Increase of serum cholesterol in man fed a bran diet.

The effects of wheat bran and other sources of dietary fibre on serum total and high density lipoprotein(HDL)-cholesterol were investigated in a group of 62 subjects, with rigid control of dietary intake. It was found that a high-fibre diet with vegetables and fruits as well as a low-fibre diet, to which isolated citrus pectin had been added to the same level as present in the vegetables and fruits diet, caused a small decrease in the concentration of serum cholesterol after 5 weeks. Surprisingly, addition of bran (on average 38 g/day) to a low-fibre diet caused an increase in the level of serum cholesterol by on average 0.34 mmol/l (P less than or equal to 0.005). The amount and type of dietary fibre had no substantial effect on the HDL-cholesterol concentration.