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PROPERLY USING HYPOALLERGENIC INFANT FORMULAS
One of the characteristics of hypoallergenic infant formulas is the partial hydrolysis of their proteins with the aim of reducing but not eliminating their allergenic potential. They differ from concentrated hydrolyzates of cow's milk proteins, which are practically devoid of potentially allergenic substances.
A hypoallergenic infant formula can be prescribed to prevent allergic symptoms in infants who have a familial history of atopy, when breast feeding which remains the best preventive approach, is not, or is no longer, desired by the mother.
The most frequently committed error with hypoallergenic infant formulas is unquestionably the systematic prescription of these products as a supplement to breast feeding. Except in the case of a family history of atopy, it is not useful to prescribe these formulas in cases of breast and bottle-feeding. A second error consists of prescribing them in cases of suspected allergy to proteins in cow's milk –a dangerous approach, because hypoallergenic infant formulas can induce serious anaphylactic reactions if allergy is present. Only concentrated hydrolyzates of cow's milk proteins should be used when allergy to these proteins is suspected.
POSTPONING DIVERSIFICATION OF THE DIET
Diversifying an infant’s diet too early increases the risk of subsequent occurrence of allergic symptoms. Several prospective studies demonstrate that the introduction of foods other than milk before the age of four months multiplies the risk of eczema or food-related allergy by a factor of 2-4 in the following months. This risk is that much higher in children with a family history of atopy. In this case, in addition to postponing diversification of the diet until six months of age, it is also necessary to postpone until after one year of age the introduction of foods known to be the most allergenic (eggs, kiwi, celery, walnuts, hazelnuts, peanuts, fish and seafood.)
Diversifying the diet too early also exposes the infant to the risk of nutritional deficiency. The introduction of new foods, inevitably leads to a reduction in ingestion of infant formula and thus of the nutrients which it contains. When the foods introduced do not compensate for such deficiencies, which is usually the case, a deficiency may occur in calcium, essential fatty acids and iron. In the past, prolonged use of milk and wheat flour diets were described as a common cause of iron deficiency while today, this type of diet is used to prevent this risk provided that an infant formula is used and not native cow's milk which is very low in absorbable iron.
Diversifying an infant’s diet too early increases the risk of subsequent occurrence of allergic symptoms. Several prospective studies demonstrate that the introduction of foods other than milk before the age of four months multiplies the risk of eczema or food-related allergy by a factor of 2-4 in the following months. This risk is that much higher in children with a family history of atopy. In this case, in addition to postponing diversification of the diet until six months of age, it is also necessary to postpone until after one year of age the introduction of foods known to be the most allergenic (eggs, kiwi, celery, walnuts, hazelnuts, peanuts, fish and seafood.)
Diversifying the diet too early also exposes the infant to the risk of nutritional deficiency. The introduction of new foods, inevitably leads to a reduction in ingestion of infant formula and thus of the nutrients which it contains. When the foods introduced do not compensate for such deficiencies, which is usually the case, a deficiency may occur in calcium, essential fatty acids and iron. In the past, prolonged use of milk and wheat flour diets were described as a common cause of iron deficiency while today, this type of diet is used to prevent this risk provided that an infant formula is used and not native cow's milk which is very low in absorbable iron.
WHOLE COW'S MILK IS PREFERABLE TO PARTIALLY SKIMMED MILK
The use of infant formulas, starter infant formulas and then follow-on formulas, are strongly recommended up to the age of one year, and fortified formulas are recommended up to the age of 2-3 years. However it happens that for mostly financial reasons, parents wish to replace these commercially prepared formulas with native cow's milk, particularly after the age of six months. In such cases partially skimmed cow's milk should not be used, as often occurs, but instead whole cow's milk, except perhaps in cases of early obesity.
Quantitatively, human breast milk contains 40 g/L of lipids and follow-on formulas or fortified formulas contain 30 g/L on average. The choice between whole cow's milk whose lipid content is 35 g/L and partially skimmed milk which contains only 16 g/L of lipids therefore is unequivocal. Qualitatively, cow's milk contains mainly saturated fat which is neither the case for infant formula nor for human breast milk. The idea of using partially skimmed cow's milk probably originated from a desire to limit intake of saturated fat. But apart from very rare cases of dyslipidemia, there is no reason to limit the intake of saturated fat in infants. On the contrary, at this age an adequate intake of essential fatty acids must be provided and whole milk is superior to partially skimmed milk.
