What is the importance of iron for the human body?

Having adequate levels of this element in our body is vital to maintaining good health. We all know that iron is important in our body, in fact it is one of the most abundant minerals on earth. It is essential to include foods that contain iron in the diet, however, for different reasons, some people cannot absorb iron well, that is when it is necessary to take a supplement.

There are different types of iron that we can take as a supplement and depending on the type, they have different absorption. Iron is a vital mineral, all cells contain it in different amounts. It is very important to have minimum iron levels to maintain good health. In fact, iron is part of hemoglobin, of red blood cells, and these are the ones that provide oxygen to the body. And this is what in turn provides us with nutrients, which in turn provides energy to the body. Iron also contributes to nerve transmissions.

In nutritional supplements, the labels are often somewhat confusing, since they speak of total iron, which is a high amount, however there is usually a second level, which is the amount of elemental iron. This amount is the iron that will actually be absorbed by the body.

Different forms of iron

It depends on the type of iron and its salt will be more or less absorbed.

  • Ferrous salts: Ferrous sulfate (20% absorbed), Ferrous fumarate (33% absorbed), and Ferrous gluconate (12% elemental iron). That is why many times a larger amount of ferrous gluconate is recommended than ferrous fumarate, to obtain the same amount of iron.
  • Ferric salts: like iron citrate and ferric sulfate, this salt in the body must be converted to ferrous iron for absorption. Although there is a new form of iron, iron protein succinylate (IPS), it is ferric iron encapsulated in milk protein, which resembles natural iron, improving its absorption and with fewer side effects.
  • Iron carbonyl: it is 100% absorbed and has a better tolerance in the organism, although the absorption is slower.
  • Polypeptide heme iron: it is the latest generation of iron and with better HIP absorption, it does not have as many side effects as iron salts. It is extracted directly from hemoglobin

Symptoms of iron deficiency

To find out if our iron levels are too low, the ideal is to go to the doctor and have an analysis done, with this we will know the levels, however, there are certain symptoms that we can suspect that we have iron deficiency.

There are three types of iron deficiency:

  • Very low iron stores: ferritin rates
  • The iron intake is too low to nourish the red blood cells, the stores are being used, although it is not considered true anemia
  • Iron deficiency anemia: there is not enough iron for the formation of red blood cells, so they are reduced in size and the oxygen supply to the tissues decreases, this is evaluated by hemoglobin levels

When there is iron deficiency, you have anemia. Red blood cells become smaller and with less hemoglobin content and with less oxygen and less transport to the lungs.

The symptoms are:

  • Tiredness and lack of energy
  • gastrointestinal pain
  • Lack of memory and concentration (learning difficulties increase in children)
  • Less ability to defend against infection
  • Lack of control of body temperature
  • Loss or fall of hair
  • Dull skin and the appearance of punctual acne

When is it recommended to take iron supplements?

  • When you suffer from anemia, when you suffer from significant and prolonged bleeding due to heavy periods, stomach ulcers, traumas or injuries. Taking emmenagogues (drugs or herbal remedies that can stimulate blood flow) for a long time
  • During pregnancy: 15 to 25 mg/day is usually recommended.
  • In fact, the World Health Organization recommends a daily oral supplement of iron and folic acid during pregnancy to prevent the risk of low birth weight and maternal anemia.
  • For premature children, sometimes, although a doctor’s prescription is always required.
  • Some children in growth period, in children always under medical prescription
  • important periods
  • Professional athletes or with very intense activity
  • Vegetarians, when the protein content of the diet is low
  • major bleeding
  • frequent blood donations
  • People who need dialysis, since during this process some blood is often lost, the diet is also lower in iron, however drug interactions must be taken into account
  • When medication is taken that is limiting the absorption of iron such as antacids, some antibiotics such as quinolones and tetracyclines, ranitidine and omeprazole. ACE antihypertensives. Hypocholesterol-lowering, colestipol and cholestyramine
  • Ailments, such as celiac people, Crohn’s syndrome

It is important to know that a lack of iron is linked to a deficiency in vitamin B12, in fact a lack of vitamin B12 also causes anemia.

Where iron is absorbed

The iron found in food is absorbed in the small intestine, as are most of the supplements that we get from food.

To improve the absorption of iron, the most important thing is to know what are the food combinations that will help this absorption. For example, when iron comes from plants, it is important to add vitamin C, since it will improve this absorption. It is as simple as adding some lemon, such as a spinach salad dressed with lemon juice. Or add a few slices of tomato to the meat.

For example, when cereals are taken with orange juice or tomatoes, iron absorption improves. It is also important to avoid foods that may be inhibitors of iron absorption. The supplements are absorbed within 20 to 30 minutes of taking it. However, those that are TR or time released -prolonged release- have a slower absorption.

Factors that can affect the absorption of iron

Both food and other substances such as medicines can influence the absorption of iron, which is why we generally have to take into account, and it is important, how and with what foods we take it for it to be effective.

  • Foods that limit iron absorption
  • Legumes and whole grains contain phytic acid, which inhibits iron absorption
  • Dietary fiber
  • Egg protein, both yolk and white
  • Tea, tannic acid (it is also contained in wine)
  • Coffee
  • Some herbs like pipermint and chamomile
  • Cocoa and chocolate

Milk inhibits the absorption of iron, which is why if we want a bowl of cereal with milk to provide us with iron, it is a mistake, milk will reduce that absorption.

