The Zendo Project

The Zendo Project

Caffeine, Energy Drinks, and Everything Else

It's the everything else that adds up.

A couple of years ago, coffee drinkers were buoyed by the release of a massive study in the New England Journal of Medicine that “did not support a positive association between coffee drinking and mortality.” In fact, the analysis by Neal D. Freedman and associates showed that even at the level of 6 or more cups per day, coffee consumption appeared to be mildly protective against diabetes, stroke, and death due to inflammatory diseases. Men who drank that much coffee had a 10% lower risk of death, and women in this category show a 15% lower death risk. Coffee, it seemed, was good for you.

Hooray for coffee—but lost in the general joy over the findings was the constant association of coffee with unhealthy behaviors like smoking, heavy alcohol, use, and consumption of red meat. And the happy coffee findings did not consider the consumption of caffeine in other forms, such as energy drinks, stay-awake pills, various foodstuffs, and even shampoos.

One of the earliest battles over “energy drinks” was an action taken in 1911 under the new Pure Food and Drug Act—the seizure by government agents of 40 kegs and 20 barrels of Coca-Cola syrup in Chattanooga. Led by chemist Harvey Wiley, the first administrator of the Food and Drug Administration (FDA), agents of the fledgling organization acted on the belief that the soft drink contained enough caffeine to pose a significant public health hazard. The court case went on forever. Eventually Coca-Cola cut back on caffeine content, and the charges were dropped.

Jump cut to 2012, and watch the FDA grapple with the same question a hundred years later, citing concerns about undocumented caffeine levels in so-called energy drinks in the wake of an alleged link between the caffeinated soft drinks and the death of several young people. According to Dr. Kent Sepkowitz, writing in the Journal of the American Medical Association, while only 6% of young American men consume the drinks, “in a recent survey of U.S. overseas troops, 45% reported daily use.” In 2006, more than 500 new energy drinks hit the market. By 2011, sales of energy drinks in the U.S. climbed by more than 15% to almost $9 billion.

Death by caffeine has long been a subject of morbid interest, and an article in the Journal of Caffeine Research  by Jack E. James of Iceland’s Reykjavik University questions these prevailing assumptions, and brings together the latest research on this perennial question, including, yes, a consideration of whether the time has come to regulate caffeine as some sort of controlled substance.

In 2013, the FDA released reports that attributed a total of 18 deaths to energy drinks. Somewhere between 3 and 10 grams of caffeine will kill you, especially if you are young, old, or suffer from various health problems. The generally accepted lethal dose is 10 g. The wide gap in estimates and mortality reports reflects the wide variation in caffeine’s effects.  Half the lethal dose can kill a child, and some adults have survived 10 times that amount. As I wrote in an earlier post (“Energy Drinks: What’s the Big Deal?”): “Energy drinks are safe—if you don’t guzzle several of them in a row or substitute them for dinner, or have diabetes, or an ulcer, or happen to be pregnant, or are suffering from hearth disease or hypertension. And if you do OD on high caffeine intake, it will not be pleasant: Severe cardiac arrhythmias, palpitations, panic, mania, muscle spasms, and seizures.”

Warning signs include racing heart, abdominal pain, vomiting, and agitation. Since the average cup of coffee weighs in at about 100 milligrams, there doesn’t seem to be much to worry about in that regard. Nonetheless, the American National Poison Data System (NPDS) has more than 6,000 “case mentions” related to caffeine. One of these cases generated considerable press coverage: the death of a 14 year-old girl with an inherited connective tissue disorder.

In his article for the Journal of Caffeine Research, James starts by noting other fatalities, including two confirmed caffeine-related deaths in New Mexico, and four in Sweden, among other long-standing historical reports. Still, not much there to wring your hands over—but James insists that data on poisonings “do not show what contributory role caffeine may have had in cases where fatal and near-fatal outcomes were deemed to have been due to other compounds also present.”

