Nutritional features of the growing organism
The child's body is characterized by maximum metabolic intensity, necessary for plastic and structural processes, as well as high energy expenditures against the background of increased physical activity. At the same time, regulatory mechanisms (neural and humoral) and enzyme systems of the gastrointestinal tract remain immature.
Energy expenditure per 1 kg of body weight in children aged 1–5 years is 80–100 kcal, in adolescents — 50–65 kcal, whereas in adults it averages 45 kcal. To compensate for such costs, the daily diet must be strictly differentiated by age, balanced, and undergo gentle culinary processing.
Macronutrient requirements
In percentage terms, energy value should be distributed as follows: proteins — 14%, fats — 31%, carbohydrates — 55%.
- Proteins: The quota of animal protein is critically important (up to 6 years — 65–70%, older — at least 60%). Protein requirement decreases with age: from 4 g/kg in children under 3 years to 2–2.5 g/kg in high school students (in adults, the norm is 0.8–1.5 g/kg). Milk is an indispensable product — its proteins are combined with easily digestible calcium.
- Fats: Perform a plastic function and serve as a source of polyunsaturated fatty acids (PUFAs). Their daily requirement is equal to the protein requirement.
- Carbohydrates: Cover high energy needs due to intensive glycolysis. Easily digestible (simple) carbohydrates quickly restore glycogen stores, but they should be given only at the end of a meal. Sweets at the beginning of a meal inhibit the secretion of digestive glands and reduce appetite.
Role of vitamins and minerals
Minerals and vitamins act as plastic material and growth stimulants. Vitamins A and D are of particular importance. Vitamin A and beta-carotene are necessary for the development of the skeleton and epithelium; they are absorbed more efficiently when taken together with fats. Vitamin D is the main regulator of phosphorus-calcium metabolism.
| Age | Ca:P (ratio) | Water (ml per 1 kg of weight) |
|---|---|---|
| Under 1 year | 1,2 : 1 | 150 |
| 1–3 years | 1 : 1 | 100 |
| Over 4 years | 1 : 1,5 | 50–60 |
Excess phosphorus or magnesium in food hinders calcium absorption and accelerates its excretion. Iron plays a crucial role in hematopoiesis: since milk is poor in it, the timely introduction of complementary foods (juices and purees) is required to prevent iron deficiency anemia.
Dietary regimen
The younger the child, the more frequent meals are required. For schoolchildren, the diet is traditionally divided into four meals:
- Breakfast (25%): a hot dish (porridge, cottage cheese) and a drink.
- Lunch (30–35%): the maximum volume, including soup, a meat/fish dish with a side dish, and a sweet.
- Afternoon snack (15–20%): liquids, fruits, light carbohydrates to replenish water and energy.
- Dinner (20%): a hot dish (mash, casserole) and a fermented milk drink.
Important: Meat and fish dishes are given only for breakfast and lunch. They take longer to digest, stimulate the central nervous system, and increase the overall metabolic rate.
Nutrition in the elderly
The aging process is accompanied by a decrease in vitality, the loss of non-renewing cellular structures (neurons, alveoli), and metabolic dysregulation. In the gastrointestinal tract, motility weakens, hydrochloric acid and pepsin secretion in the stomach drops, the pancreas atrophies, and teeth are lost.
In accordance with the law of nutritional adequacy, the diet of elderly (60+ years) and senile individuals must meet two basic principles:
- Quantitative moderation: reduction of the total calorie content and volume of consumed macronutrients against the background of age-related hypodynamia.
- Qualitative completeness: high content of essential amino acids, PUFAs, phospholipids, vitamins, and trace elements. This allows compensating for impaired absorption and prolonging the active period of life.
Briefly: answers to topical questions
What diseases develop in children with vitamin D deficiency and impaired phosphorus-calcium metabolism?
With vitamin D deficiency and impaired phosphorus-calcium metabolism, children develop nutritional rickets. This disease is a pathology in which chondrocyte differentiation is disrupted, and the mineralization of osteoid and growth plates suffers. In ICD-10, this pathology belongs to the class of endocrine, nutritional and metabolic diseases, with designated categories for vitamin D deficiency, active phase of rickets, and its sequelae.
The rule of protein timing: "Meat in the morning, kefir in the evening." Protein foods (meat, fish) stimulate the central nervous system and require prolonged digestion, so they are given for breakfast and lunch. In the evening, light fermented milk products are preferred.
Class and exam questions
Does thermal processing destroy toxins in fish?
No, thermal processing (boiling, frying) does not destroy toxins accumulated in fish.
Why cannot cow's milk be the sole food product for a child older than a few months?
1 liter of cow's milk contains only 1 mg of iron with a child's daily requirement of about 10 mg. Feeding exclusively on milk will lead to severe iron deficiency anemia.
Why should sweets be given to children strictly after a meal?
Simple carbohydrates eaten at the beginning of a meal inhibit the secretion of digestive juices and reduce appetite, causing the child to miss out on necessary proteins and fats.
What else to study on this topic
- Functions of lecithin from egg yolk in nervous tissue development and the prevention of sensitization
- Specifics of schoolchildren's nutrition when studying on the second shift
- Theories of aging: the role of xenobiotic intoxication and defects in cellular selection
- The role of histidine, lysine, and tryptophan as growth factors in children under 3 years of age
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