Table 1.

Selected micronutrients: role, signs, and symptoms of deficiencies and accurate diagnosis

Micronutrient	Functions	Symptoms and signs of deficiency	Diagnosis
Iron	Constituent of hemoglobin, carries out oxygen transport, indispensable for cognitive functions	Anemia, endocrine and immune disorders, ↑ danger for maternal death Newborns: ↓ birthweight, prematurity, perinatal complications, physical and mental retardation	At least 2 of 3: ↓ Hemoglobin ↓ Ferritin ↓ Transferrin saturation
Vitamin A	Participates in vision, immunization, reproduction, growth	Sensitivity, infections, xerophthalmia and other vision problems, blindness in children	↓ Serum retinol, ophthalmologic examination
Iodine	Constituent of thyroid hormone, CNS growth in fetus and infant	Fetus: neurological and mental retardation (permanent), cretinism Adult: goiter, ↓ mental function, hypo/hyperthyroidism	↓ Urine iodine
Folate	Constituent of vitamin B, participates in DNA synthesis, stability, and repair, disinclines mutations	Megalosblastic–macrocytic anemia Fetus: neural tube defects	↓ Concentration in serum, plasma, and erythrocytes
Zinc	Activates enzymes involved in immunization, necessary for fetus and children growth	↑ Morbidity and mortality of diarrhea, respiratory infection, and malaria	No reliable biomarker due to ↓ bio-ability

For example, iron is an essential element for oxygen transportation, the red blood cells, and several enzymes’ production and important immune functions. Its deficiency that affects millions lies hidden of the overall death rates, maternal hemorrhage, reduced mental, and physical performance. Reduced levels of blood hemoglobin, serum ferritin, and low transferrin saturation confirm the diagnosis of iron deficiency