Dietary fibre supplementation of a 'normal' breakfast administered to diabetics.

The supplementation of a breakfast by 10 g of guar, pectin, agar or locust bean gum in powder form in 13 maturity onset, non-insulin dependent diabetics failed to decrease significantly the post-prandial rise in plasma glucose and insulin seen after a similar meal without the supplement. The values of one hour post-prandial increment in blood glucose seen with guar powder were, for control meal (mean +/- SEM) 5.8 %/- 0.4 mmol/l, for test, 5.7 +/- 0.5; with pectin powder, control 6.4 +/- 0.8 mmol/l, test 5.0 +/- 1.2 mmol/l; with agar powder, control 7.5 +/- 1.0, test 7.0 +/- 0.5; with locust bean gum powder, control 5.9 +/- 1.0, test 5.0 +/- 0.7. The equivalent values for one hour insulin (microU/ml, mean +/- SEM) were, for guar powder, 51 +/0 21 and 51 +/- 16; for pectin powder 60 +/- 24 and 63 +/- 17; for agar powder, 27 +/- 9 and 36 +/- 11 and, for locust bean gum powder 53 +/- 26 and 62 +/- 18. The guar, pectin and locust gum tended to form lumps, and all the substances tested were unpalatable in powder form producing feelings of abdominal discomfort and abnormal fullness. Administering the same quantity of guar or pectin in a well hydrated form (but not premixed with the carbohydrate portion of the food) to the same people under identical conditions did not enhance its effectiveness. Supplementing diets with any of these sources of dietary fibre in either of these forms and in these amounts is unlikely to be beneficial in the management of non-insulin dependent diabetes.