Effects of prebiotics, probiotics, and synbiotics on the infant gut microbiota and other health outcomes: A systematic review.

The primary aim of this review was to systematically evaluate the literature regarding the effect of pre-, pro-, or synbiotic supplementation in infant formula on the gastrointestinal microbiota. The Cochrane methodology for systematic reviews of randomized controlled trials (RCTs) was employed. Five databases were searched and 32 RCTs (2010-2021) were identified for inclusion: 20 prebiotic, 6 probiotic, and 6 synbiotic. The methods utilized to evaluate gastrointestinal microbiota varied across studies and included colony plating, fluorescence in situ hybridization, quantitative real-time polymerase chain reaction, or tagged sequencing of the 16S rRNA gene. Fecal Bifidobacterium levels increased with supplementation of prebiotics and synbiotics but not with probiotics alone. Probiotic and synbiotic supplementation generally increased fecal levels of the bacterial strain supplemented in the formula. Across all pre-, pro-, and synbiotic-supplemented formulas, results were inconsistent regarding fecal Clostridium levels. Fecal pH was lower with some prebiotic and synbiotic supplementation; however, no difference was seen with probiotics. Softer stools were often reported in infants supplemented with pre- and synbiotics, yet results were inconsistent for probiotic-supplemented formula. Limited evidence demonstrates that pre- and synbiotic supplementation increases fecal Bifidobacterium levels. Future studies utilizing comprehensive methodologies and additional studies in probiotics and synbiotics are warranted.

Human Milk, Infant Formula, and Other Milks Fed to Infants and Toddlers in the United States, NHANES 2007-2018.

BACKGROUND: For the first time, the 2020-2025 Dietary Guidelines for Americans provide specific guidance regarding the types of foods and beverages that should be offered in the first 2 years of life. Milk, in various forms (eg, human milk, infant formula, and cow's milk) contributes a large proportion of key nutrients to the diets of infants and toddlers in the United States. OBJECTIVE: The aim of this study was to determine the types of milk (human milk, infant formula, and other milk) fed to US infants and toddlers in the past 12 years and to describe trends over time. DESIGN: This was a cross-sectional analysis of 2-day, 24-hour dietary recalls. PARTICIPANTS/SETTING: Data from the 2007-2018 National Health and Nutrition Examination Survey were used for these analyses. Infants and toddlers aged 0 through 23.9 months with 2 days of dietary recall data (n = 3,079) were included. MAIN OUTCOME MEASURES: The main outcome was proportion of infants and toddlers fed different milk types. STATISTICAL ANALYSES PERFORMED: Survey-adjusted weighted percentages were used to report sociodemographic characteristics and the proportion of subjects fed each milk type category by age group and survey cycles. Binary and multinomial logistic regressions were used to assess differences in subject characteristics by age groups. RESULTS: Sociodemographic characteristics did not differ by age group. The proportion of infants aged 0 to <6 months fed infant formula only was 60.2% in 2007-2012 and 44.8% in 2013-2018. The proportion of infants aged 6 to <12 months fed partially hydrolyzed infant formula only was 7.3% in 2007-2012 and 13.1% in 2013-2018. In toddlers (>12 months old), cow's milk was the predominant milk type in both 2007-2012 and 2013-2018. CONCLUSIONS: The percentage of infants fed any human milk increased over the past decade. Unsweetened cow's milk was the most predominate milk type consumed among toddlers.

Effects of Early Weight Gain Velocity, Diet Quality, and Snack Food Access on Toddler Weight Status at 1.5 Years: Follow-Up of a Randomized Controlled Infant Formula Trial.

This study followed children who participated in a feeding trial in which the type of randomized infant formula fed from 2 weeks significantly affected weight gain velocity during the first 4 months and weight-for-length Z (WLZ) scores up to 11.5 months. We focused on measures of anthropometry, dietary intakes, and parenting related to the provision of snack foods that were collected at the end of the trial (1 year) and the 1.5 years follow-up visit. We not only describe what toddlers are eating, but we also determined the independent and/or interactive effects of randomized formula group, early weight gain velocity, the nutrient content of the post-formula diet, and maternal snack food practices, on toddlers' weight status. Diet quality underwent drastic changes during this 6-month period. As infant formula disappeared from the diet, fruit and 100% fruit juice intake increased slightly, while intake of "What We Eat in America" food categories sweetened beverages and snacks and sweets more than doubled. Added sugars accounted for 5% of energy needs at 1 year and 9% at 1.5 years. Generalized linear mixed models revealed that, independent of the randomized formula group, greater velocities of weight gain during early infancy and lower access to snacks as toddlers predicted higher WLZ and a greater proportion of toddlers with overweight at 1.5 years. Energy and added sugar intake had no significant effects. These findings add to the growing body of evidence that unhealthy dietary habits are formed even before formula weaning and that, along with improving early diet, transient rapid weight gain and parental feeding practices are modifiable determinants that may reduce risks for obesity.