How to increase iron absorption with Vitamin C and iron deficiency


How to increase iron absorption


Iron deficiency can be considered the most common and widespread food disorder in the world, since it since it is believed to be responsible for at least 50% of cases of anemia worldwide[1]. Those most at risk are children, adolescents, pregnant women and women of childbearing age.
The causes can be hereditary and/or dietary and/or triggered by inflammatory and infectious diseases.
In this article I will only discuss nutritional iron deficiency and provide some specific information on how to increase iron absorption.


How much iron do we need?

Under normal conditions, the human body is very sparing in its use, which is why we don’t need to take much.
In an adult male, the daily loss of iron is around 1 mg, due to cell desquamation in the skin and intestines, while women of childbearing age are at a greater disadvantage due to menstruation: their losses almost double those of men, at around 1.5-2 mg per day [2].

table of iron RDA

Iron deficiency: how it occurs

Iron makes up just 0.005% of the weight of an average adult, in other words about 2.5 g in a person of my weight.
Even in the early stages of deficiency, we begin to notice symptoms related to tissue oxygen deprivation: from simple tiredness or laziness to a constant feeling of coldness in the joint extremities; from pale color to irritability and headaches.
If iron intake does not cover requirements, other symptoms will be added: cognitive disorders, increased heart rate and palpitations, shortness of breath, insomnia, loss of hair and/or appetite; increased exposure to infections and many others.
It should also be emphasized that in order to detect serious health problems that threaten the quality of life, it is not necessary to reach the final stage, i.e. anemia.


Iron absorption

The body does not produce this important mineral; the only way of supplying it is through the intake of food already containing iron.
However, this may not be enough, as its absorption is fraught with pitfalls, suggesting that humans are not ‘designed’ to assimilate this essential micro nutrient.
Of course, this is not true, as the body has the difficult task of carefully balancing the use and storage of iron, and to do this it has only one trick: limiting its absorption
Learning how to increase iron absorption can be very useful, particularly if you do not follow a diet rich in foods with high bioavailability, such as meat for example (see here why you should limit or eliminate meat).
Diets such as vegetarian, vegan or CHEtarian are rich in foods of plant origin; they are good sources of iron but of the type with lower bioavailability, moreover they naturally contain substances known as anti-nutrients, which can inhibit its absorption
Fortunately, there is nothing to fear if you possess the knowledge and follow the right precautions: very soon a precious guide will be available.
Before we look at some of the tricks, I want to explain what is different about the iron found in foods of plant and animal origin and how it is absorbed.


Heme iron and non-heme iron

Organic iron, i.e. heme iron, comes only from animal sources; inorganic iron, in other words non-heme iron, exists more in plant sources.
These two forms are absorbed by the body in different ways: foods with high bioavailability, i.e. containing heme iron, are absorbed better than those containing non-heme iron.


Iron absorption: how it occurs

Iron absorption occurs mainly in the duodenum and jejunum. Heme-type iron is naturally soluble, so it is able to pass from the intestinal lumen to the intestinal cell without receiving any treatment. Its high bioavailability derives from this fact. Non-heme iron, on the other hand, consisting mainly of insoluble form, must be converted to soluble form.
Therefore, the non-heme iron (Fe3+) arriving in the stomach from the esophagus must first be reduced (Fe3+ =>Fe2+) in order to take part in biological reactions. This reduction takes place in the stomach through the release of a specific enzyme, stimulated by the high acidity created by the gastric juices.

How to increase iron absorption with Vitamin C

In my articles and recipes, I often recommend combining foods rich in vitamin C with meals rich in non-heme iron. I have pointed out this synergistic effect several times, without explaining how the miracle happens.
Vitamin C, aka ascorbic acid, has two main roles: firstly, it plays a crucial role in the reduction of non-heme iron (Fe3+) by chelating ferric iron in a stable manner so that it arrives still soluble in the duodenum (Fe2+) and therefore more absorbable by the body.
Secondly, it prevents non-heme iron from forming insoluble bonds with substances naturally present in plant foods with inhibiting properties, such as phytates.



The improvement is not only “relative”, but remarkable: 100 mg of vitamin C taken during the main meal enables up to 4 times the amount of iron contained in food to be absorbed [4]. This is why it is better to double the recommendations of WHO (for men 90 mg and for women 70 mg of vitamin C) in order not to risk iron deficiency.
The important thing is not to overdo it: mega-doses of vitamin C may lose their effectiveness in the long term (a kind of addiction) [5].
An orange juice or a salad of coleslaw or other fresh vegetables, seasoned with fresh lemon juice, at each main meal can make all the difference when iron deficiency is a tangible risk.
Nevertheless, vitamin C alone may not be enough, as it cannot prevent iron from forming insoluble bonds with tannins (other anti-nutrients naturally present in plant-based foods), in which case you also need to be aware of additional methods on how to increase iron absorption. Next time I will be talking about them.

Have a good revolution


1) WHO. (2015). The global prevalence of anaemia in 2011.The global prevalence of anaemia in 2011 (p. 10).
2) Sheikh AB, Javed N, Ijaz Z, Barlas V, Shekhar R, Rukov B. Iron deficiency anemia in males: a dosing dilemma?. J Community Hosp Intern Med Perspect. 2021;11(1):46-52. Published 2021 Jan 26. doi:10.1080/20009666.2020.1831743
3) Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2001.
4) Effect of ascorbic acid on iron absorption from different types of meals. Studies with ascorbic-acid-rich foods and synthetic ascorbic acid given in different amounts with different meals. Hallberg L, Brune M, Rossander L Hum Nutr Appl Nutr. 1986 Apr; 40(2):97-113
5) Cook JD, Watson SS, Simpson KM, Lipschitz DA, Skikne BS (1984) The effect of high ascorbic acid supplementation on body iron stores. Blood 64: 721-726. Link:


You might also:

If you consider my work important, your support is crucial:
a small donation will carry on the Revolution!
Thank you

How to increase iron absorption with Vitamin C and iron deficiency
Article Name
How to increase iron absorption with Vitamin C and iron deficiency
To optimise iron absorption, there are a number of tricks you need to know: vitamin C, for example, is one of them
Publisher Name
CHE Food Revolution
Publisher Logo