Moderate Alcohol Consumption - Miscellaneous Benefits

Red wine could help you burn fat

Drinking red grape juice or wine - in moderation - could improve the health of overweight people by helping them burn fat better, according to a new study coauthored by an Oregon State University researcher.

The findings suggest that consuming dark-colored grapes, whether eating them or drinking juice or wine, might help people better manage obesity and related metabolic disorders such as fatty liver.

Neil Shay, a biochemist and molecular biologist in OSU's College of Agricultural Sciences, was part of a study team that exposed human liver and fat cells grown in the lab to extracts of four natural chemicals found in Muscadine grapes, a dark-red variety native to the southeastern United States.

One of the chemicals, ellagic acid, proved particularly potent: It dramatically slowed the growth of existing fat cells and formation of new ones, and it boosted metabolism of fatty acids in liver cells.

These plant chemicals are not a weight-loss miracle, cautions Shay. "We didn't find, and we didn't expect to, that these compounds would improve body weight," he said. But by boosting the burning of fat, especially in the liver, they may improve liver function in overweight people.

"If we could develop a dietary strategy for reducing the harmful accumulation of fat in the liver, using common foods like grapes," Shay said, "that would be good news."

The study, which Shay conducted with colleagues at the University of Florida and University of Nebraska, complements work with mice he leads at his OSU laboratory. In one 2013 trial, he and his graduate students supplemented the diets of overweight mice with extracts from Pinot noir grapes harvested from Corvallis-area vineyards.

Some of the mice were fed a normal diet of "mouse chow," as Shay calls it, containing 10 percent fat. The rest were fed a diet of 60 percent fat - the sort of unhealthy diet that would pile excess pounds on a human frame.

"Our mice like that high-fat diet," said Shay, "and they overconsume it. So they're a good model for the sedentary person who eats too much snack food and doesn't get enough exercise."

The grape extracts, scaled down to a mouse's nutritional needs, were about the equivalent of one and a half cups of grapes a day for a person. "The portions are reasonable," said Shay, "which makes our results more applicable to the human diet."

Over a 10-week trial, the high-fat-fed mice developed fatty liver and diabetic symptoms - "the same metabolic consequences we see in many overweight, sedentary people," Shay said.

But the chubby mice that got the extracts accumulated less fat in their livers, and they had lower blood sugar, than those that consumed the high-fat diet alone. Ellagic acid proved to be a powerhouse in this experiment, too, lowering the high-fat-fed mice's blood sugar to nearly the levels of the lean, normally fed mice.

When Shay and his colleagues analyzed the tissues of the fat mice that ate the supplements, they noted higher activity levels of PPAR-alpha and PPAR-gamma, two proteins that work within cells to metabolize fat and sugar.

Shay hypothesizes that the ellagic acid and other chemicals bind to these PPAR-alpha and PPAR-gamma nuclear hormone receptors, causing them to switch on the genes that trigger the metabolism of dietary fat and glucose. Commonly prescribed drugs for lowering blood sugar and triglycerides act in this way, Shay said.

The goal of his work, he added, is not to replace needed medications but to guide people in choosing common, widely available foods that have particular health benefits, including boosting metabolic function.

"We are trying to validate the specific contributions of certain foods for health benefits," he said. "If you're out food shopping, and if you know a certain kind of fruit is good for a health condition you have, wouldn't you want to buy that fruit?"

Light-to-moderate alcohol intake, especially of wine, may be more likely to protect against, rather than promote, weight gain

A paper from Spain provides an extensive review of the association between alcohol consumption and body weight.

The study includes descriptions of cross-sectional and prospective studies (and a few small intervention studies) among subjects who varied in age (adolescence to old age), culture (from Americans and Europeans to Asians), and principal type of beverage consumed and pattern of drinking. The authors state that many of the studies they reviewed appear to be contradictory in their results. However, based on their review, they conclude that "as positive associations between alcohol and weight gain were mainly found in studies with data on higher levels of drinking, it is possible that an effect on weight gain or abdominal adiposity may only be experienced by heavy drinkers." A second conclusion of the authors is that "the type of alcoholic beverage might play an important role in modifying the effect of alcohol consumption on weight gain," with more favourable effects generally seen among consumers of wine. A formal meta-analysis is not provided.

