Iron - Health Benefits and Best Sources

Iron is found in every cell of the human body and is considered as an essential mineral required  for conducting many metabolic activities.


Main Functions of Iron In The Body

Iron is important for the production of haemoglobin in red blood cells that delivers oxygen to all parts of the body.

It is needed for formation of myoglobin that carries oxygen to muscle tissue which leads to energy production.

It is involved in production of neurotransmitters like norepinephrine, serotonin, and dopamine; required for healthy immune system and resistance to infections

Iron supplementation appears to improve cognitive function in children and adolescents who were previously iron-deficient; iron may alleviate symptoms of ADHD (attention deficit hyperactivity disorder).


Interesting Facts 

Dietary iron occurs in two forms: heme and nonheme.

The primary sources of heme iron are hemoglobin and myoglobin, which is obtained from consumption of meat, poultry, and fish, whereas nonheme iron is obtained from cereals, pulses, legumes, fruits, and vegetables.

Heme iron is highly bioavailable (15%-35%) and dietary factors have little effect on its absorption, whereas nonheme iron absorption is much lower (2%-20%) and strongly influenced by the presence of other food components.

Ascorbic Acid, present is fruits and vegetables is essential for the absorption of non-heme iron, as it balances the negative effect caused by all iron absorption inhibitors such as pytate, zinc and calcium
Deficiency Symptoms 

Since iron is required for a number of diverse cellular functions, a constant balance between iron uptake, transport, storage, and utilisation is required to maintain iron homeostasis.

Deficiency of iron may cause symptoms such as  headaches, dizziness, irritability, pale skin, cold hands and feet, lack of energy, rapid heartbeat, low immune function, brittle nails, shortness of breath, sore or inflamed tongue or mouth, lack of appetite, blood in stools, restless legs syndrome.

Depression, insomnia, decrease in ability to concentrate, impaired mental skills that may affect memory and job performance.

Learning disabilities and short attention spans in children, irregular menstrual periods, brittle hair, hair loss, nails that are spoon-shaped or that have ridges running lengthwise.


Reasons for Deficiency

In plant-based diets, phytate (found in pulses, cereals) is the main inhibitor of iron absorption.

Calcium has been shown to have negative effects on non-heme and heme iron absorption.

Forms of caffeine such as black tea have also inhibit the absorption of iron in the body.


Ways To Reduce Deficiency of Iron

Intake of iron rich foods- especially source of meat/flesh

Increased consumption of fruits and vegetables rich in ascorbic acid to enhance nonheme iron absorption

Reduced intake of tea and coffee, which inhibit nonheme iron absorption

Germination (sprouting) and fermentation, soaking, and milling, for reducing phytic acid content in plant-based staples.

Supplementation in the form of ferrous iron salts , which are cost effective and also highly bioavailable (under doctor’s supervision).
Recommended Daily Allowance


Infants – 1.0 mg

Preschool and school age children – 0.4 mg

Adolescent girls – 0.8 mg

Adolescent boys -0.6 mg

Non-pregnant women -0.6 mg

Pregnant women second trimester–1.9 mg/1,000 Kcal of dietary energy

Pregnant women third trimester – 2.7 mg/1,000 Kcal

Adult men – 0.3 mg


Food Sources

Spirulina: 1 ounce: 8 milligrams of iron

Liver: 85gms of organic beef liver: 4.05 milligrams of iron

Lentils Soaked:  ½ cup: 3.3 milligrams of iron

Dark Chocolate: 1 ounce: 3.3 milligrams iron

Spinach: ½ cup cooked: 3.2 milligrams

Sardines: 1/4 cup: 1.8 milligrams

Black beans: ½ cup: 1.8 milligrams

Nuts 1 ounce: 1.1 milligrams

Raisins: 1/4 cup: 1.1 milligrams


An upper level intake of 45mg per day has been set for adults. Toxicity can lead to gastrointestinal irritation.



FAO; 2001. FAO/WHO.Human vitamin and mineral requirements. Rome: Food based approaches to meeting vitamin and mineral needs; pp. 7–25

Hurrell R, Egli I (2010) Iron bioavailability and dietary reference values. Am J Clin Nutr. 2010 May; 91(5):1461S-1467S
Monsen ER, Hallberg L, Layrisse M, Hegsted DM, Cook JD, Mertz W, Finch CA  (1978). Estimation of available dietary iron. Am J Clin Nutr. 31(1):134-41.
Hurrell R (2002). How to ensure adequate iron absorption from iron-fortified food. Nutr Rev.; 60(7 Pt 2):S7-15; discussion S43.
USDA (2017)
Maternal and Child Divisions of the Ministry of Health and Family Welfare (2013). Guideline for Control of Iron Deficiency Amaemia : National Iron + Initiative . Adolescent Division Ministry of Health and Family Welfare Government of India.

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