Fecal α1-Antitrypsin and Hemoglobin Excretion in Healthy Human Milk-, Formula-, or Cow's Milk-Fed Infants

Abstract

There is concern that whole cow's milk feedings may be associated with intestinal abnormalities in infants. We studied this issue by measuring random fecal samples for α1-antitrypsin (FA1AT) and hemoglobin (FH) concentrations in 820 healthy infants up to 12 months of age. Subjects were fed either human milk, formula, or fresh whole cow's milk. Solid foods were given ad libitum. Fecal samples were also tested for occult blood with Hematest reagent tablets. None of the infants younger than 6 months of age were receiving fresh whole cow's milk. We found small but statistically significant differences in mean FA1AT between the three feeding groups (P < .0001): human milk (n = 354) > formula (n = 320) > cow's milk (n = 146). The younger subjects fed either formula or human milk tended to have higher FA1AT concentrations than did the age-matched subjects who were not consuming solid foods (P ≤ .005). Daily FA1AT excretion, FA1AT concentration, and daily stool output were subsequently determined on a separate group of 40 infants 8 to 12 months of age to ascertain whether differences in total daily FA1AT excretion occur in children fed different types of milk. Total daily FA1AT excretion was similar in the three milk feeding groups. An inverse correlation between FA1AT concentration and daily stool output was also found (P < .001). The overall rate of detectable FH in 792 stool smears was 2.1% and unrelated to type of milk feeding. Of 705 stool smears, 3.5% had positive Hematest reactions. Our results indicate that exudative protein loss or intestinal bleeding, as determined by FA1AT and FH, are uncommon in healthy cow's milk-fed infants older than 6 months of age. Dietary intake of solid foods and type of milk feeding should be considered when analyzing random stool samples for FA1AT concentration in young infants. Normal human milk-fed infants may have "high" FA1AT content because of reduced stool output.

Comparative study of preterm infants fed new and existing human milk fortifiers showed favourable markers of gastrointestinal status

“…The faecal alpha-1 antitrypsin results observed here may have been due to several factors. First, alpha-1 antitrypsin is present in human milk 19,20 and appears to increase with lactation. 19 Human milk alpha-1 antitrypsin is also resistant to pasteurisation 21 and proteolysis in young infants, 22 meaning that faecal concentrations may be high, or change over time, even in the absence of enteropathy.…”

“…First, alpha-1 antitrypsin is present in human milk 19,20 and appears to increase with lactation. 19 Human milk alpha-1 antitrypsin is also resistant to pasteurisation 21 and proteolysis in young infants, 22 meaning that faecal concentrations may be high, or change over time, even in the absence of enteropathy. It is likely that this accounted for the higher levels of this protein in the two study groups when they were compared to infants who were predominantly fed preterm formula.…”

“…It is likely that this accounted for the higher levels of this protein in the two study groups when they were compared to infants who were predominantly fed preterm formula. 19,20,23 For example, Sivan et al 23 reported concentrations of faecal alpha-1 antitrypsin in a sample of preterm infants who were predominantly fed formula. These ranged from 0.34 to 1.05 mg/g stools, which was lower than the geometric mean values observed in our study (Figure 2).…”

“…The measurements then continued for another 21 days. FS day one occurred at a median (Q1-Q3) of 13 (11)(12)(13)(14)(15)(16)(17)(18) days in the new group and 14 (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) Faecal alpha-1 antitrypsin concentration was assessed by immunonephelometry, using the IMMAGE 800 (Beckman Coulter) and faecal total protein by near-infrared spectroscopy with the Fenir 8820 (Perten Instruments). All the analyses were completed in a central laboratory (Rothen Medizinische Laboratorien AG).…”

“…days in the control group. The mean days of life for study day one were 16(13)(14)(15)(16)(17)(18)(19)(20) vs 17(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) days, respectively, and 36 (33-40) vs 37(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43) for study day 21.Stool samples were collected on FS day one or the day after and at 21 ± 1 days (day 21). They were analysed for the following parameters: gastrointestinal inflammation, namely faecal alpha-1 antitrypsin, calprotectin and total protein, and maturity of gut function, namely faecal elastase-1.…”