International Scientific Forum on Alcohol Research has supported the Draft Proposal released a month ago by the United States Dietary Guidelines for 2010, with its members endorsing it as balanced and accurate and observing that it does not appear to critically appraise the literature it has used but only reports it.
Advertisement
|
 |
Some members commented that rather than just focusing on warnings against heavy drinking, the new Guidelines appear to take into account the large amount of recent epidemiologic and experimental data that support some potential beneficial health effects of moderate drinking.
Most Forum members agreed that the draft is remarkably balanced. The Committee largely agreed upon the definition of moderation as "low-risk" drinking, as responses to alcohol may relate to medications, disease, being underage, driving, pregnancy, etc. It also indicated a strong need for further investigations focused on moderate drinking and healthy lifestyle.
Here are some of the comments on the important issues which are a part of the Guidelines:
Cancer: Other than the known marked increase in risk of upper aero-digestive cancers from heavy alcohol use, a primary concern has been an increase in the risk of breast cancer among women, even they drink small to moderate amounts of wine and alcohol. This means that young and middle-aged women may have no cardiovascular benefits to expect from alcohol consumption, but an increased risk from breast cancer. This needs to be seen from the proper perspective .
The Diet Cancer Report shows a very slight increase in breast cancer risk with alcohol intake-this would not be considered clinically important in most experimental studies. The same amount of alcohol associated with breast cancer is "protective" for cardiovascular disease and total mortality. Thus, it is important to have a balanced perspective, not only acting in fear facing adverse effects, but by also accounting for beneficial effects of moderate drinking on other conditions.
Women should not be scared off from a daily drink in fear of breast cancer only to thereby lose the much greater health benefits accorded the cardiovascular system.
Diabetes: As stated by the Guidelines Committee, many studies have shown lower risk of type 2 diabetes for moderate drinkers in comparison with abstainers. A recent meta-analysis by Pietraszek in 2010 concluded that light to moderate alcohol consumption seems to reduce the risk of type 2 diabetes by 30%, while heavy drinkers have the same or higher risk than total abstainers. Crandall Study in 2009 has also shown that pre-diabetics who consume alcohol are at lower risk of developing diabetes. The analysis was from the Diabetes Prevention Program, involving patients from 27 centers throughout the US.
Another recent paper by Joosten in 2010 showed that moderate drinking considerably lowered the risk of developing type 2 diabetes even among subjects who are otherwise following a healthy lifestyle with the authors suggesting that moderate drinking should be considered as a complement, and not as an alternative, to other healthy lifestyle habits that lower the risk of chronic diseases such as diabetes and coronary heart disease.
Hypertension and stroke: A recent meta-analysis by Patra in 2010 supported earlier reports on the relation of alcohol drinking to stroke. These investigators found a dose-response relationship for hemorrhagic stroke with a monotonically increasing risk for increasing consumption, whereas ischemic stroke showed a curvilinear relationship, with a protective effect of alcohol for low to moderate consumption and an increased risk for higher exposure. The authors concluded that their results indicate that heavy alcohol consumption increases the relative risk of any stroke while light or moderate alcohol consumption may be protective.
Total mortality: A large number of recent papers relate alcohol consumption to mortality. The findings are very consistent in showing that moderate drinkers are at lower risk of both incidence and mortality from many of the disease of ageing, as well as for total mortality risk.
The Forum suggests that the Guidelines Committee should comment on definitions of moderate drinking. Rehm and others, reporting in 2007 in a report on the net effects on mortality of alcohol consumption in Canada had found that when binge drinkers were included in the moderate category, the net number of deaths associated with alcohol was increased due mainly to excess drinking outcomes in the young. When binge drinkers were excluded, the net effect was considerably fewer deaths. Emphasizing the differing health effects of binge drinking versus regular moderate consumption is an important message for the public, suggests Dr. Dr. Curt Ellison, co-Director of the Forum which submitted its comments on July 14. The final Guidelines which are declared every 5 years are expected to be announced officially by the year - end.
Cirrhosis: Excessive alcohol intake is a key factor in the development of hepatic cirrhosis. However, in a recent paper this year, Rehm et al describe a J or U-shaped curve relating the use of alcohol to the risk of cirrhosis. For light drinking, these authors state that for women in morbidity studies, one to two drinks daily had virtually the identical risk as lifetime abstention. They also state that relative to lifetime abstainers, men who consumed one to two drinks per day had lower risk of liver cirrhosis.
Alcohol and weight gain: In addition to many studies in recent years showing that moderate drinking is not associated with excess weight gain was a recent report by Wang et al (2010). Women consuming between 5 and 30 grams of alcohol per day- up to about 2.5 US drinks, were found to have a much lower risk of becoming overweight or obese, with the risk about 30% lower for those averaging 15 grams of alcohol per day or more than it was for non-drinkers.
These findings support limited previous research suggesting that women gain less weight if they consume alcohol than if they are non-drinkers, although the mechanisms for such an effect remain unclear. For unknown reasons, men may not show the same inverse association between alcohol intake and body size. Overall, most observational studies provide no evidence that light-to-moderate drinking leads to increases in weight for women who are initially of normal body size.
