Nutritional and Digestive Disorders

The digestive system described through this chapter functions correctly only when it is both supplied with an adequate and balanced diet and free of disease or dysfunction in any of its component organs; when either condition fails, one or more of a set of common nutritional and digestive disorders may result. The WBCHSE syllabus names six such conditions specifically: protein-energy malnutrition, indigestion, constipation, vomiting, jaundice and diarrhoea.

Protein-energy malnutrition (PEM) is a broad term covering a spectrum of disorders that arise from a chronically inadequate intake of protein and/or overall calories, and it remains an important public-health concern among young children in many parts of India, including West Bengal. Two named forms of PEM lie at either end of this spectrum. Kwashiorkor results from a diet that is severely deficient in protein even though total calorie intake may be near-adequate, typically appearing in young children shortly after weaning when a starchy, protein-poor diet replaces breast milk; its most characteristic feature is oedema — fluid retention causing visible swelling of the face, limbs and abdomen (giving affected children the well-known "pot-bellied" appearance) — along with retarded growth, sparse and discoloured hair, a fatty and enlarged liver, and a markedly lowered resistance to infection. Marasmus, by contrast, results from a severe deficiency of both calories and protein together — essentially, general starvation — most often in infants under one year of age; unlike kwashiorkor, it produces no oedema, but instead an extreme wasting of both muscle mass and subcutaneous fat, leaving a characteristically shrunken, wizened appearance, along with severely retarded growth.

Indigestion refers to a general feeling of discomfort, fullness or mild pain in the upper abdomen following a meal, and can arise from a number of causes, including eating too much or too quickly, consuming excessively spicy or fatty food, psychological stress and anxiety (which can inhibit normal digestive secretion and gut motility), an inadequate secretion of digestive enzymes, or infection of the digestive tract by bacteria; it commonly presents with bloating, belching and sometimes mild nausea.

Constipation is a condition in which bowel movements become infrequent and the faecal matter passed is unusually hard and difficult to expel, and is usually the result of the colon reabsorbing an excessive amount of water from faecal matter that is retained there for too long — a consequence commonly of a diet low in fibre, insufficient fluid intake, or a sedentary lifestyle that slows the normal peristaltic movement of the colon.

Vomiting is the forceful, reflex expulsion of the contents of the stomach (and sometimes the upper small intestine) through the mouth, and is controlled by a specific vomiting centre located in the medulla oblongata of the brain, which can be triggered by a variety of stimuli including irritation or infection of the stomach lining, the ingestion of certain toxins or spoiled food, motion sickness, or signals arising from other parts of the body; while an occasional protective reflex that helps expel harmful material from the stomach, prolonged or repeated vomiting can lead to significant loss of water and electrolytes and consequent dehydration. …