The essential fatty acid and iron deficiencies generated by replacing infant formulas with whole milk must be compensated for by two or three teaspoonfuls a day of sunflower oil in the infant's different meals and weekly intake of blood sausage or beef liver (preferable to calves' liver which is more costly and contains less iron).
The use of infant formulas, starter infant formulas and then follow-on formulas, are strongly recommended up to the age of one year, and fortified formulas are recommended up to the age of 2-3 years. However it happens that for mostly financial reasons, parents wish to replace these commercially prepared formulas with native cow's milk, particularly after the age of six months. In such cases partially skimmed cow's milk should not be used, as often occurs, but instead whole cow's milk, except perhaps in cases of early obesity.
Quantitatively, human breast milk contains 40 g/L of lipids and follow-on formulas or fortified formulas contain 30 g/L on average. The choice between whole cow's milk whose lipid content is 35 g/L and partially skimmed milk which contains only 16 g/L of lipids therefore is unequivocal. Qualitatively, cow's milk contains mainly saturated fat which is neither the case for infant formula nor for human breast milk. The idea of using partially skimmed cow's milk probably originated from a desire to limit intake of saturated fat. But apart from very rare cases of dyslipidemia, there is no reason to limit the intake of saturated fat in infants. On the contrary, at this age an adequate intake of essential fatty acids must be provided and whole milk is superior to partially skimmed milk.
The essential fatty acid and iron deficiencies generated by replacing infant formulas with whole milk must be compensated for by two or three teaspoonfuls a day of sunflower oil in the infant's different meals and weekly intake of blood sausage or beef liver (preferable to calves' liver which is more costly and contains less iron).
AVOIDING EXCEEDING PROTEIN ALLOWANCES
The recommended protein allowance is 10 g/day from birth to two years of age, whatever the infant's weight. Before diversifying the infant diet, the reduced protein content of infant formulas, compared to that of native cow's milk, makes it possible to meet these allowances while avoiding any excess. On the other hand, the introduction of meat and non-liquid dairy products (for example, yogurt or cheese) often coincides with exceeding these recommended allowances.
Certain dietary errors can thus lead to protein intake which is up to five times higher than recommended daily allowances: e.g. ingestion of meat, fish or eggs at lunch and dinner, excessive ingestion of dairy products, use of native cow's milk with 35 grams per liter of protein instead of follow-on or fortified formulas which only contain about 25 grams per liter. Thus, although it frequently occurs that infants’ protein intake is too high, the potential risks that such intake produces remain hypothetical. An epidemiological study has suggested that an excessive intake of protein during the first years of life may lead to subsequent obesity by stimulation of early multiplication of adipocytes. This hypothesis remains to be confirmed or refuted by a prospective study currently underway. A oversupply of nitrogen resulting from excessive protein intake can also increase nitrogen load on the kidney (impaired renal clearance) and perhaps promote certain renal disorders; this last assumption however awaits further investigation.
The recommended protein allowance is 10 g/day from birth to two years of age, whatever the infant's weight. Before diversifying the infant diet, the reduced protein content of infant formulas, compared to that of native cow's milk, makes it possible to meet these allowances while avoiding any excess. On the other hand, the introduction of meat and non-liquid dairy products (for example, yogurt or cheese) often coincides with exceeding these recommended allowances.
Certain dietary errors can thus lead to protein intake which is up to five times higher than recommended daily allowances: e.g. ingestion of meat, fish or eggs at lunch and dinner, excessive ingestion of dairy products, use of native cow's milk with 35 grams per liter of protein instead of follow-on or fortified formulas which only contain about 25 grams per liter. Thus, although it frequently occurs that infants’ protein intake is too high, the potential risks that such intake produces remain hypothetical. An epidemiological study has suggested that an excessive intake of protein during the first years of life may lead to subsequent obesity by stimulation of early multiplication of adipocytes. This hypothesis remains to be confirmed or refuted by a prospective study currently underway. A oversupply of nitrogen resulting from excessive protein intake can also increase nitrogen load on the kidney (impaired renal clearance) and perhaps promote certain renal disorders; this last assumption however awaits further investigation.
