THE HYDROGEN-ION CONCENTRATION OF HUMAN FtECES

By C. L. PASRICHA MAJOR, I.M.S.

R. Iv. GOYAL

and

S. LAL

(From the Department- of Bacteriology and Pathology, School of Tropical Medicine, Calcutta)

Howe and Hawk (1912) were the first to

determine the exact hydrogen-ion concentration of human fjeces. They examined samples of

fa}ces from three individuals and found that the

reaction of the material examined by them was always alkaline, varying with the different

subjects and conditions from pH 7.01 to 8.77. Nelson and Williams (1916) recorded that 29 of the 30 individuals examined by them passed faeces which were acid in reaction and Rettger and Cheplin (1921) reported similar observa- tions. Robinson (1922) found the pH of the human faeces to range between 7.0 and 7.5. The investigations reported in the literature have been scanty, often based on an inadequate number of observations, and the results conflict- ing. Except for the observations of Knowles, Napier and Das Gupta (1923) who determined the reactions of dysenteric stools no published data are available on the reaction of the feces of

healthy individuals living on different diets and exposed to tropical conditions.

Freshly-passed stools were collected in steri- lized dry bed-pans and care was taken to

prevent 'admixture of urine with the specimen. Suspensions of the stool were made in distilled water adjusted to pH 7.0. The suspensions Were standardized to a density which allowed a blue pencil mark made on one side of the tube to be just visible when seen through the sus-

pension. Hellige's comparator was used for the estimation of pH values. The examination was completed within 30 minutes of the passing of the stool. The stools of 214 individuals were examined

and the number of stool examinations on which this report is based is 562. The individuals examined were 165 in-patients of the Carmichael Hospital for Tropical Diseases, forty Marwaris who were in-patients of the Marwari Hospital, and 30 new-born babies from the Eden Hospital.

142 THE INDIAN MEDICAL GAZETTE [March, 1938

The 214 individuals examined belonged to the following main groups :? I. Individuals whose dietary was

Indian .. .. .. 147

Bengalis on hospital mixed diet in- cluding rice .. .. 107

Marwaris (vegetarian diet with no

rice) .. .. 40

II. Individuals whose diet was Euro-

pean .. .. 58

Europeans .. 29

Other non-Indians .. 29

The thirty new-born babies were breast fed

and their faeces were examined during the first fourteen days after birth. The 165 in-patients of the Carmichael Hospi-

tal were individuals suffering from a variety of conditions, but not suffering from any apparent intestinal lesions. They were on ordinary hos- pital mixed diet. Of the individuals examined

107 were on Indian diet (non-vegetarian and

including a liberal supply of rice) and 58 on

a European type of diet. There was no restric- tion in the dietary and the actual amount con- sumed was dependent on the appetite of the in- dividual. In a number of individuals the first stools passed after admission to hospital were

examined, and, as no (appreciable difference was noted in the results of the examination of these

samples and subsequent samples, it may be taken that the results represent the actual findings that may be expected in a sample of the general hospital population. The fseces collected from a small series of individuals in apparently good health were examined and similar results obtained. The forty Marwaris were on strict vegetarian

diet consisting mainly of wheaten flour, milk, vegetables and lentils and very little or no rice. The majority of the individuals were examined

repeatedly. In most of the subjects the pH value of the feces showed but very slight varia- tion from day to day. In a certain number, however, this variation was marked. The results of the examination of the fseces

are given in tabular form.

Table I

The reaction of the faeces (calculated on the result of the majority of the samples) in different groups of individuals examined

Diets

Indian mixed diet (plus rice) Indian vegetarian diet (no rice) European diet (no rice)

Number of individuals examined

107 40 58

Percentage distribution of individuals according TO THE REACTION OF THEIR Fy^CES

Acid

75 42 26

Alkaline

16 58 67

Variable

Table II

Showing the result of the examination of the total number of samples examined in the different groups

Diets

Indian mixed diet (plus rice) Indian vegetarian diet (no rice) European diet New-born babies, breast fed

Number of

samples of fa;ces examined

356 51 197 30

Percentage distribution of stools according TO THEIR REACTIONS

Acid (below 7.0)

74 41 35 93

Alkaline (above 7.0)

26 59 65 7

Neutral or with- in the limits 6.9 to 7.1

7 14

"

12 3.5

Table III

Showing the hydrogen-ion concentration of fceces of different groups of individuals

Diets

Indian mixed diet (plus rice).

Indian vegetarian diet (no rice).

European diet New-born babies, breast

fed.

