The Body's Iron Balance

Iron is a vital mineral, a so-called micromineral or trace element, that we need in small micro-amounts to stay healthy. Too high an intake of iron, however, becomes toxic to the body.

In our food, iron occurs as either heme iron or non-heme iron. Heme iron is found in meat and blood products (from the heme group of myoglobin and hemoglobin in muscle fibers and red blood cells, which binds iron), while non-heme iron is common in both animal and plant-based foods. Non-heme iron can be a bit more difficult for the body to absorb, and its uptake is significantly affected by what you eat, whereas heme iron is not affected to the same extent by the composition of the meal. For example, vitamin C makes non-heme iron easier to absorb, while polyphenols, found for instance in black tea, bind iron and instead make it more difficult to absorb.

Too little or too much is harmful

Since both too little and too much iron is harmful, our fantastic body has an ingeniously developed system to keep the body's and cells' iron concentration in balance, within a physiological range. The absorption from the intestine, from the food we eat, and the export of iron from the body's tissues into the blood, are controlled by the peptide hormone hepcidin, which is produced in the liver. Hepcidin slows down the absorption of iron from the food we eat, so when the body is saturated with iron, the liver increases its production of hepcidin and absorption decreases. When the tissues instead call for more iron, hepcidin levels are low and absorption increases. The liver is of great importance for the body's iron homeostasis and constantly communicates the needs of the tissues.

Iron deficiency is usually due to too little iron being supplied with food or poor absorption, primarily due to lower bioavailability in vegetarian food. Hereditary disease can also be the cause of impaired absorption but is very rare.

The opposite, high iron uptake with overload, is more common and usually has a genetic background, known as hemochromatosis. Currently, five different types of hereditary hemochromatosis are known, caused by mutations in different genes related to iron transport proteins and the regulation of iron balance. One of these is more common, especially in the population of Northern Europe, and is characterized by decreased expression of hepcidin, resulting in an inability to limit iron absorption as stores increase. Iron then accumulates in many organs, especially the liver, heart, and pancreas.

Excess iron also drives the production of reactive oxygen species, free radicals, which induces oxidative stress. The consequence is damage to cells and tissues that can eventually lead to fibrosis and loss of function in tissues and organs.

Different organs and tissues have different needs for iron, and even within the same organ, different cell types have different needs.

Transport and storage of iron

Free iron is potentially toxic in the body, so iron is constantly bound to various proteins as it is transported and stored in the tissue. Ferritin and transferrin are perhaps the two most 'well-known' proteins, as they are often included in blood tests to check the body's iron status.

Ferritin is a protein that mainly stores iron inside cells. It is a large protein that can store up to 4500 iron atoms. Being able to store large amounts of iron in cells, in a non-toxic form, is extremely important for the body's iron balance. It becomes a reservoir for future needs. Ferritin can be used in blood analysis to get a picture of the body's iron stores. However, the amount can be falsely high in the presence of inflammation in the body, as the ferritin level rises during inflammation.

When iron is to be transported in the blood to the tissues where it is needed, it binds to the protein transferrin. It is produced in the liver, and the amount of transferrin increases in cases of iron deficiency.

How iron absorption is affected by what you eat

As mentioned above, the absorption of heme iron does not seem to be affected by what else you eat. However, when it comes to non-heme iron, one can consider how to combine a meal and what to eat at the same time, depending on whether you need to increase or decrease your iron uptake.

If you need to increase your uptake, it is advantageous to eat red meat, liver, and blood products, as their heme iron is easier for the body to absorb. If you eat a lot of plant-based food and thus non-heme iron, you can consider taking extra vitamin C with your meal. Small organic acids, such as citric acid and ascorbic acid (vitamin C), increase the absorption of iron from the intestine. Drinking alcohol also increases iron absorption as alcohol inhibits the function of hepcidin, but it is not recommended in large quantities due to its other harmful effects. Red wine, however, reduces the absorption of iron from the intestine.

If you suffer from hemochromatosis, iron overload, you can drink black tea with your meal, which has been shown to reduce iron absorption by up to 70% or more. It is the polyphenols in black tea that inhibit absorption. A substance, 6-shogaol, found in ginger can also halve the uptake. Milk proteins and egg proteins also inhibit the absorption of iron. Likewise calcium, so dairy products have a doubly positive effect in reducing uptake.

Hemochromatosis and Vitamin C

Research shows that patients suffering from hemochromatosis often have a deficiency of vitamin C in their cells. Despite this, they are advised by healthcare providers to avoid vitamin C supplements because it can increase iron absorption and stimulate oxidative stress, as vitamin C acts as a pro-oxidant in conjunction with excess iron, driving the so-called Fenton reaction. According to T Levy, 2002, however, it is doses of less than 2 grams of vitamin C per day that may possibly have a pro-oxidant effect. If the cells have a deficiency, more vitamin C is needed; a lot of vitamin C is consumed by the large amounts of iron. Vitamin C in sufficient quantities always acts as an antioxidant and protects cells and tissues against oxidative stress. Levy also argues that vitamin C in higher doses has no negative impact on iron overload.

Instead of avoiding large amounts of vitamin C supplements, one can drink tea with meals, eat plenty of ginger, and perhaps avoid red meat, blood products, and organ meats, which contain large amounts of easily absorbed heme iron. Milk and egg proteins are also good with meals, and dairy products are beneficial as calcium also reduces iron absorption.

Iron and the Microbiome

Most bacteria need iron to grow and multiply, and for some species, iron is absolutely necessary for survival. Research has now shown that iron supplementation can completely alter the gut flora, primarily favoring various harmful, pathogenic strains at the expense of protective bacteria like Lactobacilli and Bifidobacteria, which can have other serious health consequences. Worth considering if you must take iron supplements.

By Camilla Ranje Nordin, Teacher in Fascia Knowledge & Fascia Treatment

Anderson & Frazer, 2017. Current understanding of iron homeostasis.

Omena et al, 2021. The effect of food and nutrients on iron overload: what do we know so far?

Levy T, 2002. Curing the Incurable, pp. 389-400.

R Hurrel & I Egli, 2010. Iron bioavailability and dietary reference values.