Fair enough. But here is where the argument gets interesting. “Considerably smaller amounts of caffeine,” writes James, "may be fatal under a variety of atypical though not necessarily rare circumstances.” Among these, he singles out: 1) Prior medical conditions predisposing patients toward unusual caffeine metabolism. 2) Unknown interactions and synergies with prescription, over-the-counter, and illegal drugs. 3) Physical stress and high-intensity sports. 4) Children, for whom caffeine is easily available.

James claims we don’t know enough to insist caffeine is essentially harmless, let along good for us in large doses. He compiled this eye-opening list of foods and other products that sometimes contain caffeine: ice cream, chewing gum, yogurt, breakfast cereal, cookies, flavored milk, beef jerky, cold and flu medications, weight-loss compounds, breath-freshener sprays and mints, skin lotion, lip balm, soap, shampoo, and, most notably, as a contaminant in illegal drugs. James says that the largest category of incidents with over-caffeinated young people involve “miscellaneous stimulants and street drugs…”

As for energy drinks themselves: “As a nonselective adenosine receptor antagonist, caffeine counteracts the somnogenic effects of acute alcohol intoxication, and alcohol may in turn ameliorate the anxiogenic effects of caffeine.” It’s an age-old practice: caffeine doesn’t sober up drunks, but it does keep them awake. James believes the evidence shows that the combination of caffeine and alcohol increases the risks of unprotected sex, sexual assault, drunk driving, violence, and emergency room visits.

Furthermore, “the ubiquity of caffeine is such that it has become a biologically significant contaminant of freshwater and marine systems….”

Finally, James offers a vision of a caffeine-regulated future, noting that Denmark, France, and Norway have already introduced sales restrictions on energy drinks. Restrictions on the sale of powdered caffeine may follow, as a valid public health measure. “Canada requires labeling in relation to the same product, advising that it should not be mixed with alcohol.” Other countries have labeled energy drinks as “high caffeine content” beverages. And Sweden regulates the number of caffeine tablets that can be purchased at one time from a drugstore.  Meanwhile, in the U.S., makers of energy drinks, unlike makers of soft drinks, do not even have to print the amount of caffeine on the label as dietary information, although this is in the process of changing. Major energy drink makers are moving to put caffeine content labels on their products, in part to shift their relationship with the FDA. Last year, The Food and Drug Administration advised consumers to avoid powdered caffeine due to health risks.

Originally published March 13, 2013

Graphics: http://www.runnersworld.com

Marijuana Deconstructed

What's In Your Weed?

Australia has one of the highest rates of marijuana use in the world, but until recently, nobody could say for certain what, exactly, Australians were smoking. Researchers at the University of Sydney and the University of New South Wales recently analyzed hundreds of cannabis samples seized by Australian police, and put together comprehensive data on street-level marijuana potency across the country. They sampled police seizures and plants from crop eradication operations. The mean THC content of the samples was 14.88%, while absolute levels varied from less than 1% THC to almost 40%.  Writing in PLoS one, Wendy Swift and colleagues found that roughly ¾ of the samples contained at least 10% total THC. Half the samples contained levels of 15% or higher—“the level recommended by the Garretsen Commission as warranting classification of cannabis as a ‘hard’ drug in the Netherlands.”

In the U.S., recent studies have shown that THC levels in cannabis from 1993 averaged 3.4%, and then climbed to THC levels in 2008 of almost 9%. By 2015, marijuana with THC levels of 20% were for sale in Colorado and Washington.

CBD, or cannabidiol, another constituent of cannabis, has garnered considerable attention in the research community as well as the medical marijuana constituency due to its anti-emetic properties. Like many other cannabinoids, CBD is non-psychoactive, and acts as a muscle relaxant as well. CBD levels in the U.S. have remained consistently low over the past 20 years, at 0.3-0.4%. In the Australian study, about 90% of cannabis samples contained less than 0.1% total CBD, based on chromatographic analysis, although some of the samples had levels as high as 6%.