Interestingly, an earlier study by Breslow in 2005 reported that among 46,000 non smokers, drinking more per occasion increased weight, while drinking smaller amounts of alcohol more frequently was associated with lower body mass, suggesting that small amounts of alcohol on a frequent basis is associated with the healthier outcome.
Alcohol and cognitive decline: Many previous studies have suggested that moderate drinking delays the decline in cognitive functioning associated with ageing. In a recent case-control study from Spain on the effects of smoking and alcohol use on the risk of Alzheimer’s Disease (AD), Garcia et al (2010) found that the risk was unaffected by any measure of tobacco consumption.
On the other hand, alcohol consumers showed a 47% lower risk of AD than never consumers, with effects mainly among women and among never smokers. No differences were noted by type of alcoholic beverage consumed. The authors conclude that mean daily total consumption of alcohol showed increasingly protective dose-response relationships in women.
Alcohol and coronary heart disease (CHD): Statin therapy has changed the natural history of CHD by reversing, stabilizing, and/or inhibiting plaque burden in the coronary arteries and elsewhere. Epidemiologic studies suggest that moderate alcohol drinking has a substantial beneficial effect, possibly second only to Statin therapy, in persons at risk.
.
Alcohol and bone health: A number of recent prospective studies have confirmed that moderate alcohol consumption is positively associated with bone mineral density (BMD). While studies in the young indicate an increase in the risk of falls above a certain level of intake, most studies in the elderly actually show a lower risk of falls and fractures among moderate drinkers in comparison with non-drinkers.
The special properties of beer might deserve a mention because of the presence of Si which may contribute to beneficial effects on bone, besides the alcohol benefits.
Alcohol and lactation: While heavy or binge drinking is never encouraged for pregnant women, prospective studies have not clearly established a link between low-moderate alcohol consumption in pregnancy and birth defects. As far as lactation is concerned, the section states that alcohol consumption has not been associated with higher rates of the neonate breast milk consumption, but that has been refuted in beer-consuming populations.
The Forum has also touched upon additional topics not emphasized in the Guidelines.
The striking differences between binge drinking and regular moderate consumption, need to be emphasized. There should also be an advisory to consume wine or alcohol with food to slow alcohol absorption since the available Data suggest that the presence of food in the stomach can slow the absorption of alcohol and thereby mitigate the associated rise in blood alcohol concentration.
Polyphenols vs. non-alcoholic substances: The Guidelines do not clearly demarcate the health benefits of red wine and it appears to suggest that ethanol is the common denominator. On the other hand, studies are increasingly demonstrating mechanisms by which non-alcoholic components of some beverages can lower cardiovascular risk. There have been hundreds of experimental studies demonstrating beneficial effects of resveratrol and other polyphenols including recent publications in2010by Huang et al, Ungvari et al and Je et al which have demonstrated protective effects against cardiovascular dysfunction from procyanidins found in red wine.
Some of the confusion about whether beer and red wine are similar or different in terms of ability to reduce CVD risk is certainly due to the variable level of phytochemicals (irrespective of the amount of alcohol consumed). Red wine can be rich source of flavonoids, but this is often not the case with modern-style fruity red wines with soft tannins. Wine with not enough maceration to extract all the flavonoids will have lower amounts of such substances.
Beer can also be a fairly good source of flavonoids, but only if there is a good proportion of hops used in the brew, and filtration is not used as part of the process which is a standard practice for most large breweries. Consequently, it is difficult to distinguish the benefit of drinking red wine over beer without knowing more about individual drinking habits, or having some idea of the characteristic of products consumed in the population under study.
Guidelines should take into account experimental evidence from studies which almost always indicate that wine or wine constituents provide additional protection than just alcohol. From a non-epidemiological point of view, the alcoholic beverages have both a hormetic component (due to alcohol) and a nutraceutical effect (due to phytochemicals).
A number of clinical trials in humans are now being done and findings link the mechanism of cardiovascular protection with the regular consumption of red wine.
The Forum also focuses on the need for Research on risks and benefits of moderate drinking .
Considerable differences of opinion were found among Forum members regarding advice regarding alcohol consumption before middle age. For adolescents, young adults and young middle-aged people, there may be no health benefit from alcohol drinking according to some. Other Forum members feel that the risk of cardiovascular disease becomes real at 55, but it has been generated by a series of events in previous decades. The concept that a good diet starting from a young age can mitigate this process and reduce the risks in later years and this should be a fundamental principle of dietary guidelines. There is a need for pertinent data on light-to-moderate drinking in younger adults, as they are drinking anyway without recommendations, concludes the panel.
For more information or a dialogue on the subject, you may correspond with Dr. Ellison at ellison@bu.edu . A copy to us will be appreciated as it would help us bring further relevant information to our readers, especially in the USA and India where a lone study by a team or researchers at AIIMS seems to claim that alcohol has negative effect on Indians even when taken in small quantities.
For AIIMS study, visit http://www.indianwineacademy.com/item_3_371.aspx
For an earlier related article, visit http://www.indianwineacademy.com/item_1_391.aspx
|
