Regular consumption of fish oil supplements may increase, rather than decrease, the risk of first-time heart disease and stroke in individuals with good cardiovascular health while potentially slowing the progression of existing cardiovascular conditions and reducing mortality risk, suggests a comprehensive long-term study published in BMJ Medicine. Fish oil is renowned for its high omega-3 fatty acids content and is commonly recommended as a dietary preventive measure against cardiovascular disease. However, the extent of protection it provides is still debated among experts. The research aimed to consolidate the evidence by estimating the relationship between the use of fish oil supplements and the emergence of new cardiovascular issues such as atrial fibrillation, heart attacks, strokes, and heart failure, as well as overall mortality in individuals without prior cardiovascular diseases.
To further explore the potential benefits of these supplements, the study examined their impact on the progression from good cardiac health to more severe conditions, including atrial fibrillation, major cardiovascular events, and death. The analysis drew on data from 415,737 participants of the UK Biobank study, primarily composed of women (55%) aged 40 to 69, who had their initial health and dietary habits surveyed between 2006 and 2010. The follow-up period was extended until the end of March 2021 or the participants’ death, during which their health outcomes were meticulously tracked using medical records.
About one-third of the participants (31.5% or 130,365 individuals) reported consistent use of fish oil supplements. This group notably included a higher proportion of older White individuals and women, who generally consumed more alcohol and preferred oily fish to non-oily variants, with fewer smokers and residents from deprived areas among them. During the nearly 12-year monitoring period, 18,367 participants developed atrial fibrillation, 22,636 experienced heart attacks, strokes, or heart failures, and 22,140 passed away—14,902 of whom had not previously suffered from atrial fibrillation or severe cardiovascular diseases.
The study findings revealed that regular use of fish oil supplements was associated with a 13% increased risk of developing atrial fibrillation and a 5% increased risk of stroke in individuals without cardiovascular diseases at the start. Conversely, for those already suffering from cardiovascular conditions, regular intake of these supplements was linked to a 15% reduced risk of advancing from atrial fibrillation to a heart attack and a 9% lower risk of progressing from heart failure to death. These observations were further influenced by factors such as age, gender, smoking habits, consumption of non-oily fish, high blood pressure, and the use of statins and blood pressure-lowering medications.
The protective effects of fish oil supplements varied: 6% higher in women and non-smokers for transitioning from good health to severe cardiovascular events, 7% lower in men, and 11% lower in older individuals for transitioning from good health to death. Since this study is observational, the researchers caution against drawing causal conclusions. They also note the absence of data on the dosage or formulation of the fish oil supplements used, and the predominantly White demographic of the participants suggests that these findings might not apply universally.
In conclusion, the researchers emphasize the need for further studies to determine the precise mechanisms by which regular use of fish oil supplements influences the development and prognosis of cardiovascular diseases. These supplements’ nuanced roles in different stages of cardiovascular health suggest a complex interaction with individual health profiles and dietary habits, warranting a deeper investigation into their benefits and risks.
More information: Ge Chen et al, Regular use of fish oil supplements and course of cardiovascular diseases: prospective cohort study, BMJ Medicine. DOI: 10.1136/bmjmed-2022-000451
Journal information: BMJ Medicine Provided by BMJ Group
