Whole wheat flour exerts cholesterol-lowering in rats in its native form and after use in bread-making

The ingestion of whole wheat flour (WWF) has been shown to exert lipid-lowering effects in rats but WWF is generally consumed after being processed (fermentation, starch gelatinization, heating). It remains to be assessed whether bread making has an influence on the potential lipid-lowering properties of flours. For this purpose, rats were fed semi-purified diets containing 70% WWF, or the same percentage of desiccated whole wheat bread (WWB) and the control group was fed with fibre-free purified starch diet. All the cereal diets showed a cholesterol-lowering effect in plasma and liver compared to control, but there was a more pronounced plasma triglyceride-lowering effect in rats fed WWB. In parallel, total steroids excretion was significantly enhanced (P <0.01) by the cereal diets, but to a greater extent by WWB. As a result, cholesterol absorption percentage was also markedly reduced in rats fed WWB diet (around 26%, compared to 38% for WWF and 52% for controls). WWF and WWB yielded butyric acid rich fermentations in the cecum, compared to the control diet, and WWB markedly enhanced propionic acid production compared to WWF. In conclusion, the baking process adds significantly to the hypolipemic effects observed previously with WWF, in spite of reduced specific viscosity.