Current trends in the composition of infant milk formulas

ARTICLE IN PRESS Current Paediatrics (2004) 14, 51–63

www.elsevierhealth.com/journals/cuoe

Current trends in the composition of infant milk formulas Martine S. Allesa,*, Petra A.M.J. Scholtensa, Jacques G. Bindelsb a

Department of Baby Foods, Numico Research BV, Bosrandweg 20, PO Box 7005, 6700 CA Wageningen, The Netherlands b Department of Nutritional Sciences, Numico Research, and Wageningen University, Wageningen, The Netherlands

KEYWORDS Infant; Formula; Long-chain polyunsaturated fatty acid; Synthetic triacylglycerol; Hydrolysed protein; Soy protein;

Summary Human milk is regarded as the best nutrition for infants. However, when breastfeeding is not possible, desirable or sufficient, infant milk formulas serve as an adequate substitute for human milk. They have been designed to provide infants with the required nutrients for optimal growth and development. In addition, infant milk formulas are now increasingly resembling human milk, for example in the area of bifidogenic effects. This review describes current trends in the design of infant formulas. Topics that will be discussed are long-chain polyunsaturated fatty acids, triacylglycerol palmitate, optimal protein concentration, the use of hydrolysed and soy protein, nucleotides and pre- and probiotics.

Nucleotide; Prebiotic;

& 2003 Elsevier Ltd. All rights reserved.

Probiotic

*

Practice point *

New infant formulas should be based on a systematic nutrition and safety evaluation

Research agenda *

*

Study the long-term effects of prebiotic oligosaccharides on modulation of the immune system, prevention of atopic symptoms and prevention of infectious diseases Find and study components for infant milk formulas that act as soluble receptor analogues for pathogens

*Corresponding author. Tel.: þ 31-317-467-800; fax: þ 31-317466500. E-mail address: [email protected] (M.S. Alles).

*

Study the effects of specific combinations of pre- and probiotics (synbiotics) Confirm the effects of nucleotides on the immune system

Introduction It has been widely accepted that breastfeeding is the best food for infants. Mothers’ milk provides all the nutritive elements for normal growth and for infants’ digestive conditions. It increases the affective relationship of the mother towards the infant. Breast milk also contains a number of protective and immunoregulatory components that may have a beneficial effect on the development of the infant’s immune system. Breastfed infants suffer fewer gastrointestinal and respiratory infections,

0957-5839/$ - see front matter & 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.cupe.2003.09.007

ARTICLE IN PRESS 52

which is especially highlighted in the lower socioeconomic groups of developing countries.1,2 There is increasing evidence of a similar protective effect of breastfeeding in developed countries.2–4 Although human milk is the first choice for the newborn infant, milk substitutes play an indispensable role in infant nutrition when breastfeeding is not possible, desirable or sufficient. Infant milk formulas have been designed to provide infants with the required nutrients for optimal growth and development. National and supranational guidelines have been defined to ensure an adequate nutritional intake for infants fed infant milk formulas. The European Union guidelines, enforced in all Member States, are summarized in Table 1. Research to improve the quality of infant milk formulas is now focused mainly on the bioactive components present in human milk. This is aimed not necessarily at mimicking the exact composition of human milk but at achieving the functional effects that are observed in breastfed infants. This paper provides an outline of new developments in the composition of infant formulas.

Lipids The quantity of fat in infant milk formulas provides an infant with 40–50% of its total daily energy intake. Most fats currently used in regular infant formulas are of vegetable origin. Two specific types of fat derived from other ingredients will be discussed below: long-chain polyunsaturated fatty acids (LCPs) and structured triacylglycerols.

Long-chain polyunsaturated fatty acids Many studies have reported that breastfeeding is associated with significantly higher scores for cognitive development after adjustment for confounding socio-economic factors.6 The components of breast milk that may partly explain the observed differences are the LCPs arachidonic acid (C20-4, n6; AA) and docosahexaenoic acid (C22-6, n-3; DHA). Both AA and DHA comprise a major proportion of the phospholipid content of the cell membranes of the retina and brain. The conventional sources of vegetable oils generally used in the manufacture of infant formulas do not contain any AA or DHA. By chain elongation and desaturation, AA and DHA may by synthesized from linoleic acid (C18:2, n-6) and a-linolenic acid (C18:3, n-3), which are present in all infant formulas. The ability to undertake this synthesis seems, however, to be limited in infants.7 As a result, red blood cell membrane levels of DHA

M.S. Alles et al.

and AA are lower in formula-fed infants than in their breastfed counterparts. Fatty acids in human milk are mostly present in the form of triglycerides. However, a relatively high proportion of AA and DHA in human milk (10–20%) is present in the form of phospholipids.8–16 In infant primates, it has been shown that the uptake of AA in the form of phospholipids is significantly higher than that of the triglyceride form.11 These lipids are probably highly protected from beta-lipolysis and are further transformed into fatty acids that play a role in myelinization.12 Sources of DHA and AA in commercially available formulas with added LCPs are single-cell oil (AA in the form of triglycerides), fish oil (DHA in the form of triglycerides) and egg lipid (AA and DHA in the form of phospholipids). The high concentration of DHA and AA in the retina and in brain tissue provided the rationale for the many studies on the effects of formulas with added DHA and AA on visual and cognitive function. Two meta-analyses by SanGiovanni et al., in preterm and full-term infants, investigated the effect of LCPs on visual resolution acuity.13,14 These meta-analyses combined estimates of behaviourally and electrophysiologically based visual resolution acuity. In both pre- and full-term infants, the authors concluded that DHA improved the visual resolution acuity at 2 and 4 months of age. In two recent important studies, by Hoffman et al. and Makrides et al. in term infants, it was shown that supplementation with DHA alone or in combination with AA elevated plasma and red blood cell concentration of the essential fatty acids.15,16 The resulting blood lipid fatty acid profiles were more similar to those observed in breastfed infants. Hoffman et al. showed that 4 months of supplementation resulted in better visual function at the age of 4 months and 1 year. Makrides et al., however, supplemented for 1 year and did not find any effect on visual acuity.16 Birch et al. studied the effects of LCP supplementation in infants who were weaned off breastfeeding.17 They showed that maturation of cortical function could be influenced by dietary LCPs beyond 6 weeks of age. In a large study by O’Connor et al., the effects of 1 year of supplementation with DHA and AA were evaluated in preterm infants.18 The authors showed improved visual development in the preterm infants at 6 months of age, as assessed by electrophysiologically based visual resolution acuity. Investigations into the effects of LCPs on cognitive function have produced variable results. The Bayley scales for mental development (MDI) and psychomotor development (PDI) are often used in

ARTICLE IN PRESS Current trends in the composition of infant milk formulas

Table 1

53

European Union guidelines for the composition of stating infant milk formula.5 Minimum per 100 kcal

Maximum per 100 kcal

Energy

60 kcal/100 ml

75 kcal/100 ml

Protein Cows’ milk protein (g) Soy protein or soy protein mixtures (g) Protein partial hydrolysates (g)

1.8 2.25 2.56

3 3 3

Fat Linoleic acid (LA) Alpha linolenic acid (ALA) Ratio LA:ALA n-3 LCP n-6 LCP Arachidonic acid Eicosapentaenoic acid (EPA) and decosahexaenoic acid (DHA)

