The research surrounding red wine’s health benefits has become popular again with the Mediterranean diet back in the news. In April, the PREDIMED study was published in the New England Journal of Medicine and concluded a Mediterranean diet supplemented with either olive oil or nuts reduces the risk of major cardiovascular events by 30% in comparison with a low-fat control diet (1). The traditional eating habits of the Mediterranean region, specifically Greece and Crete, garnered attention and have been studied since the 1960’s. People in the region have been shown to have the greatest life expectancy and the lowest incidence of CVD and cancer in the world.

The Healthy Components in Red Wine Jane and Sue

Red wine has always been part of the Mediterranean diet. However, wine is considered an alcoholic beverage and needs to be consumed in moderation (if daily, a 250ml/8oz serving size is suggested).

  • There are beneficial polyphenolic compounds found in the grape flesh. These antioxidant chemicals neutralize free radicals in the body and are thought to help keep the arteries free of bad fats.
  • The anthocyanins (another polyphenol) found in the grape skin contributes to its reddish purple colour.
  • Red wine is made by fermenting the juice (flesh) along with the skins; this is why there is a high concentration of polyphenols including anthocyanins in it.
  • Red wine also contains flavonols, specifically stilbenes (2). The main stilbene is trans-resveratrol. Resveratrol research exploded in 2003 with the initial work from Dr. David Sinclair at Harvard. Resveratrol has been linked to heart health and other positive health states. Due to the health benefits of trans-resveratrol, the resveratrol supplement industry has exploded too.

Wine BarrelsThe Research

As health professionals, we are always referring to well designed studies to support the scientific evidence for our recommendations. With the noted concern that alcohol can be an addictive substance for some people, it is important to make wise personal decisions, no matter what the research may suggest about red wine.

Wine

  • Research has suggested “moderate intake of red wine may reduce the risk of coronary heart disease”. One study involved a group of healthy participants that consumed 375ml of red wine per day for two weeks (3). The results showed that the red wine group had a reduction in oxidative stress, as well as an increase in HDL (good) cholesterol. It is suggested these findings may be due to the slight increase in total phenolics in the plasma after the consumption of red wine.
  • Another study with a severely obese population showed that red wine consumers had lower fasting concentrations of homocysteine. High homocysteine has been associated as a biomarker for cardiovascular disease. Therefore, mild to moderate red wine consumption, in obese subjects may reduce cardiovascular risk (4).

Supplements

  • Researchers are very interested in resveratrol and study it in isolation (not as part of wine). A study looked at the relationship between resveratrol supplements, cerebral blood flow and cognitive performance. Over three visits, 22 healthy adults received a placebo (visit one), a dose of 250mg of trans-resveratrol (visit two) and a dose of 500mg of trans-resveratrol (visit three). At each visit, 45 minutes after consuming the supplements, the participants performed a selection of timed cognitive tasks. The results showed an increase in cerebral blood flow due to the resveratrol. The researchers concluded that one dose of resveratrol (250mg) can modulate blood flow, but not cognitive function (5).

More research is necessary to differentiate between consuming red grapes vs. red wine vs. only resveratrol in supplemental form to identify the human health benefits in both healthy and diseased populations.

What’s Next? During the holiday season, at the party, enjoy that glass of delicious red wine and then have sparkling water with lemon for the rest of the evening. Always drink red wine and other alcoholic beverages in moderation. And remember – a rainbow of fruits and vegetables will give you plenty of polyphenols too!

References:

  1. Estruch R, Ros E, Salas-Salvado J, Covas M, Corella D, Aros, F et. al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. New England Journal of Medicine. 2013;368:1279-1290.
  2. Crozier A, Borges G. Polyphenolic constituents and the beneficial effects of moderate red wine consumption. Journal of Wine Research. 2011;22(2):131-134.
  3. Tsang C et al. The influence of moderate red wine consumption on antioxidant status and indices of oxidative stress associated with CHD in healthy volunteers. British Journal of Nutrition. 2005;93:233-240.
  4. Dixon J, Dixon M, O’Brien P. Reduced plasma homocysteine in obese red wine consumers: A potential contributor to reduced cardiovascular risk status. European Journal of Clinical Nutrition. 2002;56:608-614.
  5. Kennedy D et al. Effects of resveratrol on cerebral blood flow variables and cognitive performance in humans: A double-blind, placebo-controlled, crossover investigation. The American Journal of Clinical Nutrition.2010;91:1590-1597.