ENSURING ADEQUATE CALCIUM INTAKE
Recommended daily calcium allowances are 400-600mg a day in infants. To meet these requirements, it is necessary for infants to ingest the equivalent of 500 mg of native cow's milk (see table I)
The majority of food and nutrition surveys show that, in the majority of cases, ingestion of calcium complies with recommended nutritional allowances in infants and young children, probably because the ingestion of milk and dairy products is often adequate at this age. Nevertheless, three cases can lead to calcium deficiency:
– Inadequate ingestion of milk and dairy products. A way to quickly verify that intake is sufficient is to verify that they are present in at least three of the four child’s meals per day.
– Cow's milk protein allergy: calcium intake rapidly becomes insufficient in infants who do not receive calcium supplementation when their diet is diversified. In fact, when diversification of the diet is started, the ingestion of hydrolyzed milk (prescribed in the context of allergy) decreases and cannot be compensated for by dairy products because the child is allergic to them. Therefore, it is necessary to systematically give calcium supplementation (about 250-500 mg a day) to infants allergic to cow's milk proteins, starting with the introduction of the first foods. This should be continued until development of tolerance to cow's milk proteins i.e. at about 12-18 months of age, which makes it possible to resume a normal diet.
– Irritable bowel syndrome: infants who suffer from irritable bowel syndrome and in whom ingestion of milk is reduced deserve the same attention as described above even though the exclusion of diary products is only partial and milk avoidance is of shorter duration.
Inadequate calcium intake during childhood usually has little or no immediate consequences. On the other hand, it has now been well-demonstrated that calcium deficiency during the first years of life, particularly if it is prolonged, increases the risk of osteoporosis and bone fractures in adulthood. This is true in particular in women after menopause. Such a progression is due to the fact that the key bone minerals in adults are built up during childhood and adolescence. Consequently, an insufficient intake of calcium during childhood prevents development of optimum bone mineral mass and, results several decades later in osteoporosis and associated related complications due to inevitable physiological demineralization of the skeleton with age.
Recommended daily calcium allowances are 400-600mg a day in infants. To meet these requirements, it is necessary for infants to ingest the equivalent of 500 mg of native cow's milk (see table I)
The majority of food and nutrition surveys show that, in the majority of cases, ingestion of calcium complies with recommended nutritional allowances in infants and young children, probably because the ingestion of milk and dairy products is often adequate at this age. Nevertheless, three cases can lead to calcium deficiency:
– Inadequate ingestion of milk and dairy products. A way to quickly verify that intake is sufficient is to verify that they are present in at least three of the four child’s meals per day.
– Cow's milk protein allergy: calcium intake rapidly becomes insufficient in infants who do not receive calcium supplementation when their diet is diversified. In fact, when diversification of the diet is started, the ingestion of hydrolyzed milk (prescribed in the context of allergy) decreases and cannot be compensated for by dairy products because the child is allergic to them. Therefore, it is necessary to systematically give calcium supplementation (about 250-500 mg a day) to infants allergic to cow's milk proteins, starting with the introduction of the first foods. This should be continued until development of tolerance to cow's milk proteins i.e. at about 12-18 months of age, which makes it possible to resume a normal diet.
– Irritable bowel syndrome: infants who suffer from irritable bowel syndrome and in whom ingestion of milk is reduced deserve the same attention as described above even though the exclusion of diary products is only partial and milk avoidance is of shorter duration.
Inadequate calcium intake during childhood usually has little or no immediate consequences. On the other hand, it has now been well-demonstrated that calcium deficiency during the first years of life, particularly if it is prolonged, increases the risk of osteoporosis and bone fractures in adulthood. This is true in particular in women after menopause. Such a progression is due to the fact that the key bone minerals in adults are built up during childhood and adolescence. Consequently, an insufficient intake of calcium during childhood prevents development of optimum bone mineral mass and, results several decades later in osteoporosis and associated related complications due to inevitable physiological demineralization of the skeleton with age.
CHOOSING VITAMIN D SUPPLEMENTATION
Since 1993, infant formulas have been fortified with vitamin D based at a concentration of 400-500 IU/l (10 to 12.5 µg/l) for starter infant formulas and 500-600 IU/l (12.5 to 15 µg/l) for follow-on formulas. Consequently, dosage of recommended vitamin D supplementation in infants who are fed with an infant formula has been decreased by half (Table II).
