Total calcium absorption is similar from infant formulas with and without prebiotics and exceeds that in human milk-fed infants

Assessing conflict of interest reporting and quality of clinical trials on infant formula: a systematic review

OBJECTIVES

This study aims to assess the quality, risk of bias, and conflicts of interest (COIs) of clinical trials conducted on the effects of fortified infant formula.

STUDY DESIGN AND SETTTING

Systematic review including all randomized clinical trials targeting healthy children and using three arms: fortified infant formula; standard formula; and breastfeeding. We performed a descriptive analysis of the studies reviewed, assessed their quality using the "Risk of Bias 2- RoB 2" tool, and identified COIs.

RESULTS

A total of 40 studies were included. All showed a high overall risk of bias, with this being especially noteworthy in the "deviations from intention to treat" and "missing outcome data" domains. Of the total included studies, 29 reported conclusions in favor of the fortified formula; 15 studies reported multiple conclusions that were either contradictory or not in line with the results. COIs with industry were identified in 33 studies, and in 17 studies, these conflicts were not declared in the appropriate section.

CONCLUSION

From a methodological perspective, studies on fortified infant formula display low quality, made evident by the high risk of bias. Additionally, there are frequent COIs. These aspects must be considered by health professionals and the population when drawing up recommendations for the use of this product.

Calcium Intake and Metabolism in Infants and Young Children: A Systematic Review of Balance Studies for Supporting the Development of Calcium Requirements

Determining calcium requirements for infants and children is vital due to high calcium needs for growth. Balance studies enable comprehensive measurement of calcium metabolism and can support nutrient requirement development. This systematic review summarizes evidence from mass balance and isotopic studies in children aged 0-4 y to address key questions on calcium loss and absorption/retention identified by an expert group developing calcium requirements. Literature searches were implemented in multiple electronic databases to June 2020. Balance studies assessing calcium intake, loss, absorption, or retention in healthy children were eligible. A newly developed risk-of-bias assessment tool was used for balance studies, and a modified Grades of Recommendation, Assessment, Development, and Evaluation approach determined strength of evidence. Altogether, 23 studies (15 mass balance; 8 isotope) with 485 total participants were included. Only 3 studies were of children >6 mo. Mass balance studies suggested infant feed components may influence calcium balance. The random-effects model meta-regression on 42 mass balance study arms showed an average net calcium retention of 40.4% among infants aged 0-6 mo (β = 0.404 [95% CI: 0.302, 0.506]). Isotope studies suggested calcium intake of 240 to 400 mg/d may promote optimal calcium absorption with minimal loss, and intake from human milk may lead to greater absorption and retention efficacy than formula or solid foods. Most studies had low risk of bias. Strength of evidence was low due to variability in infant feedings, limited endogenous and dermal calcium loss measures, and few studies isolating calcium effects. To improve certainty of the body of evidence, more balance studies isolating effects of calcium intake in this age group are needed. Future work on calcium needs should incorporate both balance measures and biological endpoints of importance (e.g. bone mineral density or content) to determine adequate calcium intake for growth in infants and children.

Nutritional Assessment and Management in Paediatric Chronic Kidney Disease

Nutrition in paediatrics has always been one of the most important factors for optimal growth. Children with chronic kidney disease (CKD) need special consideration for better long-term outcomes, including nutritional status, optimal height, and cognitive function. Nonetheless, there are many obstacles to overcome to attain optimal linear growth and nutritional status in children with CKD. This review highlights the need for tools to assess the growth parameters in CKD. In addition, recommendations for dietary intake play a major role in controlling electrolyte disturbances in patients with CKD. For example, it is still unclear whether it is better to restrict phosphate sources in inorganic, organic, or food additives. The review also summarises different factors such as fluid intake, route of feeding, and essential nutrients that require particular attention in paediatric patients with CKD. In summary, a multidisciplinary team is needed to devise individual nutritional plans to achieve the best outcome and improve the quality of life of patients.

Potential Applications of Endo-β-N-Acetylglucosaminidases From Bifidobacterium longum Subspecies infantis in Designing Value-Added, Next-Generation Infant Formulas

Human milk is the optimal source of infant nutrition. Among many other health benefits, human milk can stimulate the development of a Bifidobacterium-rich microbiome through human milk oligosaccharides (HMOs). In recent years, the development of novel formulas has placed particular focus on incorporating some of the beneficial functional properties of human milk. These include adding specific glycans aimed to selectively stimulate the growth of Bifidobacterium. However, the bifidogenicity of human milk remains unparalleled. Dietary N-glycans are carbohydrate structures conjugated to a wide variety of glycoproteins. These glycans have a remarkable structural similarity to HMOs and, when released, show a strong bifidogenic effect. This review discusses the biocatalytic potential of the endo-β-N-acetylglucosaminidase enzyme (EndoBI-1) from Bifidobacterium longum subspecies infantis (B. infantis), in releasing N-glycans inherently present in infant formula as means to increase the bifidogenicity of infant formula. Finally, the potential implications for protein deglycosylation with EndoBI-1 in the development of value added, next-generation formulas are discussed from a technical perspective.

