Physiological economy in nutrition, with special reference to the minimal proteid requirement of the healthy man / an experimental study

by R. H. Chittenden

Date.		Body-weight.	Urine.
			Volume. 24 hours.	Sp. Gr.	Nitrogen.		Uric Acid.		P₂O₅.
1903		kilos	c.c.		grams		gram		grams
Oct.	11	65.4	1300	1015		10.37		0.611		1.72
	12		700	1022		9.07
	13		1050	1022		12.35		0.820		2.15
	14		1400	1017		12.01
	15		870	1020		11.48		0.671		1.76
	16		1165	1013		12.09
	17		840	1020		11.24
	18		1150	1017		10.00		0.613		1.77
	19		678	1022		7.79
	20		1165	1018		10.76		0.603		1.60
	21		1460	1017		11.91
	22		950	1019		10.71		0.643		1.73
	23		1165	1017		12.82
	24	65.4	850	1025		12.49
	25		850	1022		11.07		0.645		1.76
	26		1025	1018	⎫	8.31 daily average		0.465 daily average		1.18 daily average
	27		775	1018	⎪
	28		1140	1015	⎬
	29		765	1020	⎪
	30		860	1019	⎪
	31		1150	1015	⎭
Nov.	1		750	1020	⎫	7.91		0.469		1.30
	2		675	1022	⎪
	3		955	1014	⎪
	4		1270	1012	⎬
	5		885	1015	⎪
	6		770	1020	⎪
	7		860	1021	⎭
	8		775	1020	⎫	7.86		0.537		1.40
	9		890	1018	⎪
	10		1070	1018	⎪
	11		755	1020	⎬
	12		950	1023	⎪
	13		1100	1017	⎪
	14		980	1015	⎪
	15		630	1020	⎭
	16	65.0	700	1020	⎫	7.82		0.467		1.49
	17		1000	1015	⎪
	18		940	1018	⎪
	19		770	1023	⎬
	20		770	1025	⎪
	21		790	1020	⎪
	22		770	1021	⎭
	23		590	1025	⎫	8.55		0.476		1.67
	27		710	1024	⎬
	28		1080	1017	⎪
	29		760	1019	⎭
	30		870	1018	⎫	7.72		0.506		1.43
Dec.	1		860	1017	⎪
	2		1120	1015	⎪
	3		1450	1009	⎬
	4		720	1019	⎪
	5		720	1019	⎪
	6		510	1027	⎭
	7	65.1	700	1018	⎫	7.36		0.474		1.44
	8		650	1018	⎪
	9		860	1013	⎪
	10		975	1020	⎬
	11		800	1021	⎪
	12		830	1018	⎪
	13		750	1019	⎭
	14		860	1018	⎫	8.11		0.497		1.35
	15		870	1019	⎪
	16		880	1015	⎪
	17		820		⎬
	18		760	1021	⎪
	19		860	1017	⎪
	20		520	1023	⎭
	21		1200	1014	⎫	7.18				1.05
	22	65.0	510	1025	⎭
	23		650		⎫	6.70		0.356		0.97
	24		670		⎪
	25		500		⎬
	26		550		⎪
	27		850		⎭
	28	65.2	930		⎫	8.70		0.626		1.21
	29		1200		⎪
	30		750		⎪
	31		1280		⎬
Jan.	1		750		⎪
	2		750		⎪
	3		870		⎪
	4		1230		⎭
	5		720	1023	⎫	8.23		0.530		1.24
	6		960	1020	⎪
	7		760	1022	⎬
	8		1000	1017	⎪
	9		720	1025	⎪
	10	65.1	730	1021	⎭
	11		700	1016	⎫	7.74		0.618		1.20
	12		650	1020	⎪
	13		700	1024	⎪
	14		660	1025	⎬
	15		610	1025	⎪
	16		710	1024	⎪
	17		660	1022	⎭
	18		770	1016	⎫	7.80		0.705		1.14
	19	64.8	700	1022	⎪
	20		1130	1018	⎪
	21		830	1020	⎬
	22		600	1019	⎪
	23		480	1021	⎪
	24		750	1019	⎭
	25		680	1020	⎫	6.85		0.500		1.07
	26		800	1018	⎪
	27		800	1020	⎪
	28		700	1020	⎬
	29	64.4	1010	1014	⎪
	30		980	1018	⎪
	31		820	1015	⎭
Feb.	1		990	1015	⎫	7.98		0.535		1.24
	2		660	1020	⎪
	3	64.4	1060	1015	⎪
	4		980	1017	⎬
	5		970	1014	⎪
	6		790	1019	⎪
	7		1120	1015	⎭
	8		715	1021		8.11
	9	64.4	1225	1014		7.49		0.450
	10	64.4	770	1018		6.14		0.505
	11	64.5	715	1022		8.02		0.568
