The old advertising slogan "Guinness is Good for You" may be true after all, according to researchers.
A pint of the black stuff a day may work as well as a low dose aspirin to prevent heart clots that raise the risk of heart attacks. Drinking lager does not yield the same benefits, experts from University of Wisconsin told a conference in the US. Guinness was told to stop using the slogan decades ago - and the firm still makes no health claims for the drink.
The Wisconsin team tested the health-giving properties of stout against lager by giving it to dogs who had narrowed arteries similar to those in heart disease. They found that those given the Guinness had reduced clotting activity in their blood, but not those given lager.
Clotting is important for patients who are at risk of a heart attack because they have hardened arteries. A heart attack is triggered when a clot lodges in one of these arteries supplying the heart. Many patients are prescribed low-dose aspirin as this cuts the ability of the blood to form these dangerous clots.
The researchers told a meeting of the American Heart Association in Orlando, Florida, that the most benefit they saw was from 24 fluid ounces of Guinness - just over a pint - taken at mealtimes.