Karin M. Ostrom

Growth of Newborn, Term Infants Fed Soy Formulas For 1 Year

Few studies have measured long-term growth in infants fed soy protein-based formulas. The effect of nucleotide (NT) supplementation of soy protein-based infant formulas on growth is unknown. Growth was therefore evaluated in healthy term infants fed a soy protein-based formula (SOY; n=73), SOY with added NT (72 mg added NT/L) at human milk (HM) levels (SOYN, n=73), or mixed feeding (MF, n=67) in a randomized, masked, parallel 1-year feeding study. The MF group (a nonrandomized reference group) was fed HM exclusively from birth to 2 months of age followed by HM and/or a standard milk-based formula (Similac® with Iron with no supplemental NTs) to 1 year of age. Results indicated that growth (weight, length, and head circumference) was normal and comparable among the three groups. All three groups had similar plasma albumin (at 2 months of age) and hemoglobin levels (at 12 months of age). Thus, this study demonstrated similar growth in the first year of life among infants fed MF feeding or soy formula with or without supplemental NTs.

Immune status of infants fed soy-based formulas with or without added nucleotides for 1 year: part 2: immune cell populations.

Background Infants fed a soy protein isolate–based formula have immunization responses similar to breast-fed infants. However, cellular aspects of the immunologic development of soy-fed infants have not been studied extensively. Nucleotides added to milk-based formula benefit infant immune status, but reports of the immunologic effects of adding nucleotides to soy-based formula are not available. This study examines immune cell populations of infants fed soy protein isolate formulas with and without added nucleotides for 1 year. Methods Newborn, term infants studied in a masked 12-month feeding trial were assigned randomly to soy formula groups with and without added nucleotides (n = 94, n = 92). A nonrandomized human milk/formula-fed cohort (n = 81), was concurrently enrolled. Blood samples were collected at 6, 7, and 12 months. Thirty-two immune cell populations were characterized using three-color flow cytometry. Cellular markers were chosen to assess general pediatric immune status, emphasizing maturation and activation of B, T, and NK lymphocytes. Results All cell populations, number and percentages, were within age-related normal ranges. The only significant difference found between soy formula and human milk/formula-fed infants was the percentage of CD57+ NK T cells at 12 months (human milk/formula > soy formula, P = 0.034). There were significant differences at some time points between human milk/formula-fed and nucleotide-supplemented soy formula–fed infants in populations of lymphocytes, eosinophils, total T, helper T, naive helper, memory/effector helper, CD57−T, and CD11b+CD8+NK cells. None of the cell populations differed between infants fed soy formula versus soy plus nucleotides. Conclusions Infants fed this commercial soy formula demonstrated immune cell status similar to human milk/formula-fed infants, consistent with normal immune system development. The addition of nucleotides to soy formula did not significantly change specific individual immune cell populations but tended to increase numbers and percentages of T cells and decreased numbers and percentages of NK cells.

Decreased Regurgitation with a Soy Formula Containing Added Soy Fiber

The objective of this randomized study was to determine if fiber-supplemented soy formula reduced regurgitation in young infants. We compared regurgitation in 179 infants randomly assigned cow’s milk-based (CM, 90) formula or soy formula with fiber (SF, 89). Initial daily incidence was similar (CM, 3.6; SF, 3.9 episodes), but significantly lower after 7 days on SF (CM, 3.4; SF, 2.3; p = 0.001). Less frequent regurgitation after 7 days on SF was sustained after 28 days (CM, 48%; SF, 31% of feedings; p = 0.001). Feeding SF effectively managed regurgitation while providing balanced nutrition without altering caloric distribution as occurs with adding rice cereal to formula.

Use of Soy Fiber in Acute Diarrhea in Infants and Toddlers

Soy fiber has been shown to reduce the duration of watery stools during acute diarrhea caused by bacterial and viral pathogens in underdeveloped countries. A randomized blinded clinical trial was conducted with middle-class American children to assess the efficacy of soy fibersupplemented infant formula. Stool characteristics, intake, and weight were recorded. Infants >6 months of age (n = 44) fed soy fiber-supplemented formula (Isomil DF) had a significantly shorter estimated median duration of diarrhea (9.7 hours vs. 23.1 hours) than those fed soy formula (Isomil). The use of fiber-supplemented soy formula may reduce the duration of diarrheal symptoms in U. S. infants more than 6 months of age with acute diarrhea.