Although some research has suggested that moderate alcohol intake could increase heart health and decrease mortality risk, recently proposed updates to the Dietary Guidelines for Americans state that consuming as little as two alcoholic drinks per day could have harmful health effects, the New York Times' Anahad O'Connor reports.

Proposed updates to US alcohol guidelines recommend that Americans drink less

The United States' alcohol consumption guidelines since 1980 have defined "moderate" drinking as consuming up to two alcoholic drinks per day for men and up to one alcohol drink per day for women. According to O'Connor, "one drink" has long been defined as 12 ounces of beer, five ounces of wine, or one and a half ounces of spirits that are 40% alcohol.

The country's alcohol consumption guidelines published between 1990 and 2010 discouraged heavy drinking, but also claimed that research suggested moderate drinking could improve certain health outcomes. According to O'Connor, the guidelines noted that some studies had linked moderate alcohol consumption to fewer heart attacks and a lower mortality rate. The guidelines also stated that moderate drinking could help prevent cognitive decline as people age, O'Connor reports.

But an advisory panel of researchers working to update the country's current Dietary Guidelines for Americans said they plan to change the new recommendations to reflect that both men and women should limit their alcohol consumption to a single serving of beer, wine, or liquor per day, O'Connor reports. According to O'Connor, the researchers said there is persistent evidence showing that consuming alcohol is not associated with better health outcomes, and that lower alcohol consumption is healthier than moderate or heavy drinking.

The advisory panel is slated to release its recommended updates in a report in mid-July. The panel will send the report to the U.S. Department of Agriculture and HHS, which will review and publish finalized updates.

If the updates are finalized, the United States would be the latest in a string of countries to update their alcohol consumption recommendations to suggest lower levels. Australia, Britain, and France in recent years have updated their alcohol consumption guidelines in light of research that has linked alcohol consumption with increased cancer risk and other negative health effects.

"This is significant because the committee has finally gotten away from this idea that a small amount of alcohol is good for you," Thomas Gremillion, director of food policy at the Consumer Federation of America, told O'Connor. "They're really taking a stand and saying drinking less is always better. That's the right message and I think they deserve credit for making that change."

The two-drink per day myth

Health experts said the change would reflect research that has challenged the so-called "health halo" surrounding moderate drinking, O'Connor reports.

According to O'Connor, that halo started to form in the 1970s, when researchers released findings suggesting that people who didn't drink any alcohol were more likely to experience heart attacks than moderate drinkers. Over the next few decades, researchers continued to notice a "J-shaped curve" between alcohol consumption and mortality, with studies showing that mortality rates were lower among moderate alcohol drinkers when compared with nondrinkers, though those rates spiked among heavy drinkers.

However, O'Connor reports that the studies were observational and showed a correlation between moderate drinking and better health outcomes, not causation. Further, researchers over the years have found that the observational studies were vulnerable to selection bias, and some researchers found that people who were categorized as nondrinkers in the studies actually were formerly heavy drinkers who stopped consuming alcohol due to health problems, according to O'Connor. Researchers also found that some of the people who categorized as nondrinkers in the study had pre-existing medical conditions and avoided drinking due to their health issues.

In addition, researchers eventually realized that socioeconomic status, which can be a determinant of health and mortality, was also linked to a person's level of alcohol consumption. Specifically, researchers found that moderate drinkers also tended to be wealthier, eat healthier, and have better health care than heavy drinkers and people who did not drink at all. One study even found that 27 of the 30 risk factors for heart disease were "significantly more prevalent" among nondrinkers when compared with moderate drinkers, O'Connor reports.

"[I]n other words," O'Connor reports, "[r]ather than causing better health," the researchers discovered that "moderate drinking may be a marker for higher socioeconomic status and other lifestyle factors that promote a longer life."

When all of those revelations are taken into account, "[t]he appearance of protection vanishes like the mist on an autumn day as the sun comes up," Timothy Stockwell, an alcohol researcher and director of the Canadian Institute for Substance Use Research at the University of Victoria, told O'Connor. "All of these thousands of studies, when you do a forensic examination of them, most of them have these horrendous flaws and are open to these systematic biases."

Stockwell said he agrees with the advisory committee's proposed updates to America's alcohol consumption guidelines, but he'd word them differently, instead recommending mean and women limit their intake to "seven drinks a week … and no more than two drinks on one day."

"I would have a little flexibility," he told O'Connor.

But some experts still argue that moderate drinking can benefit health.

Erik Skovenborg, a physician and member of the International Alcohol Forum, said alcohol can have blood thinning properties and raise HDL, or "good," cholesterol.

Skovenborg recommends that people drink wine moderately, in addition to exercising regularly and eating healthy foods. "It's a pattern of things you should be doing, not just one thing," he said (O'Connor, New York Times, 7/10).