Fish oil supplements appear to increase the risk of first-time heart disease and stroke, even in people who otherwise have good cardiovascular health. On the other hand, regular intake in people with poor cardiovascular health can significantly reduce the risk of dying from heart failure.
A new study involving experts from Saint Louis University examined how taking fish oil supplements in various advanced stages of cardiovascular disease affects cardiovascular health and the risk of premature death. The results can be read in the specialist journal “BMJ Medicine”.
Fish oil against cardiovascular diseases?
Fish oil is known for its high content of omega-3 fatty acids and consumption is also recommended to prevent cardiovascular diseases. The problem, however, is that the evidence for a preventive effect is not conclusive, the researchers report.
To provide more clarity, the team examined how taking fish oil supplements affected the incidence of atrial fibrillation, heart attacks, strokes and heart failure, as well as all-cause mortality.
Influence of fish oil on heart health
In addition, the experts also investigated whether fish oil supplements affect the risk of people with good heart health experiencing atrial fibrillation for the first time, serious cardiovascular events (e.g. heart attack) or premature death.
To do this, the researchers analyzed data from a total of 415,737 participants in the UK Biobank study aged 40 to 69 years. The data collected included usual consumption of fatty and low-fat fish as well as fish oil supplements.
The health status of the participants was assessed by analyzing medical records until March 2021 or until their death. Almost a third of the participants, especially women and older participants, stated that they regularly take dietary supplements with fish oil.
According to the experts, during the average observation period of almost twelve years, 18,367 participants developed atrial fibrillation, 22,636 suffered a heart attack/stroke or developed heart failure.
In addition, a total of 22,140 participants died during the average observation period. Of these, 14,902 were not affected by atrial fibrillation or serious cardiovascular disease, the team reports.
Of the participants who initially had good cardiovascular health and then developed atrial fibrillation, 3,085 suffered heart failure, 1,180 suffered a stroke and 1,415 had a heart attack, the experts continued.
Of the participants with heart failure, a total of 2,436 people died. According to the researchers, this also applied to 2,088 people who had a stroke and 2,098 participants who had suffered a heart attack.
Increased risk from fish oil?
Further data analysis showed that regular consumption of fish oil supplements has different effects on cardiovascular health, disease progression and the risk of premature death.
In participants who did not have any cardiovascular disease at the beginning of the observation period, regular intake of dietary supplements with fish oil was associated with a 13 percent increased risk of developing atrial fibrillation, the researchers report.
According to the team, people who had no cardiovascular disease at the beginning of the observation period and regularly took dietary supplements with fish oil also had a five percent increased risk of a stroke.
Beneficial effects of fish oil on cardiovascular diseases
On the other hand, participants who were already suffering from cardiovascular disease at the beginning of the observation period had a reduced risk of developing atrial fibrillation and a heart attack by regularly taking fish oil supplements, the team reports.
In addition, the risk of fatal heart defects was reduced by nine percent for these participants by taking fish oil supplements, the researchers continued.
Further studies required
According to the experts, an analysis of the possible influencing factors showed that, among other things, gender, age, high blood pressure and the use of statins and antihypertensive medication changed the observed relationships.
“Regular consumption of fish oil supplements could have different effects on the progression of cardiovascular disease. Further studies are now required to determine the exact mechanisms for the development and prognosis of cardiovascular diseases when taking fish oil supplements regularly,” the researchers added in a current press release. (as)