Physiological Impact of Palm Olein or Palm Oil in Infant Formulas: A Review of Clinical Evidence

Palm oil/olein (PO/POL) is used in infant formulas to imitate the fatty acid profile of human milk (HM) and achieve similar levels of palmitic acid (PA). However, the positions of fatty acids on the triacylglyceride differ between PO/POL and HM, which affect fat absorption and produce unintended physiological consequences. Recent papers have reviewed evidence for physiological benefits of PO/POL and beta-palmitate (sn-2-palmitate) in infant formulas. The aim of the present review is to supplement the assessment of available clinical evidence on the physiological effects of PO/POL formulas in healthy infants. We intend to focus on PO/POL and not on sn-2-palmitate, since the latter was recently extensively reviewed. Clinical evidence supports that PO/POL in infant formulas leads to a lower fat, DHA, palmitate and calcium absorption, and bone mineralization; soft stools; and growth (weight accretion) compared to formulas without PO/POL. Consequently, it seems prudent to be considerate and cautious when adding PO/POL to infant formulas. While HM is the gold standard for infant nutrition, the development of infant formula should be based on achieving positive physiological outcomes, rather than just replicating HM nutrient composition.

Prebiotic Carbohydrates for Therapeutics

The food industry is constantly shifting focus based on prebiotics as health-promoting substrates rather than just food supplements. A prebiotic is "a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health." Prebiotics exert a plethora of health-promoting effects, which has lead to the establishment of multimillion food and pharma industries. The following are the health benefits attributed to prebiotics: mineral absorption, better immune response, increased resistance to bacterial infection, improved lipid metabolism, possible protection against cancer, relief from poor digestion of lactose, and reduction in the risk of diseases such as intestinal disease, non-insulin-dependent diabetes, obesity and allergy. Numerous studies in both animals and humans have demonstrated the health benefits of prebiotics.

Prebiotics, Bone and Mineral Metabolism

Increasing interest in functional foods has driven discovery in the area of bioactive compounds. Prebiotics are non-digestible carbohydrate compounds that, when consumed, elicit health benefits and aid in the prevention and treatment of chronic diseases. While prebiotics have been shown to improve a number of chronic, inflammatory conditions, growing evidence exists for prebiotic effects on calcium metabolism and bone health. These novel dietary fibers have been shown to increase calcium absorption in the lower intestines of both preclinical and human models. Rodent models have also been imperative for understanding prebiotic effects on bone mineral density and measures of skeletal strength. Although fewer data are available for humans, bone-related prebiotic effects exist across the lifecycle, suggesting benefits for attainment of peak bone mass during adolescence and minimized bone resorption among postmenopausal women. These effects are thought to occur through prebiotic-microbe interactions in the large intestine. Current prebiotic mechanisms for improved mineral absorption and skeletal health include alterations in gut microbiota composition, production of short-chain fatty acids, altered intestinal pH, biomarker modification, and immune system regulation. While the majority of available data support improved mineral bioavailability, emerging evidence suggests alternate microbial roles and the presence of an intricate gut-bone signaling axis. Overall, the current scientific literature supports prebiotic consumption as a cost-effective and sustainable approach for improved skeletal health and/or fracture prevention. The goal of this review is to discuss both foundational and recent research in the area of prebiotics, mineral metabolism, and bone health.

How to Manipulate the Microbiota: Prebiotics

During the last century, human nutrition has evolved from the definition of our nutritional needs and the identification of ways to meet them, to the identification of food components that can optimise our physiological and psychological functions. This development, which aims to ensure the welfare, health and reduced susceptibility to disease during life, gave birth to the concept of "functional foods". In this context, there is an increasing interest in the physiological effects induced by the dense and diverse microbiota which inhabits the human colon and whose development depends on the fermentation of undigested food residues. Thus, much research aims at identifying ways to guide these impacts in order to benefit the health of the host. It is in this context that the concept of "prebiotics" was developed in the 1990s. Since then, prebiotics have stimulated extensive work in order to clarify their definition, their nature and their physiological properties in accordance with the evolution of knowledge on the intestinal microbiota. However many questions remain open about their specificities, their mechanism(s) of action and therefore the relevance of their current categorisation.

