BehindTheMedspeak: Who knew? Diet soda enhances alcohol absorption

Anahad O'Connor's July 8, 2008 "Really?" column in the New York Times Science section was chock full of interesting information.

Along with the FunFact cited in the headline above, we also learn that "... alcohol was absorbed far more quickly when mixed with carbonated beverages than with flat mixers."

The piece follows.

The Claim: Beware of Drink Mixers Based on Diet Soda

The Facts: Usually it is solely the liquor component of a cocktail — not the mixer — that determines its inebriating effects. But some people contend the artificial sweeteners in diet soda speed the absorption of alcohol.

Odd, perhaps, but research suggests it’s true. In a 2006 study, a team of scientists recruited healthy subjects and had them consume vodka cocktails. On some occasions, it was a 20-ounce drink mixed with a sugar-sweetened beverage, and on others it was a nearly identical drink mixed instead with a diet beverage.

In the diet-mixer conditions, the alcohol entered the subjects’ bloodstream about 15 minutes faster, and their blood-alcohol concentration was higher, peaking at 0.05 percent, compared with 0.03 percent with the regular mixer.

One theory is that the alcohol is absorbed more quickly because there is no sugar to slow it down, which would mean that club soda would have a similar effect. A second study in 2007 also showed that alcohol was absorbed far more quickly when mixed with carbonated beverages than with flat mixers, possibly because of the effervescence. As a result, experts say, it’s best to choose flat mixers like orange or cranberry juice over diet sodas or juices.

The Bottom Line: Compared with sugar-sweetened drinks, artificial sweeteners can speed inebriation.

....................

Here's the abstract of the 2006 study cited above, published in the American Journal of Medicine.

Artificially sweetened versus regular mixers increase gastric emptying and alcohol absorption

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.

....................

The 2007 study published in the Journal of Forensic and Legal Medicine?

That abstract follows.

Alcohol concentration and carbonation of drinks: the effect on blood alcohol levels

Alcohol absorption and elimination vary considerably amongst individuals, and are subject to influences from a variety of factors. The effects of alcohol concentration and beverage mixer type on the rate of alcohol absorption, in a controlled environment was studied. 21 subjects (12 male, 9 female) consumed a solution containing alcohol, on three separate occasions. The three solutions were, A: Neat vodka (37.5 vol%), B: Vodka mixed with still water (18.75 vol%), C: Vodka mixed with carbonated water (18.75 vol%). The volume of alcohol each subject consumed was determined by Widmark's equation. The alcohol was drunk in a 5 min period following an overnight fast and breath alcohol concentrations were measured over a 4h period using a breathalyser. 20/21 subjects absorbed the dilute alcohol at a faster rate than the concentrated alcohol. The difference between the absorption rates was found to be significant (p<0.001). The use of a carbonated mixer had varying effects on the alcohol absorption rate. 14/21 subjects absorbed the alcohol with the carbonated mixer at a faster rate, with 7 subjects showing either no change or a decrease in rate. The mean absorption rate for solution C was 4.39+/-0.45 (mg/100ml/min), and the difference between this absorption rate and that with the still mixer (1.08+0.36) was significant (p=0.006).