Foods for Iron Deficiency

What is Iron?

Iron is an important trace mineral, essential for the proper functioning of all living organisms.

The main functions of iron in our body are: (1)

• It contributes to the transport of oxygen to various tissues.
  Iron is a key component of hemoglobin and myoglobin, proteins essential for binding oxygen and transporting it to various tissues.

• It contributes to energy release.
  Iron, as a component of proteins, contributes to the transfer of electrons in the respiratory chain, which is necessary for the combustion of macronutrients (carbohydrates, fats, proteins) in food to produce energy.
• It contributes to various functions.
  Iron is a key component of many enzymes involved in various processes within our body. For example, it contributes to DNA synthesis as a component of the enzyme ribonucleotide reductase. It also helps protect the cell from oxidative damage caused by reactive oxygen species (ROS) as a component of the enzyme catalase.

What is the path of iron in our body?

The iron intake through diet daily ranges between 5-20 mg. However, the absorption rate is only about 5-30% and depends on various factors, such as intestinal content, intestinal motility, body needs, form of iron, etc.

Therefore, only a small portion of the iron ingested from food will be transferred to the blood. Iron in the blood is transported bound to the protein transferrin.

About 75% of the iron bound to transferrin will be used for hemoglobin synthesis, 10-20% will be used for ferritin synthesis, and the remaining 5-15% for other processes.

Ferritin is a protein found inside cells and its role is to store iron so that our body can utilize it in the long term. Ferritin is mainly found in the liver, spleen, and bone marrow. Due to its role, it is used as a laboratory marker for assessing iron stores in our body.

The human body has a reduced ability to excrete iron, and therefore iron can accumulate and show toxicity. Small amounts are excreted daily through urine, skin, hair, nails, while mainly excretion is observed during menstruation in women.

Of course, it should be emphasized that the body has homeostatic mechanisms that closely control iron levels in our body to both absorb the required iron each time and prevent its accumulation in the body, a condition that can lead to serious oxidative damage due to the synthesis of free radicals.

What are the body’s iron needs?

Daily iron needs are individualized and depend on: (2)

• Gender
• Age
• Health status (breastfeeding, pregnancy)

The table below shows the recommended daily intake of iron according to the European Food Safety Authority (EFSA).

Age Group	Iron (mg/day)
Children (1-6 years)	7
Children (7-11 years)	11
Adolescents (12-17 years) – Boys – Girls	13 16
Adults (≥18 years): – Men – Women before menopause – Women after menopause	11 16 11
Pregnancy	16*
Breastfeeding	11
* Additional intake through supplements is usually recommended

Of course, iron needs differ from person to person and vary depending on the presence of other health conditions.

A healthcare professional will help you assess whether your diet is adequate to meet your iron needs or if in your case you need to take an iron supplement.

Symptoms of Iron Deficiency

Iron is an integral part of life, and its deficiency in the body is by no means desirable. However, iron deficiency is classified as one of the nutritional deficiencies frequently encountered in the population, especially among young children, women of reproductive age, and pregnant women.

Long-term iron deficiency can lead to the development of iron deficiency anemia. (3)

Anemia is characterized as a pathological condition in which there is a decrease in hemoglobin levels (and possibly red blood cell count) per unit volume of blood to levels below normal. Iron deficiency is the most common cause of anemia, which is characterized as iron deficiency anemia.

The development of iron deficiency anemia occurs gradually. Specifically, when iron intake is less than iron needs, the body initially resorts to iron stores to meet its needs. At this stage, hemoglobin levels in the blood remain within normal limits, meaning there is iron deficiency but without anemia.

However, when iron reserves cannot meet daily needs and hemoglobin levels are lower than normal, then we have iron deficiency and anemia.

Symptoms experienced by individuals with iron deficiency anemia include:

• Easy fatigue
• Shortness of breath during exertion, e.g., during exercise
• Pallor
• Drowsiness
• Difficulty concentrating
• Feeling of palpitations
• Cheilitis
• Brittle nails
• Koilonychia (spoon nails)
• Developmental problems in children

What are the forms of iron?

