DIETARY FIBER IN WEANING CEREALS - A STUDY OF THE EFFECT ON STOOL CHARACTERISTICS AND ABSORPTION OF ENERGY, NITROGEN, AND MINERALS IN HEALTHY INFANTS

We evaluated the effect of increased dietary fiber (DF) content in wea ning cereals based on wheat/soy (8.0 and 1.8% DF) and wheat/milk (5.3 and 2.0% DF) in healthy, formula-fed infants 7-17 weeks old. The study had a cross-over design, each infant acting as his or her own control . Stool characteristics and anthropometry were monitored over 4-week p eriods in groups of 34 (wheat/soy) and 23 (wheat/milk) infants. Absorp tion of zinc (Zn) and calcium (Ca) was studied by measuring the feed e xcretion of stable isotopes during 72 h (Zn-70 and Ca-42) in a subgrou p of the infants consuming wheat/soy cereals. Iron (Fe) bioavailabilit y was evaluated by analysis of the incorporation of Fe-58 into erythro cytes 14 days after administration. Fractional absorption (X +/- SD: 8 .0 versus 1.8% DF) was 45.3 +/- 27.5 versus 41.2 +/- 19.4% of Zn-70 an d 63.4 +/- 15.8 versus 64.4 +/- 10.6% of Ca-42. Bioavailability of Fe- 58 varied between 1.0% and 5.4% (8.0% DF) and from < 0.9% to 9.1% (1.8 % DF). No significant difference in energy (95.3 +/- 2.0% versus 95.7 +/- 1.2%) or nitrogen (92.6 +/- 2.3% versus 93.0 +/- 1.6%) apparent ab sorption from the total diet was found during consumption of cereal wi th 8.0 and 1.8% DF. The intake of cereal decreased with higher DF cont ent in the wheat/soy product: 34 +/- 23 g/d (8.0% DF) versus 42 +/- 23 g/d (1.8% DF), p < 0.01. While consuming the 8.0% DF product, 11 infa nts were reported to have ''gritty stools''; no other differences were observed between different groups in stool characteristics or anthrop ometry. These results demonstrate no negative effect on the absorption of energy and nutrients with higher dietery fiber intake in primarily formula-fed infants. The impact of increased dietary fiber revels rem ains unknown in less well-nourished infants.