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Nineteen obese patients with Type 2 diabetes mellitus were treated for periods of 3 months with placebo, guar gum (5 g three times daily) and metformin (500 mg three times daily) in a randomized double-blind, double-placebo, cross-over study. Both active agents decreased fasting blood glucose from 11.4 +/- 3.7 mmol l-1 (mean +/- SD) to 8.6 +/- 2.8 mmol l-1 on metformin (p less than 0.001) and to 9.5 +/- 3.9 mmol l-1 on guar gum (p less than 0.01). Metformin significantly reduced the very low density lipoprotein (VLDL) cholesterol concentration from 0.62 (+0.73, -0.34) mmol l-1 (geometric mean (+SD, -SD)) to 0.43 (+0.58, -0.25) mmol l-1, (p less than 0.02), but unless hyperlipidaemia was present there were no changes in other serum lipid or lipoprotein levels. In patients with serum cholesterol greater than 6.5 mmol l-1 decreases in serum triglycerides from 3.29 (+3.27, -1.64) to 2.46 (+2.55, -1.25) mmol l-1 (p less than 0.02) occurred with metformin. In these patients guar gum produced a reduction in serum cholesterol (from 7.70 +/- 0.90 to 6.41 +/- 1.11 mmol l-1, p less than 0.01) due to an effect on low density lipoproteins. These differential effects may be important in planning therapy when hyperlipidaemia accompanies Type 2 diabetes.

Twenty-two subjects, six of them obese, five latent diabetics, six overt diabetics, and five control subjects, were given a daily dietary supplement of 16 g guar gum and 10 g pectin for three successive days. Postprandial blood glucose and insulin responses to an initial standard meal and to a fiber-enriched meal given 72 h later were compared. A significant decrease of blood glucose levels was found in all subjects, with maximal response in the obese group. We conclude that supplementing the diet with certain fibers can be regarded as an important therapeutic measure in the treatment of diabetic and obese patients.

The effect of an alimentary pasta with a 20% (w/w) content of Guar gum was tested in normal volunteers, diabetic and hyperlipidemic patients in different out- and in-patient protocols. Acute experiments (A, B) were carried out in healthy volunteers and in diabetics, by evaluating plasma glucose, triglyceride and insulin changes after a single meal. Plasma glucose and triglyceride rises were almost completely prevented by the pasta in normal volunteers; plasma insulin levels were modified to a lesser extent. In diabetics, the rise of plasma glucose after the meal was significantly delayed. The pasta was also administered for more prolonged periods of time to diabetic and hyperlipidemic patients (experiments C-E). In the first instance, a significant improvement both in the plasma glucose levels, as well as in the daily glucose profile and glycosuria was observed. In hyperlipidemics, a reduction of triglyceride levels was particularly evident; however, in mixed types of hyperlipidemias, a significant hypocholesterolemic effect was also demonstrated. Guar gum pasta may provide a simple dietary addition for the management of common metabolic disorders.

When nine diabetic patients supplemented either their normal home diets (four patients) or metabolic ward diets (five patients) with 25 g guar gum daily for 5 or 7 days their mean urinary glucose excretion fell by 46% (P less than 0-05) and 54% (P less than 0-01), respectively. Gel-forming,, unabsorbable carbohydrate may therefore be a useful adjunct to anti-diabetic therapy, irrespective of the type of treatment or insulin dosage used.

The effects of dietary supplementation with granulated guar gum (21 g/day in three divided doses at the main meals), were compared with placebo response during three months in a double-blind, cross-over trial in 11 Type 2 (insulin-independent) diabetes. The nine patients who complete the study (two dropped out because of side-effects) showed a significant reduction in both basal and post-prandial hyperglycaemia as well as of urinary excretion of glucose during guar gum supplementation. No change in mean bodyweight was observed during the study. Mean fasting and post-prandial plasma insulin levels were similar during both study periods, but the two subjects who received no oral hypoglycaemic agents had lower insulin levels during the guar gum period. Mean serum total- and LDL-cholesterol concentrations were significantly lower during the guar gum period, whereas the HDL-cholesterol level remained unchanged. Long-term administration of guar gum induced a sustained improvement in diabetic control in Type 2 diabetes.

The diet of 10 insulin-dependent diabetics was modified for 3 months by the addition of guar gum to buttermilk rusks. Control of glycaemia was assessed by serial determination of total glycosylated haemoglobin A1. The effect of guar on serum cholesterol levels was noted. Guar gum supplementation failed to improve the long-term diabetic control, but significantly reduced serum cholesterol levels (P less than 0,01). The effect of guar on lipoprotein levels should be investigated more fully.

The effect of guar gum in lowering urinary glucose excretion and plasma cholesterol was studied in ten sulphonylurea-treated non-insulin dependent diabetic patients during a four week treatment period. The 24-hour urinary glucose excretion fell gradually and increased again to pretreatment value after withdrawal of guar. The glucose output dropped by 33 and 51% in the 3rd and 4th week of the guar treatment period (p less than 0.01) compared to the mean of the pre-plus postguar level. The plasma cholesterol concentration also fell significantly during treatment with guar (p less than 0.01).

Guar gum was incorporated into the diets of six insulin dependent diabetics drawn from one general practice. Amounts between 6 and 59.6 g daily were used for four to six weeks and compared with a previous two week control period. Unlike some other studies, little improvement was obtained in diabetic control and a small reduction in cholesterol levels occurred. The guar was well tolerated in amounts below 30 g a day.

A new type of guar-containing biscuit has been developed and incorporated into the diabetic diet in both short- and medium-term studies. It has been found to be effective in reducing the postprandial rise in the blood glucose level and in improving glycaemic control, as shown by reduced fasting blood glucose values and decreased 24-hour urinary glucose excretion. This form of guar has proved to be palatable and acceptable to patients. It was effective in smaller quantities than have previously been tested and may prove a valuable adjunct in the treatment of diabetes.

Two test meals were taken in random order on separate days by 8 non-insulin-requiring diabetic volunteers after 14-hour overnight fasts. Addition of 16 g guar and 10 g pectin to the control meal containing 106 g carbohydrate decreased markedly and significantly the rise in blood-glucose between 30 and 90 minutes and also resulted in significantly lower insulin levels between 30 and 120 minutes. When these meals were fed to 3 insulin-dependent diabetic subjects, a similar flattening of the post-prandial glucose rise ensued. This addition of certain forms of dietary fibre to the diet of diabetics significantly decreases post-prandial hyperglycaemia and would be expected to improve the control of blood-glucose concentration.