Nutrient requirements

The nutritional needs during lactation are considerably greater than during pregnancy, taking into account that between four and six months of life, a normal child reaches twice the weight it reached during nine months of gestation. At this stage, the woman needs greater quantities of nutrients for the production of breast milk and the maintenance of her own health.

The mother during lactation requires a varied diet, which includes sources of nutrients such as the following:

• Complex carbohydrates: whole grain bread, rice, whole grain cereals, potatoes and legumes.

• Proteins: dairy products, lean meats, fish and poultry without skin.

• Lipids: unsaturated fats, such as olive oil, sunflower, soybean and corn oils, should be consumed.

• Foods rich in water-soluble vitamins, such as whole fruits, vegetables and greens.

Energy requirements

During breastfeeding, it is recommended to increase energy intakes by 500 kcal/day (kilocalories per day), with respect to those required for non-breastfeeding women. The mother, between the first three and six months of the child's life, produces approximately 800 ml (milliliters) of milk per day, for which she must use the extra calories from the diet and the reserves accumulated in the form of fat.

If the nursing mother does not receive the necessary additional energy through the diet, she runs the risk of compromising the maternal body reserves, which would cause disorders in her nutritional status, which would have repercussions on her health and that of the baby. For this reason, during this stage, diets that reduce the consumption of carbohydrates and fats in order to lose body weight should not be followed. To avoid obesity, moderate physical exercise should be performed.

In order to preserve another of the basic principles of a healthy diet, the nursing mother should obtain from proteins only between 10% and 15% of the total daily energy requirements; from fats, mainly unsaturated, between 30% and 35%; from carbohydrates, mainly complex, between 50% and 55%.

Protein requirements

It is estimated that to synthesize 1 gram of breast milk protein, the mother must use two grams of dietary protein. During lactation, it is recommended to ingest about 66 grams of calories per day, 25 grams more than those recommended for non-lactating women. Additional requirements can be met by adding to the usual diet only a moderate serving of some protein-rich food, e.g., a glass of milk, an egg, an extra serving of chicken, fish, legumes, or lean beef.

If the mother does not ingest enough carbohydrates and fats to guarantee the energetic demands during lactation, the body will use proteins to obtain the required energy, causing nutrient deficiencies in the mother, which would affect her health and reduce the quality of the breast milk, causing malnutrition of the baby.

Protein deficiencies in the breastfeeding mother's body increase the risk of producing breast milk with low concentrations of casein, a phosphoprotein present in milk, which is necessary for the absorption of calcium phosphate, an essential mineral for the formation and development of bone tissue and teeth.

Carbohydrate requirements

The recommended carbohydrate intake for lactating mothers is 210 grams per day, 80 grams more than those estimated for a non-lactating woman.

The predominant carbohydrate in breast milk is lactose, known as milk sugar, which aids in the absorption of calcium, allowing for proper bone mineralization, and benefits the intestinal flora. Although the concentration of lactose is less variable in breast milk than other nutrients, its total production is reduced in malnourished mothers.

It is recommended to increase energy demands, consuming foods containing complex carbohydrates, such as whole grain bread, rice, legumes, vegetables, tubers and fruits, rich in nutrients and dietary fiber; avoiding foods that provide a lot of energy but few nutrients, such as soft drinks, cakes, pastries, jams, excess sugar added to milk, coffee or tea; fried foods, sauces, animal fats, coconut oil, palm oil and margarine.

Lipid requirements

During lactation, an increase in lipid intake is recommended, in correspondence with the increase in energy, protein and carbohydrate requirements. Lipids should guarantee between 30% and 35% of the total energy recommended for this stage.

Depending on the type of fatty acids ingested by the mother, the proportion of these in the mother's milk will be different, so healthy fatty acids such as olive oil, corn, soybean and sunflower vegetable oils, fish, nuts and avocado should be included in the mother's diet. Foods containing less healthy fatty acids, such as butter, margarine, meat fat, coconut and palm oils, should be taken only occasionally.

Vitamin requirements

Fat-soluble vitamins:

• Vitamin a (retinol): 1300 µg/day (micrograms daily) of vitamin a is recommended during lactation. Its deficiencies cause immunological alterations, increasing the risk of respiratory and diarrheal infections; its deficiencies can also cause blindness. Foods containing vitamin a are: beef, pork, turkey and chicken liver; fish, eggs and milk; spinach, carrots, parsley, broccoli leaves, pumpkin and sweet potato.

• Vitamin d: 15 µg/day (micrograms per day) of vitamin d is recommended during lactation. This vitamin is essential for the health of the skeletal system, as it promotes bone mineralization. It is obtained mainly by cutaneous synthesis, mediated by ultraviolet radiation from the sun. It can also be obtained in some foods such as egg yolk, liver, dairy products and fatty fish.

• Vitamin e (tocopherol): 17 mg/day (milligrams/day) of vitamin e is recommended during lactation. Tocopherol deficiencies cause neurological disorders due to poor conduction of nerve impulses. Foods containing vitamin e are: eggs, nuts, olives and seed oils such as sunflower and corn.