	12		850	1021		8.82		0.539
	13		490	1028		7.17		0.505
	14	64.4	795	1020		7.73		0.543
	15		780	1021	⎫	8.27		0.558
	16		920	1023	⎪
	17		660	1021	⎪
	18		640	1027	⎬
	19		730	1023	⎪
	20		840	1027	⎪
	21		700	1018	⎭
	22		440	1025	⎫	7.47		0.556
	23		600	1023	⎪
	24		750	1022	⎪
	25		830	1017	⎬
	26	64.0	870	1021	⎪
	27		910	1015	⎪
	28		950	1014	⎭
	29		600	1021	⎫	7.15		0.526
Mar.	1		680	1021	⎪
	2		1120	1011	⎪
	3		640	1021	⎬
	4		1080	1016	⎪
	5		1220	1034	⎪
	6		890	1015	⎭
	7		1000	1014	⎫	8.18		0.682
	8		650	1020	⎪
	9		750	1020	⎪
	10		850	1018	⎬
	11		950	1014	⎪
	12		1000	1016	⎪
	13	64.2	860	1019	⎭
	14		840	1020	⎫	7.83		0.540
	15		920	1016	⎪
	16		750	1020	⎪
	17		820	1017	⎬
	18		1220	1012	⎪
	19		920	1015	⎪
	20		700	1022	⎭
	21		900	1015	⎫	8.04		0.733
	22		980	1013	⎪
	23		990	1014	⎪
	24		750	1020	⎬
	25		820	1017	⎪
	26		700	1021	⎪
	27		910	1020	⎭
	28		930	1017
	30		900	1020
	31		450		⎫	7.87		0.530		1.44
Apr.	1		500		⎪
	2		420		⎪
	3		600		⎪
	4		950		⎪
	5		930		⎬
	6		980		⎪
	7		600		⎪
	8		980		⎪
	9		800		⎪
	10		810		⎭
	11	65.2	940	1017	⎫	9.46	⎫	0.496
	12		710	1024	⎬		⎪
	13		750	1024	⎭		⎪
	14		740	1020		7.55	⎬
	15		590	1024		6.51	⎪
	16		900	1016		7.51	⎪
	17		1290	1009		5.11	⎭
	18	65.2	590	1017		5.96	⎫	0.527
	19		630	1024		6.39	⎪
	20		670	1022		7.48	⎪
	21		900	1021		8.10	⎬
	22		980	1017		7.00	⎪
	23		850	1019		7.60	⎪
	24		640	1023		7.33	⎭
	25	65.0	600	1021		8.23	⎫	0.490
	26		610	1014		5.82	⎪
	27		600	1023		7.27	⎪
	28		970	1015		7.05	⎬
	29		795	1017		5.91	⎪
	30		700	1021		6.80	⎪
May	1		795	1016		5.72	⎭
	2	65.2	860	1017		6.50	⎫	0.344
	3		1120	1016		6.92	⎪
	4		1090	1015		6.54	⎪
	5		580	1021		5.92	⎬
	6		700	1020		7.29	⎪
	7		895	1017		8.97	⎪
	8		800	1016		7.30	⎭
	9	65.2	895	1019		6.28	⎫	0.416
	10		850	1019		6.27	⎪
	11		960	1019		7.26	⎪
	12		690	1022		6.29	⎬
	13		990	1017		7.96	⎪
	14		690	1022		7.21	⎪
	15		900	1015		6.15	⎭
	16	65.1	945	1014		5.10	⎫	0.364
	17		1090	1016		6.15	⎪
	18		620	1020		5.21	⎪
	19		1110	1015		6.53	⎪
	20		895	1016		6.12	⎬
	21		810	1019		6.95	⎪
	22		1110	1016		8.72	⎪
	23	65.0	685	1020		7.07	⎪
	24		560	1021		6.78	⎭
	25		1090	1010		6.02	⎫	0.420
	26		610	1017		5.97	⎪
	27		790	1016		6.83	⎪
	28		1100	1014		7.65	⎬
	29		650	1021		6.12	⎪
	30	65.0	630	1021		5.21	⎪
	31		660	1018		5.07	⎭
June	1	65.1	920	1014		5.96
	2	65.1	800	1013		5.81
	3	65.0	950	1014		7.30
	4		790	1015		6.78
	5		780	1020		8.28
	6	65.1	890	1015		6.89
	7		720	1017		5.87
	8		950	1015		5.93
	9		1060	1014		4.96
	10		940	1017		5.92
	11		1050	1019		7.62
	12		1000	1017		6.66
	13		890	1021		7.26
	14		1340	1016		6.91
	15		1190	1015		6.86
	16		720	1025		7.99
	17	65.2	800	1017		7.25
	18		820	1018		6.99
	19		920	1014		6.18
	20		890	1015		6.03
	21		900	1016		6.37
	22		760	1018		6.79
	23		630	1020		6.06
Daily average from Oct. 26, 1903			833	1018		7.43		0.516		1.28