The overall conclusions of the authors is that it is currently unclear whether alcohol consumption is a risk factor for weight gain, but if so it appears to occur mainly among heavier drinkers. They also state that "light-to-moderate alcohol intake, especially of wine, may be more likely to protect against, rather than promote, weight gain."

International Scientific Forum on Alcohol Research reviewers agreed with most of the conclusions of the authors, especially that current data do not clearly indicate if moderate drinking increases weight; further, the biologic mechanisms relating alcohol to changes in body weight are not well understood. The Forum review comments on the strong protective effects of moderate drinking on the risk of metabolic syndrome and diabetes, both of which relate to increasing obesity. Some studies suggest that even very obese people may be at lower risk of diabetes if they are moderate drinkers. Forum members also reviewed some of the distinctive mechanisms by which alcohol is metabolized in the body (it provides calories that are rapidly absorbed and are not stored in fat) that could explain differences in the effects of calories from alcohol and from other foods.

Women who drink moderately appear to gain less weight than nondrinkers

Normal-weight women who drink a light to moderate amount of alcohol appear to gain less weight and have a lower risk of becoming overweight and obese than non-drinkers, according to a report in the March 8, 2010 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

More than half of American adults drink alcoholic beverages, according to background information in the article. Alcohol contains about 7 calories per gram (with approximately 28 grams per ounce) and alcohol drinking may possibly lead to weight gain through an imbalance of energy consumed and energy burned. However, research has not consistently provided evidence that consuming alcohol is a risk factor for obesity.

Lu Wang, M.D., Ph.D., of Brigham and Women's Hospital, Boston, and colleagues studied 19,220 U.S. women age 39 or older who had a body mass index (BMI) in the range classified as normal (18.5 to 25). On an initial questionnaire, participants reported how many alcoholic beverages they typically drank per day. A total of 7,346 (38.2 percent) reported drinking no alcohol; 6,312 (32.8 percent) drank less than 5 grams; 3,865 (20.1 percent) drank 5 to less than 15 grams; 1,129 (5.9 percent) drank 15 to less than 30 grams; and 568 (3 percent) drank 30 grams per day or more.

Over an average of 13 years of follow-up, women on average gained weight progressively. Women who did not drink alcohol at all gained the most weight, with weight gain decreasing as alcohol intake increased. A total of 7,942 (41.3 percent) women who initially had normal weight become overweight or obese (BMI of 25 or higher), including 732 (3.8 percent) who become obese (BMI of 30 or higher). Compared with women who did not drink at all, those who consumed some but less than 40 grams per day of alcohol were less likely to become overweight or obese. Women who drank 15 to less than 30 grams per day had the lowest risk, which was almost 30 percent lower than that of non-drinkers.

"An inverse association between alcohol intake and risk of becoming overweight or obese was noted for all four types of alcoholic beverages [red wine, white wine, beer and liquor], with the strongest association found for red wine and a weak yet significant association for white wine after multivariate adjustment," the authors write.

Occasional drinking associated with decrease in vision impairment

Occasional drinking is associated with a reduced risk of developing visual impairment, according to a study published online this month in Ophthalmology, the journal of the American Academy of Ophthalmology.

Visual impairment – sight loss often caused by eye disease, trauma, or a congenital or degenerative condition that cannot be corrected with glasses or contact lenses – is associated with a poorer quality of life and, when severe, loss of independence. In 2020, the number of people in the United States with visual impairment is projected to increase to at least four million. This is a 70 percent increase from 2000 and is due to the growing aging population and prevalence of age-related eye diseases.

To help determine ways to decrease the growing burden of visual impairment, researchers from the University of Wisconsin School of Medicine and Public Health examined the relationships between the incidence of visual impairment and three modifiable lifestyle behaviors: smoking, drinking alcohol and staying physically active. The research was conducted as part of the Beaver Dam Eye Study, a long-term population-based cohort study from 1988 to 2013 of nearly 5,000 adults aged 43 to 84 years.

