Iron Deficiency Anaemia Overview

Study Notes

Iron constitutes 5.6% of the earth's crust, making it the fourth most abundant element after Oxygen, Silicon, and Aluminum.
Present in soil at levels 100 times greater than Calcium, Sodium, and Magnesium, and significantly more than Zinc and Iodine.

Most prevalent micronutrient deficiency globally, affecting 1.3 billion people (approximately 24% of the world population).
Compared to iron deficiency, only 275 million have iodine deficiency, and 45 million children under 5 are vitamin A deficient.
Primary cause of anemia worldwide, linked to chronic health issues and possible indicators of underlying diseases such as tumors.
Anemia is defined as hemoglobin levels below the 5th percentile of healthy populations, with a common cutoff around 11 g/dl.

Infants, children under 5 years, school-aged children, and women of childbearing age are at higher risk for iron deficiency.

South Asia: 56% (0-4 years), 50% (5-12 years), 58% (women)
Africa: 56% (0-4 years), 49% (5-12 years), 44% (women)
Latin America: 26% (0-4 years), 26% (5-12 years), 17% (women)
Gulf Arabs: 40% (0-4 years), 36% (5-12 years), 38% (women)
Developed countries: 12% (0-4 years), 7% (5-12 years), 11% (women)
Global averages: 43% (0-4 years), 37% (5-12 years), 35% (women)

Inadequate dietary intake and consumption of foods that enhance absorption or inhibit it.
Hookworm infestations, heavy menstrual bleeding, gastrointestinal bleeding, and high fertility rates contribute to deficiency.
Newborns may have low iron stores, necessitating attention.

Two forms: Hem iron (from animal sources like meat) and Non-haem iron (from plant sources like cereals and vegetables).
Milk is a poor source of iron; breastfed infants may require supplements.

Hem iron absorption ranges from 20-30%, largely unaffected by other dietary components.
Non-haem iron absorption varies (2%-100%) and is influenced by body's iron status, solubility of iron compounds, gut health, and presence of absorption inhibitors.

Foods with polyphenols: tea, coffee, cocoa, and certain cereals/vegetables can significantly reduce iron absorption.
Phytic acid-rich foods: bran, some legumes, and whole grains bind iron and decrease its availability.
Cow's milk inhibits absorption due to high calcium and casein content.

Ascorbic acid-rich foods (e.g., citrus fruits, broccoli) enhance non-haem iron absorption by converting it to more absorbable forms.
Muscle proteins help absorb iron by releasing peptides that facilitate the transformation of ferric to ferrous iron.

Transferrin is the primary protein for transporting iron, binding to transferrin receptors on body cells.
Higher transferrin receptor concentrations in iron-demanding tissues (e.g., liver, bone marrow) indicate a need for iron.
Iron is stored as ferritin and hemosiderin in the liver and bone marrow; ferritin levels help assess iron stores.