Iron – Food Sources, Recommendations, Side effects and more

Iron is a chemical compound with the symbol Fe. The mineral is not only important in the architecture and cutlery industry, but also for your body.

Just that iron is good for your body, you cannot pick an iron ore and eat it. Some foods are rich in iron and help you absorb iron.  

The blog is not about the industrial uses of iron. This blog gives you information about the importance of iron to your body.

What is Iron?

Iron is a mineral that is an important component of haemoglobin. The haemoglobin plays an important role in carrying oxygen throughout the body.

There are two types of dietary iron, haem and non-haem. Haem is found in foods like red meat, fish and poultry. Haem is mostly found in animal foods whereas, non-haem foods are mostly found in plant sources.

Lack of iron is called iron deficiency or anaemia. Iron is the most important nutrient to carry oxygen throughout the body.

If there is an iron deficiency in your body, there will be a deficient oxygen supply and your body becomes fatigued. Iron is not only important to transport oxygen throughout the body, but also in the production of certain hormones like erythroferrone.

Iron is a component of haemoglobin in erythrocytes. It is required to transport oxygen around the body and, in the formation of myoglobin, for the storage and use of oxygen in muscles.  

The oxygen released in the tissues from haemoglobin is used in oxidative metabolism. Haemoglobin binds carbon dioxide in the tissues and carries it to the lungs where it is exhaled.

Fast facts on iron

The Recommended Daily Allowance (RDA) varies between ages

According to the National Institute of Health, the recommended amount of iron varies from age and it is listed below

Age and Gender	Recommended Daily Allowance (mg)
Infants (7-12 months)	11
Children (1-3 years)	7
Children (4-8)	10
Children (9-13)	8
Boys (Teenage)	11
Girls (Teenage)	15
Adult (women)	18
Adult (men)	8
Adults (above the age of 51)	8
Pregnant women	27

Iron promotes healthy pregnancy

The reason for the increase in blood during the pregnancy period is the iron requirement increases since the pregnant woman and the baby require blood.

Iron is important during the pregnancy period. Deficiency in iron causes complications like infant’s low birth weight, premature birth, iron deficiency in baby and underdevelopment of baby’s brain.

Iron is an important nutrient during pregnancy, as it is required for the growing foetus and placenta. It also helps to increase the maternal blood cells.

Canned clams, fortified cereals

Clams are marine foods and it belongs to the molluscs. They are edible and rich in iron. Clams are steamed, boiled, fried and baked and then they can be consumed. In Tamil, clams are called matti fish.

According to PMC8623076, blood clams contain 55.8 µg/g wet weight of iron and they are excellent sources of iron.

Clams can be added to rice and other seafoods. They make the food more palatable.

Fortified cereals are those foods where nutrients and vitamins are added. These nutrients are added to foods to increase the nutrient level. Cereals are commonly fortified foods.

Fortification of food can be dated back to 1941. It was the first time that iron and other vitamins were added to bread and flour.

Too much iron may increase the risk of liver cancer and diabetes

Iron consumption above the recommended range can increase the risk of diabetes and colon cancer.

It leads to the formation of carcinogenic N-nitroso compounds in the digestive tract. Iron has the ability to form free radicals it is consumed in high quantity and it can lead to tissue damage.

Iron-rich foods

Iron deficiency is one of the common causes of anaemia. According to Global Nutrition Report, 51% of Indian women are affected anaemic. The haemoglobin contains 73% of our body’s iron.

Some foods help to prevent anaemia and increase the health of women. The foods that help to increase the haemoglobin are listed below.

Shellfish

According to USDA, 100 grams of shellfish contain 0.5 mg of iron. Shellfish are nutritious and also a very good source of iron.

Shellfish can be categorised under the haem iron. The body can absorb haem iron more easily than the other variation.

Spinach

When we hear the word spinach, we get a flash of the cartoon character Popeye the sailor man. The cartoon character was portrayed in such a way that spinach is a fuel food and when you eat it you become strong.

100 grams of raw spinach contains 2.7 mg of iron, according to USDA. The human body can absorb 1.4-7% of iron from plant sources like spinach.

Liver

Iron is stored in organs like the liver, spleen and bone marrow. Organ meat like the liver contains a dense amount of nutrients like vitamin A, folate, iron, vitamin B and copper.

According to USDA, 100 grams of beef liver contains 4.78 mg of iron. The beef liver contains other nutrients like zinc, iron, phosphorous, copper and selenium.

Organ meat also has a good source of complete protein and essential amino acids. Eating beef liver provides many health benefits and enhances the immune system and the nervous system. It also improves reproductive health and promotes growth and development.

The recommended amount of liver consumption is 100-250 grams per week according to PMC6373291.

Legumes

Iron deficiency is one of the widespread deficiencies in LMIC (low and middle-income countries). Legumes are a staple food in these countries and they are highly nutritious.

Consumption of legumes resulted in a 1.5-fold increase in iron intake and increased the haemoglobin concentration to 3.0 grams, according to PMC7490168.