In foods, iron is found in two forms:

1. Heme iron.

Rich sources of heme iron are: meat, poultry, and fish.

Heme iron is better absorbed by the body compared to non-heme iron, and its absorption is not affected by other dietary factors.

2. Non-heme iron.

Rich sources of non-heme iron are: cereals, legumes, fruits, vegetables, and nuts.

Non-heme iron is absorbed in small amounts by the body (only 5-20% of the total will be absorbed) and its absorption largely depends on the presence of other food components.

What are the sources of iron?

Iron is a micronutrient found in both animal and plant foods.

As mentioned above, iron found in animal products is better absorbed by the body as it is in a form that is easily absorbable, whereas iron detected in plant products is not absorbed to a great extent.

The table below presents various foods and their iron content. (4)

Food	Amount of iron (mg)
Animal products
100 gr. chicken liver, cooked	12,9
100 gr. oysters, cooked	9,2
100 gr. beef liver, cooked	5,1
100 gr. turkey, cooked	3,6
100 gr. beef steak, cooked	1,9
100 gr. fresh tuna, cooked	1,5
100 gr. chicken, cooked	1,2
1 boiled egg (50 g)	0.8
100 gr. salmon, cooked	0,5
Plant products
100 g dark chocolate	11,9
1 cup sun-dried tomatoes (54 g)	4.9
½ cup cooked spinach (90 g)	3.6
100 gr. lentils, boiled	3,3
100 gr. red beans, boiled	3,0
100 gr. dried apricots	2,6
30 g cashew nuts	1,9
½ cup cooked quinoa (90 g)	1.4
½ cup cooked peas (80 g)	1.2
1 medium potato cooked with skin (170 g)	1.1
30 g of almonds	1,1
100 gr. chickpeas, cooked	1,0
1 slice whole wheat bread	1.0
30 g walnuts	0,8

How to enhance iron absorption?

As we mentioned, non-heme iron is absorbed in small amounts by the body.

Some tips to enhance iron absorption from foods rich in non-heme iron are: (1)

Combine them with foods rich in vitamin C.

Vitamin C, also known as ascorbic acid, is a powerful antioxidant compound found mainly in fruits and vegetables. The presence of vitamin C helps convert non-heme iron into a form that is easily absorbable by the body. Vitamin C also appears to inhibit the negative effect that some nutritional components have on iron absorption, such as calcium, polyphenols, and phytic acids.

Foods rich in vitamin C are:

• Tomato
• Pepper
• Orange
• Onion
• Greens
• Broccoli
• Cabbage
• Cauliflower
• Grapefruit

Combine them with meat/poultry/fish

For example, you could accompany spinach rice with octopus or lentils with chicken to enhance iron absorption.

Are there factors that prevent iron absorption?

There are some components found in foods that appear to reduce iron absorption.

People with iron deficiency should limit their intake in combination with sources rich in non-heme iron.

These nutritional components that act as inhibitory factors for iron absorption are: (1)

1. Phytic acid

Foods that are good sources of phytic acids are:

• Seeds
• Legumes
• Nuts
• Whole grain products

It appears that processes such as boiling, baking, and soaking reduce the phytic acid content of foods.

For example, it appears that to reduce the action of phytic acids in legumes, you can soak them well in water before cooking.

2. Calcium

Foods that are good sources of calcium are:

• Milk
• Yogurt
• Cheese
• Nuts
• Seeds

Calcium forms complexes with iron, inhibiting its absorption.

For example, for people with iron deficiency, the combination of legumes with feta cheese should be avoided because it may affect iron absorption.