Foods that help improve iron absorption:

  • Heme iron, such as meat, poultry, or fish.
  • Add vitamin C, such as orange juice and citrus fruits.

Many times it is difficult to take iron without water, so it is better to take it with a good glass of water or replace it with orange juice, the vitamin C content helps iron absorption.

Interference of iron supplements with medications

When taking certain medications and it is necessary to also take iron, it must be taken into account that some interact.

  • Decreases the absorption of Levodopa
  • May decrease the absorption of levothyroxine
  • Calcium can interfere with the absorption of iron, if both have to be taken it is preferable to establish a period of time

Iron should not be taken with antacids, especially those containing calcium, especially people who often have heartburn take many antacids, they are also deficient in the effectiveness of iron intake.

Drugs that act on the proton pump, both omeprazole and lansoprazole, by decreasing stomach acidity, interfere with iron absorption, inhibiting it.

Minerals, such as calcium, zinc, magnesium and copper that compete with the absorption of iron, that is why when you suffer from osteoporosis and it is also necessary to take iron, you must respect them, at least four hours between taking one and the other.

Foods rich in iron

There are two types of iron, heme and non-heme.

Heme-iron is the one that comes from hemoglobin, so it comes from foods of animal origin, such as meat, fish and poultry. The absorption of this type of iron is 15-35%.

Non-heme iron is the one that comes from plants or the plant world, some foods that have expressly added iron, such as nutritional bars. The absorption of this type of iron is 2-20%, and it influences much more than heme iron, the combination of foods to improve the absorption of this iron.

  • Liver: chicken liver is the richest in iron
  • Peas: in fact, vegetarians know that the protein contained in peas and iron is an alternative to meat
  • Broccoli: this vegetable, in addition to containing iron, is also a rich source of vitamin C, which helps the iron it contains to be well absorbed.
  • Pumpkin and pumpkin seeds: they have a high iron content
  • Meat: a fillet, steak or sirloin itself is one of the best sources of iron we have, as well as a great contribution of group B vitamins
  • Oysters: a medium-sized oyster contains 3 to 5 mg of iron, and a plate of oysters gives you your daily iron requirement
  • Soy: soy beans have a content similar to that of peas, half a glass provides up to 4 mg of iron, it is a contribution of vegetable iron.
  • They also contain a high amount of protein and amino acids, fiber and vitamins.
  • Lentils: another of the legumes very rich in iron, in a glass of lentils we have a contribution of 6 mg of iron.
  • High fiber content, which is very helpful in intestinal transit, along with spinach, it is the traditional food when we feel down and without energy, which provides a high iron content
  • Spinach: the vegetable with the highest iron content is spinach, preferably cooked, since its absorption is easier in this way. A measure of spinach provides 6 mg of iron. In addition, they are also an important contribution of calcium, vitamins and fiber

Side effects when taking an overdose of iron

If iron is taken in excess it can be harmful to health, especially in young children as it can be toxic.

If we take too much iron in adults, the most common symptom is stomach pain, usually spasms, constipation, nausea and vomiting. Very high amounts of iron can even cause metabolic failure, seizures and, in some cases, even death.

Taking too much iron can compete with the absorption of other minerals such as zinc.

Some people have, due to hereditary transmission, permanently high levels of iron (hemochromatosis), it should be treated medically since in the long run it can cause liver problems and even cirrhosis, these people should avoid supplements that contain iron and vitamin C.

Normal blood iron values:

  • In adult men: 80 to 180ug/dl of blood
  • In female adults: 60 to 160ug/dl of blood
  • In children under 1 year: 100 to 250ug/dl of blood
  • In children: 50 to 120ug/dl of blood

Side effects when taking iron

The most common thing when taking iron is to suffer from constipation, to reduce these symptoms, it is preferable to eat food when taking iron. Especially fiber that helps soften the stool, since another problem is that of too hard stool, which can cause hemorrhoids. Ferrous sulfate and ferrous gluconate salts are the ones that cause the most constipation, however, ferrous gluconate is the one with the fewest side effects, such as gastrointestinal discomfort.

Black stools: one of the surprising symptoms when taking an iron supplement is that the stools are black or very dark. This is due to the unabsorbed iron that is removed in this way, even if iron is taken with other supplements.

Bismuth, licorice, and often blueberries can also cause dark stools.

Daily iron needs

Iron being part of the metabolism of red blood cells and is directly involved in the supply of oxygen, depending on each person and the moment, the needs are highly variable.

We should also assess people who eat meat or not, since the needs for heme and non-heme iron are different, since non-heme is absorbed in less quantity, the needs are greater. It is somewhat complicated to know how much iron we need, since depending on the supplement one or the other is needed.

Ferrous sulfate, which is the most common form of iron, is usually recommended at 325mg/day, which is equivalent to 65mg elemental iron up to a maximum of 200mg elemental iron daily. It is preferable if you have to take more iron to space the shots in two or three times a day.

Recommended nutritional intake of iron

First data women, second men.

  • From 0 to 6 months: 0.27mg – 0.27mg
  • 7 to 12 months: 11mg – 11mg
  • 1 to 3 years old: 7mg – 7mg
  • From 4 to 8 years: 10mg – 10mg
  • 9 to 13 years old: 8mg – 8mg
  • 14 to 18 years old: 11mg – 15mg
  • 19 to 50 years old: 8mg – 18mg
  • After 51 years: 8mg – 8mg
  • Pregnant women: 27mg
  • Breastfeeding women: 9 mg if over 18 years old. 10mg under 18 years old