• Vitamin k: 90 µg/day (micrograms/day) of vitamin k is recommended during lactation. Vitamin k deficiencies increase the risk of hemorrhage. Foods containing vitamin K are: spinach, broccoli, cabbage, lettuce, parsley, cauliflower, green beans and carrots; milk, meat, eggs, fish and liver.

Water-soluble vitamins:

• Vitamin b-1 (thiamine): 1.1 mg/day (milligrams/day) of vitamin b-1 is recommended during lactation. Mild deficiencies of this vitamin cause irritability, depression, forgetfulness and lack of concentration. Foods containing vitamin b-1 are: rice, wheat, corn; mushrooms, nuts, legumes, vegetables and fresh fruits; meats, fish, offal, eggs and dairy products.

• Vitamin b2 (riboflavin): 1.7 mg/day (milligrams/day) of vitamin b-2 is recommended during lactation. Deficiencies are very rare in the body. They can be manifested by cutaneous-mucosal symptoms, such as ulcers in the corners of the lips. They can also cause nervous and ocular disorders. Foods containing vitamin b-2 are: dairy products, meats, liver, eggs and nuts.

• Vitamin b-3 (niacin): 18 mg/day (milligrams/day) of vitamin b-3 is recommended during lactation. This vitamin contributes to maintain the good condition of the nervous system, the circulatory system and the skin. Foods containing vitamin b-3 are: meats, fish, milk and eggs; cereals and nuts.

• Vitamin b-6 (pyridoxine): 2 mg/day (milligrams/day) of vitamin b-6 is recommended during lactation. Deficiency of this vitamin causes different varieties of dermatitis and neurological symptoms including peripheral neuritis. Foods containing vitamin b-6 are: liver, meats, fish, spinach, chard, legumes, fortified cereals and nuts.

• Vitamin b-9 (folic acid): 500 µg/day (micrograms/day) of vitamin b-9 is recommended during lactation. Folic acid deficiencies can cause anemia in both children and adults. Foods containing vitamin b-9 include: animal organ meats, vegetables, legumes, nuts; whole grains, such as almonds; and in fortified foods.

• Vitamin b-12 (cobalamin): 2.6 µg/day (micrograms/day) of vitamin b-12 is recommended during lactation. Deficiencies of this vitamin cause immature red blood cells to become larger than normal, a disease known as megaloblastic anemia, and can cause short- and long-term neurological disorders. Foods containing this vitamin are: liver, kidney, meat, eggs, dairy products and oily fish. In cases of mothers who follow vegetarian diets, even without showing signs of malnutrition, they should consult with their doctor about the possible prescription of a vitamin B-12 supplement during breastfeeding.

• Vitamin c (ascorbic acid): 85 mg/day (milligrams/day) of vitamin c is recommended during lactation. Vitamin C is an antioxidant, which benefits the immune system and reduces the aging process. Foods containing this vitamin are: fresh fruits such as kiwi, lemon, tangerine, orange, grapefruit and guava; vegetables such as lettuce, spinach, broccoli, tomato, bell pepper, carrot, cauliflower and cabbage.

Mineral requirements

Calcium (ca): 1300 mg/day (milligrams/day) of calcium are recommended during lactation; 300 mg/day (milligrams/day) more than those recommended for a non-lactating woman. During lactation, the role of calcium is fundamental for the development of the child's bone tissue. To meet maternal calcium needs, it is recommended to consume 4 to 5 servings per day of dairy products, such as skim milk, skim cheese and yogurt. If dairy products cannot be consumed, there are fortified foods that can provide significant amounts; in addition, other foods that contain calcium are: vegetables, legumes, nuts, sesame seeds, small fish, when consumed with bones, such as canned sardines and fried anchovies.

Phosphorus (p): 700 mg/day (milligrams/day) of phosphorus are recommended during lactation. Foods containing phosphorus are: meats, milk, eggs, whole grains and nuts.

Iron (fe): 18 mg/day (milligrams/day) of iron is recommended during lactation. Iron is best absorbed in foods of animal origin. Examples: offal, red meat, fish, poultry.Nuts and legumes also contain iron. Combining iron-rich foods with foods containing vitamin C, such as lemon, increases iron absorption.

Zinc (zn): 25 mg/day (milligrams/day) of zinc is recommended during lactation. Zinc is essential for growth, cellular immunity and enzyme formation; it is involved in the sense of taste, smell and vision. Foods containing zinc are: red meat, fish, milk and legumes.

Selenium (se): 75 µg/day (micrograms/day) of selenium is recommended during lactation. Selenium is involved in the immune system and thyroid function. Foods containing selenium are: protein-rich foods such as meat, fish and cereals.

Iodine (i): 155 µg/day (micrograms/day) of iodine is recommended during lactation. Iodine requirements during lactation are high, as the baby must receive adequate amounts of iodine for the synthesis of thyroid hormones through breast milk. Foods containing iodine are: fish, seafood, seaweed, and iodized salt, the latter is recommended to be used in moderation, so some specialists advise taking iodine supplements to ensure the necessary intakes.