TORONTO – Have you ever felt like you’re getting mixed messages about how many glasses of wine it’s safe to pour after a long, hard day at work?

With recent pro-alcohol headlines like “Moderate drinking in men may reduce heart attack fatalities” and “A glass of wine a day keeps osteoporosis away,” not to mention “Middle-aged women who drink moderately age better,” who wants to believe 2011’s “Light drinkers face slightly higher breast cancer risk”?

A new study from Rutgers University is the newcomer at the scientific study party, and it says that even moderate amounts of alcohol consumption can decrease the production of adult brain cells by as much as 40 per cent.

Sure, it was done with rats, but psychology professor and study author Tracey J. Shors says at the structural and cellular level, it’s hard to tell the difference between human brains and those of our little rodent counterparts.

“There’s no reason to think alcohol would affect cells differently in one species versus another,” said Shors.

If you’re saying to yourself, ‘what do I really need those brain cells for anyway?’ Shors may have an answer for you.

Alcohol and your brain

The brain cells are called neurons, and are made in the thousands every day. They’re made in the hippocampus, the part of your brain necessary for many types of learning. The neurons become part of your brain, then make connections with other neurons, which make more connections, and so on. This forms the “circuitry” of the brain—also called structural plasticity in science-speak.

“The structure is what the brain is made up of – like a muscle; so you have to have the structure before you can have function,” said Shors. “So if the structure is degraded, then the function will be degraded.”

The rats were given the equivalent of between two and four drinks per day. Their blood alcohol level reached the Canadian and U.S. legal driving limit of 0.08 per cent at the high end. The 40 per cent decrease in neuron production happened after a couple of weeks of daily alcohol intake, but Shors admits there’s no reason to think the brain cells wouldn’t start being produced again once alcohol was no longer consumed.

“What we wanted to model was people who come home at night, have a couple glasses of wine—large glasses—then on weekends maybe another one or two,” said Shors. “So trying to model the amount of alcohol that a lot of people often think is okay or beneficial for them.”

‘Moderate’ is hard to define

So where does the definition of ‘moderate’ come from for these studies? Here’s what moderate meant in the research listed at the beginning of this article:

Moderate drinking in men may reduce heart attack fatalities: men who had 2 drinks/day, only for men “who have been drinking in this moderation for long periods of time”
A glass of wine a day keeps osteoporosis away: women who had 1-2 drinks/day a few times a week compared to when the women stopped drinking alcohol for two weeks 
Middle-aged women who drink moderately age better: women who had 1 drink/day compared to women who abstained, drank occasionally, or consumed more than 2 drinks/day 
Light drinkers face slightly higher breast cancer risk: women who had 3-6 drinks per week – so less than 1 drink/day—compared with non-drinkers

Clear as mud?

There are so many qualifications in scientific studies that analyze alcohol consumption that it may be best to look at all of the information and see how your personal health profile fits in.

“I think you really have to look at all the data and decide what’s important to you… it’s not everything in moderation,” said Shors.

Canada’s guidelines, introduced in November 2011, say you can reduce long-term health risks by drinking no more than:

• 10 drinks/week for women, with no more than two drinks/day most days, with no more than three on any single occasion
• 15 drinks/week for men, with no more than three drinks/day most days, with no more than four on any single occasion

“I do think that when people hear something like ‘oh a few glasses is good,’ they could think maybe if a few is good, maybe a few more is even better, and that’s certainly not true,” added Shors.