absorption of iron is very tightly regulated by the body and for significant reason. If we consume too much of a substance, such as salt, a particular vitamin or mineral etc., we have the ability to excrete it in our urine.
But the body does not have the ability to excrete iron and if absorbed in excess, can lead to iron overload, toxicity (Haemochromatosis), damage of vital organs because of iron’s free radical nature, and even death. On the other end of the spectrum is iron deficiency.
Iron is an essential nutrient in producing energy, optimal immune function, transporting oxygen around the body and synthesis of DNA. So when the body is low on iron, adverse events related to the function of iron occur.
Decreased work capacity and productivity; inability to sustain high intensity or prolonged activity; shortness of breath; decreased cold tolerance; decreased resistance to infection; adverse pregnancy outcomes; and if experienced in children less than 2 years of age results in irreversible impaired psychomotor development.
So how does one increase the body’s absorption of iron from the foods they are eating in their diet?
There are compounds found in food that either promote or inhibit the body’s ability to absorb iron and they are aptly called, Promoters and Inhibitors.
The most important promoter of non-haem iron absorption is ascorbic acid, better known as Vitamin C. Ascorbic acid is thought to enhance iron absorption by converting ferric to ferrous iron by taking an electron and by chelating iron in the gut. This keeps iron in a soluble form, allowing to to be better absorbed by the body. Other organic acids that increase absorption of non-haem iron are citric, lactic and malic acid.
Side Note: Where did Ferric And Ferrous Iron come from?
Once the food has been eaten and entered the stomach, haem iron is absorbed via a specific haem mechanism but non-haem iron has to go through another process to make it available for absorption; we are now referring to the molecule Iron (Fe) itself. In the body Iron exists in two states.
Imagine: Lady Ferrous was of the conservative sort and only ate 2 tubs of hummus (2 electrons). She is still slim enough to cross the barrier into the chess playing competition. Mr Ferric could not say no to food and ate 3 tubs of hummus (3 electrons). He’s buttons burst off his shirt and he ripped his pants while trying to squeeze through the barrier but to no avail.
|Ferrous Iron (Fe2+)||Is soluble. Can cross cell membranes and be absorbed.|
|Ferric Iron (Fe3+)||Insoluble and cannot be absorbed but is instead the storage and transported form of iron.|
Major inhibitors of iron absorption are ironically found in foods that contain non-haem iron; Phytates and Polyphenols. These compounds are found in the grain bran layer in cereals, nuts and vegetables. They bind to the iron molecule to form insoluble complexes that cannot enter cells for absorption.
For example, it is well known that spinach has a lot of iron. But what is not as well known is that spinach also has a very high quantity of phytates. So even if someone were to consume a lot of spinach for iron they will not absorb that iron as it binds to the phytate molecules and won’t be absorbed.
Other Inhibitors are calcium and zinc as they compete with iron for transport into the cells.
Below is an image of what is happening in the stomach after a meal.
S = Stomach acid
PH = Phytate/ Polyphenols
C = Vitamin C
Fe 3+ = Ferric Iron (Non- Absorbable)
Fe 2+ = Ferrous Iron (Absorbable)
So now that we understand iron and what is happening in our stomach’s when we eat foods that have iron in them we can now better formulate a plan to increase iron absorption and help prevent future iron deficiencies.
Typically an iron test will show several results and each result provides an estimate on how deficient an individual is.
|Biochemical marker||Unit||Reference Range|
|Iron||umol/L||11 – 27|
|Transferrin||umol/L||20 – 27|
|TFN Saturation||%||15 – 55|
|Ferritin||ug/L||30 – 200|
|Men||125 – 180|
N.B. These values vary according to age, gender and physiological conditions. They are obtained from the mean average plus and minus 2 standard deviations. Simply, it is not straightforward to say the results obtained are abnormal as they only factor 95% of the healthy population and you can still be healthy outside these ranges. Consult further with your GP.
When ferritin falls below the reference range this indicates that iron depletion has occurred. This is the first indicator that iron intake is too low and results in the stored iron in the liver and other storage cells has progressively reduced to the point that iron stores are exhausted. At this stage other measurements of iron are normal.
