TAKING cod liver oil every day could raise your risk of heart disease, a study suggests.
Millions take the smelly supplements to stay limber as they claim to boost joint, brain and eye health.
But data suggests healthy people who take them have a stroke risk five per cent higher than average and a 14 per cent greater chance of an irregular heartbeat.
They did bring benefits for patients who already had heart disease, appearing to lower their risk of a heart attack or early death.
Researchers from Sun Yat-Sen University in China studied 416,000 British people in their 40s, 50s and 60s.
One in three took fish oil supplements each day, with use more common in women and older people.
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Supplements have mixed benefits and risks
Writing in the journal BMJ Medicine, study author Dr Hualiang Lin said: “Regular use of fish oil supplements might have different roles in the progression of heart disease.
“In people with no known cardiovascular disease, regular use of supplements was associated with an increased risk of atrial fibrillation and stroke.
“In people with known cardiovascular disease, beneficial effects were seen.”
People take the pills to boost levels of omega 3 fatty acids, known as healthy fats that are not found in many foods other than fish and nuts.
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They are easy to buy in supermarkets and chemists and cheap – with Asda's own brand version costing just 4p per pill.
Scientists do not agree on whether it is good for you, as both too little and too much have been linked to health problems.
Dr Lin said the topic is “controversial” and it was not clear why the supplements seemed to be good for some people but bad for others.
He added: “Further studies are needed.”
What are the symptoms of stroke?
The FAST method – which stands for Face, Arms, Speech, Time – is the easiest way to remember the most common symptoms of stroke:
F = Face drooping - if one side of a person's face is dropped or numb then ask them to smile, if it's uneven then you should seek help.
A = Arm weakness - if one arm is weak or numb then you should ask the person to raise both arms. If one arm drifts downwards then you might need to get help
S = Speech difficulty - if a person's speech is slurred then this could be a sign of a stroke
T = Time to call 999 - if a person has the signs above then you need to call 999 in the UK or 911 in the US for emergency care.
Other symptoms include:
- sudden weakness or numbness on one side of the body
- difficulty finding words
- sudden blurred vision or loss of sight
- sudden confusion, dizziness or unsteadiness
- a sudden and severe headache
- difficulty understanding what others are saying
- difficulty swallowing