Clinical trials on wine and health

The ever-quotable Sir Winston Churchill once said “however beautiful the strategy, you should occasionally look at the results” and that is especially true for any proposed intervention to improve health and longevity. Whether we are talking about a glass of red wine with dinner or a potential 

blockbuster drug, clinical trials are the only objective way to know if it actually works. Drugs are required to prove their safety and effectiveness through prospective, randomized, double-blind trials, meaning that potential bias is minimized.  It’s tougher to do with lifestyle interventions like drinking wine, so we have relied on other types of studies. (These include for example observational or epidemiologic studies, which track health outcomes correlating to lifestyle factors.) There are nevertheless a few clinical trials on wine and health worth noting:

In 2015 the outcome of a 2-year interventional trial comparing the effects of red or white wine vs. no alcohol was reported in subjects with type 2 diabetes.[1] The subjects followed the Mediterranean diet and were randomly assigned to a glass or red wine, white wine, or mineral water in standardized amounts each day with dinner. Those in the red wine group experienced a significant decrease in total cholesterol and an increase in HDL cholesterol, which correlates to improvement in cardiovascular risk profile. This confirms the importance of wine as an essential component of the Mediterranean diet. Both wine groups reported better sleep, and there was no adverse effect on blood sugar control.

Two studies from the University of Rome and others looked at the effects of red wine on what is called “postprandial oxidative stress” which is elevation of oxidized fats and markers of inflammation following meals. [2]^,[3] One of the studies included red wine with a McDonald’s meal! (I am told that this is available in European McDonald’s outlets, though I wouldn’t know.) Even with a Mediterranean diet, lower levels of oxidized fats and reduced expression of pro-inflammatory genes was documented when red wine was included with the meal.

You’ve got to hand it to the Swedes for this next one.[4] In a crossover study, meaning that each subject participated in each intervention at different times, patients with type 2 diabetes were given various meals while their blood sugars were closely tracked. The diets were either low fat, low carbohydrate, or Mediterranean, skipping breakfast. Notably, the Mediterranean diet included red wine with lunch–they apparently got the memo from the study mentioned above!  Despite a higher caloric intake, blood glucose control was similar to the low fat diet. The study authors concluded that “accumulation of caloric intake from breakfast and lunch to a single large Mediterranean style lunch-meal in NIDDM [non insulin-dependent diabetes mellitus] might be advantageous from a metabolic perspective.”

Not to be outdone (one supposes) a study from Luxembourg weighed in with a report on the Mediterranean diet, red wine, and exercise in subjects with arteriosclerosis of the carotid arteries.[5] Subjects were randomized to have either no alcohol, one glass of red wine (women), or 2 glasses of red wine (men) for 20 weeks. Although most of these patients were already on statin drugs for cholesterol control because of their disease and risk for stroke, there was improvement in cholesterol profile from red wine in an additive fashion to diet and exercise.

While a handful of prospective trials on a broad subject is not conclusive, the fact that the results are similar and consistent with other ways of evaluating wine’s connection to health is compelling. Wien with meals is a beautiful strategy indeed.

“In wine, there is wisdom; in water, germs.” – Sir Winston Churchill

---

[1]Effects of Initiating Moderate Alcohol Intake on Cardiometabolic Risk in Adults With Type 2 Diabetes: A 2-Year Randomized, Controlled Trial. Ann Intern Med. 2015 Oct 20;163(8):569-79.

[2] Changes in LDL Oxidative Status and Oxidative and Inflammatory Gene Expression after Red Wine Intake in Healthy People: A Randomized Trial. Mediators Inflamm. 2015;2015:317348.

[3] Intake of red wine in different meals modulates oxidized LDL level, oxidative and inflammatory gene expression in healthy people: a randomized crossover trial. Oxid Med Cell Longev. 2014;2014:681318.

[4] A randomized cross-over trial of the postprandial effects of three different diets in patients with type 2 diabetes. PLoS One. 2013 Nov 27;8(11):e79324.

[5] A daily glass of red wine associated with lifestyle changes independently improves blood lipids in patients with carotid arteriosclerosis: results from a randomized controlled trial. Nutr J. 2013 Nov 15;12(1):147.