Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Selected biochemical parameters in blood and urine.

Selected biochemical parameters (serum protein, albumin, prealbumin, total retinol-binding protein, vitamins A and E, total carotenoids, and urinary urea and creatinine) were determined in healthy, free-living vegetarian and nonvegetarian subjects. The groups studied were composed of Seventh-day Adventist pure vegetarians, Seventh-day Adventist lacto-ovo vegetarians, Seventh-day Adventist nonvegetarians, and general population nonvegetarians. No values indicative of nutritional deficiencies were observed in any of the subjects. Serum carotenoid levels were significantly higher in Seventh-day Adventist pure vegetarians than in members of the other groups. Mean values for serum vitamin A showed no differences between the dietary groups, although 41% of general population nonvegetarian subjects (the group considered at highest risk for colon cancer) had serum vitamin A levels in the upper quartile of the distribution. From these data no conclusions can be drawn relating to the role of dietary habits as determinants of colon cancer risk.