The Australian samples also showed relatively high amounts of CBG, another common cannabinoid. CBG, known as cannabigerol, has been investigated for its pharmacological properties by biotech labs. It is non-psychoactive but useful for inducing sleep and lowering intra-ocular pressure in cases of glaucoma.

CBC, yet another cannabinoid, also acts as a sedative, and is reported to relieve pain, while also moderating the effects of THC. The Australian investigators believe that, as with CBD, “the trend for maximizing THC production may have led to marginalization of CBC as historically, CBC has sometimes been reported to be the second or third most abundant cannabinoid.”

Is today’s potent, very high-THC marijuana a different drug entirely, compared to the marijuana consumed up until the 21st Century? And does super-grass have an adverse effect on the mental health of users? The most obvious answer is, probably not. Recent attempts to link strong pot to the emergence of psychosis have not been definitive, or even terribly convincing. (However, the evidence for adverse cognitive effects in smokers who start young is more convincing).

It’s not terribly difficult to track how ditch weed evolved into sinsemilla. It is the historical result of several trends: 1) Selective breeding of cannabis strains with high THC/low CBD profiles, 2) near-universal preference for female plants (sinsemilla), 3) the rise of controlled-environment indoor cultivation, and 4) global availability of high-end hybrid seeds for commercial growing operations. And in the Australian sample, much of the marijuana came from areas like Byron Bay, Lismore, and Tweed Heads, where the concentration of specialist cultivators is similar to that of Humboldt County, California.

The investigators admit that “there is little research systematically addressing the public health impacts of use of different strengths and types of cannabis,” such as increases in cannabis addiction and mental health problems. The strongest evidence consistent with lab research is that “CBD may prevent or inhibit the psychotogenic and memory-impairing effects of THC. While the evidence for the ameliorating effects of CBD is not universal, it is thought that consumption of high THC/low CBD cannabis may predispose users towards adverse psychiatric effects….”

The THC rates in Australia are in line with or slightly higher than average values in several other countries. Can an increase in THC potency and corresponding reduction in other key cannabinoids be the reason for a concomitant increase in users seeking treatment for marijuana dependency? Not necessarily, say the investigators. Drug courts, coupled with greater treatment opportunities, might account for the rise. And schizophrenia? “Modelling research does not indicate increases in levels of schizophrenia commensurate with increases in cannabis use.”

One significant problem with surveys of this nature is the matter of determining marijuana’s effective potency—the amount of THC actually ingested by smokers. This may vary considerably, depending upon such factors as “natural variations in the cannabinoid content of plants, the part of the plant consumed, route of administration, and user titration of dose to compensate for differing levels of THC in different smoked material.”

Wendy Swift and her coworkers call for more research on cannabis users’ preferences, “which might shed light on whether cannabis containing a more balanced mix of THC and CBD would have value in the market, as well as potentially conferring reduced risks to mental wellbeing.”


Swift W., Wong A., Li K.M., Arnold J.C. & McGregor I.S. (2013). Analysis of Cannabis Seizures in NSW, Australia: Cannabis Potency and Cannabinoid Profile., PloS one, PMID: 23894589

(First published at Addiction Inbox Sept. 3 2013)

Graphics Credit: https://budgenius.com/marijuana-testing.html

Such Stuff As Dreams Are Made On: Marijuana and Sleeping

Study sheds potential light on indica vs. sativa debate.

[Thanks to Ivan Oransky (@ivanoransky) for alerting me to this study.]

Anyone who has smoked marijuana more than a couple of times knows that cannabis can alter how you sleep. The effect of cannabis on sleep is even part of the never-ending debate over Cannabis indica vs. Cannabis sativa, the two major species of the marijuana plant. Indica smokers typically report a marijuana high that is body-intensive and often soporific, sometimes leading to the condition aptly known as “couch lock.” Whereas sativa smokers, according to marijuana lore, experience a more cerebral, energetic “head high,” with fewer somatic effects. Not surprisingly, hybrid strains incorporating the alleged characteristics of both indica and sativa strains are popular in the medical marijuana community.

