I don't know whether mouthwash is a real concern, but ketogenic diets are:Tigger wrote:Obviously the testing technology employed needs to be suitable, and account would need to be taken of someone who'd, say, just used mouthwash (doesn't that only happen when people are trying to avoid the test?).
http://www.nature.com/ijo/journal/v31/n ... 3444a.htmlInternational Journal of Obesity article abstract wrote:A 59-year-old man undergoing weight loss with very low calorie diets (VLCD) attempted to drive a car, which was fitted with an alcohol ignition interlock device, but the vehicle failed to start. Because the man was a teetotaller, he was surprised and upset by this result. VLCD treatment leads to ketonemia with high concentrations of acetone, acetoacetate and beta-hydroxybutyrate in the blood. The interlock device determines alcohol (ethanol) in breath by electrochemical oxidation, but acetone does not undergo oxidation with this detector. However, under certain circumstances acetone is reduced in the body to isopropanol by hepatic alcohol dehydrogenase (ADH). The ignition interlock device responds to other alcohols (e.g. methanol, n-propanol and isopropanol), which therefore explains the false-positive result. This 'side effect' of ketogenic diets needs further discussion by authorities when people engaged in safety-sensitive work (e.g. bus drivers and airline pilots) submit to random breath-alcohol tests.
In the UK, people can demand a backup blood test. In most states in the U.S., it's not a problem because the policeman has to suspect drunkenness in the first place due to observed erratic driving or behavior, and someone who is on a weight loss diet who hasn't been drinking won't act drunk. It's only a problem at checkpoints as in the original post.
I do wonder in the UK if a blood test involves a lot of extra time going to a station; if they have portable blood test equipment that doesn't require medical personnel, like the pinprick tests for blood sugar, why not use them in the first place, rather than a less reliable breathalyzer test? And of course in the U.S., if the policeman observes erratic driving or other signs of impairment such as drunkenness, I want that driver off the road whether or not it's due to alcohol.
The problems with breathalyzers for people on ketogenic weight loss diets is a significant issue because in the U.S., and I suspect in the UK, there are one or two orders of magnitude more deaths from overweight and obesity related causes than from automobile accidents. It's a bad idea to give overweight people excuses not to lose weight, or even to make them risk inconvenience for it.