Blend of good and bad for coffee drinkers

A Nestle study finds your health can benefit from a cup of coffee. But not all studies are positive.

Coffee beats green tea by containing four times the amount of health-boosting antioxidants, which can help in preventing or postponing the onset of degenerative diseases, says a Nestle-financed study.

The study, carried out in Switzerland by the Lausanne-based Nestle Research Centre, examined the effects of green tea, cocoa, herbal teas and coffee on antioxidant activity.

"We have known for some time from our monitoring of on-going research findings that there are many potential health benefits of consuming coffee," said an official of the International Coffee Organisation.

"This latest and exciting research finding may help us better understand and prevent common diseases which are triggered by oxidative reactions."

Antioxidants reduce the effects on the human body of harmful substances known as free radicals, which may be a major contributor to cardiovascular disease, cancer, cataracts and decline of the immune and nervous system.

Fruits, vegetables, nuts and whole grains are other foods high in antioxidant vitamins such as C and E.

Robusta green coffee beans have a two-fold higher antioxidant activity than arabica, although this difference declines after roasting, say results of the study.

"In conclusion, these commonly consumed beverages have a significant antioxidant activity, the highest being soluble coffee on a cup-serving basis."

The study was published in the international publication Journal of Agricultural and Food Chemistry.

Robusta beans are used to make instant coffee and in blends with arabica coffees. Green beans are never consumed in their native state.

The study says antioxidant activity is greatly influenced by the method of preparation of a cup of coffee, which would lead to a considerable difference in the amount ingested by different countries.

One cup of coffee prepared by United States consumers contained 0.7 per cent soluble coffee, compared with 1.7 per cent for Swiss drinkers and 2.0 per cent in France.

The antioxidant activities were not affected by the addition of milk to coffee, cocoa and tea.

The study was carried out "in vitro" - in test-tubes - and further studies "in vivo" - on cells, cultures, animals, healthy humans and eventually humans with diseases - will need to be carried out.

Another study found that just one cup of coffee can stiffen arteries for more than two hours, which might raise the risk of heart attack and stroke.

But, it says, the jury is still out on the medical effects of caffeine, the most widely used drug in the world, because it is not clear how big a risk this causes and to whom.

"Our coffee break could be a health hazard but we need more information," says Charalambos Vlachopolous, of the Henry Dunant Hospital in Athens.

"We do not know yet who should abstain from coffee or what is the permitted consumption per day."

Scientists have long known that caffeine stiffens arteries, the muscular elastic tubes that carry blood from the heart to the cells, tissues and organs.

This stiffening puts extra strain on the heart and can cause a kind of hypertension. Stiff arteries, like worn rubber, are more prone to split or lose their internal protective lining.

The study, presented at a cardiology conference in Stockholm, is the first to find that a dose of caffeine equivalent to just one cup of coffee is enough to stiffen arteries, albeit temporarily.

"Until the time that we have all the pieces of the jigsaw put together, some people, especially the hypertensives and the elderly, should be more cautious with their caffeine consumption or switch to decaffeinated drinks," says Mr Vlachopolous.

- REUTERS