Red meat

The meat that produces red colour when exposed to oxygen is called red meat. The red colour of the meat is due to the presence of the protein myoglobin.

The meat of veal, lamb, and other animals is called red meat. Red meat is an exclusive source of haem according to PMC 3257743.

Studies have shown that high consumption of red meat, particularly in the form of haem, increases the risk of non-communicable diseases like cancer, type II diabetes and cardiovascular disease, according to PMID 27744145.

According to World Cancer Research Fund International, red meat consumption should not exceed 500 grams per week.

Pumpkin seeds

For every 100 grams of pumpkin seeds, the iron content is 3.3 mg, according to USDA. Pumpkin seeds are mostly considered as portable snacks.

Pumpkin seeds can be combined with other foods and they give the food a crunchy punch. They can be added to any sweets like Kesari, halwas and other foods.

A clinical study was conducted with eight healthy female, single or non-pregnant subjects, aged 20-37 consumed 30 grams of pumpkin seed kernels, which provides 4.0 mg iron/day for four weeks.

Blood samples were collected on day 20 of menstrual cycles before and after consumption of pumpkin seeds.

The statistical analysis showed a significant difference between the pre- and post-consumption phases for higher serum iron.

The results showed that adding another food source of iron such as pumpkin seed kernels improves the iron content in blood, according to PMID 18198398.

Quinoa

Quinoa is classified as a pseudocereal, it belongs to the amaranth family. Chenopodium quinoa is the scientific name of quinoa.

Quinoa is rich in nutrients like iron, calcium, copper and zinc. One cup of cooked quinoa contains 2.8 mg of iron.

Quinoa is a great source of iron and it is the best alternative option for people with celiac disease, as the cereal comes with the tag of ‘gluten-free’.

Quinoa is a good source of dietary iron and at the same time, it contains iron inhibitors that will keep your body from absorbing all iron content. So, there will be no risk of overconsumption of iron.

Turkey

Turkey is a delicious and nutritious meat. When compared to the other meat like chicken, turkey has a slight difference in iron content.

The iron content is high in turkey and it contains more iron content than the chicken. According to USDA, 100 grams of turkey contains 1.4 mg of iron.

Broccoli

According to PMC8750575, broccoli contains 1 mg of iron for every 100 grams. Vegetables like broccoli and cauliflower are reported to have high iron content when compared to other vegetables.

Tofu

Tofu contains 5.4 mg per 100 grams of tofu, as per USDA. After consuming tofu, the mean haemoglobin values increased and decreased the anaemia prevalence, according to PMID 18589021.

Consuming tofu can help prevent anaemia.

Dark Chocolate

Dark chocolate not only satisfies your cravings but also has high iron content. Dark chocolate does not contain any added sugar, so it can be used as the best alternative.

However, increased consumption of dark chocolate can cause weight gain, according to PMC4696435. Dark chocolate contains 12mg of iron per 100 grams.

Fish

Fish is consumed for its health benefits. Salmon fish contains 0.3mg of iron for every 100 grams.

According to PMC5744034, consumption of fish can reduce anaemia by 43% and also increases the circulating and stored iron content.

Benefits of Iron

Iron is important for the process of DNA synthesis and it also plays an important role in the metabolic process. Iron is important to carry out our day-to-day activities.

Healthy pregnancy

Iron is an important nutrient during the pregnancy period for women. It is not only important for the women, but also for her infant to develop healthily.

Low and high iron content in the blood can cause complications for both the mother and infant.

Adverse health complications like premature birth, gestational diabetes, gastrointestinal health and neurodegenerative diseases during ageing are reported according to PMC5748777.

Globally 40% of pregnant women and 47% of preschool children are anaemic, according to a report published in PMC5748777.

According to PMC7324901, iron deficiency can cause abnormal cognitive performance and emotional regulation in newborn babies. And these can even persist in their adulthood stage after the iron repletion.

Energy

Iron plays an important role in the production of energy. The mitochondrial energy production is controlled by a mitochondrial-specific iron pool.

Mitochondria are considered as the powerhouse of the cell. It produces the major energy required by our body.

There is evidence that the endosomal iron in the erythroid cells, from the transferrin-mediated uptake, is delivered to the mitochondria through a mechanism called as ‘kiss-and-run’.

In addition to its structural and enzymatic roles in mitochondrial protein function, iron also plays a direct role in epigenetic regulation of gene transcription.

Better Athletic performance

Iron not only transports oxygen throughout the body but is also required during the metabolism reaction like energy metabolism and thermoregulation.

Anaemia not only causes health issues when you are moving or during any athletic participation. Even when you are at rest, iron deficiency can affect you.

The nutrient acts as an antioxidant in our body and its requirement is needed as a trace mineral in every cell.

According to PMID 19474138, iron deficiency in female athletes affected the basic training and with iron supplementation, the researchers were able to correct the problem.

Sources of Iron

Dietary iron can be divided into two primary forms, haem and nonhaem. Haem iron has better bioavailability and is absorbed easier into the blood without the need for any absorption-enhancing factors.

Haem iron is available in foods like red meat, chicken, poultry, fish and eggs. Nonhaem iron is a dietary source for vegetarian foods.

