Switching to a fibre-rich and low-fat diet increases colonic folate contents among African Americans

How dietary patterns impact colonic bacterial biosynthesis of vitamins and utilization by humans is poorly understood. Our aim was to investigate whether a reciprocal dietary switch between rural South Africans (traditionally high fibre, low fat) and African Americans (Western diet of low fibre, high fat) affects colonic folate synthesis. Colonic evacuants were obtained from 20 rural South Africans and 20 African Americans consuming their usual diets at baseline. For two weeks thereafter, rural South Africans were provided with a Western diet (protein 27%, fat 52%, carbohydrate 20% and fibre 8 g/d) and African Americans were provided with a high fibre, low fat diet (protein 16%, fat 17%, carbohydrate 63% and fiber 43 g/d). Colonic evacuants were again collected. No difference between groups at baseline in the folate content of 3-hour evacuants was observed. The high fibre low fat diet consumed by African Americans during the intervention produced a 41% increase in mean total folate content compared with b...