The next stage is iron-deficient erythropoiesis. This is detected by a TFN saturation below 15% and a low serum iron level and indicates that iron supply to marrow in the bones is insufficient for the continued production of haemoglobin needs.
Iron-deficiency anaemia transpires when the supply of iron to the marrow is so low that Haemoglobin concentration falls below normal. In addition, to adapt to such low iron, the red blood cells may become small (microcytosis) and pale in colour (hypochromia).
After the blood analysis results have been collected, there are three options to improve iron levels.
- Iron Infusion
- Iron Supplements
- Make little tweaks to diet to help iron absorption
Talk to a trusted GP before you make any decisions and keep in mind what is the best option for you. If you are quite iron deficient (anaemia or erythropoiesis) an iron infusion may be the best option. Keep in mind though that there are risks involved and it is not the most pleasant of experiences.
Iron supplements are an alternative. Make sure to purchase a brand of iron supplement that also has Vitamin C in it as this will help immensely with the absorption of the iron. Be warned that constipation and other gastrointestinal side effects are common with oral iron therapy.
Deliberate tweaks to diet can be made to help with the absorption of non-haem iron.
|Relative absorption of non-haem iron in foods|
Whole wheat flour
|Red wine||White wine|
Aim to eat foods from the medium to high availability column in the above table at every meal or at least once a day.
Green leafy vegetables are a good source of iron but due to the high phytate content, is hard to absorb. To combat this problem it helps to lightly steam or cook greens as this disrupts the phytate compound, allowing the iron to be more easily absorbed.
Also note that cereals like oats, barley wheat etc. do contain iron but phytate is present in the bran layer of the grain. The less refined the grain is, the more phytate, the harder it is to absorb the non-haem iron. The more refined, the less phytate as the bran layer has been removed, the easier it is to absorb non-haem iron.
The conundrum here is that the bran layer is excellent for fibre and movement of the bowels. So depending on the individual it is a toss up of what is more important. Fibre or iron from cereals. Vegans typically get more fiber than other diets and tend to consume more than their fair share of fruits and vegetables so swapping for more refined cereals may not impact too greatly on fibre intake.
Don’t forget – Vitamin C is the most important promoter of of non-haem iron absorption. Give curries a big squeeze of lime juice for added flavour; Lemon juice on salads is delicious and helps with iron absorption; add a vibrant mix of strawberries and others on breakfast cereals in the morning. Making a conscious effort to add vitamin C to a meal will help immensely.
Another alternative is to cook with utensils that have iron in them. A great example of this is the Iron Fish (http://www.luckyironfish.com/). When cooking with a utensil like the iron fish, very small particles of iron (minute) break away into the food, adding to its iron content.
Below is a table providing the recommended daily intake of iron for adults. These can change based on physiological condition.
|1-3 yr||4 mg/day||9 mg/day|
|4-8 yr||4 mg/day||10 mg/day|
|9-13 yr||6 mg/day||8 mg/day|
|14-18 yr||8 mg/day||11 mg/day|
|9-13 yr||6 mg/day||8 mg/day|
|14-18 yr||8 mg/day||15 mg/day|
|>70 yr||5 mg/day||8 mg/day|
We have finally made it to the end! Yay! This was a huge article to write and if you made it to the end and understood the majority of it congratulations! You are far ahead of the bell curve on intelligence (this took me several months to learn in my degree).
Please, please share this knowledge with your friends. It was a matter of urgency that I wrote this article as a dear friend of mine recently discovered she was iron deficient and due to lots of misinformation, assumed that she needed to eat red meat.
Iron is a big topic and I am more than happy to answer any questions you may have to help further your vegucation. Until next time my fellow vegans!
Farmer, B., Larson, B. T., Fulgoni, V. L., Rainville, A. J., & Liepa, G. U. (2011). A vegetarian dietary pattern as a nutrient-dense approach to weight management: an analysis of the national health and nutrition examination survey 1999-2004. Journal of the American Dietetic Association, 111(6), 819-827. Retrieved from http://www.andjrnl.org/article/S0002-8223(11)00275-6/abstract
Essentials of Human Nutrition (4th ed.) by Jim Mann and Stewart Truswell