Table 3.

Spearman correlation coefficients between two 24 h urine collections^* and the food composition database (FCD), the dish composition database (DCD) and the dish composition database with reported portion size (DCD with reported PS) for estimates of protein, sodium and potassium intakes in Japanese men (n 161) and women (n 163) aged 20–69 years

	Protein intake				Na intake				K intake
	Crude		Deattenuated		Crude		Deattenuated		Crude		Deattenuated
	r	P	r	P	r	P	r	P	r	P	r	P
Men
FCD†	0·37	<0·0001	0·43	<0·0001	0·32	<0·0001	0·40	<0·0001	0·48	<0·0001	0·59	<0·0001
DCD‡	0·22	0·004	0·26	0·0008	0·12	0·13	0·15	0·06	0·36	<0·0001	0·44	<0·0001
DCD with reported PS§	0·27	0·0005	0·32	<0·0001	0·25	0·002	0·31	0·0001	0·45	<0·0001	0·56	<0·0001
Women
FCD†	0·28	0·0002	0·33	<0·0001	0·36	<0·0001	0·45	<0·0001	0·37	<0·0001	0·42	<0·0001
DCD‡	0·19	0·02	0·22	0·005	0·22	0·004	0·27	0·0004	0·20	0·01	0·22	0·004
DCD with reported PS§	0·26	0·0008	0·31	0·0001	0·33	<0·0001	0·41	<0·0001	0·34	<0·0001	0·39	<0·0001

^*Nutrient intake based on the mean of two 24 h urine collections was calculated as follows: protein intake (g/d) = 24 h urinary urea-N (g/d)/(0·85 × 0·81) × 6·25^(39,40); Na intake (mg/d) = 24 h urinary Na (mg/d)/0·86⁽⁴¹⁾; and K intake (mg/d) = 24-h urinary K (mg/d)/0·77⁽⁴¹⁾.

^†Estimated from each food in the 4 d dietary record using the Standard Tables of Food Composition in Japan⁽²⁸⁾.

^‡Estimated from each dish in the 4 d dietary record using the DCD with standard PS (weight of each dish in the DCD)⁽²⁵⁾.

^§Calculated by adjusting the nutrient content of a dish in the DCD by the reported PS of the dish in the 4 d dietary record. The calculation method was as follows: estimated nutrient intake from a dish adjusted by the reported PS = nutrient content of the dish in the DCD (g) × reported PS of the dish in the dietary records (g)/standard PS of the dish in the DCD (g).