EFFECTS OF MILK VISCOSITY ON GASTRIC-EMPTYING AND LACTOSE-INTOLERANCEIN LACTOSE MALDIGESTERS

The possibility of delaying gastric emptying and improving lactose dig estion and tolerance by increasing milli viscosity was studied in 13 l actose maldigesters who ingested three test milks with different visco sities (range: 33-1892 mPa.s) in random order at intervals of 1 wk. Ea ch test portion was 500 mL and provided approximate to 1900 kJ and 18 g lactose. The different Viscosities were obtained by adding varying p roportions of rice starch and maltodextrin to a basic milk formula. A combined [C-13]glycine-hydrogen breath test was used to measure gastri c emptying and lactose digestion simultaneously. Participants reported their gastrointestinal symptoms by using a four-grade scale. Mean (+/ - SEM) gastric-emptying half times were 78 +/- 5.7 min for low-viscosi ty milk (30 mPa.s), 86 +/- 5.0 min for moderate-viscosity milk (80 mPa .s), and 78 +/- 4.5 min for high-viscosity milk (1.9.10(3) mPa.s). Mea n orocecal transit times (180 +/- 24, 163 +/- 23, and 180 +/- 24 min, respectively) were not significantly different. There were no milk-dep endent differences in breath-hydrogen excretion or in the severity of gastrointestinal symptoms. The milks were well tolerated; > 50% of the subjects reported nondisturbing symptoms or none. We conclude that ga stric emptying, orocecal transit time, and lactose digestion and toler ance were not affected by altering milk viscosity. This may have been due to the high energy content of the test milks, which in itself led to slow gastric emptying.