The effect of a shift from a mixed diet to a lacto-vegetarian diet on human urinary and fecal mutagenic activity.
This is an investigation of the effects of a shift from a well-balanced mixed diet to a lacto-vegetarian diet on the mutagenic activity in urine and feces. The participants were 20 normal-weight, non-smoking subjects (4 men and 16 women, mean age 44 years, range 27-61 years). The fecal samples were assayed for direct-acting mutagens with the fluctuation test for weak mutagens and the urinary samples were assayed with the same assay but with a metabolic activation system, a so-called S9 fraction. The switch from a mixed diet to a lacto-vegetarian diet was not a shift from a so-called high to a low risk diet for colon cancer but rather from a 'medium high risk diet' to a 'low risk diet', even though there were significant changes in nutrients and food components between the two diets. There was a decrease in fat (P = 0.009) and protein intake (P = 0.04) and an increase in total carbohydrate (P = 0.001), fiber (P = 0.001), calcium (P = 0.006) and vitamin C intake (P = 0.019). Among the food preparation methods the use of frying decreased (P = 0.02) and the habit of eating a new vegetable meal increased (P = 0.05). Three months after the dietary shift the concentration of fecal direct-acting mutagens decreased significantly (P less than 0.05), though the total mutagenic activity excreted in feces per 24 h was not different between the two diet periods. Both the concentration and the total amount of promutagens in the urine were decreased after 3 months on the lacto-vegetarian diet. The decrease in fecal mutagenic activity might be explained by a higher fiber intake, which leads to higher water content in feces and thereby a dilution of fecal mutagenic compounds.
Johansson
G
G
Department of Medical Nutrition, Karolinska Institute, Huddinge University Hospital, Sweden.
Holmén
A
A
Persson
L
L
Högstedt
R
R
Wassén
C
C
Ottova
L
L
Gustafsson
J A
JA
D000328:Adult; D000818:Animals; D001835:Body Weight; D003296:Cooking; D004032:Diet; D014676:Diet, Vegetarian; D004043:Dietary Fiber / Q000008:administration & dosage; D004435:Eating; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008892:Milk; D009152:Mutagenicity Tests; D009153:Mutagens / Q000032:analysis*; D014556:Urine / Q000737:chemistry*
D004043:Dietary Fiber; D009153:Mutagens