*Anuradha Dutta & **Shweta Suri
Iron is an essential trace mineral which serves as a carrier of oxygen to the tissues from the lungs by red blood cells. Most of the iron present in the body is in the form of hemoglobin which transports oxygen in the blood. In addition, iron serves as an integrated part of important enzyme systems in various tissues. Several iron-containing enzymes such as 1-hydroxy-2-naphthoate 1,2-dioxygenaseplay an important role in performing oxidative metabolism to transfer energy within cells, specifically in the mitochondria. The deficiency of iron in blood can lead to a variety of serious health issues, including iron deficiency anemia which occurs either due to poor dietary intake of iron or poor bio-accessibility of iron from the diet.
There are 2 types of iron in the diet; Heme iron and Non-Heme iron:
- Heme Iron is present in animal food like meat, liver and spleen. Heme iron is not affected by ingestion of other food items. Its rate of absorption is 5-10%.
- Non-Heme Iron is mostly present in cereals, millets, vegetables and beans (Green leafy veggies- Spinach, Amaranth, Mustard , Fenugreek, Onion stalks, Colocassia leaves, Mint etc) The absorption of non-heme iron varies greatly from 2% to 20% because it is strongly influenced by the iron status of the body and presence of absorption enhancers or inhibitors.
Enhancers are components present in food that boosts absorption of iron from diet such as ascorbic acid (vitamin C), organic acids, and muscle protein. Foods containing ascorbic acid reduces iron from ferric to ferrous forms, thereby increasing its absorption. Similarly, muscle protein enhances iron absorption due to the effect of cysteine containing peptides.
On the contrary, Inhibitors of iron bind with iron decreasing free iron in the gut and forming complexes that are not absorbed in the body. Polyphenols, Phytate/Phytic acid, Tannins, and Calcium are few examples of iron inhibitors present in foods.
Iron is required in all stages of a human’s lifespan. Iron requirements are also high in adolescents, particularly during the period of growth spurt. Adolescent girls commonly have their growth spurt before menarche, but growth is not finished at that time. In this stage, iron requirements increases to a level above the average iron requirements in menstruating women. In the case of infants and adolescents, the increased iron demand is the result of rapid growth. For women of reproductive age, the principle reason is the excessive blood loss during menstruation. During pregnancy, there is a significant increase in iron requirement due to the rapid growth of the placenta and the fetus.
The table gives information about the iron content of foods not their bioavailability
Rich sources of iron: Tofu, seafood, beans , organ meat.
Medium sources of iron : whole grains
Poor sources of iron: all vegetables, spinach, peas, potatoes, fruits, milk and milk products, fats and oils.
There are several ways to enrich diet with iron. One such method is food fortification.
It is the addition of one or more essential nutrient to a food, whether or not it is normally present in the food, for the purpose of preventing or correcting a demonstrated deficiency in the population. Food Safety and Standards Authority of India in October, 2016 gave fortification guidelines for staples such as rice, wheat flour (folic acid, iron, vitamin B12), milk, edible oil (vitamins A and D) and salt (iodine and iron). Food fortification resource center housed in FSSAI have taken a step for preventing iron deficiency anaemia. In India, Tata Salt Plus, priced at an economical rate, is an iodine plus iron fortified salt, developed by the National Institute of Nutrition, Hyderabad through double fortification technology.
There are some barriers which determine the effectiveness of fortification such as bioavailability of iron, selection of vehicle (food/matrix), the balance between inhibitors and enhancers and total iron intake of an individual. Iron compounds such as Ferrous Sulfate and Fumarate are used for fortification of refined wheat flour with low levels of iron inhibitors. Likewise, elemental iron is also compatible with most food matrixes but is very poorly absorbed and, thus, is not useful even at high levels of fortification. The fortification of staple foods and condiments could be successfully implemented with good attention to the selection of fortificants that are bioavailable and with due consideration to balance inhibitors and enhancers.
*Professor (Extension Home Science KVK), Department of Foods & Nutrition, College of Home Science, G. B. Pant University of Agriculture & Technology Pant Nagar
**Ph. D. Research Scholar Department of Foods & Nutrition, College of Home Science, G. B. Pant University of Agriculture & Technology Pant Nagar