Supplements taken by millions ‘increase heart and stroke risk’ in worrying study

Millions of Britons take fish oil supplements, which are rich in Omega 3 fatty acids, to boost brain function, heart health and gut wellness – but recent research suggests regular use could increase the risk of heart disease and stroke for some people A British study sparked worries that fish oil, a popular household supplement for decades, might heighten the risk of cardiac complications. Fish oil, abundant in Omega 3 fatty acids, has long been believed to support brain function, cardiovascular health and digestive wellbeing. Nevertheless, comprehensive research indicates that routine use of fish oil supplements may raise a person’s chances of developing heart disease or experiencing a stroke. However, for individuals already living with cardiovascular conditions, regular intake of fish oil might assist in slowing the advancement of these ailments. “Regular use of fish oil supplements might be a risk factor for atrial fibrillation and stroke among the general population,” the study’s authors declared in their conclusions, published in BMJ Medicine. The investigation included 415,737 participants (55% women) aged 40-69 years from the UK Biobank, an extensive database holding information on the diets, lifestyles and medical conditions of thousands of British people. Participants were surveyed between 2006 and 2010, gathering fundamental demographic information, including usual dietary consumption of oily fish, non-oily fish and fish oil supplements, according to Mirror US. The study examined the potential influence of these supplements on the risk progression from healthy heart function to atrial fibrillation, potentially leading to serious cardiovascular incidents such as heart attacks and, eventually, death. Participants were divided into groups, with their health monitored through medical record data until March 2021 or their death. Nearly one-third (130,365; 31.5%) of participants reported regular fish oil supplement consumption. This cohort included higher proportions of elderly white people and women. The researchers observed that the group consuming greater amounts of oily fish and alcohol also contained fewer current smokers and people living in disadvantaged areas. The findings indicated that regular fish oil supplement use played different roles in cardiovascular health, disease development and mortality, reports Surrey Live. Among those without known cardiovascular disease at the monitoring period’s outset, regular fish oil supplement use was linked to a 13% increased risk of developing atrial fibrillation and a 5% increased risk of experiencing a stroke, according to a press release issued by the research team. Conversely, amongst those who already had cardiovascular disease at the monitoring period’s start, regular fish oil supplement use was linked to a 15% reduced risk of progression from atrial fibrillation to a heart attack and a 9% reduced risk of progression from heart failure to death. Further examination of the analysis revealed that various factors including age, sex, smoking status, non-oily fish consumption, high blood pressure , and statin and blood pressure medication use increase the risk of heart conditions, together with fish oil intake. What does the British Heart Foundation say The British Heart Foundation later looked into the survey and assessed the evidence and research methods. The British Heart Foundation said: “This research should not be concerning to people who regularly take fish oil supplements, but it’s also not a green light to start taking them to prevent heart and circulatory diseases. Instead, people should look at their whole diet when aiming to reduce their risk of heart disease, they advised. “A healthy, balanced diet which includes oily fish can provide you with omega-3 and all the other nutrients essential for keeping your heart healthy. The traditional Mediterranean diet has been shown time and again to reduce the risk of heart attack or stroke,” she said. New study into diabetics A major international trial has found that daily fish oil supplements significantly reduced life-threatening cardiovascular events in dialysis patients, it was reported in March 2026 by Science Daily . People who took four grams per day had a 43% lower risk of heart attack, stroke, cardiac death, or vascular-related amputations compared with those on placebo. The findings stand out because few treatments have successfully lowered heart risk in this high-risk group. The research, known as the PISCES trial, included 1,228 participants receiving dialysis treatment at 26 sites across Australia and Canada. The results were presented at the American Society of Nephrology Kidney Week 2025 and published in The New England Journal of Medicine. Participants who took four grams of fish oil each day experienced significantly fewer major cardiovascular events than those who received a placebo. The supplement contained the omega-3 fatty acids EPA and DHA, which are naturally found in fish oil. Overall, the group taking fish oil had a 43 percent lower rate of serious cardiovascular events. These included heart attack, stroke, cardiac death and vascular related amputations. Other studies into fish oil supplements A recent study has found that regular consumption of fish oil supplements is linked to a 6% increased risk of serious cardiovascular events in women and non-smokers, while men taking the supplements saw a reduction in death rates by 7%. The team behind the research pointed out that due to the nature of their observational study, they cannot conclusively determine cause and effect. They also noted the lack of information on the dosage or type of supplements used by participants. Nonetheless, the researchers have stated: “Regular use of fish oil supplements might have different roles in the progression of cardiovascular disease. Further studies are needed to determine the precise mechanisms for the development and prognosis of cardiovascular disease events with regular use of fish oil supplements.”