Effect of hydrolyzed guar fiber on fasting and postprandial satiety and satiety hormones: a double-blind, placebo-controlled trial during controlled weight loss.

OBJECTIVE

To evaluate the effects of a completely soluble fiber on fasting and postprandial hormone levels, respiratory quotient (RQ) and subjective ratings of satiety during a controlled weight-loss program.

DESIGN

In a five-week prospective, randomized, double-blind study, a 3.3 MJ (800 kcal)/d diet was provided during a two-week wash-in period. Then, during the intervention weeks, separated by a one-week wash-out period, a 3.3 MJ (800 kcal) formula containing either 20 g fiber or placebo daily, was given in a cross-over design and on days 1, 3 and 7 of the intervention weeks (weeks 3 and 5) measurements were taken after an overnight fast.

SUBJECTS

25 obese but otherwise healthy females (age: 46+/-6 y, body mass index (BMI): 35+/-6 kg/m2) were studied.

MEASUREMENTS

Body weight; hunger/satiety ratings; glucose, insulin, cholecystokinin (CCK) and leptin concentrations; RQ during the intervention weeks.

RESULTS

In the fasting state, the supplement had no effect on any of the measured parameters, including blood concentrations of glucose, insulin, CCK, and leptin, RQ and satiety ratings. In the 2 h postprandial period following the test meal, none of the measured parameters differed significantly from that following the non-fiber-supplemented meal, except for the CCK response. CCK demonstrated an overall higher concentration after the fiber-supplemented meal (P=0.007), even after adjustment for age, weight, height and treatment sequence. The postprandial peak in CCK also occurred earlier (at 15 min vs 30 min) after completion of the fiber-supplemented meal.

CONCLUSIONS

The results indicated that a hydrolyzed guar gum fiber supplement produced a heightened postprandial CCK response, but did not alter other satiety hormones or increase satiety ratings, in either the fasting or the postprandial state.