3. Polyphenols

Foods that are good sources of polyphenols are:

• Coffee
• Tea
• Cocoa (and by extension, chocolate)
• Wine, especially red wine
• Fruits such as berries, grapes, pomegranate, cherries, strawberries, etc.
• Vegetables such as red onion, red cabbage, broccoli, etc.
• Whole grain products such as oats and cereals, rice, etc.

People with iron deficiency should avoid combining these foods with sources rich in iron.

As seen above, the combination of appropriate foods is necessary to achieve maximum iron absorption.

Should I take an iron supplement?

Iron needs vary depending on age, gender, and health condition. A proper and balanced diet can in most cases meet our iron needs. However, in cases where needs are increased, such as during pregnancy or if you have anemia, or when the diet is not sufficient, as in vegetarian and vegan diets, a healthcare professional may recommend supplementary iron intake.

There are several iron supplements available in the market, which some might be tempted to try as they promise immediate boost.

According to the 2011 European Parliament regulations, dietary supplements should follow a series of labeling rules to ensure the best possible information for consumers. (5)

Specifically, dietary supplements should state on their nutritional label the percentage of the reference value for the nutrient in question (% Nutrient Reference Value, NRF). In other words, to inform the consumer to what extent the particular supplement will meet the daily needs of the body for this nutrient.

Regarding iron, the reference value is considered to be 14 mg.

However, as we mentioned, the body’s iron needs depend on various factors, such as age, gender, and the individual’s health condition. Therefore, before deciding to choose a dietary supplement, you should consult with your treating physician, who is the most qualified to guide you appropriately on whether you need to take an iron supplement, in what dose, in what form, and for how long. For example, if you are diagnosed with iron deficiency anemia, your treating physician will recommend an iron supplement.

Also, iron interacts with medications and other dietary supplements, which if you are taking should be taken into account and appropriate instructions given.

If you take the correct dose of iron according to your treating physician’s instructions, you probably won’t experience side effects. In some cases, however, taking an iron supplement may cause symptoms such as the following:

• diarrhea
• bloating and intestinal gas
• Constipation
• nausea

In any case, if you experience unwanted symptoms, talk to your healthcare professional.

If your healthcare professional has suggested taking an iron supplement, it’s best to take it at least one hour before your breakfast (on an empty stomach) or at least two hours after your meal. In any case, ask your healthcare professional and carefully read the instructions for use.

In conclusion

Iron deficiency is a common nutritional deficiency and can lead to the development of iron deficiency anemia.

Iron is found in both animal and plant products. However, iron of animal origin is more easily absorbed compared to iron found in plant foods.

Because of this, to enhance iron absorption, you should keep in mind which foods act as enhancers and which as inhibitors of iron absorption.

By making the right food combinations, you can increase your daily iron intake.

Of course, in cases of diagnosed iron deficiency anemia or in other cases, your treating physician will recommend the consumption of an iron supplement to address the iron deficiency.

In any case, the consumption of any supplement should be done under the guidance of a healthcare professional.

Bibliography

1. Abbaspour N, Hurrell R, Kelis R. Review on iron and its importance for human health. J Res Med Sci. 2014 Feb; 19(2): 164–174.
2. 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: a Report of the Panel on Micronutrients. Washington, DC: National Academy Press. 2001.
3. National Institute of Health. Iron Fact Sheet for Health Professionals. Available at: https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/#en5. (Accessed at January 2023).
4. USDA. Available at: https://fdc.nal.usda.gov/fdc-app.html#/. (Accessed at January 2023).
5. Official Journal of the European Union. REGULATION (EU) No 1169/2011 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 25 October 2011 on the provision of food information to consumers, amending Regulations (EC) No 1924/2006 and (EC) No 1925/2006 of the European Parliament and of the Council, and repealing Commission Directive 87/250/EEC, Council Directive 90/496/EEC, Commission Directive 1999/10/EC, Directive 2000/13/EC of the European Parliament and of the Council, Commission Directives 2002/67/EC and 2008/5/EC and Commission Regulation (EC) No 608/2004.