Influence of two guar preparations on glucose and insulin levels during a glucose tolerance test in healthy volunteers.

Dietary fiber deficiency may be alleviated with an increase in fiber-rich foods or fiber in the form of guar. The efficacy of a solid guar preparation and a liquid form on glucose and insulin levels during a glucose tolerance test in 12 healthy volunteers was examined. The first half of the study tested the efficacy of a new guar preparation (GU-052, Steigerwald, Darmstadt, Germany). Six volunteers ingested 75 glucose and 12 g guar mixed in 450 ml water. The other 6 received the same drink without guar. Blood was withdrawn for the determination of glucose and insulin before ingesting the glucose solution and after 15, 30, 45, 60, 90, 120, 180, 210 and 240 min. One week later the groups were crossed over. The second half of the study tested the efficacy of GU-052 against a solid preparation consisting of 5 g guar and 1.13 g additive (Glucotard, Boehringer, Mannheim, Germany). Volunteers receiving GU-052 with the glucose drink showed no increase in plasma glucose. Volunteers without GU-052 reached a maximal plasma glucose value of 6.66 +/- 1.30 mmol/l 30 min after glucose ingestion from an initial value of 5.28 +/- 0.40 mmol/l. A second smaller peak was observed 120 min after glucose ingestion. A 2.5-fold increase from 16.17 +/- 4.30 to 40.10 +/- 19.00 microIU/ml in insulin concentration occurred in the volunteers ingesting GU-052, whereas a 6-fold increase from 19.33 +/- 12.20 to 114 +/- 48.8 microIU/ml insulin occurred in the volunteers without GU-052. A second peak in insulin at 120 min which occurred in the volunteers without GU-052 was not apparent when the volunteers ingested GU-052. The comparison of GU-052 and Glucotard showed that GU-052 maintained the glucose level, whereas Glucotard allowed the plasma glucose to reach 6.67 +/- 0.98 microIU/l. The increase in insulin was not as great with GU-052 as with Glucotard. This study shows that guar suppresses glucose and insulin levels during a glucose tolerance test. The guar form influences the efficacy.

Influence of guar on serum lipids in patients with hyperlipidaemia.

The antihyperlipidaemic effect of a guar preparation which absorbs a particularly large amount of water has been examined in 13 patients with Type II hyperlipidaemia. A 30-day pre-treatment phase was followed by 60 days of treatment with 4 g guar dissolved in 200-ml liquid at each meal-time (total guar 12 g/day), and a 60-day post-treatment observation period. Routine other clinical blood tests were performed 30, 15 or 0 days before treatment, 15, 30 and 60 days after the start of treatment, and 30 and 60 days after its end. Total cholesterol fell by 0.85 mmol.l-1, from a pre-treatment concentration of 7.4 mmol.l-1 to a treatment value of 6.5 mmol.l-1, and LDL-cholesterol fell by 0.64 mmol.l-1, from 5.5 mmol.l-1 to a treatment value of 4.8 mmol.l-1. There was no significant change in triglyceride and VLDL concentrations during the study. A slight but significant fall in HDL-cholesterol was seen. The sole adverse effect was occasional intestinal discomfort.