Protein intake at 9 mo of age is associated with body size but not with body fat in 10-y-old Danish children.

BACKGROUND

During the complementary feeding period, infants shift from a daily protein intake (PI) of approximately 1 g/kg body wt to an intake 3-4 times as high. A high PI probably has both endocrine and physiologic effects and may increase the risk of obesity.

OBJECTIVE

We examined the associations between PI in infancy and body size and composition in late childhood.

DESIGN

We conducted an observational cohort study of 142 Danish healthy term infants (63 boys) born during 1987-1988. At 9 mo of age, diet, weight, length, skinfold thicknesses, insulin-like growth factor I, and serum urea nitrogen were determined. At 10 y of age, 105 children (51 boys) participated in a follow-up study. Diet, weight, height, skinfold thicknesses, percentage of body fat (dual-energy X-ray absorptiometry), insulin-like growth factor I, and serum urea nitrogen were determined.

RESULTS

At 9 mo of age, PI (in g/d and percentage of energy) was strongly correlated with body size (length and weight) but not with measures of adiposity. PI at 9 mo of age was positively associated with height and weight but not with percentage of body fat at 10 y of age. Inclusion of parental body size in the models did not change the associations, but the significant associations were attenuated when body size at 9 mo of age was included.

CONCLUSIONS

PI in infancy seems to stimulate early growth. This might explain part of the association between early PI and body size at 10 y of age, but a continuous effect of protein on growth during childhood cannot be excluded. PI in infancy was not associated with any measure of body fat at 10 y of age.