Although there is no official sanction for it in the medical community, marijuana is often dispensed medically for sleep problems. One piece of common wisdom holds that the higher the THC content of marijuana, the more helpful it will be in promoting sleep and improving poor sleep. The stronger the better, in other words. Similarly, indica strains are assumed to promote sleep more than sativa strains.

In an effort to clear the air, so to speak, a group of researchers, writing in Addictive Behaviors, sought to “document naturalistic choice of particular medical cannabis types among individuals who self-report using cannabis for the treatment of sleep problems…. Little research has documented species or cannabinoid concentration preferences among individuals who use medical cannabis for particular conditions…. We also evaluated the interaction between the type of cannabis used and diagnosis of cannabis use disorder among study participants.”

The researchers recruited participants from a medical cannabis dispensary in California under procedures approved by the VA and Stanford University review boards. 163 people with a mean age of 40, who used cannabis twice a day on average, provided self-reported information on their cannabis use for the study. 81 participants reported using cannabis for the management of insomnia, and another 14 reported using cannabis to reduce nightmares. (Frequent smokers insist they dream less. THC does appear to decrease the density of REM cycles, leading to more restful, dream-free sleep, according to some studies. )

So what did they find?

—“Individuals who reported using cannabis for nightmares, compared to those who did not, preferred sativa to indica.” (Small effect.)

Indica, considered the “heavier” high, might have seemed the likely choice here.

—"Individuals who self-report using cannabis to treat symptoms of insomnia and those with greater self-reported sleep latency reported using cannabis with significantly higher concentrations of CBD.” (Large effect.)

Again, a somewhat counterintuitive finding, since it is widely believed that CBD conduces toward a more wakeful state than THC alone.

—“Individuals who used sleep medication less than once/week used cannabis with higher THC concentrations than those who used sleep medication at least once a week.” (Large effect.) “There were no differences in THC concentration as a function of self-reported sleep quality, or use for insomnia or nightmares.”

Pretty straightforward finding: THC makes you sleepy. It is not clear, however, that above a certain threshold, more THC makes you even sleepier. In fact, some researchers would consider this finding unexpected, given that high THC concentrations have been shown to have a stimulating effect.

—“Older individuals were less likely to have cannabis use disorder compared to those younger….

No surprise about the older folks, since prior studies show a decrease in the prevalence of cannabis use disorders with age.

—“Individuals who preferred sativa or primary sativa hybrid strains were less likely to have cannabis use disorder compared to those who preferred indica or primary indica hybrid strains.” (Small effect.)

If replicated, this finding could have significant implications; both in strengthening programs to reduce marijuana smoking among the very young, and it warning consumers that some evidence suggests indica strains may be more addictive than sativa strains in plants with similar THC/CBD levels and ratios.

—“Neither concentration of THC nor CBD were associated with cannabis use disorder.”

Common sense, but useful to remember. In other addictive behaviors, such as heroin and alcohol abuse, the relative strength of the drug is not the primary determinant of its addictive potential.

Caveats and design limitations: The survey relied on retrospective reports of sleep quality and pot preferences. Also lacking is an examination of additional variables such as PTSD and co-occurring substance abuse.

Jack London and his Alcoholic Memoirs

Meet John Barleycorn.

In the early years of the 20th Century, writer Jack London was the equivalent of a rock star. A ruggedly good-looking sportswriter, globetrotting war correspondent, successful novelist and short story writer, London came up the hard way on the Oakland docks in California. He had his first drink at the age of 5, ran an oyster smuggling operation as a teenager, and allegedly brought the sport of surfing from Waikiki to the West Coast. At least one critic has referred to him as the Norman Mailer of the early 1900s.