(g) (mg) (mg) F F F F F

4.4 300 50 5 F F F F

6.5 1200

Carbohydrates Lactose Saccharose Precooked or gelatinized starch

(g) (g)

7 3.5 F F

14 F 20% of total carbohydrates 2 g/100 ml and 30% of total carbohydrates

Minerals Sodium Potassium Chloride Calcium Phosphorus Magnesium Iron Zinc Copper Iodine Selenium

(mg) (mg) (mg) (mg) (mg) (mg) (mg) (mg) (mg) (mg) (mg)

20 60 50 50 25 5 0.5 0.5 20 5 F

60 145 125 F 90 15 1.5 1.5 80 F 3

Vitamins Vitamin A Vitamin D Thiamin Riboflavin Niacin Panthothenic acid Vitamin B6 Biotin Folic acid Vitamin B12 Vitamin C Vitamin K Vitamin E

(mg RE) (mg) (mg) (mg) (mg NE) (mg) (mg) (mg) (mg) (mg) (mg) (mg) (mg a-TE)

60 1 40 60 0.8 300 35 1.5 4 0.1 8 4 0.5 mg a-TE/g LCPs In no case less than 0.1 mg/100 kJ

180 2.5 F F F F F F F F F F F

Nucleotides Total Cytidine-5-monophosphate Uridine-5-monophosphate Adenosine-5-monophosphate Guanosine-5-monophosphate Inosine-5-monophosphate

(mg) (mg) (mg) (mg) (mg) (mg)

F F F F F F

5 2.5 1.75 1.5 0.5 1.0

a-TE, alpha-tocopherol equivalents.

15 1% of total fat content 2% of total fat content 1% of total fat content EPA content may not exceed DHA content

ARTICLE IN PRESS 54

this area. The MDI assesses perception, memory, learning, problem-solving and vocalization, as well as early verbal communication and abstract thinking. The PDI measures mainly gross motor abilities, and hand and finger manipulation. Lucas et al. conducted a large intervention study with DHA and AA in term infants and found no effects on the development of infants with 6 months intervention.19 There was also no difference between the breast- and formula-fed infants in this study. In contrast, Birch et al. found an improvement in the MDI at 18 months of age in infants who had received a DHA- and AA-supplemented formula during the first 4 months of life.20 No effects on the PDI were found. O’Connor et al. described evidence for improved motor development among preterm infants of less than 1250 g birthweight who were randomized to the DHA plus AA groups.18 There were no differences in the MDI at 12 months of corrected age. Similarly, Fewtrell et al. found no significant difference in the MDI and PDI in preterm infants fed formulas with and without LCPs at 18 months of age.21 In 1998, Willatts et al. undertook a randomized trial in 44 infants to test the effects of LCP (AA and DHA) supplementation from birth to age 4 months on infant cognitive behaviour at 10 months of age.22 They used the means–end problem-solving test, arguing that standard tests of infant development such as Bayley scales measure perceptual and motor skills rather than cognitive ones. The authors indeed found significantly better problem-solving scores in the infants fed LCP-enriched formulas. This finding may be of great importance as these scores in infancy are related to higher childhood IQ scores. More recently, the same group reported important long-term benefits of LCP supplementation during infancy on the speed of processinginformation (unpublished results) and blood pressure. These results provide a strong rationale for using LCPs in infant milk formulas. Many expert committees and professional organizations (the British Nutrition Foundation, World Health Organization/ Food and Agricultural Organization of the United Nations and the International Society for the Study of Fatty Acids and Lipids) have recommended that AA and DHA should be added to infant formulas. A group of international paediatric LCP experts, assembled in the Munich Consensus Group, recently published recommendations based on the latest scientific evidence.23 They concluded that infant formulas for term infants should contain at least 0.2% of the total fatty acids as DHA and 0.35% as AA. For preterm infants, the group recommended the inclusion of at least 0.35% DHA and 0.4% AA.

M.S. Alles et al.

Structural position of palmitic acid The structure of fats may explain partly the differences in bowel habit between formula- and breastfed infants.24–26 Quinlan et al. were able to relate stool hardness to stool composition.25 They concluded that differences in the triacylglycerol palmitate content of formula- and breast milk resulted in more calcium soap formation in formula-fed infants and thus in harder stools. Carnielli et al. studied the effects of palmitic acids in different stereoisomeric positions in preterm and full-term infants.27,28 They observed a significantly higher absorption of fatty acids and calcium in infants fed formulas containing triglycerides similar to those found in human milk (palmitic acid esterified predominantly at the sn-2 position) compared with infants fed regular formulas (with the palmitic acid esterified mainly at the sn-1 and 3 positions). Kennedy et al. showed that changing the stereoisomeric structure of palmitate in infant formula resulted in reduced stool level of soap fatty acids and softer stools.29 The stools of breastfed infants in the study were, however, still softer than those of infants fed the new formula with the synthetic triacylglycerol (sn-2 palmitate). In the same study, a significantly higher bone mineral content was observed in infants fed the new formula, suggesting an improved utilization of calcium. Adaptation of the triacylglycerol structure of fat in the infant formula thus leads to a better absorption of fat and calcium, resulting in several functional benefits for the infant.

Protein The protein of cows’ milk-based infant formulas has been modified to provide an infant with essential amino acids and to mimic the protein composition of human milk as closely as possible. This section will consider the effects of a decreased concentration of protein in cows’ milk protein-based infant formulas and the nutritional aspects of hydrolysed infant formulas and soy protein formulas.

Protein quantity Most infant milk formulas contain a mean protein: energy ratio of about 2 g/100 kcal. It is not, however, known whether this is the optimal ratio for infants. It is apparent that formula-fed infants have a higher protein intake than breastfed infants.30–33 Research has focused on reducing the

ARTICLE IN PRESS Current trends in the composition of infant milk formulas protein concentration of infant milk formulas.32,34– 40 These studies have indicated that infant formulas with protein concentrations above 1.7 g/100 kcal appear to be adequate, and no differences with respect to growth indices have been shown between the different formulas with varying protein concentrations. No specific benefit of a lower protein concentration in infant formulas has, however, been shown.

Hydrolysed protein Infants who suffer from dietary protein intolerance have for many years been successfully managed with protein hydrolysates of greatly reduced allergenicity. A commentary on current developments and unresolved issues in the dietary treatment and prevention of food allergy in infancy has been published in a joint statement by the European Society for Paediatric Allergology and Clinical Immunology (ESPACI) Committee on Hypoallergenic Formulas and the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Committee on Nutrition.41 They have concluded that, in the treatment of allergic conditions, the causal protein should be completely excluded from the diet. For exclusively breastfed infants, this means that the lactating mother should be advised to follow a strict elimination diet because the breast milk may contain antigens from her own diet. For formula-fed infants, a product based on extensively hydrolysed protein or a product based on an amino acid mixture should be selected. The committee further commented on preventive therapies and strongly recommended breastfeeding during the first 4–6 months as this might greatly reduce the incidence of allergic manifestations. In formula-fed infants with a documented hereditary risk of atopy, exclusive feeding with a formula with a confirmed reduced allergenicity was recommended because it can reduce the incidence of adverse reactions, especially to cows’ milk protein. With respect to products of moderately reduced allergenicity, the committee stated that more studies are needed. Discussions on the effects of different types of either partially or extensively hydrolysed protein are currently ongoing. These discussions have not brought us much further, and other factors in the dietary management of atopic diseases may be more important. An interesting field of research is the role of the intestinal microflora in the development of the immune system and the induction of oral tolerance (see probiotics below).

