Soy protein for the prevention and treatment of children with cow-milk allergy

The separation and identification of the residual antigenic fragments in soy protein hydrolysates

Soybean is one of the major food allergens. In this study, soy protein isolate was hydrolyzed by Neutrase and Flavourzyme. The hydrolysates were separated by ultrafiltration and ion-exchange chromatography. The antigenicity of proteins was determined by indirect competitive ELISA. The molecular weight distribution was characterized by SDS-PAGE. The amino acid sequence of chromatography fractions was analyzed by LC-MS. The results showed that proteins with >50 kDa in hydrolysates had the highest antigenicity and were further separated into F1 -F5 fragments by ion-exchange chromatography. Fragment F4 , which was the most antigenic, was analyzed by LC-MS. The results of mass spectrometry showed that most of the peptides that contained antigen epitopes in chromatography fraction F4 belonged to glycinin subunits. The antigenicity of soy protein was reduced by enzymatic hydrolysis, but glycinin showed resistance to enzymatic hydrolysis. PRACTICAL APPLICATIONS: The identification of residual antigenicity in soy protein hydrolysates by LC-MS provides important information on the resistance mechanism of enzymatic hydrolysis of soybean protein allergens. In addition, the efficient separation of soy protein hydrolysates could be beneficial for developing low-allergenic soybean products.

Lactose-Free Milk or Soy-Based Formulas Do Not Improve Caregivers' Distress or Perceptions of Difficult Infant Behavior

OBJECTIVES

The aim of the study was to test the hypothesis that caregiver-reported difficulties in infant behavior and caregivers' distress will significantly improve on lactose-free (LF) milk-based or LF soy-based formulas compared with a milk-based, lactose-containing formula.

METHODS

In this double-blind randomized controlled trial, infants (mean age: 4.97 weeks) with caregiver-reported feeding problems on a milk-based lactose-containing formula were randomized to receive either LF milk-based (n = 96), LF soy-based (n = 97), or milk-based, lactose-containing (n = 103) formula. Study formula was infants' sole item of diet for 14 days. Infants' caregivers completed measures of infant behavior and caregivers' distress for the week preceding baseline and again for the week preceding the 14-day follow-up.

RESULTS

Infants who received LF milk or LF soy-based formulas did not significantly differ from those who received milk-based, lactose-containing formula on follow-up caregiver-reported measures of infant difficultness from the Infant Characteristics Questionnaire, F(2, 277) = 0.83, nor on measures of caregivers' distress, assessed with measures of caregivers' mental health and parenting efficacy, F(2, 285) = 0.73-1.07. Across the 3 formula groups, scores on outcome measures significantly improved from baseline to follow-up (P < 0.001).

CONCLUSIONS

Our study does not support LF milk or LF soy-based formulas to alleviate common infant behaviors such as fussiness, crying, or need for attention. Moreover, the data suggest that some difficulties in infant behaviors, as well as caregivers' distress and perceived efficacy in parenting difficult infants, may improve within a couple weeks of reporting difficulties to the pediatrician.

Safety of soya-based infant formulas in children

Soya-based infant formulas (SIF) containing soya flour were introduced almost 100 years ago. Modern soya formulas are used in allergy/intolerance to cows' milk-based formulas (CMF), post-infectious diarrhoea, lactose intolerance and galactosaemia, as a vegan human milk (HM) substitute, etc. The safety of SIF is still debated. In the present study, we reviewed the safety of SIF in relation to anthropometric growth, bone health (bone mineral content), immunity, cognition, and reproductive and endocrine functions. The present review includes cross-sectional, case-control, cohort studies or clinical trials that were carried out in children fed SIF compared with those fed other types of infant formulas and that measured safety. The databases that were searched included PubMed (1909 to July 2013), Embase (1988 to May 2013), LILACS (1990 to May 2011), ARTEMISA (13th edition, December 2012), Cochrane controlled trials register, Bandolier and DARE using the Cochrane methodology. Wherever possible, a meta-analysis was carried out. We found that the anthropometric patterns of children fed SIF were similar to those of children fed CMF or HM. Despite the high levels of phytates and aluminium in SIF, Hb, serum protein, Zn and Ca concentrations and bone mineral content were found to be similar to those of children fed CMF or HM. We also found the levels of genistein and daidzein to be higher in children fed SIF; however, we did not find strong evidence of a negative effect on reproductive and endocrine functions. Immune measurements and neurocognitive parameters were similar in all the feeding groups. In conclusion, modern SIF are evidence-based safety options to feed children requiring them. The patterns of growth, bone health and metabolic, reproductive, endocrine, immune and neurological functions are similar to those observed in children fed CMF or HM.