In 1913, the author of the Call of the Wild published what was arguably his least successful book, John Barleycorn, a non-fiction account carrying the subtitle Alcoholic Memoirs. John Sutherland, professor of English Literature at University College in the UK, wrote in his introduction to the Oxford edition of Jack London’s book that London had pitched the book as “the bare, bald, absolute fact… of my own personal experiences in the realm of alcohol.” As Sutherland notes, “The drunk’s stigma was, however, indelible in 1913. No one of London’s public standing had ever come clean on the question of problem drinking before—at least not while at the zenith of their power and fame.”

Yet what are we to make, Sutherland asks, of London’s assertions, “three times in the first five pages, that drinker he may be, but ‘I was no hereditary alcoholic… I have no constitutional predisposition for alcohol.’”? Is this, the critic asks, “self-delusion or self-knowledge?”

After reading the book, I would have to say a little bit of both, given the limitations of medical knowledge at the time.  In London’s view, common back then, “dipsomania” was a chemical, congenital defect, much maligned and considered to be as rare as one in every several thousand drinkers. Nonetheless, several prominent London biographers have asserted that Jack London was chronically drunk-sick in his later years, ultimately dying of uremia and other complications brought on by years of excessive drinking. Writer Upton Sinclair claimed in 1915 that he had seen London wandering Oakland “dazed and disagreeably drunk.” Still others claim London’s bar bills were always modest and much of John Barleycorn is fiction. Yet London writes frankly of his morning shakes and hair-of-the-dog drinking and suicidal impulses. Describing his life in 1910, London writes: “I achieved a condition in which my body was never free from alcohol. Nor did I permit myself to be away from alcohol…. There was no time in all my waking time, that I didn’t want a drink.”

Was Jack London a Hemingway-style brawler or a hopeless alcoholic? As we have come to understand, it is sometimes possible to be both, for a while. Jack London was not writing for a medical journal, he was relating the experiences of his own life. And when the battle for universal suffrage began in earnest, London was an early an enthusiastic backer, on the grounds that if women got the vote, alcohol prohibition would surely follow, and the children of American would be saved from the wiles of John Barleycorn.

The lack of enthusiasm for the book when it was published stemmed, in part, from these built-in ambiguities. In addition, writes Sutherland, “John Barleycorn is an extended meditation on pessimism, or alcohol induced melancholy.” These days, we are more likely to refer to this condition as depression. This was not the Jack London his fans had come to know and love, even though London insisted in the book that he was “writing of the effects of alcohol on the normal, average man. I have no word to say for or about the microscopically unimportant excessivist, the dipsomaniac.”

For all the hedging, there is plenty of recognizable plain talk about the devotees of Mr. Barleycorn: “When good fortune comes, they drink. When they have no fortune, they drink to the hope of good fortune. If fortune be ill, they drink to forget it. If they meet a friend, they drink. If they quarrel with a friend and lose him, they drink…. He coarsens and grossens them, twists and malforms them out of the original goodness and fineness of their natures.”

In another passage describing the tavern life of tradesmen and laborers, he “saw men doing, drunk, what the would never dream of doing sober…. Time and again I heard the one explanation: If I hadn’t been drunk I wouldn’t a-done it.”

And as time passes, Jack London, the resolutely non-alcoholic, highly-regarded novelist, finds the terrain underneath his own feet is changing: “And the thing began so imperceptibly, that I, old intimate of John Barleycorn, never dreamed whither it was leading me…. It was at this time I became aware of waiting with expectancy for the pre-dinner cocktail. I wanted it, and I was conscious that I wanted it…. And right there John Barleycorn had me. I was beginning to drink regularly, I was beginning to drink alone.”

These developments shook up London sufficiently for him to ask himself: “Had I, a non-alcoholic, by long practice, become an alcoholic?” He has no trouble marshaling evidence for the argument: “The more I drank the more I was required to drink to get an equivalent effect…. Whenever I was in a hurry, I ordered double cocktails. It saved time.”

