Abstract
In acute studies guar flour, guar powder and guar granules reduced mean post prandial insulin levels in normal subjects following liquid glucose. The flour and powder also reduced mean plasma GIP levels compared to glucose alone. Guar granules had no effect on the mean plasma glucose, insulin or GIP responses of either normal or non insulin dependent diabetic (NIDDM) subjects to a solid mixed meal but guar powder reduced mean post prandial plasma glucose, insulin, and GIP levels in both groups. Guar flour was not investigated. The mean glycosylated haemoglobin level of seven NIDDM subjects taking 25g guar powder in bread daily for eight weeks was reduced after four weeks. Mean total serum cholesterol levels were also reduced whilst subjects were following the regimen but on termination returned to pretrial levels. In addition, the response to a meal immediately before and after supplementation was similar indicating guar powder has no carry over effect. Guar flour prevented the hypoglycaemia caused in two of six subjects by consumption of a drink containing alcohol and sucrose and a high carbohydrate snack. However it also caused higher blood alcohol levels and they appeared more intoxicated for five hours after the meal. When guar gum was given with a fat load it did not affect chylomicronaemia implying it is unlikely to impair bile salt reabsorption as has been suggested. Guar flour incorporation into a predominantly protein meal did not affect the rate of liquid or solid gastric emptying in normal subjects but significantly increased mean post prandial gastrin secretion. This may be due to the significant reduction in mean post prandial GIP levels also seen or to the buffering capacity of guar flour. None of the subjects enjoyed guar containing foods and it was difficult to prepare acceptable products. Therefore until a better formulation is available guar gum is of limited use in diabetic management.