The researchers found that over 20 years visual impairment developed in 5.4 percent of the population and varied based on lifestyle behaviors as follows:

Occasional drinkers (those who have consumed alcohol in the past year, but reported fewer than one serving in an average week): Over 20 years, 11 percent of non-drinkers (people who have not consumed alcohol within the past year) developed visual impairment while 4.8 percent of occasional drinkers did so. After adjustment for age, these figures show a 49 percent decrease in odds of developing visual impairment in those who were occasional drinkers compared to those who consumed no alcohol.

Alcohol consumption may decrease risk of ALS

A population-based case-control study of the rare but devastating neurological disease amyotrophic lateral sclerosis (ALS) has shown that the risk of such disease is increased among smokers, as has been shown previously. However, surprisingly, the risk of ALS was found to be markedly lower among consumers of alcohol than among abstainers.

Forum reviewers thought that this was a well-done and important paper, as it is a population-based analysis, with almost 500 cases of ALS, a very large number of cases for this rare disease. They were especially struck by the magnitude of the difference in risk of ALS between alcohol consumers and never drinkers: the risk among drinkers was about one half that of non-drinkers.

Said one reviewer: "The results in this study are astonishing in this mysterious disease. One should expect that alcohol, as a toxic agent, rather should contribute to the development of ALS than to prevent it. The lower risk among drinkers compared with non-drinkers is remarkable."

Modest Alcohol Consumption Lowers Risk of Liver Disease

People with nonalcoholic fatty liver disease (NALFD) who consume alcohol in modest amounts – no more than one or two servings per day – are half as likely to develop hepatitis as non-drinkers with the same condition, reports a national team of scientists led by researchers at the University of California, San Diego School of Medicine.

The findings are published in the April 19, 2012 online issue of The Journal of Hepatology.

NALFD is the most common liver disease in the United States, affecting up to one third of American adults. It’s characterized by abnormal fat accumulation in the liver. The specific cause or causes is not known, though obesity and diabetes are risk factors. Most patients with NAFLD have few or no symptoms, but in its most progressive form, known as nonalcoholic steatohepatitis or NASH, there is a significantly heightened risk of cirrhosis, liver cancer and liver-related death.

NALFD is also a known risk factor for cardiovascular disease (CVD). Patients with NAFLD are approximately two times more likely to die from coronary heart disease than from liver disease. The study’s authors wanted to know if the well-documented heart-healthy benefits of modest alcohol consumption outweighed alcohol’s negative effects.

“We know a 50-year-old patient with NAFLD has a higher risk of CVD,” said Jeffrey Schwimmer, MD, associate professor of clinical pediatrics at UC San Diego, director of the Fatty Liver Clinic at Rady Children’s Hospital-San Diego and senior author. “Data would suggest modest alcohol consumption would be beneficial (in reducing the patient’s CVD risk) if you don’t take liver disease into account. When you do take liver disease into account, however, the usual medical recommendation is no alcohol whatsoever.”

Schwimmer and colleagues discovered that the benefits of modest alcohol consumption were compelling, at least in terms of reducing the odds of patients with NAFLD from developing more severe forms of the disease. Patients with NASH are 10 times more likely to progress to cirrhosis, the final phase of chronic liver disease. Cirrhosis is the 12th leading cause of death in the U.S., killing an estimated 27,000 Americans annually.

“Our study showed that those people with modest alcohol intake – two drinks or less daily – had half the odds of developing NASH than people who drank no alcohol,” said Schwimmer. “The reasons aren’t entirely clear. It’s known that alcohol can have beneficial effects on lipid levels, that it increases ‘good’ cholesterol, which tends to be low in NAFLD patients. Alcohol may improve insulin sensitivity, which has a role in NAFLD. And depending upon the type of alcohol, it may have anti-inflammatory effects.”

The study also found that in patients with NAFLD, modest drinkers experienced less severe liver scarring than did lifelong non-drinkers.

The study did not evaluate the effects of different types of alcohol, such as beer or spirits. Schwimmer said to do so would require a much larger study. Also, the study’s findings do not apply to children. All of the participants in the study were age 21 and older.

The current paper is based on analyses of 600 liver biopsies of patient’s with NAFLD by a national panel of pathologists who had no identifying clinical information about the samples. The study excluded anyone who averaged more than two alcoholic drinks per day or who reported consuming five or more drinks in a day (binge-drinking) at least once a month. All of the patients were at least 21 years of age. Schwimmer said the findings indicate patients with liver disease should be treated individually, with nuance.

