Review article: malnutrition and maltreatment--a comment on orlistat for the treatment of obesity

Long-term inhibition of intestinal lipase by orlistat improves release of gut hormones increasing satiety in obese women

BACKGROUND

Reduced postprandial secretion of peptide YY (PYY), glucagon-like peptide-1 (GLP-1), cholecystokinin, and increased hunger was reported after a single dose of orlistat, an inhibitor of intestinal lipase. As yet, the influence of long-term therapy with orlistat on PYYand GLP-1 release has not been studied. Our study was aimed at assessing the influence of 8-week therapy with orlistat as a component of a weight loss program on pre-prandial circulating PYY and GLP-1 levels.

METHODS

Forty obese women, without concomitant diseases, were randomly allocated to groups receiving orlistat or placebo during an 8-week weight management program. Body mass, body composition and plasma levels of PYY, GLP-1 and insulin (for QUICKI calculation) were determined prior to and at the end of therapy.

RESULTS

Women treated with orlistat obtained significantly greater body and fat mass loss than those receiving placebo (9.0 ± 3.1 vs. 5.9 ± 3.2% and 21.9 ± 10.9 vs. 7.4 ± 15.6%, respectively). Only in those treated with orlistat a slight, but significant increase of the QUICKI was found (8.0 ± 16.5 vs. -0.1 ± 12.7 %, respectively). Weight loss was followed by a significant increase of plasma levels of PYY and GLP-1 in group treated with orlistat, and was about 2-times greater than receiving placebo. The increase was independent of body mass changes.

CONCLUSION

The long-term inhibition of intestinal lipase by orlistat increases the pre-prandial levels of GLP-1 and PYY, independent of body mass changes. Therefore, it seems that long-term treatment with orlistat may exert hunger suppressing and insulin sensitizing incretin effect beyond weight reduction.

Long-term effects of lipase inhibition by orlistat on gastric emptying and orocecal transit time of a solid meal

BACKGROUND

We assessed the impact of a prolonged lipase inhibition upon gastric emptying (GE) and orocecal transit time (OCTT) of a 355-kcal low-fat solid meal.

METHODS

In double-blind manner, 40 obese women BMI > 30 kg/m2, randomly allocated into two equal groups, took orally t.i.d. 120 mg orlistat or placebo during 8 weeks of a weight-reducing management. At randomization and after 2 months, GE was measured simultaneously with OCTT by means of a 13C-octanoic acid and a hydrogen breath test, respectively. Lipolytic activity was evaluated with a 13C-mixed triglyceride breath test (13C-MTGBT).

RESULTS

A profound lipase inhibition by orlistat was confirmed by a 79.5% +/- 16.9% reduction of the cumulative 6-h 13C recovery with 13CMTGBT. GE remained unchanged either in the orlistat (T1/2, 188 +/- 35 min start versus 198 +/- 36 min end) or the placebo (T1/2, 191 +/- 35 min start versus 180 +/- 39 min end) group. OCTT increased from 208 +/- 54 min to 271 +/- 64 min (P < 0.01) after orlistat treatment and did not change significantly (216 +/- 76 vs. 234 +/- 72 min) in the placebo group.

CONCLUSIONS

No adverse effect on the GE and a moderate prolongation of the OCTT of a low-fat solid meal is to be expected under a prolonged treatment with orlistat at a typical dosage regimen.