milk, which is the average volume of milk reported from studies of breastfed infants in this age category (Heinig et al., 1993), and (2) that provided by the usual intakes of complementary weaning foods consumed by infants in this age category. Such an approach would be in keeping with the current recommendations of the Canadian Paediatric Society (Health Canada, 1990), American Academy of Pediatrics (AAP, 1997), and Institute of Medicine (IOM, 1991) for continued breastfeeding of infants through 9 to 12 months of age with appropriate introduction of solid foods.

Only one relatively recent published source of information about B vitamin intake from solid foods for infants aged 7 through 12 months was found (Montalto et al., 1985), and it covered only three B vitamins: thiamin, riboflavin, and niacin. These researchers’ estimates are based on data from 24-hour dietary intakes from the 1976–1980 National Health and Nutrition Examination Survey (NHANES II) for infants aged 7 to 12 months. The infants were consuming formula; intake from solid food was reported separately.

For the B vitamins and choline, two other approaches were considered as well: (1) extrapolation upward from the AI for infants ages 0 through 6 months by using the metabolic weight ratio and (2) extrapolation downward from the EAR for young adults by adjusting for metabolic body size and growth and adding a factor for variability or from the AI if the recommended intake for adults was an AI. Both of these methods are described below. The results of these methods are compared in the process of setting the AI.

For the B vitamins and choline, if data were not available to set the EAR and Recommended Dietary Allowance (RDA) or an AI for children ages 1 year and older and for adolescents, the EAR or AI has been extrapolated down by using a consistent basic method. The method relies on at least four assumptions:

1. Maintenance needs for the B vitamins and choline expressed with respect to body weight ([kilogram of body weight]^0.75) are the same for adults and children. Scaling requirements as the 0.75 power of body mass adjusts for metabolic differences demonstrated to be related to body weight, as described by Kleiber (1947) and explored further by West and colleagues (1997). By this scaling a child weighing 22 kg would require 42 percent of what an adult