Although pharmaceutical packaging of vitamin D has been adjusted, many infants continue to receive the previously prescribed doses of vitamin D, i.e double those currently recommended. The harmful effects of a prolonged excess of vitamin D, nevertheless, continue to be relatively hypothetical. It has been suggested that this excess may be responsible for hypercalciuria and associated complications, in particular in infants with vitamin D hypersensitivity.
Since 1993, infant formulas have been fortified with vitamin D based at a concentration of 400-500 IU/l (10 to 12.5 µg/l) for starter infant formulas and 500-600 IU/l (12.5 to 15 µg/l) for follow-on formulas. Consequently, dosage of recommended vitamin D supplementation in infants who are fed with an infant formula has been decreased by half (Table II).
Although pharmaceutical packaging of vitamin D has been adjusted, many infants continue to receive the previously prescribed doses of vitamin D, i.e double those currently recommended. The harmful effects of a prolonged excess of vitamin D, nevertheless, continue to be relatively hypothetical. It has been suggested that this excess may be responsible for hypercalciuria and associated complications, in particular in infants with vitamin D hypersensitivity.
CHOOSING FLUORIDE SUPPLEMENTATION
Fluoride supplementation is recommended in infants and young children because of its preventive function against the occurrence of dental cavities. In infants, dosage should take into account fluoride concentrations in tap water (Table III). In children who brush their teeth, it should also be taken into account the amount of fluoride contained in toothpaste, because it is estimated that a child swallows about half of the toothpaste he/she uses. For this reason, it always recommended to use toothpaste specially designed for children (since the fluoride content is limited) and to limit the amount of toothpaste applied to the toothbrush.
Excessive intake of fluoride may cause fluorosis which is reflected by unsightly whitish stains on the teeth and also tooth fragility. In rare cases, it can also result in bone growth disorders.
Fluoride supplementation is recommended in infants and young children because of its preventive function against the occurrence of dental cavities. In infants, dosage should take into account fluoride concentrations in tap water (Table III). In children who brush their teeth, it should also be taken into account the amount of fluoride contained in toothpaste, because it is estimated that a child swallows about half of the toothpaste he/she uses. For this reason, it always recommended to use toothpaste specially designed for children (since the fluoride content is limited) and to limit the amount of toothpaste applied to the toothbrush.
Excessive intake of fluoride may cause fluorosis which is reflected by unsightly whitish stains on the teeth and also tooth fragility. In rare cases, it can also result in bone growth disorders.
CONCLUSION
The aim of this dietary advice, which practitioners can give to parents of infants and young children, is to prevent the occurrence of the most frequently observed dietary errors observed at these ages.
Because although dietary errors have little or no immediate harmful consequences, they do represent all of the risk factors of the subsequent occurrence of a disorder which can be more or less serious in nature.
The aim of this dietary advice, which practitioners can give to parents of infants and young children, is to prevent the occurrence of the most frequently observed dietary errors observed at these ages.
Because although dietary errors have little or no immediate harmful consequences, they do represent all of the risk factors of the subsequent occurrence of a disorder which can be more or less serious in nature.
Prof. Patrick TOUNIAN
Hôpital Armand-Trousseau, Assistance Publique des Hôpitaux de Paris
Hôpital Armand-Trousseau, Assistance Publique des Hôpitaux de Paris
References
Comité de nutrition de la société française de pédiatrie. Alimentation du nourrisson et de l’enfant en bas âge. Réalisation pratique. Arch Pediatr 2003 ; 10 : 76-81.
Tounian P. Alimentation du nourrisson normal. Encycl Méd Chir (Elsevier, Paris), Pédiatrie, 4-002-H-10, 1999, 6p.
Chandra RK. Five-year follow-up of high-risk infants with family history of allergy who were exclusively breast-fed or fed partial whey hydrolysate, soy, and conventional cow's milk formulas. J Pediatr Gastroenterol Nutr 1997; 24: 380-8.
Fergusson DM, Horwood LJ, Shannon FT. Early solid feeding and recurrent childhood eczema: a 10-year longitudinal study. Pediatrics 1990; 86: 541-6.
Kalkwarf HJ, Khoury JC, Lanphear BP. Milk intake during childhood and adolescence, adult bone density, and osteoporotic fractures in US women. Am J Clin Nutr 2003; 77: 257-65.
Table I: Milk equivalences in terms of calcium
Table II: Recommended vitamin D supplements in infants (add 400 IU/day in children with dark skin)
Table III: Recommending fluoride supplementation by age and fluoride content in tap water
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