Artificially Sweetened Versus Regular Mixers Increase Gastric Emptying and Alcohol Absorption
Article Outline
Abstract
Background
Mixed alcoholic drinks are increasingly being consumed in “diet” varieties, which could potentially empty more rapidly from the stomach and thereby increase the rate of alcohol absorption when compared with “regular” versions containing sugar.
Methods
We studied 8 healthy males twice in randomized order. On each day, they consumed an orange-flavored vodka beverage (30 g ethanol in 600 mL), made with either “regular” mixer containing sucrose (total 478 kcal), or “diet” mixer (225 kcal).
Results
Gastric half-emptying time measured by ultrasound (mean
±standard deviation) was less for the “diet” than the “regular” drink (21.1±9.5 vs 36.3±15.3 minutes, P <.01). Both the peak blood ethanol concentration (0.053±0.006 vs 0.034±0.008 g%, P <.001) and the area under the blood ethanol concentration curve between 0 and 180 minutes (5.2±0.7 vs 3.2±0.7 units, P <.001) were greater with the “diet” drink.
Conclusions
Substitution of artificial sweeteners for sucrose in mixed alcoholic beverages may have a marked effect on the rate of gastric emptying and the blood alcohol response.
Keywords: Gastric emptying, Ultrasound, Ethanol/blood/metabolism/pharmacokinetics, Alcoholic beverages/adverse effects, Humans
Premixed alcoholic drinks are popular among the young, particularly women,1 a group often following restricted energy or “low carb” diets. “Ready-to-drink” beverages were initially formulated with sugar, but “diet” versions containing artificial sweeteners are becoming available, and many drinkers mix their own alcoholic drinks using “diet” beverages.
It is now well established that the rate of gastric emptying is a major determinant of alcohol absorption.2, 3, 4 Gastric emptying is closely regulated to approximately 2-3 kcal per minute by feedback arising from interaction of nutrients with the small intestine.5 Hence, the addition of sucrose to an alcoholic beverage would be expected to slow gastric emptying when compared with a non-nutritive sweetener. However, the potential for sugar-free drinks to empty more rapidly from the stomach and thereby increase the rate of alcohol absorption, when compared with the original formulations, has apparently not been recognized.
Our aim was to evaluate blood ethanol concentrations and the rate of gastric emptying in healthy volunteers following ingestion of either sucrose-containing or artificially sweetened alcoholic drinks. We hypothesized that “diet” beverages would empty from the stomach more rapidly, resulting in higher blood ethanol concentrations.
Subjects and methods
Eight healthy male volunteers (aged 24.9±3.6 years, body mass index 23.4±1.6 kg/m2) were studied twice, after fasting overnight and abstaining from alcohol for 48 hours. Studies were separated by at least 3 days, and were randomized and double-blinded. All subjects gave written, informed consent, and the protocol was approved by the Research Ethics Committee of the Royal Adelaide Hospital.
At t=−5 minutes, subjects consumed a 600-mL orange-flavored vodka drink (5% alcohol) within 5 minutes. On one day, a “regular” drink was given, containing sucrose. On the other day, a “diet” drink was provided, sweetened with aspartame and acesulphame potassium (Table). Both drinks were served at 22°C, after dissipation of gas bubbles. Blood was sampled via a cannula at t=−5, 15, 30, 60, 90, 120, and 180 minutes, and the ethanol concentration measured by gas chromatography.
Table. Content of the “Regular” and “Diet” Beverages
| “Regular” | “Diet” | |
|---|---|---|
| Vodka (Wodka Wyborowa®, Turew, Poland) | 75 mL | 75mL |
| Fanta Orange™ (Coca Cola Amatil, Sydney, Australia) | 525 mL | - |
| Fanta Lite Orange ™ (Coca Cola Amatil, Sydney, Australia) | - | 525 mL |
| Total volume | 600 mL | 600 mL |
| Ethanol | 30 g | 30 g |
| Carbohydrate | 65 g | 2.6 g |
| Energy | 478 kcal | 225 kcal |
| pH | 3.4 | 3.3 |
Measurements of antral area were performed by ultrasound (Aloka SSD-650 CL, 3.5-MHz annular array probe, Tokyo, Japan). Subjects were seated, and the transducer positioned vertically to visualize the antrum in cross section, with the superior mesenteric vein and abdominal aorta in a longitudinal section.6, 7 Antral area was measured, using the built-in caliper and calculation software, at t=−5, and at 10-minute intervals from t=0 to 120 minutes. Gastric half-emptying time was defined as the time when antral area decreased to half the maximum increase above baseline.8 We have demonstrated that this method correlates closely with scintigraphy for measurement of liquid half-emptying time.7
Statistical Analysis
Antral area and blood ethanol concentrations were compared using repeated measures analysis of variance. Peak blood ethanol concentrations, half-emptying values, baseline and maximum antral areas, and areas under the blood ethanol concentration curves, calculated using the trapezoidal rule, were compared using Student’s paired t tests (Statview 5.0, SAS Institute, Cary, NC). Data are mean±standard deviation. P values <.05 were considered significant.