55

Besides of the use of hydrolysed protein in the treatment and prevention of allergy, it may also be used in other target groups. Lucassen et al. studied the effect of an extensively hydrolysed whey formula in the dietary management of infantile colic.42 They showed that this type of formula was effective in reducing the duration of crying in a primary care setting. The use of protein hydrolysed formulas is also sometimes proposed in preterm infants, for example to improve gastric emptying. Rigo et al. studied the nutritional adequacy of such formulas and showed some differences compared with those preterm infants fed whole-protein formulas, mainly with respect to plasma amino acid concentration and mineral balance.43 They concluded that extensive nutritional studies are needed before the use of hydrolysed formulas can be promoted for preterm infants. Several studies in preterm infants have, however, subsequently shown appropriate plasma amino acid concentrations, adequate nitrogen retention and growth.44–46 A preterm formula with hydrolysed protein has recently been found to accelerate the gastrointestinal transit of milk and stools47 and improve the feeding tolerance of very low-birthweight infants, leading to a more rapid establishment of full enteral feeding.48 Today’s hydrolysates apparently represent a safe and nutritionally adequate source of protein for preterm infants.

Soy protein Soy formulas are still widely used for infants suffering from cows’ milk allergy but their use has been discouraged for several years. A number of studies have shown that infants with such allergy also react to soy protein formulas. Zeiger et al. reported the prevalence of combined allergy to both cows’ milk and soy in infants and children to be between 0% and 63%.49 In recent years, however, it has become clear that we should differentiate between IgE-mediated reactions and non-IgEmediated reactions to cows’ milk protein and soy protein.50 In infants and children suffering from non-IgE-mediated reactions to cows’ milk protein, such as enterocolitis or enteropathy, it appears that up to 60% of individuals also react to soy protein.51 In these infants, the use of soy formulas should be discouraged.51,52 However, in infants and children suffering from IgE-mediated allergy to cows’ milk, it has been shown that the incidence of combined allergy to both cows’ milk protein and soy protein is much lower than previously reported, the prevalence ranging from 0% to 14%.49,53–55 Thus, for many infants, soy formulas are a good substitute for

ARTICLE IN PRESS 56 cows’ milk-based formulas.52 According to the review by Businco et al., the effect of soy formulas on the prevention of food allergy has not been clearly established.56 Another topic for recent discussion has been the concentration of isoflavones in soy formulas and their impact as phytoestrogens during a developmental stage of life.57,58 Isoflavones are oestrogenlike structures that are present in soy products but also appear in breast milk.59 The most important isoflavones present in soy are daidzein and genistein.60 Isoflavones, also called phytoestrogens, are structurally similar to oestrogens and may bind to oestrogen receptors in in vitro animal models.61–64 On a weight-for-weight basis, infants fed the recommended amount of soy formula would consume 3–5 times the amount of isoflavones that has been shown to affect the menstrual cycle and levels of luteinizing hormone and follicle-stimulating hormone in adult premenstrual women.65,66 Not much is, however, known about the oestrogenic effect of these phytoestrogens in infants. There have been no reports of endocrine effects in infants fed modern soy formulas and no evidence of abnormal pubertal development in adolescents who received soy-based formula in their childhood.66–69 Similarly, there have been no findings of infertility in adults who consumed soy formulas in their childhood.68 The metabolizable form of the phytoestrogens probably plays an important role here. Isoflavones are present in soy formulas in the conjugated form, which may be less biologically active than unconjugated forms.60 Isoflavone hydrolysis and deconjugation in the intestinal tract depends on the presence of intestinal enzymes and intestinal bacteria. It is not known whether infants are able to metabolize conjugated isoflavones. However, Cruz et al. have shown that isoflavones are present in the urine of young infants, which suggests that isoflavones are to some extent absorbed from the intestinal tract.70 Notwithstanding the lack of clinical evidence on the oestrogenic effects of soy isoflavones in infants, several authorities have expressed their concern over the use of soy protein formulas in infants. The current opinion of the Scientific Committee on Food is that soy-based infant formulas should be reserved for specific situations and that cows’ milkbased formulas should be the standard choice.71

Nucleotides Nucleotides account for 2–5% of the non-protein nitrogen fraction of human milk.72,73 They are

M.S. Alles et al.

present in human breast milk in larger quantities than in cows’ milk or infant milk formulas.74 Nucleotides have therefore been added to some commercially available infant formulas in several countries since 1965.75 Nucleotides are structures that consist of a purine or pyrimidine base, a sugar and one or more phosphate groups. They can be formed by de novo synthesis or by the salvage pathway.75 In the de novo pathway, nucleotides are synthesized from amino acid precursors, whereas in the salvage pathway, nucleotides are formed from nucleosides and bases that are derived from the breakdown of endogenous or dietary nucleotides. The salvage pathway requires less energy than the de novo synthesis of nucleotides.74,75 The absorption of dietary nucleotides by epithelial cells is difficult because of the highly negative charge of the phosphate groups.76 Removal of the phosphate groups of nucleotides results in the formation of nucleosides, which are more easily absorbed by the intestinal epithelial cells.76,77 After absorption, nucleosides are degraded and metabolized into forms that can be readily salvaged by other cell types.76 Healthy individuals exist almost independently of the exogenous supply of nucleotides, using less than 5% of their dietary nucleotides.78 In these subjects, the endogenous supply of nucleotides is maintained by de novo synthesis and the salvage pathway. Under certain conditions, however, the body’s requirements for exogenous nucleotides may increase, for example when the body is growing rapidly, such as in early infancy.78 Clinical trials with full-term infants have shown that there are no benefits of nucleotide supplementation on infant growth.79 In infants who were born small for gestational age, however, improved growth in terms of weight, length and head circumference was found after nucleotide supplementation.80 It has been suggested that nucleotides have an important role in the development of immune function. Carver et al. compared nucleotide-supplemented infant milk formula with regular infant milk formula and observed a higher level of natural killer cell activity when nucleotides were added.81 This effect was significant at 2 months of age and remained consistently higher at 4 months of age, although the difference was not always significant. In the same study, a significantly higher production of interleukin-2 was shown in the mononuclear cells of infants in the nucleotide-supplemented group. These results were not, however, confirmed in a more recent study by Cordle et al.82 They did not find any significant difference in the B- or T-lymphocyte populations of infants fed soy protein isolate formulas for 1 year with or without added

ARTICLE IN PRESS Current trends in the composition of infant milk formulas nucleotides.82 Pickering et al. studied 311 infants who were fed human milk, nucleotide-supplemented milk formula or iron-supplemented formula.83 The vaccine response of infants against the Haemophilus influenzae B (Hib) vaccine, the diphtheria tetanus and pertussis (DTP) vaccine and the oral polio vaccine was then studied. The nucleotide-supplemented infants had a higher total Hib antibody level and higher IgG Hib antibody concentration. There were, however, no apparent differences in terms of the polio antibody responses and IgG response to tetanus immunization. Ostrom et al. did not observe any significant differences in the antibody responses to Hib or DTP between infants fed soy formula and those fed nucleotidesupplemented soy formula.84 Yau et al. studied the effect of nucleotides on diarrhoea and immune responses in healthy term infants in Taiwan.85 They observed a significantly lower risk of diarrhoea in infants fed an infant formula fortified with nucleotides, but there was a significantly increased risk of upper respiratory tract infections in this group. Nucleotides have also been suggested as being involved in the development of the intestinal microflora, having an effect on lipoprotein metabolism and reducing the number of episodes of diarrhoea.83,86–92 The clinical trials that have so far been carried out to demonstrate these effects are still limited, and the results obtained have been controversial. More research is needed to confirm the suggested benefits of nucleotides.