“For a patient with cirrhosis or viral hepatitis, the data says even small amounts of alcohol can be bad. But that may not be applicable to all forms of liver disease. Forty million Americans have NAFLD. Physicians need to look at their patient’s overall health, their CVD risk, their liver status, whether they’re already drinking modestly or not. They need to put all of these things into a framework to determine risk. I suspect modest alcohol consumption will be an appropriate recommendation for many patients, but clearly not all.”

Alcohol can reduce asthma risk

Drinking alcohol in moderate quantities can reduce the risk of asthma, according to Danish researchers.

The study, presented at the European Respiratory Society's Annual Congress in Amsterdam, found that drinking 1-6 units of alcohol a week could reduce the risk of developing the condition.

The research examined 19,349 twins between the ages of 12 and 41 yrs of age. All participants completed a questionnaire at the start and end of the study to compare alcohol intake with the risk of developing asthma over 8 yrs.

The results showed that the lowest risk of asthma was seen in the group which had a moderate intake of alcohol, as less than 4% of those who drank 1-6 units per week developed asthma.

The highest risk of asthma was observed in people who drunk rarely or never, as they were 1.4-times more likely to develop the condition. Heavy drinkers also had an increased risk of asthma development and were 1.2-times more likely to develop asthma.

The results also suggested that a preference for beer drinking was associated with an increased risk of asthma when compared with no preference.

Previous studies have found a link between excessive intake of alcohol and asthma attacks; however, this is the first study of its kind to show a link between alcohol intake and the onset of asthma for adults over a long period of time.

Moderate alcohol consumption lowers the risk of metabolic diseases

With the emergence of an epidemic of obesity and type 2 diabetes (DM) throughout the world, the association of lifestyle habits that may affect the risk of metabolic diseases is especially important. Most prospective studies have shown that moderate drinkers tend to have about 30% lower risk of developing late onset diabetes than do non-drinkers, and moderate drinkers also tend to be at lower risk of developing metabolic syndrome (MS). A cross-sectional analysis of 6172 subjects age 35 -75 in Switzerland related varying levels of alcohol intake to the presence of DM, MS, and an index of insulin resistance (HOMA-IR).

Study findings: In multivariate analysis, the prevalence of the metabolic syndrome, diabetes and mean HOMA-IR decreased with low-risk drinking and increased with high-risk drinking. Adjusted prevalence of the metabolic syndrome was 24% in non-drinkers, 19% in low-risk, 20% in medium-to-high-risk and 29% in very-high-risk drinkers. Adjusted prevalence of diabetes was 6.0% in non-drinkers, 3.6% in low-risk, 3.8% in medium-to-high-risk and 6.7% in very-high-risk drinkers. These relationships did not differ according to beverage types.

Moderate drinkers also had the lowest weight, tryglycerides, and blood pressure. All drinkers had higher HDL-cholesterol values (that is 'good cholesterol) than did non-drinkers.

Forum comments:

Metabolic syndrome is the name given to a so called 'lifestyle disease', where patients exhibit multiple medical problems including high blood pressure, late on set diabetes, and high cholesterol.

The strengths of this paper include being population-based and having a large number of subjects who reported that they consumed 14 or more drinks/week. Also, there was a good percentage (27%) of subjects reporting no alcohol intake during the one week of assessment used for classifying subjects. Another strength is the careful confirmation of drinking status with state-of-the-art laboratory tests. In multivariate analysis, the prevalence of the metabolic syndrome, diabetes and mean HOMA-IR decreased with low-risk drinking and increased with high-risk drinking. No differences were noted according to the type of beverage consumed.

Drinking Wine Protects Skin From Radiation

Drinking wine while undergoing radiation treatment for breast carcinoma may reduce the incidence of skin toxicity in breast cancer patients, according to a study in the August,2009 issue of the International Journal of Radiation Oncology*Biology*Physics, the official journal of the American Society for Radiation Oncology (ASTRO).

Preventing radiation therapy-induced side effects is an important part of a patient’s cancer treatment management. Several medications are available to help protect healthy organs from the effects of radiation, but they are often expensive, have side effects themselves and can provide protection to tumor cells as well as healthy cells.