Soy protein infant formulae and follow-on formulae: a commentary by the ESPGHAN Committee on Nutrition

This comment by the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) Committee on Nutrition summarizes available information on the composition and use of soy protein formulae as substitutes for breastfeeding and cows' milk protein formulae as well as on their suitability and safety for supporting adequate growth and development in infants. Soy is a source of protein that is inferior to cows' milk, with a lower digestibility and bioavailability as well as a lower methionine content. For soy protein infant formulae, only protein isolates can be used, and minimum protein content required in the current European Union legislation is higher than that of cows' milk protein infant formulae (2.25 g/100 kcal vs. 1.8 g/100kcal). Soy protein formulae can be used for feeding term infants, but they have no nutritional advantage over cows' milk protein formulae and contain high concentrations of phytate, aluminum, and phytoestrogens (isoflavones), which might have untoward effects. There are no data to support the use of soy protein formulae in preterm infants. Indications for soy protein formulae include severe persistent lactose intolerance, galactosemia, and ethical considerations (e.g., vegan concepts). Soy protein formulae have no role in the prevention of allergic diseases and should not be used in infants with food allergy during the first 6 months of life. If soy protein formulae are considered for therapeutic use in food allergy after the age of 6 months because of their lower cost and better acceptance, tolerance to soy protein should first be established byclinical challenge. There is no evidence supporting the use of soy protein formulae for the prevention or management of infantile colic, regurgitation, or prolonged crying.

Allergenic Proteins in Soybean: Processing and Reduction of P34 Allergenicity

Soybean ranks among the "big 8" of the most allergenic foods, and with increasing consumption of soybean products, the incidence of soy-caused allergies is expected to escalate. Soybean and its derivatives have become ubiquitous in vegetarian and many meat-based food products, and as a result, dietary avoidance has become difficult. However, soybeans can be manipulated in a variety of ways to alter their allergenicity. Several studies have focused on reducing the allergenicity of soybeans by changing the structure of the immunodominant allergen P34 using food processing, agronomic, or genetic manipulation techniques. A review of the literature pertaining to these studies is presented here.

Infant diet and type 1 diabetes in China

Infant milk and food introduction may be linked to type 1 diabetes risk in high incidence populations. Dietary data through age 12 months was collected for 247 type 1 diabetic cases and 443 controls in China, a low incidence population, to determine if milk and solid food intake differed. Age range at introduction to milk and formulas was similar in cases and controls but solid food introduction more often occurred before age 3 months in cases. Logistic regression analyses showed soy milk formula consumption at 4-6 (OR = 2.0; 95% CI: 1.1-3.4) and 7-12 months of age (OR = 1.5; 95% CI: 1.0-2.1) was associated with a twofold higher risk of type 1 diabetes, while steamed bread consumption (4-6 months, OR = 0.44; 95% CI: 0.28-0.68; 7-12 months, OR = 0.48; 95% CI: 0.34-0.69) and higher SES (4-6 months, OR = 0.55; 95% CI: 0.39-0.78; 7-12 months, OR = 0.57; 95% CI: 0.40-0.83) were negatively associated. Drinking cow's milk at 7-12 months (OR = 0.60; 95% CI: 0.43-0.85) was negatively associated with type 1 diabetes while consuming vegetables at 4-6 months (OR = 1.5; 95% CI: 1.0-2.2) was positively associated. Results suggest that infant milk and solid food intake are associated with type 1 diabetes in China. Prospective studies may determine how these dietary factors impact disease etiology, particularly for at-risk-populations.