Pre- and probiotics Prebiotic oligosaccharides One of the differences between breastfed and formula-fed infants lies in the development of the intestinal flora. Initial colonization of the germfree intestine of the newborn takes place during delivery when it comes into contact with the flora of the mother and/or the hospital environment. After this first inoculation, the infant’s intestinal flora changes rapidly under the influence of diet and other environmental factors. The development of the intestinal microflora was first studied at the beginning of this century when the microflora of formula-fed and breastfed infants were compared. It was shown that bifidobacteria were the predominant micro-organisms in breastfed infants. This observation was confirmed later by several research groups, but some studies conflicted with the original theory.93 In a recent

57

study by Harmsen et al., new molecular identification and detection methods were used to compare the fecal flora of breastfed and formula-fed infants.94 The authors confirmed that bifidobacteria are dominant in breastfed infants, where as the amounts of Bacteroides spp. and bifidobacteria are similar in formula-fed infants. The important growth-promoting bifidus factors in human milk are the human milk oligosaccharides. These are complex structures that contain both free oligosaccharides and oligosaccharides bound to either glycolipids or glycoproteins.93 The monomers of free oligosaccharides are D-glucose, D-galactose, N-acetylglucosamine, L-fucose and sialic acid. They resist digestion in the small intestine and reach the large bowel, where they may undergo fermentation. The oligosaccharides have two important functions in the infant: (1) They are important bifidogenic factors and selectively stimulate the growth of bifidobacteria in the colon of the breastfed infant (the so-called prebiotic function). (2) They are soluble receptor analogues for pathogens and thereby have a direct inhibitory effect on certain pathogenic micro-organisms. Several studies have investigated the prebiotic effects of specific oligosaccharides used to supplement infant formulas. Nagendra et al. concluded that the incorporation of 0.5% lactulose in human milk was sufficient to stimulate a bifidobacterial flora.95 Rueda et al. studied the influence of supplementing an adapted milk formula with 1.43 mg gangliosides/100 kcal.96 They obtained these acidic glycosphingolipids from porcine brain and concluded that gangliosides at concentrations present in human milk significantly modify the fecal flora. Four double-blind, controlled studies have been conducted using a mixture of 90% transgalactooligosaccharides and 10% fructo-oligosaccharides to test the effects on infants’ fecal flora. Boehm et al. concluded that such a mixture had clear bifidogenic effects in preterm infants.97 The bifidogenicity of the mixture was accompanied by changes in the stools that made them more similar to the stools found in breastfed infants. In a study by Moro et al., the dosage effect of the mixture of 90% transgalacto-oligosaccharides and 10% fructo-oligosaccharides was tested in term infants.98 Supplementation with either 0.4 or 0.8 g oligosaccharides/100 ml significantly increased the number of bifidobacteria in the fecal flora, making it more similar to the flora of breastfed infants. In a third trial, the effects of a formula containing the prebiotic mixture, partially hydrolysed whey proteins and

ARTICLE IN PRESS 58

structured synthetic triacylglycerol (sn-2 palmitate) were tested in term infants.99 After 6 weeks, significantly more bifidobacteria were measured in the feces of the infants fed with the new formula than in those fed regular formulas. This was also shown by Knol et al.100 who tested the effects in infants aged 4–12 weeks who had previously been formula-fed for at least 4 weeks. In addition, Knol observed that the pattern of subspecies of bifidobacteria was very similar in the prebiotic and the breastfed groups. With regard to this specific mixture of oligosaccharides, the Scientific Committee on Food of the European Commission has concluded, based on all the available scientific data, that it has no major concerns about the use of up to 0.8 g/dl of a combination of 90% transgalactooligosaccharides and 10% fructo-oligosaccharides in an infant formula.101 A study by Guesry et al. tested the effect of fructo-oligosaccharides alone in term infants, using three different doses.102 The number of stools was significantly increased with the highest dose of fructo-oligosaccharides (3 g/day), but no bifidogenic effects were observed in any of the groups. It is thus likely that the various types of nondigestible oligosaccharides differ in their efficacy as prebiotic factors in infant formulas. The research to find and study novel components for infant formulas that act as soluble receptor analogues for pathogens has just started.

Probiotic bacteria Probiotics are live microbial food components that beneficially affect the host by improving its intestinal microbial balance. In a study by Langhendries et al. Bifidobacterium bifidus was added to infant formulas.103 The prevalence of colonization with bifidobacteria was higher in the infants fed formulas with bifidobacteria than in controls and was similar to that in breastfed infants. The use of probiotic bacteria (such as lactobacilli and bifidobacteria) in infant formulas also has possible therapeutic applications. de Roos and Katan reported on papers published between 1988 and 1998 that had reviewed the health effects of probiotic bacteria and concluded that the consumption of foods containing Lactobacillus GG might shorten the course of rotavirus infection.104 Since 1998, several studies have been carried out using probiotic bacteria in the treatment or prevention of diarrhoea. Two recent meta-analyses have been performed to assess whether treatment with lactobacilli might improve the clinical outcome in children with acute infectious diarrhoea.105,106

M.S. Alles et al.

Both studies concluded that lactobacilli are effective as a treatment for acute diarrhoeal illness in children, shortening the duration of diarrhoea by 0.6–0.7 days. Lactobaccillus GG has been shown to be effective in the prevention of infectious diarrhoea in undernourished children at high risk of infection,107 in hospitalized infants to prevent nosocomial infections,108 in children receiving oral antibiotic therapy to avoid antibiotic-associated diarrhoea109,110 and in children attending day care centres to prevent respiratory infection.111 Probiotic bacteria are also thought to play a role in the control of allergic inflammation at an early age. The intestinal microflora of infants with (a high risk of) food allergies seems to have a different composition.112–115 It is thought that specific strains of bacteria modulate the immune responses to dietary antigens, for example by effects on the balance between pro- and anti-inflammatory cytokines. It has been demonstrated that supplementing with Bifidobacterium animalis BB-12 or Lactobacillus GG modifies the allergic inflammation in infants with atopic eczema, compared with a placebo.116,117 A significant improvement in skin condition of these infants was shown in two clinical trials. In two recent studies by the same group, the probiotic strain Lactobacillus GG was shown to be effective in the prevention of early atopic disease in children at high risk when given to mothers prenatally and to their infants postnatally.118,119 Probiotic bacteria are thus promising components for infant formulas, with interesting applications in the prevention and treatment of infectious diarrhoea and allergy. Current research deals with the question of whether particular probiotics are highly specific for their effect or whether closely related strains also show a similar range of function. Moreover, we will in the coming years learn the extent to which the effects of probiotics and prebiotics overlap and under which circumstances a combined, synbiotic approach makes sense.

