Micronutrients: Types, Deficiency diseases: Public health

Micronutrients: Types, Deficiency diseases: Public health


There are two major classes of nutrients in food: macronutrients and micronutrients. Macro means big, and macronutrients take their name from the fact they make up the bulk of the nutrition in the food: carbohydrates, protein, and fat. And micro-nutrients, they are called micronutrients because they are needed only in minuscule amounts, these substances are the “magic wands” that enable body to produce enzymes, hormones and other substances essential for proper growth and development. The requirement amounts are so tiny but their absence leads in severe conditions.

Types of micronutrients

Micronutrients can be classified into 4 groups:

  1. Water-soluble vitamins: They include all B vitamins and vitamin C.
  2. Fat-soluble vitamins: They include rest of vitamins, i.e. Vitamin A,D, E, and K.
  3. Micro-minerals: Common minerals like Calcium, phosphorus, magnesium, sodium and potassium falls into this category.
  4. Trace minerals: These include iron, manganese, copper, zinc, and selenium. They are needed relatively in smaller amount than micro-minerals. 

Although only required in small amounts, micronutrients are not produced in the body and must be derived from the diet. Iodine, vitamin A and iron are most important in global public health terms; their lack represents a major threat to the health and development of populations the world over, particularly children and pregnant women in low-income countries. Micronutrient Defi ciencies (MNDs) are of great public health and socioeconomic importance worldwide. They affect low-income countries but are also a significant factor in health problems in industrialized societies with impacts among wide vulnerable groups in the population, including women, children, the middle-aged, and the elderly

The major micronutrient deficiencies which are of public health importance include vitamin A, iron and iodine deficiencies. The deficiencies of these micronutrients cause a variety of morbidities and increased mortality which are most severe in children, adolescent girls and pregnant women. 

Below are given some major disorder caused by deficiency in macronutrients.

MicronutrientsMajor deficiency disorders
IodineGoiter, hypothyroidism, , increased risk of stillbirth, birth defects infant mortality, cognitive impairment
Ironanemia, reduced learning and work capacity, increased maternal and infant mortality, low birth weight
ZincPoor pregnancy outcome, impaired growth (stunting), genetic disorders, decreased resistance to infectious diseases
Vitamin ANight blindness, xerophthalmia, increased risk of mortality in children and pregnant women
Folate (Vitamin B6)Megaloblastic anemia, neural tube and other birth defects, heart disease, stroke, impaired cognitive function, depression
Cobolamine (Vitamin B 12)Megaloblastic anemia (associated with Helicobacter pylori induced gastric atrophy)
Thiamine (Vitamin B1)Beriberi (cardiac and neurologic), Wernicke and Korsakov syndromes (alcoholic confusion and paralysis)
Riboflavin (Vitamin B2)Non specifi c – fatigue, eye changes, dermatitis, brain dysfunction, impaired iron absorption
Niacin (Vitamin B3)Pellagra (dermatitis, diarrhea, dementia, death)
Vitamin B6Dermatitis, neurological disorders, convulsions, anemia, elevated plasma homocysteine
Vitamin CScurvy (fatigue, hemorrhages, low resistance to infection, anemia)
Vitamin DRickets, osteomalacia, osteoporosis, colorectal cancer
CalciumDecreased bone mineralization, rickets, osteoporosis
SeleniumCardiomyopathy, increased cancer and cardiovascular risk
FluorideIncreased dental decay, affects bone health
Table Source: Public Health Reviews, Vol.32, 243-255: Micronutrient Deficiency Conditions Theodore H Tulchinsky