Wine Consumption: Is Less More?
Regular wine consumption is a characteristic of the traditional Mediterranean diet and is associated with a reduced risk of developing several diseases, yet many people today are uncertain about how much is actually beneficial. The key is of course a moderate consumption of alcohol because a high consumption, or binge drinking, increases the risk of heart disease, stroke, cognitive impairment and liver disease.
For example, it is known that about 25 grams per day of ethanol (about 180 ml of wine at 14% alcohol) actually enhances insulin sensitivity and adiponectin levels, which stimulates glucose metabolism and the burning of fat for energy.1 Wine has also been associated with a reduction in the risk of developing diabetes in one large Australian study.2
Nevertheless, finding an association in epidemiological studies is not the same as identifying and treating actual causes, and clinical trials usually have to follow such promising statistics. In this case, the effect of wine consumption has been measured in clinical trials with varying results, and one positive trial using 360 ml/day significantly lowered insulin resistance by 43%.3 Remember that 360 ml is half a bottle of wine and about two standard drinks, the amount usually allowed for men, while women are only supposed to consume half this amount due to their lower average body weight and smaller livers.
This advice has been around for about thirty years and a recent article shed some light on the science behind this calculation. It turns out that a member of the working committee set up by the Royal College of Physicians in 1987, which was responsible for the first set of drinking guidelines, actually admitted that they ‘pulled the guidelines out of thin air.’4
Drinking spirits such as tsipouro (distilled wine pomace) or anise-flavoured ouzo, which have a very high alcohol content and were usually only consumed in a single ‘finger’ measure, is not the same as drinking wine. This is because the protective effect of wine is considered to arise mostly from the polyphenols and not the alcohol (ethanol). Even so, there is evidence of a limited benefit from drinking ethanol apparent in its cardio-protective activity. Ethanol apparently improves the ratio of so-called good to bad cholesterol (HDL:LDL); helps reduce a tendency to blood clots; preconditions the muscle of the heart, and therefore protects against damage. It also encourages the enzyme responsible for alcohol metabolism to break down aldehydes which are harmful to heart muscles.5
Context is also important because alcoholic drinks were traditionally consumed in Europe as part of a wholefood diet including fruit, vegetables, nuts, legumes, wholegrains, fish, cheese and olive oil. The effect of this phytonutrient-rich diet is evident in the data when rates of coronary heart disease are compared between countries, such as between America and France. In the 1950s an association was made between dietary fats, serum cholesterol and heart disease in America, as well as in some European countries, leading to the formulation of the ‘diet-heart’ hypothesis, but France proved one of several exceptions to this rule. France in fact had a high saturated fat intake and correspondingly low heart disease rate, an obvious problem for the proponents of this flawed theory, who called it the ‘French paradox’. Scientists who later pursued the source of the anomaly concluded that it was the regular consumption of red wine that compensated for the high saturated fat intake, and since then the focus has been on one particular protective nutrient in red wine called resveratrol.
Wine polyphenols such as phenolic acids, stilbenes, tannins, flavanols, flavonols, and anthocyanins,6 including resveratrol, have many health benefits. For instance, they lower the risk of heart disease via several mechanisms: they reduce a tendency to the formation of blood clots and platelet aggregation; they prevent LDL cholesterol from oxidising; and they enhance the endothelium-dependent relaxation of blood vessels, and so reduce the risk of obstruction in vessels.5 Resveratrol on its own is associated with a number of significant benefits: it reduces inflammation; has cardio-protective activity; inhibits the formation of neuro-degenerative diseases like Alzheimer and Parkinson disease; has anticancer properties; and is antidiabetic.
Resveratrol also appears to promote longevity and has been trialled in the laboratory on creatures such as nematodes and fruit flies with the result that it increases their lifespan significantly. The pathways by which resveratrol influences organisms are in fact multiple, resulting in stress modulation and curtailment of the development of chronic diseases. One particular pathway is via the mitochondria which are the powerhouses of our cells, and resveratrol helps the mitochondria resist an age-related decline in function, while simultaneously increasing aerobic capacity.7
Resveratrol is also found in grape seeds which are present in the cake leftover from pressing called pomace. The seeds in fact contain many useful medicinal compounds, apart from omega-3 fatty acid and vitamin E, making grape-seed extract a valuable supplement. They contain oligomeric procyanidin complexes (OPCs) including catechin and epicatechin, which are potent antioxidants that have significantly greater effect than vitamins C, E and beta carotene. They also demonstrate antibacterial, antiviral and anticarcinogenic activity, and will even help protect the body from drug and chemical toxicity. Just like the phytonutrients in wine, these OPCs are beneficial to the circulatory system because they improve capillary integrity, reducing inflammation and accelerating wound healing. These factors are useful in treating conditions as varied as venous insufficiency and the complications of myocardial ischemia.8
In light of all these benefits, it would be fair to assume that a regular intake of grape seed extract is preferable to a glass or two of wine every day, although perhaps not as pleasant or sociable. Indeed socialising is known to be part of the overall picture of protective traditional lifestyles associated with improved health and a decreased risk of age-related diseases.
1. Khemayanto H, Shi B. Role of Mediterranean diet in prevention and management of type 2 diabetes. Chin Med J (Engl) 2014;127:3651–6.
2. Hodge AM, English DR, O’Dea K, Giles GG. Alcohol intake, consumption pattern and beverage type, and the risk of Type 2 diabetes. Diabet Med J Br Diabet Assoc 2006;23:690–7.
3. Napoli R, Cozzolino D, Guardasole V, et al. Red wine consumption improves insulin resistance but not endothelial function in type 2 diabetic patients. Metabolism 2005;54:306–13.
4. Barrowclough A. How the standard drink was defined, and why some people ignore it. The Australian 2016;May 14.
5. Mochly-Rosen D, Zakhari S. Focus on: The cardiovascular system: what did we learn from the French (Paradox)? Alcohol Res Health J Natl Inst Alcohol Abuse Alcohol 2010;33:76–86.
6. Basli A, Soulet S, Chaher N, et al. Wine polyphenols: potential agents in neuroprotection. Oxid Med Cell Longev 2012;2012:805762.
7. Catalgol B, Batirel S, Taga Y, Ozer NK. Resveratrol: French paradox revisited. Front Pharmacol 2012;3:141.
8. Braun, Cohen. Herbs & Natural Supplements, An Evidence-based guide. Elsevier; 2005.