Implementation This paper has described the most important new developments in the composition of infant formulas. Through research and innovation, infant milk formulas are constantly being improved, with the aim of achieving in formula-fed infants all the functional effects that are observed in breastfed infants. Examples are the bifidogenic effects of oligosaccharides and the cognitive effects of LCPs; both ingredients are now added to infant formulas to improve their functionality. The basis for the

ARTICLE IN PRESS Current trends in the composition of infant milk formulas

composition of infant formulas is set in the standard in the European Union (EU) Commission Directive of 14 May 1991.5 This allows members to submit proposals for amendments to the composition of infant formulas. Since 1991, the inclusion of nucleotides, selenium, phospholipids and LCPs has been allowed. There are no clear criteria for testing the adequacy of new infant formulas. Linear and ponderal growth and other anthropometrical, biochemical and metabolic factors are often evaluated over short periods of time (for example 1–3 months). A working group of the Committee on Medical Aspects of Food and Nutrition of England and Wales (UK COMA) has issued guidelines on the nutritional assessment of infant formulas.120 Besides formulating general principles for assessing an infant formula nutritionally, the working group has defined three stages of specific interest within the clinical trial: study design, study conduct and handling/presentation of the data. For each of these stages, a number of recommendations are given. In 2001, the ESPGHAN Committee on Nutrition published a medical position paper in the Journal of Pediatric Gastroenterology and Nutrition supporting the general concepts outlined in the report of the UK COMA group.121 The Association of the Food Industries for Particular Nutritional uses of the European Union (IDACE), representing the infant formula industry, has recently passed a position paper to the EU in which it has suggested modifying the Directive where it concerns claims.122 IDACE defines two categories of claim: descriptive and informative statements related to the composition of the formula, and claims related to infant health. For the first type, no additional proof is needed as long as the claims comply with the General Labelling Directive 200/13/EC. Objective and scientifically verified data are, however needed to support the second group of claims. IDACE has defined the conditions for obtaining such data. For example, a minimum of two independent clinical trials or a multicentre equivalent are needed to support the claim, and all studies should be interpreted in the light of outcomes for healthy infants exclusively breastfed for at least 4 months. In 2002, a scientific workshop was held under the auspices of the Child Health Foundation Germany and ESPGHAN to discuss the nature of the clinical evaluations needed for introducing innovations to infant formulas and other dietetic products for infants. Participants represented universities, infant food industries, consumer organizations, the European Commission and food regulatory bodies from some EU Member states. Based on this

59

workshop, ESPGHAN has published a medical position paper.123 To facilitate comparison between studies, ESPGHAN has outlined the core data that should be collected for all randomized nutrition trials. These includes, for example, data on characteristics of the cohort, compliance, efficacy and safety. The authors encourage further improvement of the proposed core dataset based on scientific developments and the practicalities of performing and reporting clinical studies. A systematic nutritional and safety evaluation of formula feeds, based on generally accepted guidelines such as those indicated above, will increase the quality of the scientific rationale underlying new infant formulas.

References 1. Cesar JA, Victora CG, Barros FC, Santos IS, Flores JA. Impact of breastfeeding on admission for pneumonia during postneonatal period in Brazil: nested case-control study. BMJ 1999;318(7194):1316–20. 2. Plank SJ, Milanesi ML. Infant feeding and infant mortality in rural Chile. Bull World Health Organ 1973;48(2):203–10. 3. Raisler J, Alexander C, O’Campo P. Breast-feeding and infant illness: a dose–response relationship? Am J Public Health 1999;89(1):25–30. 4. Wilson AC, Forsyth JS, Greene SA, Irvine L, Hau C, Howie PW. Relation of infant diet to childhood health: seven year follow up of cohort of children in dundee infant feeding study. BMJ 1998;316(7124):21–5. 5. European Commission. Commission Directive of 14 May 1991 on infant formulae and follow-on formulae (91/321/ EEC). OJ L 175, p. 35, last consolidated 25 May 1999. 6. Anderson JW, Johnstone BM, Remley DT. Breast-feeding and cognitive development: a meta-analysis. Am J Clin Nutr 1999;70(4):525–35. 7. Koletzko B, Rodriguez-Palmero M. Polyunsaturated fatty acids in human milk and their role in early infant development. J Mammary Gland Biol Neoplasia 1999;4(3): 269–84. 8. Harzer G, Haug M, Dieterich I, Gentner PR. Changing patterns of human milk lipids in the course of the lactation and during the day. Am J Clin Nutr 1983;37(4):612–21. 9. Wang L, Shimizu YKaneko S, et al. Comparison of the fatty acid composition of total lipids and phospholipids in breast milk from Japanese women. Pediatr Int 2000;42(1):14–20. 10. Bitman J, Wood DL, Mehta NR, Hamosh P, Hamosh M. Comparison of the phospholipid composition of breast milk from mothers of term and preterm infants during lactation. Am J Clin Nutr 1984;40(5):1103–19. 11. Wijendran V, Huang MC, Diau GY, Boehm G, Nathanielsz PW, Brenna JT. Efficacy of dietary arachidonic acid provided as triglyceride or phospholipid as substrates for brain arachidonic acid accretion in baboon neonates. Pediatr Res 2002; 51(3):265–72. 12. Wijendran V, Lawrence P, Diau GY, Boehm G, Nathanielsz PW, Brenna JT. Significant utilization of dietary arachidonic acid is for brain adrenic acid in baboon neonates. J Lipid Res 2002;43(5):762–7. 13. SanGiovanni JP, Parra-Cabrera S, Colditz GA, Berkey CS, Dwyer JT. Meta-analysis of dietary essential fatty acids and

ARTICLE IN PRESS 60

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26. 27.

28.

29.

M.S. Alles et al.

