Total food duplicates for 24 hours were collected from farmers in Japa
n, once in 1977-1981 (109 subjects) and then in 1991-1992 (72 subjects
). Nutrients (including energy, protein, fat, some minerals, and sever
al vitamins) in each food item in the food duplicate were estimated ta
king advantage of the values given in the Standard Tables of Food Comp
ositions in Japan. The number of the food items in each food duplicate
was counted excluding duplication. Analyses demonstrated that the dai
ly nutrient intake (especially that of energy, protein and vitamin B-1
) has a significant association with the number of items of food taken
a day, that the daily intake of most nutrients is sufficient when 30
food items were taken a day, but that the sufficient supply of calcium
and iron needs an intake of more than 30 food items.