The effect of pectin and wheat bran on platelet function and haemostatis in man.

The hypothesis that dietary fibre might protect against the development of ischaemic heart disease through an effect on platelet aggregation and blood clotting has been tested in eleven healthy volunteers. In two separate studies the effect of pectin and wheat bran has been measured in subjects living on controlled diets in a metabolic suite. In the pectin study volunteers consumed a basal diet, typical of that normally eaten in the UK, for 6 weeks but for one 3-week period took an additional 36 g/d pectin (Bulmers Firmagel--high methoxy pectin). Although serum cholesterol concentrations were significantly lowered (5.73 +/- 0.36 mmol/l control; 5.18 +/- 0.35 mmol/l + pectin, P less than 0.025), platelet aggregation, platelet fatty acid composition, dilute blood clot lysis time and bleeding times were unaltered. In a similar study in which the volunteers took white bread for 3 weeks and brown and wholemeal breads for a further 3 weeks each, no change was seen in platelet function or in haemostasis. It is concluded that if dietary fibre does protect against heart disease it is probably not through an effect on platelet aggregation or haemostasis.