Vegetarian foods show low bioavailability and the absorption of iron depends on the balance between the dietary enhancer, inhibitors and body iron stores.

25% of haem iron gets absorbed while 17% of nonhaem iron foods get absorbed. Based on the bioavailability, the estimated iron absorption varies from 14-18% for mixed diet consumption whereas 5-12% is the bioavailability for the vegetarian diet.

Some of the foods that are rich in iron are listed below.

• Liver
• Red meat
• Beans 

Leguminous grains play an important role in nutrition and it is also one of the staple foods in underdeveloped countries.

Beans such as red kidney beans, edamame beans and chickpeas can be included in the vegetarian diet.

These beans give your diet a nonhaem iron and some zinc nutrients. The common beans contain iron in the range of 18.8-82.4 mg per gram and zinc in the range of 32.6-70.2 mg per gram, according to PMC3292239.

Beans can be consumed with bean broth to get its full iron and zinc contents.

Nuts

Nuts are a good snack and also help to increase the iron content in your body. These nuts can make a healthy alternative to your fried snacks.

They also satisfy your cravings and make you feel full for a long time. Some of the nuts that are easily available are cashews, pistachios, walnut, almond and peanuts.

Cashews are iron-rich and a handful of them may contain 1.8mg of iron. They have a crunchy taste and are the best alternative for your cravings. This will help you calm your appetite and also provides nutrients.

Almonds are considered as whole nutrient foods. The desired way to eat almonds is by soaking them overnight and then consuming them in the morning.

A handful of almonds contains 1.05mg of iron. Almonds can be consumed also in the form of almond milk and almond butter.

Walnuts are said to increase your brain function and sharpen your brain. Walnuts help to increase the haemoglobin levels and one handful of walnuts contains 0.82mg of iron.

Pistachios are green nuts with a slight sweet taste. These nuts are favourite for everyone. Pistachios are a healthy snack and a handful of pistachios contains about 1.11mg of iron.

If you cannot include any of the nuts in your diet you can include peanuts. It is also called as ‘poor man’s cashew nut’. Peanuts are loaded with nutrients and proteins.

Peanuts can fulfil your iron deficiency and they are one of the best sources of proteins. You can take peanuts as peanut butter or as a chutney. You can also just eat boiled peanuts. A handful of peanuts contain 1.3 mg of iron.

Dried fruit

Nuts and dried fruits are essential in the Mediterranean diet. There is evidence for the management and prevention of metabolic conditions due to the consumption of nuts and dried fruits.

Dried dates contain about 0.3-10.4 mg per 100 grams, according to PMC6927593. Dates contain vitamin C and fibre that effectively absorbs iron.

Fortified breakfast cereals

Iron contributes to your daily health and reduces tiredness and fatigue if added to your daily diet.

Fortified cereals can be added to your diet if you cannot take iron in your daily diet. The food you eat in the morning gets absorbed by your body fully.

So fortified cereal may be the best option to include in your breakfast. The iron may be absorbed by your body fully. Some of the fortified cereals are rice crisps, cornflakes, oats, what biscuits, bran flakes, muesli, whole grain pillows, millets and granola.

Soybean flour

Soybean flour is made of soybeans. The soybeans are roasted and grounded and then made as flour. It is considered as a protein-rich food and is used in many foods.

The bioavailability of soybean flour ranges from 76 to 78%. With the addition of vitamin C, ascorbic acid, meat or cysteine the iron bioavailability can be increased to 95.5-102%.

A study was conducted with wheat flour and soybean flour. These two flours were used to make biscuits. The results revealed that the protein content and iron content increased from 11.07 to 17.86% and 1.56 to 1.99 mg per 100 grams respectively, according to PMC4576960.

Side effects of iron

Iron is an essential nutrient but when overloaded people may find few discomforts and side effects.

People with iron overloaded may experience hereditary hemochromatosis and also have a history of hemolytic anaemia.

Some of the common side effects are listed below.

Backache

Overconsumption of iron can cause backache in some people.

Fever with increased sweating

Sometimes iron supplements can cause secondary hyperhidrosis. It is a medical condition caused due to over intake of iron.

Flushing

Flushed skin is caused when the blood vessels are filled with more blood. This is a consequence of over intake of iron.

Headache

When iron is consumed more than the recommended dietary allowance (RDA) it causes severe migraine and headaches.

Metallic taste

People after consuming iron supplements may experience a metallic taste.

When iron is consumed in excess it may cause early symptoms like

• nausea
• numbness
• pain

Conclusion

Iron is a required trace mineral that our body needs for numerous reactions. The main function is oxygen transport. Thus, if a person has iron-deficiency anaemia they might struggle to cope with daily activities.

People might experience dizziness, nausea and vomiting due to iron deficiency. Iron supplementation may work for people with iron-deficiency anaemia.

Iron supplementation will not help people of normal iron status and may even lead to iron overload. So, consult your doctor before taking any iron supplements.

Instead of taking any iron supplements, you can eat foods that are rich in iron. They might bring a balance to your diet.

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