Will eating a lot of boozy Christmas food affect your breathalyser test results?

You’re likely to be welcomed with an eggnog when you arrive at a Christmas party. You accept it because it's just one drink and these things are simply a concoction of egg yolks, sugar and just a smidge of brandy – practically a dessert, right? 

But wait, you haven’t factored in that slice of bourbon-soaked fruit cake, rum-laced tiramisu, Bailey-infused trifle and rum truffles yet. Yes, they are boozy but they are also small bites, you figured. Surely, not everything alcoholic adds up and affects your breathalyser test results if you get behind the wheel?

You might be right, said doctors such as National University Hospital’s Dr Lee Guan Huei, who is the head and a senior consultant with Division of Gastroenterology and Hepatology, Department of Medicine. “The amount of alcohol in such alcohol-infused treats is very small and would not add much to breathalyser results or impair driving.”

However, Dr Edward Cheong, a general surgeon specialising in gastrointestinal surgery with Panasia Surgery Group, has a different view. “Every little bit adds up. Especially if the alcohol stays in your mouth longer.”

Dr Cheong is referring to gastroesophageal reflux disease or GERD that causes you to repeatedly regurgitate what you’d eaten back up your oesophagus, including the alcohol in the food and drink you’ve had. “Any food that results in gastroesophageal reflux can affect the breathalyser result,” he said.

Another consideration is whether you have eaten anything before imbibing. “On an empty stomach, the alcohol from these alcohol-infused treats will be quickly absorbed,” added Dr Cheong.

And since we’re on the topic of alcohol lingering in your mouth, what about mouthwash? “I am not aware of any study that measures the effect of mouthwashes but I believe the alcohol would evaporate very rapidly," said Dr Lee.

The silver lining if you have gastro issues and do get stopped to take a breathalyser test, Dr Lee said, is that you “may have to undergo a blood alcohol concentration (BAC) test as well, which cannot be affected by GERD”.

TAKE NOTE OF YOUR LIMIT

As a reminder, the legal limit for alcohol intake is 35mg of alcohol for every 100ml of breath, which would yield a BAC of 0.01 to 0.05 (see table below). That, according to the link Dr Lee cited, would translate into one to two drinks.

“A drink is considered a beer (12oz), a glass of wine (8oz) or a shot of liquor (1.5oz) such as vodka or gin; each has about the same amount of alcohol,” said Dr Lee.

In general, a shot of liquor is estimated to be metabolised by your body in an hour, a pint of beer in two hours and a large glass of wine in three hours, said Dr Cheong. But as you may already know, these durations can be affected by various factors such as gender and body mass.

“Men and women have different tolerances to alcohol due to their differences in body mass and their level of alcohol dehydrogenase in the body. A smaller individual tends to get intoxicated quicker,” said Dr Cheong.

Furthermore, if you’re on medication, certain ones can extend the duration your body needs to metabolise alcohol. These medications can include inhalers for asthma as well as alcohol-containing chest rubs, breath sprays and oral gels for mouth sores and toothaches, said Dr Cheong.

Asthma medications are inhaled and they can remain in the airways longer than other medicines. That smear of chest rub to relieve coughing? It can contain alcohol and create a false positive in a breathalyser test, said Dr Cheong. “Oral gels can contain anbesol, a local anaesthetic, that can cause a person to test positive for alcohol consumption. Some breath sprays also have a high alcohol content,” he said.

With so many variables at play and not mentioning, the different views from different experts, you'd be playing it safe by not driving if you’re planning on indulging in a few rum balls. And tiramisu. And champagne jelly shots.