Researchers at the Department of Oncology and the Center for High Technology Research and Education in Biomedical Sciences at Catholic University in Campobasso, Italy, the Catholic University Department of Radiotherapy in Rome, Italy, and at the National Research Council’s BioMatLab in Rome, Italy, conducted this study to determine if the natural antioxidants in wine would provide a radioprotective effect in preventing acute skin toxicity in patients undergoing radiation therapy after conservative surgery for breast carcinoma.

The study consisted of 348 patients divided into three groups based on the dose/fractionation scheme used. Patients consuming wine had a lower incidence of Grade 2 or higher acute toxicity than those who did not consume alcohol. Patients who drank one glass of wine per day had a 13.6 percent incidence of skin toxicity versus a 38.4 percent incidence in patients who did not drink wine. “If wine can prevent radiotherapy-induced toxicity without affecting antitumor efficacy, as we observed, it also has the potential to enhance the therapeutic benefit in cancer patients without increasing their risk of serious adverse effects,” Vincenzo Valentini, M.D., a radiation oncologist at Catholic University in Rome, Italy, one of the study authors, said. “The possibility that particular dietary practices or interventions can reduce radiation-induced toxicity is very intriguing.”

Moderate consumption of alcohol can improve immune response to vaccination

It's the time of year when many of us celebrate the holidays with festive foods and drinks, including alcohol. No better time then to ask if it is true, as is widely held, that moderate consumption of alcohol is beneficial to health.

A research team led by an immunologist at the University of California, Riverside now has data that could put the question to rest. The researchers found that moderate alcohol consumption could bolster our immune system, and potentially our ability to fight infections.

The finding, published in the journal Vaccine, can help lead to a better understanding of how our immune system works. It can also pave the way for potentially new interventions to improve our ability to respond to vaccines and infections, benefiting vulnerable populations, such as the elderly for whom the flu vaccine, for example, has been found to be largely ineffective.

"It has been known for a long time that moderate alcohol consumption is associated with lower mortality," said Ilhem Messaoudi, an associate professor of biomedical sciences in the School of Medicine and the lead author of the research paper. "Our study, conducted on non-human primates, shows for the first time that voluntary moderate alcohol consumption boosts immune responses to vaccination."

Messaoudi did the bulk of the research while she was an assistant professor at the Oregon Health and Science University, where she collaborated with Kathleen Grant, a professor of behavioral neuroscience and a coauthor on the research paper. She joined UC Riverside earlier this year.

To study the impact of alcohol consumption on the immune system, the researchers trained 12 rhesus macaques to self-administer/consume alcohol on their own accord. The team first vaccinated the animals (against small pox) and then allowed them to access either 4 percent ethanol (the experimental group) or calorically matched sugar water (the control group). All the animals also had open access to water as an alternative fluid, as well as food. The researchers then proceeded to monitor the animals' daily ethanol consumption for 14 months. The animals were vaccinated one more time, seven months after the experiment began.

The research team found that over nine months of the animals' ethanol self-administration, mean daily ethanol intake varied markedly among them.

"Like humans, rhesus macaques showed highly variable drinking behavior," Messaoudi said. "Some animals drank large volumes of ethanol, while others drank in moderation."

The animals' voluntary ethanol consumption segregated them into two groups: animals in the first group were those that consumed more alcohol, averaged a blood ethanol concentration (BEC) greater than the legal limit of 0.08 percent and were therefore designated 'heavy drinkers'; animals in the second group consumed less alcohol, averaged a BEC of 0.02-0.04 percent and were designated 'moderate drinkers.'

"Prior to consuming alcohol, all the animals showed comparable responses to vaccination," Messaoudi said. "Following exposure to ethanol, however, the animals showed markedly different responses after receiving the booster vaccine."

The researchers found that, as expected based on human epidemiological data, those animals that drank the largest amounts of alcohol showed greatly diminished vaccine responses compared to the control group. In contrast, animals that drank moderate amounts of ethanol displayed enhanced vaccine responses.

"These surprising findings indicate that some of the beneficial effects of moderate amounts of alcohol consumption may be manifested through boosting the body's immune system," Messaoudi said. "This supports what has been widely believed for some time: moderate ethanol consumption results in a reduction in all causes of mortality, especially cardiovascular disease. As for excessive alcohol consumption, our study shows that it has a significant negative impact on health."

