The level of Mn in human milk is low, 5ug/L; cow milk-based infant formula contain 30-100ug/L and soy formula, 200ug/L. Little is known about Mn absorption in infants or whether regulation occurs. As Mn and Fe interact at the level of intestinal absorption, evaluation of Mn intakes on Fe absorption and status is important. Newborn rhesus monkeys (6/group) were fed either: Whey-dominant milk formula with 35ug Mn/L; same formula with 100ug Mn/L; Casein-dominant formula with 35ug Mn/L; or Soy formula with 200ug Mn/L. Anthropometry and blood were taken monthly. At 6 wks and 3 mo, infants were dosed with 54Mn and 59Fe and whole body retention was measured. Plasma Zn/Cu, blood Mn and serum Ft were analyzed. Hgb values were similar in all groups; Ft was low in the soy-fed group at 4 and 5 mo; no diff. were seen between groups in wt, length, plasma Zn or Cu. At 6 wks, Mn and Fe retent. were sign. lower in the soy-fed group (5 and 12%, res.) than in other groups (Mn:20,18,15%; Fe:40,40,43%)suggesting that Mn and Fe are absorbed less from soy than milk formula. At 3 mo, Mn and Fe absorpt. was similar (Mn: 8,8,10,9%; Fe: 17,23,30,27%) indicating no diff. in %Mn retained between diet groups. Blood Mn levels at 5 mo reflected Mn intake (5.6±2.7, 11.4±2.1,5.3±2.2, 15.3±2.9ug/L), therefore, diff. body burdens of Mn do not appear to affect Mn or Fe retention.Thus, Mn absorpt. doesn't seem to be homeostatically regulated and lower Mn levels in formula will result in less Mn accumulated in infants, which may also have positive effects on Fe status.
|Original language||English (US)|
|State||Published - Mar 20 1998|
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)
- Biochemistry, Genetics and Molecular Biology(all)
- Cell Biology