Malnutrition, infection and hygiene

Malnutrition means any deviation from normal, optimum nutrition. It includes undernutrition (too little energy or nutrients) and overnutrition (too much). India faces both at once, the double burden of malnutrition:

• Undernutrition: many low-birth-weight babies (under 2.5 kg, often because the mother herself was undernourished; the book puts it at about one-third of babies), underweight and stunted (too short for age) children and women, widespread anaemia, and vitamin A and iodine deficiency.
• Overnutrition: rising overweight and obesity, especially in cities; the National Family Health Survey (NFHS-4) found 31.3 per cent of urban women and 26.6 per cent of urban men overweight or obese. With it come diabetes, heart disease and high blood pressure.

Effects of key micronutrient deficiencies:

• Iodine: goitre (swelling of the thyroid gland in the neck); in pregnancy it can cause stillbirth and cretinism (severe mental and physical retardation in the child). Iodised salt prevents it.
• Iron: anaemia, with tiredness, poor concentration, poor cognitive development and school performance, lower work capacity, and danger to mother and baby in pregnancy.
• Vitamin A: eye problems from night blindness to permanent blindness.

Nutrition and infection feed each other. Poor nutrition weakens immunity, so infections take hold more easily. Infection then drains nutrients, through vomiting, diarrhoea and fever, reduces appetite and raises the body's needs, which worsens malnutrition. Without good food, clean water, hygiene and care, this becomes a vicious cycle, hardest on children, the elderly and those already undernourished.

What causes disease? Two groups of factors:

• Host (intrinsic) factors, within the person: age, sex, heredity, nutritional status, lifestyle and physical activity.
• Environmental (extrinsic) factors: physical (air, water, soil, housing, climate, noise), biological (insects, animals, bacteria, viruses) and psychosocial (culture, customs, beliefs, health services, attitudes).

Hygiene protects health, alongside good food:

• Personal hygiene: regular bathing, washing hands before eating and after using the toilet, care of teeth, hair and nails, clean clothes, and toilet hygiene.
• Environmental hygiene: safe water supply, clean housing, proper sewage and excreta disposal, regular garbage collection, vector control (mosquitoes spread malaria and dengue through their bites; flies carry germs to food) and food sanitation.
• Safe (potable) drinking water is free from disease-causing germs, harmful chemicals and bad smell or taste. At home it can be made safer by boiling, filtering, chlorinating or using a purifier, and must be stored covered, in clean containers.

Food-borne illness (diarrhoea, dysentery, typhoid, cholera, hepatitis) happens when food contains harmful germs or their toxins in large enough amounts. Common causes:

• spoiled or contaminated raw food, and unsafe water;
• poor storage, and leaving cooked food at temperatures between about 4 and 60 degrees C, the range in which germs multiply fastest;
• undercooking, slow cooling or careless reheating;
• cross-contamination: for instance, chopping salad on the same board used for raw meat without washing it;
• food left uncovered, and food handlers with unwashed hands or illness.
• So keep hot food hot, cold food cold (refrigerate perishables), cook thoroughly, keep food covered, and work with clean hands, utensils and surfaces.