Alcohol abuse kills 25,000 Americans annually and is one of the leading causes of preventable death in the country. Two thirds of U.S. adults consume approximately four drinks a week, considered to be a moderate amount by most consumers.

"If you have a family history of alcohol abuse, or are at risk, or have been an abuser in the past, we are not recommending you go out and drink to improve your immune system!" Messaoudi said. "But for the average person that has, say, a glass of wine with dinner, it does seem, in general, to improve heath, and cardiovascular function in particular, and now we can add the immune system to that list."

The study was carried out under strict accordance with the recommendations outlined in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health, the Office of Animal Welfare and the U.S. Department of Agriculture. The study was also approved by the Oregon National Primate Research Center Institutional Animal Care and Use Committee.

"Next, we plan to harness our observations made in this study to address bigger questions on the immune system, such as how can we boost our immune responses to vaccination, a particular challenge for our elderly," Messaoudi said.

Glass of Wine a Day May Ward Off Depression

In the same way that a little wine may be good for the heart, it might also help avoid depression, a Spanish study suggests.

So while drinking a lot of wine or other alcohol may be a sign of depression or other mental health problems, alcohol in moderation may benefit mental health, the study authors contend.

"One drink a day, preferentially wine, may help prevent depression," said lead researcher Dr. Miguel Martinez-Gonzalez, chair of the department of preventive medicine and public health at the University of Navarra, in Pamplona.

But several mental health experts not involved with the study had reservations about the findings. And the research only found an association between moderate drinking and emotional well-being; it didn't prove cause-and-effect.

Martinez-Gonzalez said he thinks the apparent benefit of wine in preventing depression may work the same way that moderate drinking helps prevent heart disease.

"Depression and heart disease seem to share some common mechanisms because they share many similar protective factors and risk factors," he said. However, he added that depression prevention is not a reason to start drinking.

"If you are not a drinker, please don't start drinking," he said. "If you drink alcohol, please keep it in the range of one or less drinks a day and consider drinking wine instead of other alcoholic beverages."

The report was published in the online journal BMC Medicine.

Tony Tang, an adjunct psychology professor at Northwestern University, in Evanston, Ill., said the new research "is consistent with other studies suggesting modest health benefits of very modest drinking."

But, Tang said other factors may be at work in the potential connection between wine and depression. He noted that compared to nondrinkers, those in the Spanish study who drank a moderate amount of wine were more likely to be married men who were also physically active.

Being single or divorced, living alone and being sedentary "are well-established risk factors of depression. Thus, perhaps the correlation between modest drinking and depression is a coincidence caused by these other known factors," he said.

"An adequate social life is the most important factor we know that protects people from depression," Tang said. "Perhaps not drinking is a sign of serious social isolation in Spain while drinking a glass of wine a day is simply a sign of having a normal social life."

For the study, researchers followed more than 5,500 light-to-moderate drinkers for up to seven years. All the participants were part of a large Spanish study on nutrition and cardiovascular health, and were between 55 and 80 years old.

None of the individuals had suffered from depression or had alcohol-related problems at the start of the study. Over seven years, with medical exams, interviews with dietitians and questionnaires, the researchers kept tabs on participants' mental health and lifestyle.

Wine was the most popular drink and participants who drank two to seven glasses a week were the least likely to suffer from depression, compared to nondrinkers.

These findings remained significant even after the researchers took factors such as smoking, diet and marriage into account.

Eva Redei, a distinguished professor in the department of psychiatry and behavioral sciences at the Feinberg School of Medicine at Northwestern University, in Chicago, also expressed doubts about the direct effect of wine on depression.

"Considering the increase of major depression in the age group examined in this study, the finding of protective effects of moderate alcohol consumption is intriguing," she said.

However, it raises more questions than answers. "Is moderate wine consumption related to increased socialization, decreased cardiovascular events, or as it seems, increased activity? These questions are not answered by this study, but the findings are definitely worth noticing," Redei said.

"Is it possible that 'in vino veritas' [in wine there's truth] reflects a bigger truth?" she asked.

