Don’t take regular fish oil just to prevent heart disease
Grade AMedium benefitMoneyFreeLittle timeNo willpower
Two large trials enrolled 26,000 and 15,000 people with diabetes respectively. Those who took 1 gram of fish oil daily showed no difference from non-users in terms of major cardiovascular events or death rates. The fact that eating fish is healthy does not mean fish oil capsules are equally beneficial. Skipping them can save you 400–1,000 yuan each year.
- Cost
- Roughly 1–3 yuan per day, or 400–1,000 yuan per year. It requires no extra time to take.
- Benefit
- The VITAL trial followed 25,871 participants for 5.3 years; those taking 1 gram of fish oil daily showed no difference in major cardiovascular events or mortality compared to non-users. The hazard ratio for major events was 0.92 (95% CI 0.80–1.06), well below 1, indicating no benefit. All-cause mortality showed a similar pattern (HR 1.02, 95% CI 0.90–1.15). The ASCEND trial, involving 15,480 diabetic patients over 7.4 years, also found no difference in severe vascular events (RR 0.97, 95% CI 0.87–1.08) or mortality (RR 0.95, 95% CI 0.86–1.05). These results appear favorable only because many assume “eating fish is healthy” equates to “fish oil capsules are beneficial.”
- Notes
- Controversy exists: One trial did show benefits. The REDUCE-IT trial included 8,179 high-risk patients with existing cardiovascular disease or diabetes, already on statins and with elevated triglyceride levels (135–499 mg/dL). Those taking 4 grams of prescription-grade pure EPA daily saw a 25% lower risk of events (HR 0.75, 95% CI 0.68–0.83). However, this was a high-dose prescription medication for a specific high-risk group, not ordinary fish oil supplements for the general population. This discussion excludes the health benefits of eating fish itself. 〔17.2〕
Sources · 3
- Manson JE et al. (2019). Marine n-3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer. NEJM. doi.org/10.1056/NEJMoa1811403
- ASCEND Study Collaborative Group (2018). Effects of n-3 Fatty Acid Supplements in Diabetes Mellitus. NEJM. doi.org/10.1056/NEJMoa1804989
- Bhatt DL 等 (2019). Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia. New England Journal of Medicine. doi.org/10.1056/NEJMoa1812792（备注里那项高纯度处方鱼油试验）