Cholesterol, inflammation, blood pressure
Red wine contains over 500 different chemical substances. One class, called “polyphenols,” has been widely investigated for imparting the apparent antioxidant and anti-inflammatory effects of red wine.
Alcohol and polyphenols are thought to have several positive health impacts. One is a contribution to an increase in HDL-cholesterol or “good cholestrol” and a decrease in LDL-oxidation or “bad cholesterol.” They also contribute to a decrease in inflammation. They are thought to increase insulin sensitivity. And they are understood to improve blood pressure.
There is no consistent pattern when wine is compared to beer and spirits. Some report wine’s superiority in a reduction from IHD and mortality. Others report it for beer and spirits. Others suggest there is no difference. This suggests that alcohol and polyphenols both contribute to explaining the French paradox, in addition to lifestyle factors.
Despite the beneficial effects of wine and alcohol consumption, drinking is still a potential risk-factor for atrial fibrillation, the most-common “rhythm alteration” of the heart.
How much should you drink?
In much of the research, adverse effects were increasingly observed with excessive or binge-consumption of wine, while low-to-moderate intakes lowered IHD and mortality risks.
In response, various governing bodies have come forth with guidelines for alcohol consumption. These follow similar patterns, but vary remarkably by country and source. And the definition of “one standard drink” used in each guideline is highly variable, and discrepant between country borders. This causes great confusion. Readers should be wary of this when interpreting alcohol consumption guidelines.
The World Health Organization recommends low-risk alcohol consumption of no more than two standard drinks per day with at least two non-drinking days during the week. Here one standard drink is defined as 10 g of pure ethanol.
The American Heart Association recommends alcohol in moderation — less than or equal to one to two drinks per day for men and one drink per day for women. Here one drink is defined as 12 oz. of beer, 4 oz. of wine, 1.5 oz. of 80-proof spirits, or 1 oz. of 100-proof spirits.
The Dietary Guidelines for Americans 2015 – 2020 developed by the United States Department of Agriculture recommends a moderate consumption of alcohol. This equates to up to two standard drinks per day for men and one for women. Here, one standard drink is defined as 14 g of pure ethanol.
The Canadian Centre for Addiction and Mental Health guidelines recommend low-risk alcohol consumption — up to three drinks per day for men and two for women. One drink is defined as 12 oz. of 5 per cent beer, 5 oz. of 12 per cent wine, and 1.5 oz. of 40 per cent spirits.
Future research opportunities
Observational data around alcohol consumption and heart health suggests that a light-to-moderate intake, in regular amounts, appears to be healthy. However, when mathematical models have been applied to determine causation (an approach known as Mendelian randomisation) the results have been mixed.
Some studies have found light-to-moderate drinking beneficial, while others have reported long-term alcohol consumption to be harmful for the heart.
For doctors, it is quite clear what to recommend to patients when it comes to diet, exercise and smoking. Given the inconsistencies in the findings relating to alcohol, and wine specifically, recommendations for consumption are less obvious.
For wine drinkers too, definitive answers on wine and health remain elusive. There is, however, immense research potential in this area for the future.
And as all the guidelines say, one or two glasses of red wine tonight will be just fine.
Adrian Baranchuk is Professor of Medicine, Queen’s University, Ontario & Bryce Alexander is Medical Student, Queen’s University, Ontario & Sohaib Haseeb is student, Queen’s University, Ontario
Source: The Conversation