It will be seen by a study of the analytical data that Dr. Underhill had an average daily excretion of nitrogen through the kidneys from October 26, 1903, to June 23, 1904, of 7.43 grams. From October 26 to April 13, a period of nearly six months, the average daily excretion was 7.81 grams of nitrogen, while from the latter date to June 23 the average daily excretion amounted to 6.68 grams of nitrogen. Taking the body-weight at 65 kilos, the lower nitrogen figure would mean a metabolism of 0.102 gram of nitrogen per kilo of body-weight, closely akin to the figures obtained with the two preceding subjects.

An excretion of 6.68 grams of nitrogen corresponds to the metabolism of 41.75 grams of proteid matter, while the excretion of 7.43 grams of nitrogen implies the metabolism of 46.4 grams of proteid, being less than one-half the ordinarily accepted requirement for the healthy adult.

During this long period of eight months the body-weight was stationary, carrying with it the assumption that the body was in a condition of nitrogen equilibrium. It should be emphasized in connection with Dr. Underhill’s case, that throughout the entire period of eight months, and more, there was perfect freedom in the choice of food. Further, it will be noticed by a study of the dietary made use of in the balance experiments that Dr. Underhill did not reduce his nitrogen intake by any exclusion of meat. He practically made use of his ordinary diet, such as he had always been accustomed to, but with a decided diminution of the amount of proteid food, accompanied by a gradual reduction in the total amount of food consumed each day. His diet, therefore, was in no sense a vegetable diet. Meat was conspicuous in his daily food, but naturally in reduced quantities.

On February 9 a nitrogen balance was attempted, in which a careful comparison of the nitrogen content of all intake and output was made for a period of six days. By a study of the results of this balance period, shown in the accompanying tables, it will be noticed that not only was there no deficiency of nitrogen, but the body was laying on nitrogen at the rate of 0.158 gram per day. Further, it will be observed that the fuel value of the food per day averaged only a little over 2000 calories. Yet this amount of food, with its comparatively low fuel value, carried with it only 8.83 grams of nitrogen per day. Upon this quantity of food the body was able to maintain itself, with a little nitrogen to spare and with sufficient fuel value in the food to supply all the energy required for muscular contraction, mental effort, and the maintenance of body temperature.

Tuesday, February 9, 1904.

Breakfast.—Bread 22 grams, tea 146 grams.

Lunch.—Macaroni 129 grams, fried sweet potato 85.5 grams, bread 59 grams, butter 15 grams, fig cake with wine sauce 115 grams, sugar 15 grams, coffee 210 grams.