Impact on iron status of introducing cow's milk in the second six months of life.

To determine the impact on iron status of introducing cow's milk (CM) into the diet during the second 6 months of life, nutrient intake was assessed and iron status measured in 100 infants. Nutrient intake for 40 of the 45 infants, age 8 to 13 months, fed CM as the primary beverage for at least 3 months prior to the study and for 45 of 55 infants the same age fed a milk-based infant formula (FF) as the primary beverage for at least 3 months were assessed. All infants in the study were healthy, and the majority were taking no medications or supplements other than vitamins or fluoride for 3 weeks prior to the assessment. Blood drawn by peripheral venipuncture was analyzed by Coulter Counter for complete blood count; plasma albumin, iron, ferritin, transferrin saturation, and total iron-binding capacity were measured in all infants. CM-fed infants had significantly lower mean iron and vitamin C intakes, plasma albumin, transferrin saturation, and ferritin than did FF infants. The frequency of low plasma iron, low transferrin saturation, and low plasma ferritin was significantly greater in CM-fed than in FF infants. The percentage of subjects with three or more abnormal iron indices was more than twice as great in CM-fed infants (58%) as in FF infants (23%). Feeding infants iron-fortified formula to 12 months of age appears to deter iron deficiency.