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Health Watch: Moderate Drinking Helps Memory, Heavy Drinking May Cause Dementia

Plus, researchers examine link between wine and irregular heartbeat, and a French lab finds toxins in vats

Esther Mobley
Posted: August 27, 2014

Alcohol abuse in middle age could lead to dementia later in life, asserts a new paper from researchers at the University of Exeter in the United Kingdom and published in the American Journal of Geriatric Psychiatry. Previous investigations have suggested that current levels of alcohol consumption can influence dementia risk, but no study had examined whether alcohol use disorders (AUDs) affect long-term memory impairment.

Researchers looked at 6,542 people in the Health and Retirement Study, a nationally representative study of middle-aged adults in the U.S. during a period of 19 years. At baseline and follow-up examinations, subjects self-reported their alcohol risk factors, and memory was assessed using word-recall tests.

"History of AUDs more than doubled the odds of memory impairment," the authors wrote. These findings did not change when adjusted for potentially mediating factors such as hypertension, cardiovascular disease and head injury.

Although the study did not address why alcohol might affect memory, the authors suggest several factors may be at play. "Excessive alcohol consumption inhibits the function of glutaminergic cells," affecting the function of neurotransmitters, Dr. Iain Lang, a study coauthor, told Wine Spectator. Lang added that alcohol can increase the release of free radicals, which damage cell membranes. Heavy consumption of wine, beer and spirits may have distinct effects on long-term memory, but this study did not distinguish among alcohol types.

For those who drink moderately, the news is sunnier. "Most studies have found a beneficial effect of moderate drinking on memory and cognition in later life," said Lang. "It is possible that any damaging effects of alcohol are outweighed, at moderate levels of consumption, by beneficial effects on the blood supply to the brain."

Could wine be bad for your heart?

The potential of red wine to mitigate the risk of heart disease has been confirmed by many studies in the past, but new research suggests alcohol may have a negative effect on one function of the human heart: your heartbeat. Alcohol consumption, even in light to moderate amounts, appears to be associated with atrial fibrillation (AF), an abnormal heartbeat or flutter that increases the risk of stroke, heart failure and dementia, according to a study published in the Journal of the American College of Cardiology.

Researchers from the Karolinska Institute in Sweden took their data from the Cohort of Swedish Men and the Swedish Mammography Cohort, two large-scale studies. Among the 79,019 subjects (none of whom had AF at baseline), there were 7,245 cases of AF reported over 12 years of follow up. Subjects self-reported their alcohol consumption by volume and type.

The authors found that the more one drank, the greater the likelihood of developing AF. Compared with subjects who reported having less than one drink per week, those who drank 15 to 21 drinks per week increased their risk of AF by 14 percent; those who drank in excess of 21 drinks per week, 39 percent.

Spirits tended to have the greatest impact on the risk of AF, with wine also increasing risk; beer did not. This may have to do with the respective alcohol levels of the beverages. The authors point to other findings that "chronic alcohol ingestion leads to depression of heart function," as well as atrial electromechanical delays in otherwise healthy men. Higher alcohol content, therefore, may play a role in AF development.

Potentially toxic compound found in some French wines

From sulfites to egg whites to isinglass, today's wine lover is acutely aware of what goes into the wine she drinks. Few, however, are likely aware of plasticizers used to coat tanks at wineries. Now a study from France reports that the coatings of many wine vessels contain compounds called phthalates, some of which, at high enough concentrations, can be toxic. The study also found that these phthalates are migrating into some wines and spirits in potentially alarming quantities.

"Phthalates are universally present in our environment," Pascal Chatonnet, director of Laboratoire Excell and an author of the paper, told Wine Spectator. The compounds are "extensively used in the plastic industry to improve the physical and mechanical properties of plastic products." Most types and concentrations of phthalates are perfectly safe, but in the past, toxic phthalates were more commonly used. In many countries, these dangerous phthalates have been banned for years.

