Key antioxidants found in fruits, vegetables and nuts do not cut the risk of heart disease in those most at risk, researchers said.
Vitamins C, E and beta carotene – which the body converts into vitamin A – have no effect on lowering the chances of heart disease or death in high-risk women, a study found.
Some previous studies have linked all three to a reduced risk of cardiovascular disease.
The study, published in the Archives of Internal Medicine, involved examining data for 8,171 women over the age of 40 who took part in the Women’s Antioxidant Cardiovascular Study in the US, starting in 1995 or 1996 and ending in 2005.
The women all had a history of cardiovascular disease or had three or more risk factors for developing it, such as high blood pressure, diabetes or high cholesterol.
They were randomly split into groups and given either 500 milligrams of ascorbic acid (vitamin C) every day, 600 units of vitamin E every other day or 50 milligrams of beta carotene every other day. Around half of each of the three groups of women acted as controls.
Over an average follow-up period of 9.4 years, 1,450 women suffered one or more cardiovascular events.
These included 274 heart attacks, 298 strokes and 889 procedures such as angioplasty – to open up the arteries – or heart bypass surgery.
A total of 395 women died due to cardiovascular events, out of a total of 995 deaths.
The resulting analysis found that none of the antioxidants, either alone or in combination, had an effect on reducing the risk of a cardiovascular event or death.
Antioxidants have been hailed for their ability to neutralise free radicals – which are known to damage cells in the body and their DNA.
Last week, a study found that antioxidant overload may underlie diseases such as inherited heart failure and Alzheimer’s.
Beta carotene is a compound that provides the colour in yellow and orange fruit and vegetables.
Major dietary sources of beta carotene are yellow and green leafy vegetables and fruits such as spinach, carrots, red peppers, mango, melon and apricots.
Vitamin C is found in peppers, broccoli, sprouts, sweet potatoes, oranges and kiwi fruit.
Nuts and seeds
Meanwhile, the richest sources of vitamin E are soya, corn and olive oil; nuts and seeds and wheatgerm.
The authors of today’s study, led by Nancy Cook, an associate professor of medicine at Harvard Medical School, concluded: ‘Overall, we found no benefit on the primary combined end point for any of the antioxidant agents tested, alone or in combination.
‘We also found no evidence for harm. While additional research into combinations of agents, particularly for stroke, may be of interest, widespread use of these individual agents for cardiovascular protection does not appear warranted.’
Ellen Mason, cardiac nurse at the British Heart Foundation (BHF), said: ‘This study adds to the stockpile of evidence suggesting that taking antioxidant supplements in order to protect your heart does not seem to work.
‘We are not saying to avoid foods that have naturally occurring antioxidants such as fruit and vegetables. These are vital for good health.
‘There is not one magic food that can give us good heart health, and a healthy diet is only part of looking after your heart.
‘But if you want to eat well for your heart then eating foods low in saturated fat, with loads of fruit and vegetables is a good start.’
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