When I visited my 76-year-old mother the other day, she seemed worried and annoyed with me.
‘Why did you tell me to take fish oil supplements?’ she complained. ‘They will give me a stroke!’
Despite my telling her she didn’t need to worry, she was adamant, explaining she’d read about it in the paper and heard it on Radio 4’s Today programme, and so it must be true.
The research, which hit the headlines recently and which has got my mother — and no doubt many others — worried, was published in the journal BMJ Medicine.
It showed that regular consumption of fish oil supplements might be a risk factor for atrial fibrillation (AF, or irregular heartbeat), and stroke.
Taking a fish oil supplement lowers the risk of developing conditions like MS
No wonder my mother was worried.
But before you bin your fish oil (aka omega-3) pills — as my mother was about to do after five years of taking them — let me tell you what I’ve decided after investigating the study (and reviewing many others). I will continue to have my daily supplement, not least as I hate eating fish! And I think you should carry on, too.
This is because the research was observational. In other words, no experiments were done — the researchers simply observed what happened to groups of people in terms of their health outcomes, some who’d taken fish oils and others who hadn’t.
What observational studies tell us is if there is an association between something (here, fish oil pills) and an outcome (the chances of developing AF or having a stroke).
But an association doesn’t mean that it caused the illness.
The journal BMJ Medicine published research that shows those who regularly consume fish oil supplements might be a risk factor for strokes
For years, coffee was associated with ill health and cancer when we now know that generally speaking, in moderation, it’s good for you.
The problem had been that the many studies showing that coffee drinkers had higher rates of cancer were based on people who also smoked.
The best type of research is a randomised controlled trial — where half of the participants are given fish oils and half a placebo (a fake tablet) — and the outcomes are looked at by researchers who don’t know who is taking what.
Even these gold-standard studies can be flawed.
I’ve spent much of my career looking at these issues, including writing a textbook on it.
I won’t get too technical but one issue, for example, is a mistake in the way a study has been designed. For example, people given the supplements are healthier than the placebo group to start with, so their better outcomes are incorrectly attributed to the pills.
The Journal of the American Heart Association found that those who took the supplements daily for five years – reduced their risk of dying from cardiovascular disease by 7 per cent
The new research, by scientists from the U.S., China, Denmark and the UK, was based on data from more than 400,000 patients from the UK Biobank — an ongoing study started in 2006. Participants underwent blood tests and filled in questionnaires then were followed up for the next 30 years using their NHS records.
The results were, on the surface, surprising and, for someone like me who has a fish oil pill each day — and who recommends this to his friends and family — somewhat alarming.
These showed that if you were healthy and took omega-3 pills, you had a 13 per cent higher chance of developing AF compared with if you didn’t take the tablets. The risk of a stroke was 5 per cent higher.
Most people who have AF don’t know they have it. So maybe those who took fish oils were more health conscious so got themselves checked more, and hence had a higher chance of their AF being spotted.
But what about higher risks of a stroke?
While there was a small increase in stroke, on closer examination the statistical analysis showed that this difference could be anywhere from no difference at all, to an 11 per cent increase.
This, in layman’s terms, is so unconvincing a spread in numbers that we can’t conclude that fish oils make your chances of stroke higher.
There were other contradictory findings: those who developed AF had a 13 per cent lower chance of it leading to a heart attack or a stroke.
How could this be the case if fish oils were harmful? The only conclusion we can draw from this is that we can’t draw any conclusions from this study!
Therefore, we need to look at better studies — randomised controlled studies.
For instance, in 2019 the Journal of the American Heart Association published a review of 13 trials, involving more than 125,000 patients. This found that taking fish oil supplements daily for five years reduced the risk of dying from cardiovascular disease by 7 per cent.
Meanwhile, there is also the suggestion that fish oils may help prevent depression.
The cause of depression is not truly understood. However we do know that inflammatory chemicals such as cytokines can cross the blood-brain barrier and interfere with chemical messengers in the brain (called neurotransmitters) and increase the risk of developing it. That is if you have an inflammatory condition.
This was something I experienced personally — I have the inflammatory gut condition ulcerative colitis and when I took fish oils after the death of my dad, which left me feeling down, I really think that the pills helped.
Omega-3s can also apparently help with brain health. In 2022, the journal Cureus: Journal of Medical Science published a review of nine randomised controlled studies which concluded that the ‘ingestion of omega-3 fatty acids increases learning, memory, cognitive well-being, and blood flow in the brain’.
The condition I fear most is dementia, which is another reason I take fish oils.
But the main reason is the potential impact on my life expectancy, crucially my healthy life expectancy.
Fish oils seemed to blunt the harmful impact of inflammation and cortisol rises triggered by everyday chronic stress, such as work deadlines, which are so common in all our lives, according to a study in the journal Molecular Psychiatry in 2021.
Another review that year, in the highly respected journal Nature Communications, found that people with the highest levels of omega-3s in their blood had 17 per cent lower rates of mortality from all causes than those with the lowest levels.
So where does this leave us? Based on my examination of the science behind the headlines, I’m going to keep taking my daily fish oil tablet. And I’d recommend that my mother — and anyone else — does so, too.
@drrobgalloway