Past studies on animals indicate that potential dangers from phthalates could include malformations of male sex organs and an increased risk of certain types of cancers.

If the dangerous phthalates have been off the market for years, why look into the problem now? "China has stopped this year the importation of some wines and spirits" because of their phthalate content, Pascal explained. Pascal and his team decided to do a quick survey of the situation in France and identify the main sources of phthalate residues in contact with wines and spirits.

For the study, Chatonnet and his colleagues examined 100 wine samples from all over France and 30 samples of grape spirits from southwest France. Of the 13 phthalate compounds targeted, only three were found in significant quantities: dibutyl phthalate (DBP), diethylhexyl phthalate (DEHP) and butyl benzyl phthalate (BBP). They found that 17 percent of the samples contained no detectable quantity of any phthalates; 19 percent contained non-quantifiable traces. Just 15 percent of samples contained DEHP and BBP, but a surprising 59 percent showed significant quantities of DBP.

The E.U. lists DBP, DEHP and BBP as toxic for reproduction and prohibits their use in certain products, including children's toys, cosmetics and implantable medical devices. In the United States, the Consumer Products Safety Commission (CPSC) has likewise banned their use in toys. (In American manufacturing, DBA has also been used in textiles, food packaging, dental materials and cosmetics, according to the Occupational Safety and Health Administration.)

The EPA continues to investigate the potential effects of these phthalates, and has added them to a list of "chemicals that present or may present an unreasonable risk of injury to health or the environment." In animal studies, DBP in particular has been found to cause a condition similar to human testicular dysgenesis syndrome, and in human trials, both prenatal and adult exposure to DBP has been linked to limited reproductive function.

The scientists also examined the polymer-based items in winemaking facilities that might be responsible for the transmission of phthalates to beverages—such as vats, pumps, hoses, gaskets and tanks. While several of these materials showed significant phthalate concentrations, Chatonnet and his coauthors concluded that "the epoxy resin coatings used on vats represented the major source."

Alcohol can increase the extraction of phthalates, so spirits were likely to contain larger amounts of the compounds. Chatonnet said the risk of "a glass of wine is nothing in comparison with some other products." He noted that several years ago, the soft-drink industry in the E.U. stopped using bisphenol, a product often used in epoxy resin alongside phthalates, forcing producers to manufacture their cans differently.

Chatonnet urges wineries not to use vats or other polymer materials that were coated more than 10 years ago; many of these, made with phthalates that were later banned, have a high contamination potential. His team is also working to develop a preparation that could be applied to materials to eliminate their risk of phthalate migration.

Paul Jennings
Malaysia —  August 27, 2014 10:55pm ET
A question about the dementia study: what is their definition of "moderate", "heavy", and "excessive" alcohol consumption as referenced in the article?
Esther Mobley
New York, NY —  August 28, 2014 11:07am ET
Paul,

The University of Exeter study measured whether people had alcohol use disorders (AUDs), rather than measuring volume of regular alcohol consumption. The AUDs were assessed based on a questionnaire called the CAGE instrument, which screens for alcohol dependence. It consists of questions such as "Have you ever taken a drink first thing in the morning to steady your nerves or get rid of a hangover?" The authors used the results from the questionnaire to determine whether someone had a history of alcohol abuse, and then they measured that against performance on the cognitive function tests.

The study did not examine the effects of moderate alcohol consumption. When we spoke to Dr. Iain Lang, he cited previous research that had found beneficial effects of moderate drinking on memory. Similarly, the claim that "heavy drinking may have distinct effects on long-term memory" is based on the authors' previous knowledge of this topic, but was not taken up directly in this study.

The definitions of light, moderate and heavy drinking can range widely among scientific studies, which can be very confusing. You're right to point out that when we're talking about the effects of certain levels of alcohol consumption, it's important to be as specific as possible.

Esther Mobley
Assistant editor

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