Reaping the health benefits of wine
For thousands of years, wine has evolved as part of human culture and diet. The role of wine throughout time has developed from a source of nutrition to a cultural complement to food that has also been proved to be compatible with a healthy lifestyle. The chemistry behind red and white wines reveals unique compounds that have been demonstrated to decrease the risk of developing cardiovascular diseases, cancer, and diabetes. This article discusses the differences between red wine and white wine with regards to their chemical constituents, proposed health benefits, and food pairings.
The molecule shown above is catechin, the building block of proanthrocyanidins. They are found mainly in Grape seeds, but are also present in the skin and stems of grapes.
Properties of Red Wine
Astringency is the dry, rough sensation in our mouths after tasting most red wines. An example of an astringent is the naturally occurring compound tannin, which is found at high concentrations in red wine. Tannins can affect the color, aging ability, and texture of the wine. They react with proteins found in saliva that result in the drying sensation left in the mouth after their consumption. There are natural tannins that are found in grapes, known as proanthrocyanidins, which release natural pigments that give red wines their signature color. As the wine ages, the tannins present will come across as softer and its astringent taste subsides. Leaving a wine bottle uncorked for a long period of time will also result in a milder taste due to introduction of oxygen from the air into the bottle. Studies have been conducted stating that tannins in the form of proanthrocyanidins result in improved vascular health after short- or long-term consumption of foods and supplements that contain them. A few effects that they have on the human body include dilation of blood vessels, control over reactions related to inflammation, improved glucose metabolism in type 2 diabetics, and regulation of some reactions involved in cancer processes.1 These beneficial health effects are noticeable in southwestern France and Sardinia where the wines made there contain higher amounts of proanthrocyanidins; consequently, these regions are associated with increased longevity in their population.2
The main reason why individuals like to drink red wine with red meats is due to the balance between high tannin content in red wines and high fat content in meats. Whereas the oral astringents found in red wine cause our mouths to feel dry and rough, the fat in steaks results in a slippery sensation. Since the dry wine and slippery meat elicit opposite responses, they work together to reduce the opposing sensation. If, for instance, you had only water while eating meats, the sensation that our mouths and cheeks are coated with fat from the meats would be readily apparent.
Red Wine, Cardiovascular Health, and Cancer Prevention
You may have heard in the past that drinking one glass of red wine a day can help reduce the risk of getting some form of cardiovascular disease or cancer. The compound responsible for these claims is resveratrol, which is found mainly in red wines. With regards to the prevention of cardiovascular diseases, studies have shown that resveratrol can reduce myocardial damage and decrease plaque buildup in arteries that leads to atherosclerosis, which is accumulation of fats and cholesterol inside the arteries.3 Furthermore, high doses of resveratrol significantly decreased blood pressure, whereas lower doses had no effect.3 Unfortunately, red wine contains around 2 mg of resveratrol per glass of wine and you would need more than 150 mg of resveratrol a day for a significantly lowered blood pressure.4 This equates to 75 glasses of red wine a day! Although red wine alone will evidently not be sufficient in decreasing blood pressure, even low doses of resveratrol like those found in red wines have been shown to intervene in the detainment of cardiac aging. This may also aid in explaining why those living in some regions of France have incredible cardiovascular health, despite having diets rich in saturated fats.5
Resveratrol has also been demonstrated to inhibit tumor formation, promotion, and progression. It can switch off genes involved in the initiation and advancement of cancer, along with preventing replication of cancerous cells.6 Additionally, resveratrol is known to prevent cancer since it belongs in a class of molecules known as antioxidants. Antioxidants, like vitamin C and vitamin E, can help prevent cancer by neutralizing highly reactive free radicals. Free radicals are molecules that cause major damage to the cells and increase the risk of cancer development.
Properties of White Wine
One of the main differences between red wines and white wines come from their preparation. When red wines are made, the grape skins are crushed along with the pulp and both of these components then go on to be fermented. In white wines, however, only the pulp of the grape is fermented. The previously mentioned proanthrocyanidins that contribute to the characteristic ruby color of red wines is mainly found in grape skins. In one study conducted by Dr. Mario Falchi of the University of Milan, it was found that both grape pulp and grape skin extracts are equally effective in protecting rats from heart attacks. Both the skin and the pulp had the same level of antioxidant activity.7 With regards to food pairing, white wines tend to go well with fish or chicken because it has a higher acidity than red wines. A similar concept is adding acidic lemon juice to fish or chicken in order to add more taste to the dish. Typically, the intensity of the dish should match the intensity of the wine. The greater concentration of bitter tannins in red wine can overpower the flavor of the fish or chicken, making white wine a more suitable alternative.
References and Additional Reading
1. Beecher GR. Proanthocyanidins: Biological activities associated with human health. Pharm Biol. 2004;42(SUPPL.):2-20. doi:10.1080/13880200490893474.
2. Corder R, Mullen W, Khan NQ, et al. Oenology: Red wine procyanidins and vascular health. Nature. 2006;444(7119):566-566. doi:10.1038/444566a.
3. Bonnefont-Rousselot D. Resveratrol and Cardiovascular Diseases. Nutrients. 2016;8(5). doi:10.3390/nu8050250.
4. Siemann EH, Creasy LL. Concentration of the Phytoalexin Resveratrol in Wine. Am J Enol Vitic. 1992;43(1).
5. Catalgol B, Batirel S, Taga Y, Ozer NK, Laher I, Andriantsitoaina R. Resveratrol: French paradox revisited. 2012. doi:10.3389/fphar.2012.00141.
6. Kumar DS, Shankar P, Rao GU. Health Benefits of Resveratrol. Int J Pharm Sci Nanotechnol. 2009;2(1):407-412.
7. Falchi M, Bertelli A, Lo Scalzo R, et al. Comparison of Cardioprotective Abilities between the Flesh and Skin of Grapes. J Agric Food Chem. 2006;54(18):6613-6622. doi:10.1021/jf061048k.
