Table 2.

Intakes of protein, sodium and potassium estimated by two 24 h urine collections (UC), the food composition database (FCD), the dish composition database (DCD) and the dish composition database with reported portion size (DCD with reported PS) in Japanese men (n 161) and women (n 163) aged 20–69 years

	Protein (g/d)				Na (mg/d)				K (mg/d)
	Median	P25	P75	P *	Median	P25	P75	P *	Median	P25	P75	P *
Men
Two 24 h UC†	89·8	79·5	103·5	–	5240	4360	6595	–	2602	2096	3095	–
FCD‡	82·9	69·7	93·2	<0·0001	4442	3588	4895	<0·0001	2667	2263	3231	0·14
DCD§	74·7	64·0	85·5	<0·0001	5017	4151	5903	0·03	2550	2157	3011	0·52
DCD with reported PS‖	88·2	73·6	99·8	0·07	5635	4626	6846	0·03	2881	2464	3391	<0·0001
Women
Two 24-h UC†	68·3	59·4	79·5	–	4442	3520	5311	–	2305	1794	2768	–
FCD‡	66·9	58·6	76·3	0·41	3586	2932	4265	<0·0001	2560	2169	2878	0·0002
DCD§	72·4	60·5	83·0	0·06	4765	3857	5848	0·01	2595	2175	3037	0·0002
DCD with reported PS‖	72·3	62·8	82·5	0·009	5018	3861	5930	0·0006	2652	2254	3017	<0·0001

P₂₅, 25th percentile; P₇₅, 75th percentile.

^*Differences from values derived from the two 24 h UC were tested by Wilcoxon signed-rank tests.

^†Nutrient intake based on the mean of two 24 h UC 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).