There were other warnings: “Where was this steady drinking leading? But trust John Barleycorn to silence such questions. ‘Come on and have a drink and I’ll tell you all about it,’ is his way.”

London concludes, before taking most of it back in later pages: “There are hundreds of thousands of men of this sort in the United States to-day, in clubs, hotels, and in their own homes—men who are never drunk, and who, though most of them will indignantly deny it, are rarely sober. And all of them fondly believe, as I fondly believed, that they are beating the game.”

And finally, this: “But a new and most diabolical complication arose: The work refused to be done without drinking. It just couldn’t be done. I had to drink in order to do it.”

In the end, let us hear from his last wife, Charmian, who made the following entry in her diary on July 1, 1912: “I know now that Jack, facing the writing of John Barleycorn, intends to drink moderately in the future, just to prove to an unbelieving public that he is the opposite of an ‘alcoholic’, that he is not afraid of being an alcoholic, and never was an alcoholic. Perhaps he is right, but I feel a trifle dashed.”

Photo Credit: http://www.erbzine.com/

Alcohol Industry Turns Moderation Into a Sales Message

A warning or an advertisement?

You almost have to admire the tenacity shown by the liquor industry in its passive aggressive method of turning a warning label into additional advertising.

Perhaps it was foolish to suppose that forcing the liquor industry to brand all bottles and advertisements with the catch-phrase, “Drink Responsibly,” or “Drink Moderately,” or some responsible variation on that theme, would do any good—or would be observed in good faith by alcohol companies.

To begin with, a majority of heavy or at-risk drinkers consider their intake to be moderate already, says Alcohol Concern, a national charity in the UK. According to a survey of drinkers in Wales, respondents thought they’d had enough to drink when they lost control or felt unwell: ‘when the rooms starts to spin’ or ‘when I have to be put in a taxi.’”

Secondly, the alcohol industry won’t play fair when it comes to displaying these modest messages. Alcohol Concern conducted a small study of alcohol advertising in a selection of consumer lifestyle magazines commonly available in supermarkets. Specifically, the study looked at the presence and placement of “drink responsibly” or “enjoy responsibly” messages in the advertising—a message alcohol companies have pledged to place voluntarily on labels.

The group sampled 18 issues, primarily food and diet magazines, sold at low cost, or sometimes given away in-store. Alcohol advertising represented as high as 40% of total advertising in some of the issues. The web address of Drinkaware, another public education charity, funded by the alcohol industry, was found in 94% of the alcohol advertisements. But as the study points out, “referencing an educational website hardly constitutes pulling out all the stops to make, as one leading drinks company ABInBev puts it, responsible drinking ‘a fundamental part of our dream to be the Best Beer Company bringing people together for a Better World.”

In total, “36% of alcohol adverts and advertorials included a specific drink responsibly message…. only in a minority of cases were the drink responsibly messages kept simple….” The Better World, it seems, will include a whole lot of branding.

Examples of industry embellishment are everywhere: Bacardi Rum ads asked you to “Live Passionately, Drink Responsibly,” while Martini cuts right to the point with its version, “Enjoy Martini Responsibly.” Grey Goose’s creative alternative is “Sip Passionately, Drink Responsibly,” while Diageo wants you to “Celebrate Life Responsibly.”

My personal UK favorites come from Jack Daniels: “Play with your Heart. Drink with Care. Live Freely. Drink Responsibly.”. Another example from Jack Daniels also illustrates the dichotomy: “Makes This Season a Winter to Remember. Drink Responsibly.” They read almost like a set of opposing commands: Play recklessly while you drink carefully. Live wild and free, except for your responsible drinking.

