The distribution of nutrient intake within families.

1. During 1978 and 1979, the 343 members of seventy-nine families representative of households with two adults and two or three children living in Cambridge, England, completed 7-d records of food consumption using the semi-weighed technique. Nutrient intakes were calculated using food composition tables. 2. Amongst males, the average intakes of energy and most nutrients were highest in men and boys aged 11-17 years, and lowest in boys under 5 years. Amongst females, intakes were highest in girls aged 11-17 years, and lowest in those under 5 years. At each age, intakes in males were generally higher than those in females. 3. Nutrient distribution within families was described using the ratio, intake of each subject:intake of the male head of the household. The problems inherent in using this ratio are discussed. 4. The distribution of nutrient intakes within the families was not in accordance with the recommended daily amounts (RDA). Men and young boys received more than their fair share of the family diet, while women and girls aged 5-17 years received less. 5. Estimates of dietary adequacy based on the averages of family consumption and requirements (RDA) concealed up to twofold variations in the adequacy of diet of different age-sex-groups. 6. The interpretation of dietary adequacy in household food surveys should take into account the distribution of nutrient intakes within the household, as the distribution may be substantially different from that predicted by the RDA.