long-chain polyunsaturated fatty acids as they relate to visual resolution acuity in healthy preterm infants. Pediatrics 2000;105(6):1292–8. SanGiovanni JP, Berkey CS, Dwyer JT, Colditz GA. Dietary essential fatty acids, long-chain polyunsaturated fatty acids, and visual resolution acuity in healthy fullterm infants: a systematic review. Early Hum Dev 2000;57(3): 165–88. Hoffman DR, Birch EE, Birch DG, et al. Impact of early dietary intake and blood lipid composition of long-chain polyunsaturated fatty acids on later visual development. J Pediatr Gastroenterol Nutr 2000;31(5):540–53. Makrides M, Neumann MA, Simmer K, Gibson RA. A critical appraisal of the role of dietary long-chain polyunsaturated fatty acids on neural indices of term infants: a randomized, controlled trial. Pediatrics 2000;105(1 Part 1):32–8. Birch EE, Hoffman DR, Castaneda YS, Fawcett SL, Birch DG, Uauy RD. A randomized controlled trial of long-chain polyunsaturated fatty acid supplementation of formula in term infants after weaning at 6 wk of age. Am J Clin Nutr 2002;75(3):570–80. O’Connor DL, Hall R, Adamkin D, et al. Growth and development in preterm infants fed long-chain polyunsaturated fatty acids: a prospective, randomized controlled trial. Pediatrics 2001;108(2):359–71. Lucas A, Stafford M, Morley R, et al. Efficacy and safety of long-chain polyunsaturated fatty acid supplementation of infant-formula milk: a randomized trial. Lancet 1999;354(9194):1948–54. Birch EE, Garfield S, Hoffman DR, Uauy R, Birch DG. A randomized controlled trial of early dietary supply of longchain polyunsaturated fatty acids and mental development in term infants. Dev Med Child Neurol 2000;42(3): 174–81. Fewtrell MS, Morley R, Abbott RA, et al. Double-blind, randomized trial of long-chain polyunsaturated fatty acid supplementation in formula-fed to preterm infants. Pediatrics 2002;110(1 Part 1):73–82. Willatts P, Forsyth JS, DiModugno MK, Varma S, Colvin M. Effect of long-chain polyunsaturated fatty acids in infant formula on problem solving at 10 months of age. Lancet 1998;352(9129):688–91. Koletzko B, Agostoni C, Carlson SE, et al. Long-chain polyunsaturated fatty acids (LC-PUFA) and perinatal development. Acta Paediatr 2001;90(4):460–4. Morley R, Abbott RA, Lucas A. Infant feeding and maternal concerns about stool hardness. Child Care Health Dev 1997;23(6):475–8. Quinlan PT, Lockton S, Irwin J, Lucas AL. The relationship between stool hardness and stool composition in breastand formula-fed infants. J Pediatr Gastroenterol Nutr 1995;20(1):81–90. Weaver LT, Ewing G, Taylor LC. The bowel habit of milk-fed infants. J Pediatr Gastroenterol Nutr 1988;7(4):568–71. Carnielli VP, Luijendijk IH, van Goudoever JB, et al. Feeding premature newborn infants palmitic acid in amounts and stereoisomeric position similar to that of human milk: effects on fat and mineral balance. Am J Clin Nutr 1995;61(5):1037–42. Carnielli VP, Luijendijk IH, van Goudoever JB, et al. Structural position and amount of palmitic acid in infant formulas: effects on fat, fatty acid, and mineral balance. J Pediatr Gastroenterol Nutr 1996;23(5):553–60. Kennedy K, Fewtrell MS, Morley R, et al. Double-blind, randomized trial of a synthetic triacylglycerol in formulafed term infants: effects on stool biochemistry, stool

30.

31.

32.

33.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

characteristics, and bone mineralization. Am J Clin Nutr 1999;70(5):920–7. Fomon SJ, Thomas LN, Filer Jr, LJ, Anderson TA, Bergmann KE. Requirements for protein and essential amino acids in early infancy. Studies with a soy-isolate formula. Acta Paediatr Scand 1973;62(1):33–45. Butte NF, Garza C, Smith EO, Nichols BL. Human milk intake and growth in exclusively breast-fed infants. J Pediatr 1984;104(2):187–95. Janas LM, Picciano MF, Hatch TF. Indices of protein metabolism in term infants fed human milk, wheypredominant formula, or cows’ milk formula. Pediatrics 1985;75(4):775–84. Salmenpera L, Perheentupa J, Siimes MA. Exclusively breast-fed healthy infants grow slower than reference infants. Pediatr Res 1985;19(3):307–12. Raiha N, Minoli I, Moro G. Milk protein intake in the term infant. I. Metabolic responses and effects on growth. Acta Paediatr Scand 1986;75:881–6. Picone TA. Growth, serum biochemistries, and amino acids of term infants fed formulas with amino acid and protein concentration similar to human milk. J Pediatr Gastroenterol Nutr 1989;9:351–60. Axelsson IE, Jakobsson I, Raiha N. Formula with reduced protein content: effects on growth and protein metabolism during weaning. Pediatr Res 1988;24(3):297–301. Fomon SJ, Ziegler EE, Nelson SE, Frantz JA. What is the safe protein–energy ratio for infant formulas. Am J Clin Nutr 1995;62:358–63. Fomon SJ, Ziegler EE, Nelson SE, Rogers RR, Frantz JA. Infant formula with protein–energy ratio of 1.7 g/100 kcal is adequate but may not be safe. J Pediatr Gastroenterol Nutr 1999;28:495–501. Ziegler EE, Carrie-Fassler A, Haschke F, Nelson SE, Jeter JM. Modified whey formula with protein–energy ratio 1.8 g/ 100 kcal: metabolic balance studies in infants. J Pediatr Gastroenterol Nutr 2000;31(Suppl. 2):S173. Raiha NC, Fazzolari-Nesci A, Cajozzo C, et al. Whey predominant, whey modified infant formula with protein/ energy ratio of 1.8 g/100 kcal: adequate and safe for term infants from birth to four months. J Pediatr Gastroenterol Nutr 2002;35(3):275–81. Host A, Koletzko B, Dreborg S, et al. Dietary products used in infants for treatment and prevention of food allergy. Joint Statement of the European Society for Paediatric Allergology and Clinical Immunology (ESPACI) Committee on Hypoallergenic Formulas and the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Committee on Nutrition. Arch Dis Child 1999;81(1):80–4. Lucassen PL, Assendelft WJ, Gubbels JW, van Eijk JT, Douwes AC. Infantile colic: crying time reduction with a whey hydrolysate: a double-blind, randomized, placebocontrolled trial. Pediatrics 2000;106(6):1349–54. Rigo J, Salle BL, Picaud JC, Putet G, Senterre J. Nutritional evaluation of protein hydrolysate formulas. Eur J Clin Nutr 1995;49(Suppl. 1):S26. Mihatsch WA, Pohlandt F. Protein hydrolysate formula maintains homeostasis of plasma amino acids in preterm infants. J Pediatr Gastroenterol Nutr 1999;29(4):406–10. Szajewska H, Albrecht P, Stoitiska B, Prochowska A, Gawecka A, Laskowska-Klita T. Extensive and partial protein hydrolysate preterm formulas: the effect on growth rate, protein metabolism indices, and plasma amino acid concentration. J Pediatr Gastroenterol Nutr 2001;32(3):303–9.

