New alcohol research shows drinking small amounts can still be harmful to health

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• Amna Nawaz:

  We're coming to the end of Dry January, where millions of Americans abstain from alcohol for the entire month.

  This yearly ritual again underscores the accumulating evidence that drinking alcoholic beverages, even in what are considered relatively small amounts, can be harmful to our health.

  William Brangham has the latest, including how Canada is considering radically revising its recommendations for drinking.

• William Brangham:

  That's right.

  Canadian health authorities had previously said that a low-risk amount of alcohol was about 10 drinks per week. But, just recently, a panel of advisers to the government, citing some of this research about alcohol's impacts, suggested lowering that to two drinks per week.

  For more on all of this, I'm joined by Dr. Tim Naimi. He's an alcohol epidemiologist and the director of the University of Victoria's Canadian Institute for Substance Use Research.

  Dr. Naimi, great to have you on the "NewsHour."

  Before we get to this changing guidance, can you just remind our audience, what do we know about alcohol's impact on us?

  Dr. Tim Naimi, University of Victoria: Sure.

  Well, alcohol is one of the leading behavior-related causes of health problems and deaths, and also some social problems and economic costs, ranging from things like injuries and accidents, to cancers, and, actually, heart and cardiovascular disease.

  So it causes a wide range of health effects. And, of course, those have been long appreciated at high — high levels of consumption, but even for some lower levels as well.

• William Brangham:

  It also has impacts on our mental health as well, I take it?

• Dr. Tim Naimi:

  Yes.

  Well, there's a really complicated, but important relationship between alcohol and things like depression and anxiety in particular. So, yes, so alcohol may play a causal role in those, but can certainly also exacerbate or make worse existing mental health conditions, particularly depression.

• William Brangham:

  I want to talk about dosage for a second. You mentioned this in passing.

  But is it true that these harmful effects go up the more you drink, so a little bit is better than a moderate amount is better than a large amount?

• Dr. Tim Naimi:

  Exactly right.

  When it comes to health, less is more. And that's actually the main — the main message stemming from the new Canadian guidelines. It's not that anyone needs to get down to a number. We know that the lowest level of risk is associated with a really small amount of alcohol. As little as two drinks per week is the lowest risk.

  But the main message behind the new Canadian guidelines and the main message — and this, I think, is consistent with other guidelines. The big point to keep in mind is, no matter what level you drink at, that consuming less will be good for health. And we really want to reach out to people.

  And I think this is — we're talking about the public health community broadly, not just to people who are already drinking a little bit and might cut back further, but people — if you're drinking six or seven drinks a day, and you can cut down to three or four, that would be fantastic for your health.

  So, just want to kind of reach a broad spectrum of drinkers. That's the basic idea.

• William Brangham:

  It still must come as a bit of a shock that something that is so widely accepted in our society can be implicated in cancer and heart disease and all of these other things?

  I mean, I think people think of drunk driving, and they understand that…

• Dr. Tim Naimi:

  Right.

• William Brangham:

  … and maybe drunken violence and things like that, but cancer and heart disease, do you think that the public fully appreciates those, those risks?

• Dr. Tim Naimi:

  Right, William.

  Well, I think you're right. I think people are aware of sort of impaired driving and crashes. They're aware of maybe cirrhosis of the liver. And maybe they're aware of, like, fetal alcohol spectrum birth defects and so forth. But I think they're much less aware of cardiovascular disease, and particularly in terms of the risk of cancer.

  I should mention that alcohol is actually considered a class one carcinogen or cancer-causing agent by the World Health Organization. So that's the same category as benzene and tobacco smoke. And some studies estimate that a drink of alcohol has about the same cancer-causing potential as one to two cigarettes, depending on your sex.

  As an example, the risk of breast cancer goes somewhere between eight and 10 percent increase with each additional drink that a woman consumes per day on average. So, that's an important thing. And we know from surveys that only a small fraction of the population understands the cancer link.

• William Brangham:

  Help me understand, though. We — it feels like we have been getting some conflicting guidance.

  I think many people remember being told that moderate amounts of drinking for certain people can be beneficial. There was that infamous study years ago that red wine was good for your heart.

  Are those things just — have those gone by the wayside now?

• Dr. Tim Naimi:

  Even for those studies, above very small amounts of alcohol, the risks started to increase.

  So it's really an argument about, how low is that point? So, broadly speaking, I think the science is consistent that sort of less is better, down to very low amounts. Yes, I do think — I do think some of that science has gone by the wayside.

  And without getting deep into the weeds, the basic idea there is that somebody — for example, a red wine drinker in their 50s who's been drinking just a small amount for their whole life is actually somebody, those people tend to be super healthy and have a lot of social advantages, and so maybe the red wine is a reflection of that, and — but not its cause. And that's the basic problem with the previous research on that.

• William Brangham:

  As I mentioned, a lot of Americans are doing this Dry January.

  Is there any evidence that that, stopping for a 30-day window, is useful?

• Dr. Tim Naimi:

  Well, it depends on what you're going for, right?

  I think the main idea behind Dry January or, this year, Damp January seems to be in fashion, which is sort of cutting back, but not stopping completely, in a way, these are sort of experiential versions of what most of the guidelines around the world are recommending, which is to sort of cut back on your drinking.

  And some people may experience immediate changes. I mean, the main idea is just to explore doing sort of things or activities or people that are less alcohol-centric, if you will. Some people get some sleep benefits immediately. Some, depending on how much they are drinking, will — may lose some weight.

  But the idea is to explore it. There is some evidence that, even six months later, people who don't intend to continue will be drinking a bit less than they were in the start of January. So there may be sort of a — the idea is here for us to just sort of to do a check on one's relationship with alcohol and maybe a bit of a reset after what is always the heaviest drinking time of the year in the U.S.

• William Brangham:

  All right, Dr. Tim Naimi at the University of Victoria, thank you so much for being here.

• Dr. Tim Naimi:

  Oh, it's great to be on "NewsHour." Thanks for having me.