The research Associations of habitual fish oil supplementation with cardiovascular outcomes and all-cause mortality: evidence from a large population-based cohort study, explored whether regular use of fish oil supplements would lower the risk of developing cardiovascular issues such as heart attacks and strokes.
Omega-3 fatty acids in fish oil are known to be beneficial in protecting people from cardiovascular disease by providing benefits to blood pressure, lowering inflammation and supporting heart blood flow.
Despite the widespread presence and awareness of the use of fish oil supplements, “clear gaps in knowledge remain” regarding the association between omega 3 fatty acids and the prevention of CVD incidents, the researchers explained.
Conflicting research exists, with data from laboratory studies, epidemiological investigations and randomized controlled trials suggesting omega 3 fatty acids play a part in the prevention of CVD. Trials and meta-analyses, however, have shown that supplementation of omega 3 fatty acids has no beneficial impact on CVD prevention.
As the relationship remains uncertain, the researchers at UK Biobank believed that a large scale cohort study could provide important information on the connection between fish oil supplements and clinical outcomes.
Study design
The research team used population-based cohort data from a total of 427,678 male and female participants, between 40 and 69 years of age from 22 assessment centers across England, Scotland, and Wales.
None of the participants had CVD or cancer at baseline. The participants were enrolled in the survey between 2006 and 2010 and were then followed up until the end of 2018.
The research, published in the British Medical Journal, asked all participants to answer questions on their habitual use of supplements, including fish oil.
Participants filled out a questionnaire and completed a face-to-face interview, as well as provided biological samples and a selection of physical measurements.
When compared with non-users of fish oil supplements, the study found that fish oil users were older and more likely to be female, not current smokers, and physically active.
Additionally, fish oil supplement takers reported eating oily fish more frequently and had a higher incidence of hypertension and longstanding illness, but a reduced prevalence of diabetes. Fish oil supplement takers were also more likely than non-users to take antihypertensive drugs, aspirin, vitamin supplements, and mineral and other dietary supplements.
Study Findings
The study suggests that habitual fish oil supplementation was linked with considerably lower all-cause mortality and incidence of, and mortality from, CVD and heart attack.
Specifically, the scientists found that fish oil supplements is associated with a 13% reduced risk of overall death, a 16% lower risk of dying from cardiovascular disease, and a 7% lower risk of cardiovascular disease events such as suffering a heart attack or stroke.
Within the observation study, the scientists identified that the protective association of fish oil intake against CVD events was stronger in people with prevalent hypertension. In addition, the study also suggests that the association seemed stronger for CVD mortality than for the incidence of CVD, therefore suggesting that fish oils could have a greater impact among individuals with established CVD events.
Currently, there is a lack of evidence to demonstrate which component of omega 3 fatty acids (docosahexaenoic acid, eicosapentaenoic acid, or docosahexaenoic acid and eicosapentaenoic acid) could be helpful for CVD outcomes or all-cause mortality.
Highlights from other research
Commenting on the advantages of fish oil supplementation, the researchers highlighted five key takeaways from previous studies:
1. Several previous studies have suggested that supplementation with omega 3 fatty acids has beneficial effects on blood pressure, plasma triglycerides, and heart rate; indicating a protective effect against the development of CVD.
2. A number of trials have shown that omega 3 fatty acids can improve flow-mediated arterial dilatation, which is a measure of endothelial function and health.
3. Omega 3 fatty acids have been identified as possessing antiarrhythmic properties that could be clinically beneficial.
4. Studies have said that fish oil can reduce thrombosis.
5. Studies have revealed that the anti-inflammatory properties of fish oil could play a preventive part in the pathophysiology of CVD outcomes.
The research team stated that future studies are required to assess how much fish oil supplements impact the ability to achieve a “clinically meaningful effect.”
Source: BMJ
2020; 368 :m456 doi: https://doi.org/10.1136/bmj.m456
“Associations of habitual fish oil supplementation with cardiovascular outcomes and all cause mortality: evidence from a large population based cohort study”
Authors: Z. Li et al.