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

During pregnancy and lactation, female physiology adapts to meet the added nutritional demands of fetuses and neonates. An average full-term fetus contains ∼30 g calcium, 20 g phosphorus, and 0.8 g magnesium. About 80% of mineral is accreted during the third trimester; calcium transfers at 300-350 mg/day during the final 6 wk. The neonate requires 200 mg calcium daily from milk during the first 6 mo, and 120 mg calcium from milk during the second 6 mo (additional calcium comes from solid foods). Calcium transfers can be more than double and triple these values, respectively, in women who nurse twins and triplets. About 25% of dietary calcium is normally absorbed in healthy adults. Average maternal calcium intakes in American and Canadian women are insufficient to meet the fetal and neonatal calcium requirements if normal efficiency of intestinal calcium absorption is relied upon. However, several adaptations are invoked to meet the fetal and neonatal demands for mineral without requiring increased intakes by the mother. During pregnancy the efficiency of intestinal calcium absorption doubles, whereas during lactation the maternal skeleton is resorbed to provide calcium for milk. This review addresses our current knowledge regarding maternal adaptations in mineral and skeletal homeostasis that occur during pregnancy, lactation, and post-weaning recovery. Also considered are the impacts that these adaptations have on biochemical and hormonal parameters of mineral homeostasis, the consequences for long-term skeletal health, and the presentation and management of disorders of mineral and bone metabolism.

The Effect of Prebiotics on Calcium Absorption and Utilization

Calcium is an essential nutrient that modulates bone, cardiovascular, and other health parameters. Unfortunately, calcium consumption is below recommended intakes worldwide. Increasing calcium absorption efficiency is one strategy for improving calcium nutrition. Prebiotics, carbohydrates that are fermented by bacteria in the large intestine, have been shown to increase calcium-absorption efficiency in humans and animal models. The mechanism that mediates this increase in calcium absorption is still unclear; however, it is theorized that prebiotics and their breakdown products may increase calcium absorption by modifying the colonic lumen, the large intestine itself, or the microbial populations living in the large intestine. Further research elucidating this mechanism is necessary before this prebiotic effect can be fully harnessed.

Beneficial effects of human milk oligosaccharides on gut microbiota

Human milk is the gold standard for nourishment of early infants because it contains a number of bioactive components, such as human milk oligosaccharides (HMOs). The high concentration and structural diversity of HMOs are unique to humans. HMOs are a group of complex and diverse glycans that are resistant to gastrointestinal digestion and reach the infant colon as the first prebiotics. N-acetyl-glucosamine containing oligosaccharides were first identified 50 years ago as the 'bifidus factor', a selective growth substrate for intestinal bifidobacteria, thus providing a conceptual basis for HMO-specific bifidogenic activity. Bifidobacterial species are the main utilisers of HMOs in the gastrointestinal tract and represent the dominant microbiota of breast-fed infants, and they may play an important role in maintaining the general health of newborn children. Oligosaccharides are also known to directly interact with the surface of pathogenic bacteria, and various oligosaccharides in milk are believed to inhibit the binding of pathogens and toxins to host cell receptors. Furthermore, HMOs are thought to contribute to the development of infant intestine and brain. Oligosaccharides currently added to infant formula are structurally different from the oligosaccharides naturally occurring in human milk and, therefore, they are unlikely to mimic some of the structure-specific effects. In this review, we describe how HMOs can modulate gut microbiota. This article summarises information up to date about the relationship between the intestinal microbiota and HMOs, and other possible indirect effects of HMOs on intestinal environment.

Biochemical markers of bone resorption are present in human milk: implications for maternal and neonatal bone metabolism

AIM

This study investigated breast milk and maternal serum concentrations of biochemical markers of bone resorption, which may be implicated in both maternal and neonatal bone metabolism.

METHODS

Tests were carried out on 85 parturients 3-4 days after they gave birth. We measured their breast milk and serum concentrations for soluble receptor activator of nuclear factor kappaB ligand (sRANKL) and cross-linked N-telopeptide of type I collagen (NTx). The sRANKL and NTx concentrations were associated with several perinatal parameters.

RESULTS

Soluble receptor activator of nuclear factor kappaB ligand was detectable in breast milk at considerably lower concentrations than in maternal serum (p < 0.001), and these breast milk sRANKL concentrations were decreased in maternal diabetes (b = -0.366, 95% CI -0.622 to -0.110, p = 0.006). Breast milk NTx concentrations were higher in exclusive lactation (b = 0.269, 95% CI 0.014-0.524, p = 0.039), but lower in Caesarean sections (b = -0.224, 95% CI -0.428 to -0.019, p = 0.032).

CONCLUSION

Soluble receptor activator of nuclear factor kappaB ligand is downregulated in breast milk, particularly in the case of diabetes. Breast milk NTx upregulation characterises exclusive lactation, and its downregulation characterises Caesarean section deliveries. Nutritional interventions in foetal life and early infancy may programme adult bone health and ameliorate diseases with developmental origins, such as osteoporosis.