In sum, the UK alcohol industry just can’t play it straight. And while the U.S. record is better—Alcohol Concern cites American studies showing some sort of responsibility message in 9 out of 10 U.S. advertisements—U.S. distributors are not above a little brand promotion in the message, either. A random search for American alcohol ads quickly yielded Miller High Life’s “Great Beer. Great Responsibility. #IamRich.” Bud Light recently found itself in the gaffe business, forced to pull the cute little tagline on its cans: “Perfect Beer For Removing ‘No’ From Your Vocabulary For the Night. #UpForWhatever.” As Mashable covered the controversy on Twitter, “Bud Light campaign tells drunk people to remove ‘No” from their vocab.”

Perhaps the richest example unearthed by Alcohol Concern in UK supermarket magazines was the drink responsibly message found on one ad, where “the magazine pages had to be physically pulled back in order to read the message, in tiny type (known as ‘mouseprint’), along the left margin of the advert.”

To return to the first question: What, exactly, does responsible drinking mean? “If it’s sticking to current government-endorsed recommended limits,” the study asks, “then why does this advice not appear in a single alcohol advert or advertorial captured in this study?

Moderate Drinking Doesn’t Help Your Heart

Mendelian meta-analysis and the alcohol “flush” allele.

Less than a year after the massive Mendelian randomization meta-analysis published in the British Medical Journal, a group of researchers recently wrote an editorial in the journal Addiction, which would seem to put a lid on the matter:

The foundations of the hypothesis for protective effects of low-dose alcohol have now been so undermined that in our opinion the field is due for a major repositioning of the status of moderate alcohol consumption as protective…. Health professionals should not recommend moderate alcohol consumption as a means of reducing         cardiovascular risk for patients. At the policy level, the hypothesis of health benefits from moderate drinking should no longer play a role in decision making.

To recap: In the Mendelian meta-analysis, drinkers with a genetic variant linked to the so-called alcohol flush reaction, which leads to lower consumption among those who drink, also correlated with a decreased risk of cardiovascular disease. “Carriers of the rs1229984 A-allele had lower levels of alcohol consumption and exhibited lower levels of blood pressure, inflammatory biomarkers, adiposity measures, and non-HDL cholesterol, and reduced odds of developing coronary heart disease, compared with non-carriers of this allele.”

But as it turned out, this relationship only held for drinkers, not for abstainers.

Why, then, have so many epidemiologists agreed for several decades now that “moderate” alcohol intake has a protective effect against heart diseases? According to the editorial authors—drug researchers from Australia, Canada, the U.S., and Sweden—earlier research tended to use “abstainers” as the key reference group to which drinkers were compared. Studies that separated former drinkers and occasional drinkers from abstainers got different results—they didn’t show significant protection correlating with moderate alcohol consumption. The theory, say the researchers, is that non-addicted drinkers spontaneously reduce their alcohol intake with age and medical concerns. Some of these people with a declining health profile are counted as “abstainers.” But when former and current drinkers are combined, then compared with life-long abstainers to address selection bias, “the observed disparity in health status between abstainers and low-dose drinkers was eliminated.”

But it’s not quite over. Michael Rioerecke and Jurgen Rehm at the Center for Addiction and Mental Health in Toronto, argue in another Addiction editorial that there are still a few things unaccounted for: The allele in question is assumed to be randomly spread throughout the population, which may or may not be true, especially since allele carriers are relatively rare in several European countries. The allele is also assumed to be mediated by average alcohol intake. Binge drinking, which allele carriers presuming engage in less, is not assessed in the study.  In short, they write, “we do not know if the average level of alcohol intake of the allele carriers within the strata of average consumption was indeed lower than that of the non-carriers.” Nonetheless, even Rioerecke and Rehm concede that the evidence continues to look promising for this revision of conventional drinking wisdom. More than 100 studies have shown relatively stable associations between alcohol and heart disease, and absent a new breakthrough method of epidemiological study, this one stands a good chance of holding firm.

Graphics credit: http://www.keyingredient.com/