The nutritional needs of the healthy child

The requirements of all nutrients during infancy increase proportionally to the growth of the body, the development of bones, muscles and organs, as well as to the physical exercise performed. Individual needs depend on various factors such as size, age, physical activity, and the child's metabolism. Until the age of ten, the approximate age at which sexual development and maturation begin, the nutritional needs of boys and girls are similar.

Energy needs

During the stage of absolute breastfeeding, which should continue until six months of life, lactose, the main carbohydrate contained in breast milk, provides 40% of the total energy, while fats, mainly in the form of triglycerides, provide between 40% and 50% of the total energy required.

The progressive introduction of other foods up to twelve months of age should not exceed the energy intakes that continue to be provided by breast milk or formula. Salt, sugar or honey should not be added to any of the incorporated foods.

From one year of life onwards, five meals a day should be planned and energy intakes should be dosed, considering two main meals and three lighter meals. The energy requirements of children per kilogram of weight are much higher than those of an adult, taking into account that a preschool child requires, on average, between 80 and 100 kilocalories per kilogram of weight per day, while adults require, on average, between 30 and 40 kilocalories per kilogram of weight per day. Such values are justified by the energy needs necessary to support the child's growth and development processes.

From two years of age, the percentage of energy provided by proteins, lipids and carbohydrates in the child's diet should be close to the percentages recommended for the adult stage, which are: proteins between 10% and 15%; lipids between 30% and 35%; and carbohydrates between 50% and 55% of the total energy required.

Protein requirements

During absolute breastfeeding, the proteins contained in milk intervene in the digestion of lipids and complex carbohydrates; they favor the absorption of minerals and vitamins, such as calcium, zinc, iron and folates; they participate in antimicrobial activity; they stimulate the intestinal flora; and they induce the growth and maturation of the gastrointestinal tract.

From six months of life, with the gradual increase of complementary feeding, animal proteins are introduced, and the following guidelines should be followed:

• It is recommended to first introduce foods of milder flavor, such as chicken or veal, later on rabbit, pork, etc.

• Fish consumption should begin between six and eight months of age, with white meat fish, such as hake, sole or megrim; after one year of age, introduce small oily fish.

• Swordfish, shark and bluefin tuna should not be offered until after three years of age, due to their mercury concentrations.

• It is recommended to introduce egg yolks after nine months of age and egg whites after one year of age.

Offal is not recommended. They can be offered only sporadically after the first year of life. In general, during infancy, only children on vegetarian diets, those suffering from certain pathologies, and those from low-income or dysfunctional families are at risk of protein deficiencies.

Lipid requirements

During absolute breastfeeding, milk will provide 98% of the fat in the form of triglycerides, which, due to their structure, are better absorbed than artificial milks. The rest of the lipids are phospholipids, free fatty acids, cholesterol, and fat-soluble vitamins, essential for protein synthesis and conduction of nerve impulses. The levels of polyunsaturated fatty acids depend on maternal intakes. Lipids play structural roles in the formation of membranes and participate in the synthesis of neurotransmitters, among others.

From two years of age, lipids should provide between 30% and 35% of the total energy provided by the diet. It is recommended that this contribution be obtained from the different types of fats in the following proportions:

• Approximately 15% to 20% of monounsaturated fatty acids, mostly obtained from olive oil.

• Between 7% and 8% of saturated fatty acids, coming from whole milk, butter, fatty meats, etc.

• Between 7% and 8% of polyunsaturated fatty acids, mainly from oily fish and nuts.

Carbohydrate requirements

During the stage of absolute breastfeeding, the lactose contained in breast milk provides 40% of the total energy needed by the baby, it also favors intestinal colonization by lactobacillus bifidus, a bacterium that resides in the colon, contributes to digestion, and is associated with a lower epidemiological incidence of allergies.

Between four and six months of life, in addition to breast milk, the infant should be offered complex carbohydrates, contained in gluten-free cereals such as corn or rice, either mixed with water, with adapted milk or with breast milk; it is recommended to give them with a spoon instead of a bottle to avoid excessive intakes. Afterwards, cereals containing gluten such as wheat, oats, barley and rye should be introduced, always before seven months of age, to reduce the risk of developing celiac disease.

Simple carbohydrates, such as table sugar and honey, should not be introduced into the child's diet before the first year of life.

Carbohydrates should constitute the major caloric intake of the diet, representing between 50% and 55% of the total energy ingested. The recommended carbohydrates are complex carbohydrates, such as rice, corn, pasta, bread, legumes, potatoes, and vegetables.

Water requirements

During exclusive breastfeeding it is not necessary to provide water. Only after starting complementary feeding should we give water to the baby; the quantities demanded are very variable, so it is recommended to offer water several times a day and it will be the child himself who regulates the amount to be ingested at each moment.

From the age of one year, the child should drink between one and one and a half liters of liquids, preferably water, this demand may be higher if vomiting, diarrhea, fever or very high ambient temperature occurs.

Those responsible for children should be attentive to ensure that they are properly hydrated, especially during group physical activities. At this age, children prefer to postpone the satisfaction of any physiological need, so as not to take time away from play.

Water is essential during any stage of life, among its main functions are:

• Participate in the digestion of nutrients and their transport to the cells.

• Regulating body temperature.

• Eliminating waste products through urine.

Mineral and vitamin needs

Vitamins and minerals, although they do not provide energy to the body, are essential to perform important catalytic functions in metabolism, which constitute the basis of life on a molecular scale and allow the various activities of cells, such as growth, reproduction, maintenance of their structures, and response to stimuli, among others.

Vitamins can be easily destroyed due to their high sensitivity to different physical and chemical agents, such as heat, light, oxidants, reducing agents, humidity, acids and bases. For this reason, they can suffer losses during culinary processes, especially if foods are subjected to prolonged cooking, with vitamin C, folic acid and vitamin B1 being the most sensitive. Minerals are not destroyed or altered by heat, oxygen or acids; they can only be lost in the water used to wash the food when it is not consumed.

Most vitamins and minerals cannot be stored in the organism and that is why they must be taken regularly, from the daily diet. During infancy, deficiencies of all vitamins and minerals are very serious, bu