ARTICLE IN PRESS Current trends in the composition of infant milk formulas

46. Picaud JC, Rigo J, Normand S, et al. Nutritional efficacy of preterm formula with a partially hydrolyzed protein source: a randomized pilot study. J Pediatr Gastroenterol Nutr 2001;32(5):555–61. 47. Mihatsch WA, Hogel J, Pohlandt F. Hydrolysed protein accelerates the gastrointestinal transport of formula in preterm infants. Acta Paediatr 2001;90(2):196–8. 48. Mihatsch WA, Franz AR, Ho. gel J, Pohlandt F. Hydrolyzed protein accelerates feeding advancement in very low birth weight infants. Pediatrics 2002;116(6):1199–203. 49. Zeiger RS, Sampson HA, Bock SA, et al. Soy allergy in infants and children with IgE-associated cows’ milk allergy. J Pediatr 1999;134(5):614–22. 50. Host A. Cows’ milk protein allergy and intolerance in infancy. Some clinical, epidemiological and immunological aspects. Pediatr Allergy Immunol 1994;5(5 Suppl):1–36. 51. Burks AW, Casteel HB, Fiedorek SC, Williams LW, Pumphrey CL. Prospective oral food challenge study of two soybean protein isolates in patients with possible milk or soy protein enterocolitis. Pediatr Allergy Immunol 1994;5(1):40–5. 52. American Academy of Pediatrics. Committee on Nutrition. Soy protein-based formulas: recommendations for use in infant feeding. Pediatrics 1998;101(1 Part 1):148–53. 53. Hill DJ, Davidson GP, Cameron DJ, Barnes GL. The spectrum of cows’ milk allergy in childhood. Clinical, gastroenterological and immunological studies. Acta Paediatr Scand 1979;68(6):847–52. 54. Bock SA, Atkins FM. Patterns of food hypersensitivity during sixteen years of double-blind, placebo–controlled food challenges. J Pediatr 1990;117(4):561–7. 55. Ragno V, Giampietro PG, Bruno G, Businco L. Allergenicity of milk protein hydrolysate formulae in children with cows’ milk allergy. Eur J Pediatr 1993;152(9):760–2. 56. Businco L, Bruno G, Giampietro PG. Soy protein for the prevention and treatment of children with cow-milk allergy. Am J Clin Nutr 1998;68(6 Suppl):1447S–52S. 57. Irvine C, Fitzpatrick M, Robertson I, Woodhams D. The potential adverse effects of soybean phytoestrogens in infant feeding. N Z Med J 1995;108(1000):208–9. 58. Barnes S. Evolution of the health benefits of soy isoflavones. Proc Soc Exp Biol Med 1998;217(3):386–92. 59. Slavin JL. Phytoestrogens in breast milkFanother advantage of breast-feeding? Clin Chem 1996;42(6 Part 1):841–2. 60. Irvine CH, Shand N, Fitzpatrick MG, Alexander SL. Daily intake and urinary excretion of genistein and daidzein by infants fed soy- or dairy-based infant formulas. Am J Clin Nutr 1998;68(6 Suppl):1462S–5S. 61. Shemesh M, Lindner HR, Ayalon N. Affinity of rabbit uterine oestradiol receptor for phyto-oestrogens and its use in a competitive protein-binding radioassay for plasma coumestrol. J Reprod Fertil 1972;29(1):1–9. 62. Shutt DA, Cox RI. Steroid and phyto-oestrogen binding to sheep uterine receptors in vitro. J Endocrinol 1972;52(2): 299–310. 63. Mathieson RA, Kitts WD. Binding of phyto-oestrogen and oestradiol-17 beta by cytoplasmic receptors in the pituitary gland and hypothalamus of the ewe. J Endocrinol 1980; 85(2):317–25. 64. Setchell KD, Borriello SP, Hulme P, Kirk DN, Axelson M. Nonsteroidal estrogens of dietary origin: possible roles in hormone-dependent disease. Am J Clin Nutr 1984;40(3): 569–78. 65. Cassidy A, Bingham S, Setchell KD. Biological effects of a diet of soy protein rich in isoflavones on the menstrual cycle of premenopausal women. Am J Clin Nutr 1994; 60(3):333–40.

61

66. Essex C. Phytoestrogens and soy based infant formula. BMJ 1996;313(7056):507–8. 67. Knight DC, Eden JA. A review of the clinical effects of phytoestrogens. Obstet Gynecol 1996;87(5 Part 2): 897–904. 68. Klein KO. Isoflavones, soy-based infant formulas, and relevance to endocrine function. Nutr Rev 1998;56(7): 193–204. 69. Strom BL, Schinnar R, Ziegler EE, et al. Exposure to soybased formula in infancy and endocrinological and reproductive outcomes in young adulthood. JAMA 2001;286(7): 807–14. 70. Cruz ML, Wong WW, Mimouni F, et al. Effects of infant nutrition on cholesterol synthesis rates. Pediatr Res 1994; 35(2):135–40. 71. European Commission Scientific Committee on Food. Report of the scientific committee on food on the revision of essential requirements of infant formulae and follow-on formulae. SCF/CS/NUT/IF/65 Final. 18 May 2003. 72. Janas LM, Picciano MF. The nucleotide profile of human milk. Pediatr Res 1982;16(8):659–62. 73. Thorell L, Sjoberg LB, Hernell O. Nucleotides in human milk: sources and metabolism by the newborn infant. Pediatr Res 1996;40(6):845–52. 74. Barness LA. Dietary sources of nucleotidesFfrom breast milk to weaning. J Nutr 1994;124(1 Suppl):128S–30S. 75. Cosgrove M. Perinatal and infant nutrition. Nucleotides. Nutrition 1998;14(10):748–51. 76. Sanderson IR, He Y. Nucleotide uptake and metabolism by intestinal epithelial cells. J Nutr 1994;124(1 Suppl):131S–7S. 77. Yu VY. The role of dietary nucleotides in neonatal and infant nutrition. Singapore Med J 1998;39(4):145–50. 78. Jyonouchi H. Nucleotide actions on humoral immune responses. J Nutr 1994;124(1 Suppl):138S–43S. 79. Uauy R. Dietary nucleotides and requirements in early life. In: Lebenthal, editor. Textbook of gastroenterology and nutrition in infancy. 2nd ed. New York: Raven Press, 1989, p. 265–80. 80. Cosgrove M, Davies DP, Jenkins HR. Nucleotide supplementation and the growth of term small for gestational age infants. Arch Dis Child Fetal Neonatal Ed 1996;74(2):F122. 81. Carver JD, Pimentel B, Cox WI, Barness LA. Dietary nucleotide effects upon immune function in infants. Pediatrics 1991;88(2):359–63. 82. Cordle CT, Winship TR, Schaller JP, et al. Immune status of infants fed soy-based formulas with or without added nucleotides for 1 year. II. Immune cell populations. J Pediatr Gastroenterol Nutr 2002;34(2):145–53. 83. Pickering LK, Granoff DM, Erickson JR, et al. Modulation of the immune system by human milk and infant formula containing nucleotides. Pediatrics 1998;101(2):242–9. 84. Ostrom KM, Cordle CT, Schaller JP, et al. Immune status of infants fed soy-based formulas with or without added nucleotides for 1 year. I. Vaccine responses, and morbidity. J Pediatr Gastroenterol Nutr 2002;34(2):137–44. 85. Yau K-IT, Huang C-B, Chen W, et al. Effect of nucleotides on diarrhoea and immune responses in healthy term infants in Taiwan. J Pediatr Gastroenterol Nutr 2003;36:37–43. 86. Gil A, Corral E, Molina MAJA. Effects of the addition of nucleotides to an adapted milk formula on the microbial pattern of faeces in at term newborn infants. J Clin Nutr Gastroenterol 1986;1:127–32. 87. Balmer SE, Hanvey LS, Wharton BA. Diet and faecal flora in the newborn: nucleotides. Arch Dis Child Fetal Neonatal Ed 1994;70(2):F137.