Paediatric atopic dermatitis in Perth general practice

Ninety-seven Perth general practitioners completed a self-administered postal questionnaire that aimed to examine their caseload and management practices for childhood atopic dermatitis (AD). General practitioners saw a median of two new cases and three follow-up consultations per month for childhood AD, and referred a median of 10% of cases to a specialist, usually a dermatologist. Most (77%) recommended emollients for all patients, but only 21% specifically reported advising their use immediately after bathing. Sixty-one percent would use topical corticosteroids in all or most patients, but cream preparations were more commonly used (58%) than ointments (40%). Atrophy was rated as a common or very common side-effect of topical corticosteroid therapy by 23% of general practitioners. Twenty-six percent reported using oral corticosteroids in children with AD. Dietary changes would be recommended in at least a few AD patients by 79% of general practitioners, and 31% would recommend a change from cow's milk to soy in the absence of a history of dietary triggers. We conclude that general practitioners appeared generally well informed about AD management. However, dermatologists, through targeted education, may be in a position to help general practitioners further improve outcomes for these patients.

[Infant formulas and soy protein-based formulas: current data]

For many years soy bean-based formulas (SBBF) were the only dietary product used for infants with cow's milk intolerance. At the present time, their place in infant nutrition is reduced as a result of the availability of new dietary products without lactose and/or cow's milk proteins and the recognition of soy bean protein allergy. There is no evidence that SBBF have any efficiency in infant colic. SBBF have no indication in the prevention of allergy, nor in premature infants' nutrition. Their main indication is the feeding of infants of vegetarian parents who do not want to use cow's milk products. Studies have shown that SBBF contain large quantities of phytoestrogens, particularly isoflavone. Because of experimental data suggesting a possible deleterious effect of phytoestrogens on the neuroendocrine maturation, the reduction of their content in SBBF must be considered.

Food allergen avoidance in primary prevention of food allergy

Approximately 5-10% of children suffer from allergy to one or more foods. Primary prevention through a hypoallergenic diet may reduce the prevalence of food allergy and associated co-morbidity, such as eczema and urticaria. Breastfeeding has many advantages and should be recommended for all children. Those with a history of atopy in the immediate family are at a higher risk and maternal diet during lactation, avoiding highly allergenic foods, may enhance the benefit. Cow's milk should be strictly avoided, and supplements, if required, should be with a hypoallergenic formula. Delayed introduction of egg, nuts, wheat and fish has also been suggested. Dietary restriction may have nutritional consequences for the mother and child and supervision by a dietician is essential. Maternal diet during pregnancy is not advisable as the benefit is minimal and there may be adverse effects on the foetal nutrition. In high risk infants, a combined approach, where breastfeeding with maternal avoidance of highly allergenic foods, supplemented by extensively hydrolysed formula during the first 6 months of life, in addition to the delayed introduction of solid foods, has been shown to reduce the development of food allergy in infants.

Nutritional and health benefits of soy proteins

Soy protein is a major component of the diet of food-producing animals and is increasingly important in the human diet. However, soy protein is not an ideal protein because it is deficient in the essential amino acid methionine. Methionine supplementation benefits soy infant formulas, but apparently not food intended for adults with an adequate nitrogen intake. Soy protein content of another essential amino acid, lysine, although higher than that of wheat proteins, is still lower than that of the milk protein casein. Adverse nutritional and other effects following consumption of raw soybean meal have been attributed to the presence of endogenous inhibitors of digestive enzymes and lectins and to poor digestibility. To improve the nutritional quality of soy foods, inhibitors and lectins are generally inactivated by heat treatment or eliminated by fractionation during food processing. Although lectins are heat-labile, the inhibitors are more heat-stable than the lectins. Most commercially heated meals retain up to 20% of the Bowman-Birk (BBI) inhibitor of chymotrypsin and trypsin and the Kunitz inhibitor of trypsin (KTI). To enhance the value of soybeans in human nutrition and health, a better understanding is needed of the factors that impact the nutrition and health-promoting aspects of soy proteins. This paper discusses the composition in relation to properties of soy proteins. Also described are possible beneficial and adverse effects of soy-containing diets. The former include soy-induced lowering of cholesterol, anticarcinogenic effects of BBI, and protective effects against obesity, diabetes, irritants of the digestive tract, bone, and kidney diseases, whereas the latter include poor digestibility and allergy to soy proteins. Approaches to reduce the concentration of soybean inhibitors by rearrangement of protein disulfide bonds, immunoassays of inhibitors in processed soy foods and soybean germplasm, the roles of phytoestrogenic isoflavones and lectins, and research needs in all of these areas are also discussed. This integrated overview of the widely scattered literature emphasizes general concepts based on our own studies as well as recent studies by others. It is intended to stimulate interest in further research to optimize beneficial effects of soy proteins. The payoff will be healthier humans and improved animal feeds.