Wine your way to good health

The relative longevity of the French and the Italians has led to wide acclaim of their ‘Mediterranean Diet’, which is rich in olive oil and red wine.

Studies have shown that red wine, when drank in moderation, lowers the rates of heart disease, and scientists have been investigating which specific constituents of red wine confer this benefit. For the sake of clarity, drinking in moderation is defined as one or two servings of 150 millilitres per day.

It has been suggested that it is not the alcohol content in red wine that is responsible for the observed heart-protecting effect, but rather specific constituents of the red grape. The question that naturally follows is: does drinking red grape juice confer the same benefit as drinking red wine?

Beneficial properties

There are reports that suggest that, like red wine, consuming red grapes has benefits, especially due to the naturally-occuring compounds found in the skin of the grapes that have inter-related beneficial properties.

These include antioxidants called flavonoids, which protect the heart by removing the damaging by-products of normal cell function known as free radicals; as well as a compound called resveratrol, which is thought to reduce the formation of blood clots.

For those who like to drink a glass or two of red wine with their meals, before you stock up your rack or cellar, please read on as: (i) the constituent of red wine that is responsible for the heart-protecting effect and, (ii) whether the heart-protecting benefit can be attained from any red wine, have been challenged.

A team of scientists led by Professor Roger Corder at the William Harvey Research Institute found that the heart-protecting effect of red wine is attributed to a group of compounds that is found in the skin of red grapes called polyphenols.

Polyphenols were found to decrease the body’s production of a chemical messenger called endothelin-1, which has been previously shown to contribute to the formation of fatty plaques in the walls of blood vessels that supply the heart.

The heart is a muscle with its own blood supply, and the accumulation of fatty plaques in the blood vessels that supply the heart make them narrow and result in the heart being starved of oxygen, causing a section of the heart tissue to die. This is what is colloquially referred to as a heart attack.

In a podcast with the leading science journal Nature, Professor Corder explained that, unlike resveratrol, which occurs in minute quantities and thus demands the consumption of litres of red wine for its heart-protecting benefit, one glass of red wine contains sufficient polyphenols for its beneficial effect.

No longer dominated by European selections — with the establishment of thriving vineyards in South America (frequently referred to as the ‘New World’), Australia and South Africa — red wine has increasingly become more accessible and affordable.

However, Professor Corder’s research also found that grapes grown in the Italian island of Sardinia and in the South West of France have higher levels of polyphenols than red grapes grown elsewhere in the world. Moderate consumption of red wine from these specific regions is Professor Corder’s explanation for the benefits of the ‘Mediterranean Diet’.

Favourable altitude

His rationale is two-fold, that (a) the amount of UV light from the sun affects the production of polyphenols in the skin of red grapes, and thus the high altitude in Sardinia is favourable and, (b) the species of red grapes grown in South West of France, known as the tannant grape, has a naturally higher amount of polyphenols.  

It is said that an apple a day keeps the doctor away, the jury is still out on whether it is a glass of red wine a day or a glass of red grape juice a day that will keep the cardiologist at bay.

Disclaimer: Excessive consumption of alcohol is harmful. People who already have heart defects — such as heart failure — are discouraged from drinking alcohol as it has harmful effects on the heart.