ARTICLE IN PRESS 62

88. Sanchez-Pozo A, Pita ML, Martinez A, Molina JA, SanchezMedina F, Gil A. Effects of dietary nucleotides upon lipoprotein pattern of newborn infants. Nutr Res 1986; 6:763–71. 89. Sanchez-Pozo A, Morillas J, Molto L, Robles R, Gil A. Dietary nucleotides influence lipoprotein metabolism in newborn infants. Pediatr Res 1994;35(1):112–6. 90. Gil A, Lozano E, De-Lucchi C, Maldonado J, Molina JA, Pita M. Changes in the fatty acid profiles of plasma lipid fractions induced by dietary nucleotides in infants born at term. Eur J Clin Nutr 1988;42(6):473–81. 91. DeLucchi C, Pita ML, Faus MJ, Molina JA, Uauy R, Gil A. Effects of dietary nucleotides on the fatty acid composition of erythrocyte membrane lipids in term infants. J Pediatr Gastroenterol Nutr 1987;6(4):568–74. 92. Brunser O, Espinoza J, Araya M, Cruchet S, Gil A. Effect of dietary nucleotide supplementation on diarrhoeal disease in infants. Acta Paediatr 1994;83(2):188–91. 93. Kunz C, Rudloff S. Biological functions of oligosaccharides in human milk. Acta Paediatr 1993;82(11):903–12. 94. Harmsen HJ, Wildeboer-Veloo AC, Raangs GC, et al. Analysis of intestinal flora development in breast-fed and formula-fed infants by using molecular identification and detection methods. J Pediatr Gastroenterol Nutr 2000; 30(1):61–7. 95. Nagendra AR, Viswanatha S, Arun Kumar S, Murthy BK, Venkat Rao S. Effect of feeding milk formula containing lactulose to infants on faecal bifidobacterial flora. Nutr Res 1995;15:15–24. 96. Rueda R, Sabatel JL, Maldonado J, Molina-Font JA, Gil A. Addition of gangliosides to an adapted milk formula modifies levels of fecal Escherichia coli in preterm newborn infants. J Pediatr 1998;133(1):90–4. 97. Boehm G, Lidestri M, Casetta P, et al. Supplementation of a bovine milk formula with an oligosaccharide mixture increases counts of faecal bifidobacteria in preterm infants. Arch Dis Child Fetal Neonatal Ed 2002;86(3):F178. 98. Moro G, Minoli I, Mosca M, et al. Dosage-related bifidogenic effects of galacto- and fructooligosaccharides in formulafed term infants. J Pediatr Gastroenterol Nutr 2002;34(3): 291–5. 99. Schmelzle H, Wirth S, Skopnik H, et al. Randomized doubleblind study of the nutritional efficacy and bifidogenicity of a new infant formula containing partially hydrolyzed protein, a high beta-palmitic acid level, and nondigestible oligosaccharides. J Pediatr Gastroenterol Nutr 2003;36(3): 343–51. 100. Knol J, Steenbakker GMA, van der Linde EGM, et al. Bifidobacterial species that are present in breast fed infants are stimulate and in formula fed infants by changing to a formula containing prebiotics. J Pediatr Gastroenterol Nutr 2002;34(4):477. 101. European Commission Scientific Committee on Food. Additional statement on the use of resistant short chain carbohydrates (oligofructosyl-saccharose and oligogalactosyl-lactose) in infant formulae and in follow-on formulae. SCF/CS.NUT/IF/47 Final. 14 December 2001. 102. Guesry PR, Bodanski H, Tornsit E, Aeschlimann JM. Effect of 3 doses of fructo-oligosaccharides in infants. J Pediatr Gastroenterol Nutr 2000;31(2):S252. 103. Langhendries JP, Detry J, Van Hees J, et al. Effect of a fermented infant formula containing viable bifidobacteria on the fecal flora composition and pH of healthy full-term infants. J Pediatr Gastroenterol Nutr 1995;21(2):177–81. 104. de Roos NM, Katan MB. Effects of probiotic bacteria on diarrhoea, lipid metabolism, and carcinogenesis: a review

M.S. Alles et al.

105.

106.

107.

108.

109.

110.

111.

112.

113.

114.

115.

116.

117.

118.

119.

120.

121.

of papers published between 1988 and 1998. Am J Clin Nutr 2000;71(2):405–11. Van Niel CW, Feudtner C, Garrison MM, Christakis DA. Lactobacillus therapy for acute infectious diarrhoea in children: a meta-analysis. Pediatrics 2002;109(4):678–84. Huang JS, Bousvaros A, Lee JW, Diaz A, Davidson EJ. Efficacy of probiotic use in acute diarrhoea in children: a meta-analysis. Dig Dis Sci 2002;47(11):2625–34. Oberhelman RA, Gilman RH, Sheen P, et al. A placebocontrolled trial of Lactobacillus GG to prevent diarrhoea in undernourished Peruvian children. J Pediatr 1999;134(1): 15–20. Szajewska H, Kotowska M, Mrukowicz JZ, Armanska M, Mikolajczyk W. Efficacy of Lactobacillus GG in prevention of nosocomial diarrhoea in infants. J Pediatr 2001;138(3): 361–5. Vanderhoof JA, Whitney DB, Antonson DL, Hanner TL, Lupo JV, Young RJ. Lactobacillus GG in the prevention of antibiotic-associated diarrhoea in children. J Pediatr 1999;135(5):564–8. Arvola T, Laiho K, Torkkeli S, et al. Prophylactic Lactobacillus GG reduces antibiotic-associated diarrhoea in children with respiratory infections: a randomized study. Pediatrics 1999;104(5):e64. Hatakka K, Savilahti E, Ponka A, et al. Effect of long term consumption of probiotic milk on infections in children attending day care centres: double blind, randomized trial. BMJ 2001;322(7298):1327. Kalliomaki M, Kirjavainen P, Eerola E, Kero P, Salminen S, Isolauri E. Distinct patterns of neonatal gut microflora in infants in whom atopy was and was not developing. J Allergy Clin Immunol 2001;107(1):129–34. Kirjavainen PV, Apostolou E, Arvola T, Salminen SJ, Gibson GR, Isolauri E. Characterizing the composition of intestinal microflora as a prospective treatment target in infant allergic disease. FEMS Immunol Med Microbiol 2001; 32(1):1–7. Kirjavainen PV, Arvola T, Salminen SJ, Isolauri E. Aberrant composition of gut microbiota of allergic infants: a target of bifidobacterial therapy at weaning? Gut 2002;51(1): 51–5. Ouwehand AC, Isolauri E, He F, Hashimoto H, Benno Y, Salminen S. Difference in Bifidobacterium flora composition in allergic and healthy infants. J Allergy Clin Immunol 2001;108(1):144–5. Majamaa H, Isolauri E. Probiotics: a novel approach in the management of food allergy. J Allergy Clin Immunol 1997; 99(2):179–85. Isolauri E, Arvola T, Sutas Y, Moilanen E, Salminen S. Probiotics in the management of atopic eczema. Clin Exp Allergy 2000;30(11):1604–10. Kalliomaki M, Salminen S, Arvilommi H, Kero P, Koskinen P, Isolauri E. Probiotics in primary prevention of atopic disease: a randomized placebo-controlled trial. Lancet 2001;357(9262):1076–9. Rautava S, Kalliomaki M, Isolauri E. Probiotics during pregnancy and breast-feeding might confer immunomodulatory protection against atopic disease in the infant. J Allergy Clin Immunol 2002;109(1):119–21. Committee on Medical Aspects of Food and Nutrition. Guidelines on the nutritional assessment of infant formulas. Report on health and social subjects No. 47. London: HMSO, 1996. Aggett PJ, Agostini C, Goulet O, et al. The nutritional and safety assessment of breast milk substitutes and other dietary products for infants: a commentary by the espghan

ARTICLE IN PRESS Current trends in the composition of infant milk formulas

committee on nutrition. J Pediatr Gastroenterol Nutr 2001;32(3):256–8. 122. IDACE position on claims in annex IV for infant formulae (proposal for modification of Council Directive 91/321/ EEC). REF 01/071. 2001.

63

123. Aggett P, Agostoni C, Axelsson I, et al. Core data for nutrition trials in infants: a discussion document–a commentary by the espghan committee on nutrition. J Pediatr Gastroenterol Nutr 2003;36(3):338–42.