Number of samples of feces examined

356

51

197 30

Percentage of fceces showing different pH values

4-5

5

0

3 10

5-6

34

16

9 34

6-7

36

25

24 50

7-8

18

35

48 3

8-9

7

24

16 3

March, 1938] REACTION OF HUMAN FJECES : PASRICHA, GOYAL & LAL 143

The examination of the faeces was repeated several times in a number of apparently healthy individuals. In the majority the range of varia- tion of the pH values of the fieces was ex-

tremely small, or if there was any marked variation it was of a temporary nature. The

following eight individuals however showed wide variations in the refaction of samples of stools

examined on different days. No adequate ex-

planation can be advanced for such changes.

Table IV

Showing day to day variation in the pH values of the faces of eight individuals

Serial no. 1

7.8 7.3 7.1 8.1 6.4 7.4 8.1 7.9

6.8 7.3 5.7 6.9 6.7 5.5 7.5 8.1

6.5 6.4 7.4 8.1 6.1 7.8 7.3

7.2 6.0 7.0 6.7 4.8 6.1 7.6 6.9

6.3 8.2 7.5

8.6 7.8 7.5

8.5

8.0 6.9

5.1 5.0

7.8 8.3 6.8

Table V

Showing the reaction of faces of different consistency. The results are given as percentage of the number of individuals examined

Diets

odian mixed diet (plus rice)

European diet

The macroscopic appearance of the stool

Formed Semi-solid Liquid

Acid Alkaline Acid Alkaline Acid Alkaline

57 43 75 25 62 38

100 13 87 18 82

+i be seen from the tabulated results that

dur' Inajl0rity breast-fed babies examined

V) the first fourteen days after birth were

rpQS+^ stools which were distinctly acid in

milt st??^s ?f two babies fed on cow's

nr-^ ? ^ere found to be alkaline. This confirms

evious findings. In European and other non-Indian adults on uropean type of hospital diet with a compara-

. VeJy heavy meat intake the reaction of the

J^ef. though somewhat variable tended to be ^ aline. The consistency of the stool showed

at whereas the formed specimens were in- anably alkaline, the majority of the semi-solid rJ1^lIid stools were also alkaline in reaction. the reaction of the fa>ces of Indians on the

f*? types of Indian diet showed strikingly dif- ferent results. In the majority of the individuals n hospital mixed diet, which included a liberal Sllpply of rice, the fsecal reaction Was definitely n. the acid side, whereas in individuals on a

" :ri.ct vegetarian diet with no rice, the faecal re- action, although in the majority alkaline, tended 10 be more variable. Although the .two diets,

the ordinary mixed Bengalee diet and the Mar- wari diet, are not comparable, the one outstand- ing feature is the presence of rice in fairly large proportions in the former, and very little or no rice in the latter type of diet. In order to

determine the effect of rice on the reaction of fseces the rice was cut off in the diet of four individuals and replaced by ordinary breTad. The normal diet of these four subjects was

ordinary mixed Bengalee diet including rice and

their faeces examined prior to the stoppage of rice were -consistently acid in reaction (the average pH was 5.0, 5.3, 5.5 and 6.0). After

varying periods (4, 6, 11 and 11 days), the reactions of the fseces became alkaline and re-

mained alkaline as long as rice was excluded from the diet. It appears that the main factor in the determination of fsecal reaction is the

diet; a preponderance of carbohydrates pro- duces an acid stool.

Summary 1. The pH of 562 samples of fseces from 214

individuals were determined by the colorimetric method.

2. The fsecal reaction of breast-fed ba,bies was found to be acid whereas those fed on cow's milk were passing alkaline stools.

3. In Europeans and other non-Indian adults on European diet the reaction of the faeces

though somewhat variable was alkaline. 4. The reaction of the faeces of Indians

varied according to the type of diet. The (Continued at foot of next page)

(C ontinued from previous page)

majority of subjects on the hospital type of

Bengalee mixed diet which includes rice were found to be passing acid stools whereas in Marwaris on vegetarian diet with no rice the faecal reactions though more variable thaii in individuals on European diet tended to be alkaline. The exclusion of rice from Bengalee diet and its replacement by bread changed the reaction of the fa;ces from acid to alkaline.

References

Howe, P. E., and Hawk, P. B. (1912). Joum. Biol. Chem., Vol XI, p. 120.

Knowles, R., Napier, L. E., and Das Gupta, B. M. (1923). Indian Med. Gaz., Vol. LVIII, p. 151. Nelson, C. F., and Williams, J. L. (1916). Journ.

Biol. Chem., Vol. XXVIII, p. 231.

Rettger. L. F.. and Cheplin. H. A. (1921). A Treatise on the Transformation of the Intestinal Flora, with

Special Reference to the Implantation of Bacillus, acidophilus. Yale University Press, New Haven. Robinson, C. S. (1922). Journ. Biol. Chem., Vol. LII,

p. 445.