Not just for the heart, red wine shows promise as cavity fighter

For anyone searching for another reason to enjoy a glass of red wine with dinner, here's a good one: A new study has found that red wine, as well as grape seed extract, could potentially help prevent cavities. They say that their report, which appearsed in ACS' Journal of Agricultural and Food Chemistry, could lead to the development of natural products that ward off dental diseases with fewer side effects.

M. Victoria Moreno-Arribas and colleagues explain that dental diseases are extremely common throughout the world. Cavities, periodontal disease and tooth loss affect an estimated 60 to 90 percent of the global population. The problems start when certain bacteria in the mouth get together and form biofilms, which are communities of bacteria that are difficult to kill. They form plaque and produce acid, which starts damaging teeth. Brushing, fluoride in toothpaste and water and other methods can help get rid of bacterial plaques, but the effects are limited. In addition, currently used antimicrobial rinses can change the color of the gums and alter taste, so people are less likely to use them for as long as they should. Some research has suggested that polyphenols, grape seed extract and wine can slow bacterial growth, so Moreno-Arribas' team decided to test them under realistic conditions for the first time.

They grew cultures of bacteria responsible for dental diseases as a biofilm. They dipped the biofilms for a couple of minutes in different liquids, including red wine, red wine without the alcohol, red wine spiked with grape seed extract, and water and 12 percent ethanol for comparison. Red wine with or without alcohol and wine with grape seed extract were the most effective at getting rid of the bacteria.

Red wine increases performance-enhancing hormone testosterone

Red wine and green and white tea could give athletes and players a boost in the sports arena by increasing the amount of performance-enhancing hormone testosterone in their bodies, according to researchers from London's Kingston University.

However not only could the beverages help them to trophy success, it could also allow them to beat anti-doping tests. A team led by Professor Declan Naughton, from the University's School of Life Sciences, found that and green and white tea might reduce the amount of testosterone excreted by the body, which could distort the findings of drug tests taken from urine samples.

Testosterone is a naturally-occurring steroid hormone present in both men and women. It can increase muscle mass, boost stamina and speed up recovery. Sportspeople, however, are prohibited from taking it, or a synthetic version of it, to try to gain a competitive edge.

Although red wine is not a banned substance away from the sports field, Professor Naughton's team has referred its findings to the World Anti-Doping Agency because of the newly-discovered side effect of potential change to the amount of testosterone in the body.

"Previous research has shown the effect over-the-counter anti-inflammatory drugs can have on enzymes," Professor Naughton explained. "Since many of these drugs are derived from plants, we decided to look at the effect particular foods and beverages can have on enzymes involved in testosterone excretion. We chose green tea and then red wine because both have a huge variety of natural molecules and we wanted to see if they affected the amount of testosterone excreted in urine."

"The catechins stop enzymes tagging molecules for excretion so the kidneys don't recognise them as needing to be removed and leave them circulating in the body," Professor Naughton explained. "We found that green and white tea could inhibit the enzyme by about 30 per cent. The levels of catechins in a strong cup of green tea matched those we used in our experiments."

The increased levels of testosterone from drinking green and white teas may provide a  boost. "It's like having extra testosterone without actually taking any," Professor Naughton said. "By not excreting it from the body, athletes could potentially increase their testosterone levels for improved performance.

The team found that a compound in red wine, known as quercetin, partially blocked the action of an enzyme called UGT2B17, which looks for testosterone and then sends a message to the kidneys to excrete it.

Professor Naughton stressed that the research had so far been conducted in test tube experiments and had yet to be trialled on humans. "A full clinical study would be needed to determine the effects on people but, if the same results were found, it would confirm that compounds in red wine can reduce the amount of testosterone in urine and give a boost to testosterone levels," he explained.

The effect of red wine on an individual would vary because of factors such as weight, fitness, health and diet, making it hard to estimate how much was needed to improve performance, Professor Naughton said.

Teetotallers are not exempt from the effects. In fact, the alcohol content of red wine has very little impact because non-alcoholic molecules are responsible for inhibiting testosterone excretion.

The team also found the results were the same for red wine extract in supplement form. The active compounds such as quercetin are found in many foodstuffs as well as supplements.

The findings have been published in leading international journal Nutrition.