Results
All subjects tolerated the study well, and none found either drink unpleasant.
Antral Area and Gastric Emptying
Neither baseline nor maximum antral area differed between the 2 days. Antral area decreased more rapidly with the “diet” drink (P <.001) (Figure 1), and the gastric half-emptying time was less than for the “regular” drink (diet 21.1±9.5 minutes vs regular 36.3±15.3 minutes, P <.01).
Figure 1.
Antral area (mean
±standard deviation) after consumption of “regular” (filled circles, solid line) or “diet” (open circles, dashed line) mixed alcoholic drinks. The antral area at baseline is plotted as the first data point. The decrease in antral area is more rapid after the “diet” drink, indicative of faster gastric emptying (P <.001).
Blood Ethanol Concentrations
Blood ethanol concentrations were greater after the “diet” than the “regular” drink (P <.001) (Figure 2). Both the peak blood ethanol concentration (0.053±0.006 vs 0.034±0.008 g%, P <.001) and the area under the blood ethanol concentration curve (5.2±0.7 vs 3.2±0.7 units, P <.001) were greater after the “diet” drink.
Figure 2.
Blood ethanol concentration (mean
±standard deviation) after consumption of “regular” (filled circles, solid line) or “diet” (open circles, dashed line) mixed alcoholic drinks. Both peak alcohol concentration and the area under the curve after the “diet” drink are greater (P <.001 for each).
Discussion
Our study establishes that substitution of a “diet” mixer for a “regular” one containing sucrose, in a mixed alcoholic beverage, has a major impact on the rate of gastric emptying and alcohol absorption in healthy adults. Although we anticipated these effects from previous studies indicating that gastric emptying is regulated at a relatively constant caloric rate5 and that alcohol absorption is dependent on gastric emptying,2 the magnitude of the difference in blood alcohol concentrations was striking. Indeed, the mean peak blood ethanol concentration (ie, >.05 g%) after the “diet” drink would preclude subjects from legally driving a motor vehicle in many jurisdictions, whereas this act would be legal after consuming the “regular” drink.
Our observations are consistent with those of Hey et al, who reported that the area under the curve for blood ethanol concentration over 180 minutes was about 30% less after a sucrose-containing vodka-based drink, when compared with drinking vodka alone.9 Although differences in gastric emptying were thought likely to account for this difference, it was not measured in this study, and the volumes and pH of the drinks were not matched. In the current study, beverages were matched for volume and pH. The osmolarity of “diet” mixers is considerably less than that of “regular” soft drinks (about 30 vs 700 mOsm/kg),10 which may have contributed to more rapid emptying, although differences in caloric load are more important.11
That the rate of gastric emptying is a major determinant of alcohol absorption2, 4 is probably mainly due to the greater surface area for absorption provided by the small intestine compared with the stomach; metabolism of alcohol within the stomach by gastric alcohol dehydrogenase is almost certainly minor.3 In addition to substantially higher blood ethanol concentrations after the “diet” compared with the “regular” drink, we observed that the area under the concentration curve was markedly greater (with no subsequent crossover of the curves), consistent with the concept of rapid absorption due to accelerated gastric emptying, as well as proportionally less first-pass metabolism.4 Hepatic metabolism of ethanol is saturated at relatively low doses, so that disproportionate increments in blood ethanol concentrations result from modest increases in the rate of gastric emptying.3, 4, 12 We studied lean males, but the influence of gastric emptying on alcohol absorption has also been demonstrated in females,2, 3 and emptying of nutrient liquids does not vary substantially by sex or body mass index.13 Therefore, it is likely our findings can be generalized. As neither drink was unpalatable,14 it is unlikely that minor taste differences between them would influence gastric emptying.
Our study highlights that factors other than just the alcohol content of a beverage need to be taken into account in considering safe levels of consumption and the potential for intoxication. In particular, the substitution of artificial sweeteners for sugars in mixed alcoholic drinks potentially has a profound impact on blood alcohol concentrations, despite the drinks being similar in all other respects.
Acknowledgments
The authors with to thank the Drug and Alcohol Resource Unit, Royal Adelaide Hospital; Chang Gung Memorial Hospital, Kaohsiung, Taiwan; the Faculty of Medicine, Siriraj Hospital, Mahidol University, Thailand; and the Faculty of Health Sciences, University of Adelaide, for their support.
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PII: S0002-9343(06)00182-3
doi:10.1016/j.amjmed.2006.02.005
© 2006 Elsevier Inc. All rights reserved.