Microbial enzymatic production and applications of short-chain fructooligosaccharides and inulooligosaccharides: recent advances and current perspectives

The industrial production of short-chain fructooligosaccharides (FOS) and inulooligosaccharides is expanding rapidly due to the pharmaceutical importance of these compounds. These compounds, concisely termed prebiotics, have biofunctional properties and hence health benefits if consumed in recommended dosages. Prebiotics can be produced enzymatically from sucrose elongation or via enzymatic hydrolysis of inulin by exoinulinases and endoinulinases acting alone or synergistically. Exoinulinases cleave the non-reducing β-(2, 1) end of inulin-releasing fructose while endoinulinases act on the internal linkages randomly to release inulotrioses (F3), inulotetraoses (F4) and inulopentaoses (F5) as major products. Fructosyltransferases act by cleaving a sucrose molecule and then transferring the liberated fructose molecule to an acceptor molecule such as sucrose or another oligosaccharide to elongate the short-chain fructooligosaccharide. The FOS produced by the action of fructosyltransferases are 1-kestose (GF2), nystose (GF3) and fructofuranosyl nystose (GF4). The production of high yields of oligosaccharides of specific chain length from simple raw materials such as inulin and sucrose is a technical challenge. This paper critically explores recent research trends in the production and application of short-chain oligosaccharides. Inulin and enzyme sources for the production of prebiotics are discussed. The mechanism of FOS chain elongation and also the health benefits associated with prebiotics consumption are discussed in detail.

Calcium and fat metabolic balance, and gastrointestinal tolerance in term infants fed milk-based formulas with and without palm olein and palm kernel oils: a randomized blinded crossover study

BACKGROUND

Effects of palm olein (POL) on calcium and fat metabolic balance and gastrointestinal (GI) tolerance have been clinically evaluated but its use in combination with palm kernel oil (PKO), and canola oil has not been similarly assessed in infants.

METHODS

Calcium and fat balance and GI tolerance were evaluated in 33 healthy term infants (age = 68-159 d) in a randomized, double-blinded, 14 d crossover trial at a day care center in Salvador, Brazil; followed by a 4d hospital ward metabolic balance study in 17 of the male subjects. The study compared two commercially available milk-based powdered formulas in Brazil; one containing POL (44% of total fat), PKO (21.7%) and canola oil (18.5%) as predominant fats (PALM), and the other containing none (NoPALM). Occasional human milk (HM) supplementation was allowed at home.

RESULTS

Formula and HM intakes, and growth were not different (p > 0.05). Calcium absorption (%) for infants fed NoPALM (58.8 ± 16.7%; means ± SD) was higher (p = 0.023) than those fed PALM (42.1 ± 19.2%), but was not significant (p = 0.104) when calcium intake was used as a covariate. Calcium intake was higher (p < 0.001) in NoPALM versus PALM fed infants. However, calcium retention (%) was higher in infants fed NoPALM compared to PALM with (p = 0.024) or without (p = 0.015) calcium intake as a covariate. Fat absorption (%) for NoPALM was greater than PALM fed infants (NoPALM = 96.9 ± 1.2 > PALM = 95.1 ± 1.5; p = 0.020 in Study Period I). Mean rank stool consistency was softer in infants fed NoPALM versus PALM (p < 0.001; metabolic period). Adverse events, spit-up/vomit, fussiness and gassiness were not different (p > 0.05). Formula acceptability was high and comparable for both formula feedings, regardless of HM supplementation.

CONCLUSIONS

Term infants fed PALM based formula (containing palm olein, palm kernel and canola oils) demonstrated lower calcium retention and fat absorption, and less softer stool consistency versus infants fed NoPALM based formula. Study suggested formula fat differences may affect GI function in infants.

Probiotics and prebiotics in pediatric diarrheal disorders

INTRODUCTION

In pediatrics, prebiotics and/or probiotics are added to infant formula, mainly to prevent diseases such as diarrheal disorders. Probiotic food supplements and medication are frequently used in the treatment of diarrheal disorders. This paper reviews the recent published evidence on these topics.

AREAS COVERED

Relevant literature published using PubMed and CINAHL was collected and reviewed. Recent review papers were give special attention.

EXPERT OPINION

The addition of pre- and/or probiotics to infant formula seems not harmful, but the evidence for benefit is limited. Most probiotics are commercialized as food supplements, and therefore do not qualify for medication legislation. Worldwide, Saccharomyces boulardii is the only strain which is registered as "medication" in the majority of countries. Efficacy data can only be considered if performed with the commercialized product. Some products reduce the risk for antibiotic-associated diarrhea and reduced the duration of acute infectious diarrhea with about 24 h. Overall, data in the other indications (inflammatory bowel disease, irritable bowel syndrome) are disappointing, although there are some recent promising results. The use of food supplements as medication opens the discussion to create a category of "medical food."