VITAL researchers note that it is the largest and longest randomized test of daily high-dose vitamin D (vitamin D3 [cholecalciferol], 2000 IU) and omega-3 fatty acid supplement (Omacor® fish oil, 1 gram) for the prevention of cancer and cardiovascular disease of generally healthy men and women without these baseline conditions. The trial included 25,871 adults -12,786 men aged 50 years and over and 13,055 women aged 55 and following an average of 5.3 years. This study is actually several studies in one because three efforts were conducted and looked at 3 types of results.
Looking at the only oil-based operation, 1 gram of prescription oil-based fish oil was given, equal parts of EPA / DHA were given once a day to 12,933 people over 50 years. They were followed for more than 5 years (5.3 years to be exact). The aim of this part of the study was to answer the question: Do fish oils generally work to reduce heart disease? This means that the primary outcome was primary prevention of important cardiovascular events, which were a combination of myocardial infarction, stroke or death from cardiovascular disease were recorded. Secondary endpoints included coronary revascularization procedures and other unintentional findings that showed people developing heart disease.
After more than 5 years, the study results were published in New England Journal of Medicine. A total of 12,933 participants received active omega-3 vs 12,938 who received placebo. Of these, 386 of the previous and 419 of the latter experienced a larger CVD event, which was not significantly different (HR, 0.92; 95% CI, 0.80-1.06) To summarize these results: fish oils did not change the primary results compared to placebo, statistically.
Among subgroups, however, was 40% reduction in the risk of total MI among omega-3 group members who consumed less than 4.5-6 ounces of fish per week (P= .048) and a 19% reduction in major CVD events. It would be logical that if a diet is missing in a specific nutrient, it would be better to insure that nutrients in a pill form would improve health. Over time, it may be found that healthy oils are absolutely essential for good health. Perhaps in a fish-free diet, fish diet or a diet that lacks healthy oils makes fish oils a difference.
In addition, HR was a total of MI 0.23 for subjects with African anesthesia who took omega-3 compared to placebo (number of events, 9 and 39 respectively; P= 0.001). It is a 77% decrease in MI risk. What was the reason for the good results in the African family population? More studies are needed to reveal what really happens. However, it was noted that the benefits of fish oils were irrelevant to how much fish these participants ate during the week, and the blood levels in EPA and DHA in this subgroup were similar to the others.
Thinking about the mechanism of action of fish oils for cardiovascular disease makes me wonder how it worked in this subpopulation. According to the authors of this study, MOA for fish oil is antithrombotic, hypotriglyceridemic, hypotension and antiinflammatory effects; prevented growth of atherosclerotic plaques; decrease in heart rate decreased susceptibility to cardiac arrhythmia and promotion of nitric oxide induced endothelial relaxation whereby n-3 fatty acids can reduce the risk. Epigenetics and pharmacogenomics are new sciences of genetic variations. The medical information seems to be more and more detailed.
To get an opinion about fish oil, the result is between studies of the past and understand why we get conflicting results; we must pay special attention to confusing factors such as:
- Other drug use on fish oils such as statins, aspirin and beta blockers
- Baseline nutrition status
- Baseline disease severity
- Ethnic differences
- Same existing disease states.
- DHA dose and EPA
It is only by examining all these differences as we will be able to find out who exactly benefits from fish oil. We already know that everyone benefits from a healthy diet of whole foods and healthy oils, but when do fish oil pills improve health? The answers come slowly.
Manson J, Cook NR, Lee IM, et al. Marine n-3 fatty acids and prevention of cardiovascular disease and cancer. N Engl J. Med. 2018; DOI: 10,1056 / NEJMoa1811403