One of the great mysteries of nutrition science has been the “French Paradox.”
Even though the French consume fairly large proportions of saturated fat from meats and cheese, they enjoy low rates of heart disease.
Many people in France drink a modest amount of red wine with meals … and they show better cardiovascular health and a reduced risk of diabetes, compared with their abstinent Gallic compatriots.
Saturated fat tends to raise cholesterol levels, but the idea that cholesterol causes cardiovascular disease is a gross oversimplification that's well on its way to obsolescence (See “Cholesterol Fiasco Undermines Accepted Theory”).
Polyphenol antioxidants and the French paradox
One explanation for the French Paradox could be their love of red wine, which – like extra virgin olive oil and some fruits and vegetables – is rich in polyphenol “antioxidants”.
The potent polyphenols in which grapes and red wine abound appear to enhance artery health and reduce unhealthful oxidation of LDL cholesterol.
Among polyphenols, top heart-health candidates include the procyanidins in grape skins, and the anti-fungal – and possible anti-aging agent – called resveratrol (see “Red Wine Constituent Gives Mice Radical Metabolic Makeovers” and “Antioxidant from Grapes and Wine Might Extend Life- and Health-Spans.”)
Previous research has linked diets rich in grapes, red wine, and other foods rich in polyphenols to reduced risks for cardiovascular disease, cancer, and other chronic diseases.
But, although progress toward explanations for the French Paradox has been pretty rapid, we still do not understand all of the underlying reasons for these beneficial effects.
New experiment and a prior human study suggest a polyphenol/omega-3 link
In a surprising turn of events, two studies suggest that the polyphenols in red wine – and in other foods, like cocoa, berries, and extra virgin olive oil – may work their heart-health wonders by protecting omega-3s in the body from being oxidized by free radicals.
Since omega-3s are proven to protect heart health, these findings could provide another, indirect reason for red wine’s apparent heart-health benefits.
Two years ago, researchers from France and Italy detected the first sign that red wine might help maintain higher blood levels of omega-3s (di Giuseppe R et al. 2009).
Their study – conducted in 1,604 women and men from Italy, Belgium, and England – linked red wine consumption to higher blood levels of omega-3 EPA and DHA in women and with higher levels of EPA and DHA in red blood cells.
In men, drinking red wine was only linked to higher blood levels of omega-3 EPA … which, like DHA, is proven to aid heart health.
However, no association was found between drinking beer or spirits and having higher omega-3 levels, which led them to make an obvious inference:
“Components of wine other than alcohol (polyphenols) might exert these effects. Part of the alcohol-induced cardio-protection [documented in many studies] may be mediated through increased [blood levels of] marine [seafood-source] omega-3s.” (di Giuseppe R et al. 2009)
Now, a test-tube study from Italy provides “mechanistic” evidence that the polyphenols in red wine protect omega-3s from oxidation.
Test tube experiment affirms red wine’s power to protect omega-3s
Researchers from Italy’s University of Milan investigated the effects of red wine polyphenols on the susceptibility of the essential omega-3 and omega-6 fatty acids in human blood to being oxidized (Cazzola R, Cestaro B 2011).
And their results showed that wine polyphenols significantly protected omega-3 and omega-6 fatty acids from the destructive process called “peroxidation”.
The results also indicated that red wine polyphenols protect omega-3s more than they protect omega-6 fatty acids.
This aspect of the study seems significant, because the excess consumption of omega-6s and inadequate intake of omega-3s that typifies American diets is associated with higher heart risks. (See “Heart Group's Omega-6 Advice Takes a Huge Hit” in the “Omega-3 / Omega-6 Balance” section of our news archive.)
These findings suggest yet another explanation for the anti-inflammatory effects attributed to moderate consumption of red wine, cocoa, and other sources of procyanidin-type polyphenols.
In fact, along with extra virgin olive oil, red wine is a significant source of polyphenols in Mediterranean-type diets, with moderate consumption contributing up to a whopping one gram of polyphenols daily.
What the study found
The authors of the new study set out to investigate the effects of red wine polyphenols on the vulnerability of omega-3 and omega-6 fatty acids to become oxidized … particularly the fatty acids most involved in the inflammatory response: omega-6 AA, omega-3 EPA, and omega-3 DHA (Cazzola R, Cestaro B 2011).
The researchers found that the wine polyphenols increased all three fatty acids’ resistance to peroxidation … but they provided more protection to the omega-3 DHA and EPA than to omega-6 AA.
The oxidation process tended to raise the ratio of omega-6 AA to omega-3 EPA … which is bad for heart and overall health. But they found that red wine polyphenols delayed any such increase in the AA:EPA ratio.
As the researchers concluded, “These results … [provide] a biochemical rationale for future ‘in vivo’ [animal or human clinical] studies on the benefits to health of moderate red wine consumption.” (Cazzola R, Cestaro B 2011)
Taken together, the findings of these two studies suggest that people who drink red wine in moderation will maintain higher omega-3 levels than peers who start out with the same omega-3 blood levels but drink no red wine.
This is the kind of outcome to which we’re happy to say “cheers”, and raise a tasty glass of cabernet!
Cazzola R, Cestaro B. Red wine polyphenols protect n-3 more than n-6 polyunsaturated fatty acid from lipid peroxidation. Food Res Int. In Press, Accepted Manuscript, Available online 2 August 2011, ISSN 0963-9969, DOI: 10.1016/j.foodres.2011.07.029
di Giuseppe R, de Lorgeril M, Salen P, Laporte F, Di Castelnuovo A, Krogh V, Siani A, Arnout J, Cappuccio FP, van Dongen M, Donati MB, de Gaetano G, Iacoviello L; European Collaborative Group of the IMMIDIET Project. Alcohol consumption and n-3 polyunsaturated fatty acids in healthy men and women from 3 European populations. Am J Clin Nutr. 2009 Jan;89(1):354-62. Epub 2008 Dec 3.