The finding helps explain the French paradox - why people with high-fat diets have a relatively low incidence of heart disease.
Dr Simon Maxwell, of the Department of Medicine at Queen Elizabeth Hospital, Birmingham, analysed the blood of 10 healthy volunteers after they ate meals with wine. The researchers believe it is the first time that beneficial effects of red wine in the blood have been seen on human digestion.
The three glasses of wine were equivalent to 5.7ml of Bordeaux per kilogram of body weight, Dr Maxwell says in a letter to the Lancet.
Red wine is said to be beneficial because of its effect on blood cholesterol. It promotes the activity of anti-oxidant chemicals which act to decrease LDL-cholesterol, the harmful blood fat. The anti-oxidants from the wine protect LDL from oxidation making the oxidised particles less likely to cause the arteries to thicken.
'After ingestion of red wine, serum anti-oxidant activity rose rapidly to reach a peak after 90 minutes, before a gradual decline. Anti-oxidant levels were still raised at four hours,' he says.
Dr Maxwell says he was not surprised by the findings since analysis of the wine itself showed it to be very high in anti-oxidant activity.