http://www.digitaljournal.com/science/mixing-alcohol-with-diet-beverages-raises-breath-alcohol-levels/article/451047

Mixing alcohol with diet beverages raises breath alcohol levels

Posted Dec 2, 2015 by Tim Sandle
Breathalyzers are used to assess the level of alcohol a person has consumed. It can be used to assess drink-driving or in some workplaces. New research suggests mixing alcohol with diet drinks makes the readings higher.
Health conscious tipplers may be closer to finding out just how many calories they are imbibing as c...
Health conscious tipplers may be closer to finding out just how many calories they are imbibing as consumer advocates push for EU nutritional labelling on alcoholic drinks in the face of strong industry resistance
Emmanuel Dunand, AFP/File
It may seem like the right thing to do: mixing high calorie alcoholic drinks with low calorie mixers. However, the combination of diet beverages with alcohol seemingly enhances the assessment of blood alcohol levels on the breath.
When someone drinks, around 10 percent of alcohol, after it has been absorbed into the bloodstream, leaves the body via breath (the remainder is excreted through urine or perspiration, or is metabolized by the body.) Assessing alcohol content on the breath is the basis of breathalyzers. In the U.S, for example, a 0.10 - 0.12 blood alcohol content (assessed from breath measurements) is indicative of someone being unfit to drive, as a result of "significant impairment to motor coordination and loss of good judgment. Speech may be slurred; balance, vision, reaction time and hearing will be impaired. Probably not thinking straight."
The alcohol levels a person has in their body, assessed using a breathalyzer, is not an exact science. The breathalyzer looks for peak breath alcohol concentrations. The calibration of the instruments used varies, and there are difference readings for different people who have consumed the same quantities of alcohol. Another variability, according to a new study, is with the beverages that an alcoholic drink has been mixed with.
Scientists based at Northern Kentucky University have discovered that alcoholic drinks mixed with diet sodas could raise breath alcohol levels higher than when alcoholic drinks are combined with regular sodas. This finding is based on a small study. Here, Tech Times reports, the science group had 10 men and 10 women, aged 21-30 years old, drink five various mixed beverages over five drinking sessions. The levels of alcohol varied, and the drinks were either mixed with diet or sugared soda. As a control, one drink was soda without alcohol.
The outcome was that drinkers of alcohol mixed with diet soda showed between a 22 and 25 percent higher peak breath alcohol concentrations compared to those who drank the same levels of alcohol with regular soda. The differences, the researchers speculate, is due to the way the body goes through "gastric emptying." Here alcohol seems to enter the bloodstream faster with diet drinks.
The study is published in the journal Drug and Alcohol Dependence, in a paper headed "Effects of artificial sweeteners on breath alcohol concentrations in male and female social drinkers."