Changes of Salt Metabolism under Conditions of Hot Climate

The disturbance of sodium chloride (NaCL) metabolism is of particular importance. At slight perspiration of total NaCL lost by organism daily (15-20g) 2-6 g/day is lost with sweat. At significant perspiration NaCL losses reach great values (sweat contains 0.3-0.6 % NaCL) and cause serious disturbances of salt metabolism, not compensated even at full replacement of water loss. The compensation reactions of organism to prevent salt deficiency are: decrease of chloride content in sweat up to 0.1 %, decrease of diuresis up to minimum (360-400 ml/day). Oliguria (decrease of diuresis) is a characteristic reflex directed not so much at maintenance of water in tissues, but at maintenance of Na in organism. The addition of NaCL to food is not required, as food completely covers the needs for salt, and excessive NaCL causes potassium elimination with urine and occurrence of its deficiency in organism.

In some cases at large losses of salt with sweat a serious condition - salt exhaustion - can occur with the following symptoms: severe gastric spasms, vomiting, apathy, fainting, cramps (increase of muscle excitability at decrease of chlorides in plasma). For treatment additional introduction of NaCL is required.

In conditions of hot climate some restrictions of water consumption are necessary. For example, while working at +39-40ºC a person needs 6 l/day of water in divided portions 100-150 ml each.

Hygiene of Nutrition in Conditions of Hot Climate.

Features of Nutrition in Hot Climate

At long action of high temperature and humidity of air the decrease of basic metabolism up to 10 % is marked due to effect of heat on vegetative nervous system. There can be decrease of appetite (especially to meat food), salivation, gastric secretion and motility.

In a diet of population of some regions with hot climate (Africa, Southeast Asia, South America) significant deficiency of proteins of animal origin with prevalence of vegetable carbohydrates (carbohydrate monophagia) is marked. It is connected to a low standard of life of the population, religious and traditional factors. A large content of cellulose in food causes constant mechanical irritation of intestines, especially large intestine, and development of colitis. High temperature and carbohydrate nutrition results in activation of fermentative processes in intestines, especially in children, causing toxic dyspepsia.

Only carbohydrate nutrition with deficiency of irreplaceable amino acids, animal fats and some vitamins results in occurrence of specific diseases, such as:

· Kvashiorcor (in translation - "the red boy") – a severe children’s disease after weaning, i.e. deprivation of breast milk and commencement of nourishment with carbohydrate food (deficit of animal protein, methionine, fat-soluble vitamins) that causes growth inhibition, delay in weight, edemas, dermatoses and skin depigmentation, mental retardation, fatty liver infiltration, atrophy of pancreas, hypochromic anemia.

· Spru – a severe chronic disease characterized by persistent diarrhea, gastritis, anemia, atrophy of mucous membrane of stomach and intestines, disturbances in bone marrow and liver; gradually general cachexia develops (big loss of body masses).

· A specific food poisoning of tropic climate is heliotropic toxicosis (heliotropic hepatitis) which occurs at use of cereals with admixture of heliotrope weed. The disease starts with gastroenteritis and in 1-2 weeks proceeds to ascites, atrophy of liver, decrease of proteins in blood, anemia, leukopenia. The disease may quickly lead to death at hepatic insufficiency or in 1-2 years to development of liver cirrhosis.

In tropic climate there are good conditions for development of microbes in food, therefore food poisonings of microbe etiology (toxicoinfections, bacterial toxicoses) are rather common there (see theme “Food poisonings”).