Modern studies of prebiotic non digestible carbohydrates continue to expand and demonstrate their colonic and systemic benefits. However, virtually nothing is known of their use among ancient populations. In this paper we discuss evidence for prebiotic use in the archaeological record from select areas of the world. It is suggested that members of our genus Homo would have had sufficient ecological opportunity to include prebiotic-bearing plants in diet as early as ~ 2 million years ago, but that significant dietary intake would not have taken place until the advent of technological advances that characterized the Upper Paleolithic of ~40,000 years ago. Throughout human evolution, hominid populations that diversified their diet to include prebiotic-bearing plants would have had a selective advantage over competitors.
Ingestion of brown rice cereal has been found to improve skin conditions, while the effects of wheat bran cereal were limited (Ide et al., J. Integr. Study Diet. Habits, 2005, in press). The effects of these breakfast cereals on the composition of intestinal flora and the intestinal environment were investigated. Two different types of breakfast cereals, wheat bran cereal that is particularly rich in dietary fiber and brown rice cereal fortified with vitamins and minerals, were consumed twice a day by young female volunteers. The control group ingested their usual diet. Composition of fecal flora, fecal moisture, fecal pH, fecal enzymic activities and concentrations of intestinal putrefactive products and short chain fatty acids as well as skin conditions were analyzed. The populations of Enterobacteriaceae and Streptococcaceae significantly decreased after two weeks of wheat bran cereal consumption. Moisture of feces was significantly decreased and the properties of feces and defecation frequency were improved by wheat bran cereal. Activity of β-glucosidase increased significantly and the concentrations of putrefactive products decreased slightly. The effects of brown rice cereal on composition of intestinal flora and intestinal environment were not obvious. No direct correlation between the effects on the intestinal environment and skin conditions was found. The results suggest that the two different types of breakfast cereals used in the present study have different impacts on the intestinal environment and skin conditions.