Influence of An Exclusive Meat Diet on the Human Intestinal Flora.

Abstract

In connection with a comprehensive clinical and laboratory investigation of the effect of an exclusive meat diet on man, conducted under the auspices of the Russell Sage Institute of Pathology, an unusual opportunity was presented for a study of the reaction of the intestinal flora to such a diet. Two subjects (A and S) of these experiments continued on this diet for over a year and the third (D) for 10 days. The prescribed dietary included the choice of many cooked meats, both fat and lean portions. The protein daily intake ranged from 85 to 180 gm. and the carbohydrate (in the meat) from 5 to 10 gm. For a general statement in regard to dietary and clinical conditions reference is made to the report of C. W. Lieb and for diet analyses to that of W. S. McClellan and E. F. DuBois. The fecal specimens of all 3 subjects, while on the meat diet, were of much the same character, consisting of finely divided, compact material, greyish-green, with a mild acid aromatic odor and very seldom at all offensive. The reactions ranged from neutral to moderate acidity (pH 7.0 to 6.0) and in no instance were frankly alkaline. The direct microscopic counts of the total numbers and principal bacterial types, as differentiated by morphology and reaction to the gram stain, yielded similar findings for all. The change from the mixed to a whole meat diet caused an abrupt drop in the total bacteria, amounting approximately to 50%. In subject A this decrease was particularly marked and during the thirteenth month reached 76%. It was apparently due principally to the suppression of the lactic acid producing types such as Lactobacillus acidophilus, enterococci and streptococci and to a less extent, B. coli. Free spores and spore-bearing bacteria remained at approximately the same level but spirochaetes, numerous in one subject, disappeared soon after the change to meat.