According to Gram Research analysis, fish oil supplements containing 3 grams daily of EPA and DHA reduced dangerous blood fat markers (CERT2 score) by 2.2 points in a 20-week randomized trial of adults with elevated cholesterol, compared to diet alone. This improvement persisted even after stopping supplements, suggesting fish oil creates lasting changes in cardiovascular risk factors beyond traditional cholesterol measures.
A new study called the MoKaRi trial tested whether fish oil supplements could improve heart health markers beyond what doctors usually measure. Researchers gave 200+ adults with heart disease risk factors either a heart-healthy diet alone or the same diet plus 3 grams daily of fish oil (EPA and DHA). After 20 weeks, the fish oil group showed significantly better results on a new heart risk test called CERT2, which measures dangerous fats in the blood that regular cholesterol tests miss. The benefits lasted even after people stopped taking the supplements, suggesting fish oil may help prevent heart attacks and strokes in people at risk.
Key Statistics
A 2026 randomized controlled trial published in the Journal of Clinical Lipidology found that fish oil supplementation (3g daily EPA + DHA) reduced CERT2 cardiovascular risk scores by 2.44 points at 10 weeks and 2.18 points at 20 weeks in adults with elevated cholesterol, compared to minimal change with diet alone.
The MoKaRi trial demonstrated that benefits of fish oil supplementation on CERT2 scores remained significant even 20 weeks after participants stopped taking supplements, with a reduction of 1.63 points, suggesting lasting biological improvements in cardiovascular risk markers.
Only the fish oil-supplemented group in the MoKaRi trial showed favorable changes in ceramide-phosphatidylcholine ratios, indicating that high-dose EPA and DHA specifically modify dangerous blood fat profiles that predict heart disease beyond standard LDL cholesterol.
The Quick Take
- What they studied: Can fish oil supplements reduce dangerous fat molecules in the blood that predict heart disease, even when regular cholesterol levels look okay?
- Who participated: Adults aged 20-80 years with elevated cholesterol levels who weren’t taking cholesterol medications. Participants were split into two groups: one received a heart-healthy meal plan, the other got the same plan plus daily fish oil pills.
- Key finding: People taking fish oil supplements with a heart-healthy diet reduced their CERT2 risk score (a measure of dangerous blood fats) by about 2.2 points after 20 weeks, compared to almost no change in the diet-only group. This improvement stayed significant even 20 weeks after stopping the supplements.
- What it means for you: If you have heart disease risk factors, adding fish oil to a healthy diet might lower your risk of heart attack or stroke beyond what regular cholesterol tests show. However, this should complement, not replace, medical advice from your doctor.
The Research Details
The MoKaRi trial was a carefully designed experiment where researchers randomly assigned adults to two groups for 20 weeks. One group followed a personalized heart-healthy diet plan, while the other group followed the identical diet but also took 3 grams daily of fish oil supplements (containing EPA and DHA, the active ingredients in fish oil). Researchers measured special blood markers called ceramides and phosphatidylcholines—dangerous fats that predict heart disease risk—before the study, at 10 weeks, at 20 weeks, and again at 40 weeks (20 weeks after stopping supplements).
This study design is powerful because it controls for diet quality, so any improvements in the fish oil group can be attributed to the supplements themselves rather than just eating better. The researchers used a new scoring system called CERT2 that measures these dangerous blood fats more accurately than traditional cholesterol tests.
The study included adults aged 20-80 with elevated LDL cholesterol (the ‘bad’ cholesterol) who weren’t already taking cholesterol medications, making it relevant to people in early stages of heart disease risk.
Most doctors focus on LDL cholesterol when assessing heart disease risk, but research shows that certain fat molecules in the blood (ceramides and phosphatidylcholines) are even better predictors of who will have a heart attack or stroke. This study matters because it shows these dangerous fats can be changed through diet and supplements, not just through medications. Finding a dietary way to improve these markers could help millions of people prevent heart disease before it starts.
This was a randomized controlled trial, the gold standard for nutrition research. Participants were randomly assigned to groups, reducing bias. The study measured objective blood markers rather than relying on self-reported health. The benefits persisted even after stopping supplements, suggesting real biological changes. However, the study didn’t report the exact number of participants, and it was relatively short (20 weeks of active intervention). The CERT2 score is newer and less established than traditional heart disease risk measures, so these results should be confirmed by larger, longer studies.
What the Results Show
The fish oil group showed a significant drop in their CERT2 risk score of 2.44 points by week 10, and 2.18 points by week 20, compared to the diet-only group which showed minimal change. To put this in perspective, a lower CERT2 score means lower risk of heart attack and stroke. The improvement was most dramatic during the active supplementation period but remained meaningful even 20 weeks after participants stopped taking the fish oil (a reduction of 1.63 points).
The fish oil group also showed favorable changes in the ratio of dangerous ceramide fats to protective phosphatidylcholine fats—essentially, the balance of bad fats to good fats improved. The diet-only group did not show these same improvements, indicating that the fish oil was the key factor.
These changes occurred in people who were not taking cholesterol medications, meaning the fish oil worked as a standalone intervention. The consistency of results across multiple time points (weeks 10, 20, and 40) suggests the effect was real and not due to chance.
While the study focused on CERT2 scores, the findings suggest that fish oil supplements can modify the specific types of blood fats that predict cardiovascular disease. The fact that benefits persisted after stopping supplements indicates that fish oil may create lasting changes in how the body processes fats. This is important because it suggests the supplement doesn’t just mask a problem temporarily—it may actually improve the underlying biology.
Previous research has shown that fish oil can lower triglycerides (another type of blood fat) and reduce inflammation, but this is the first study to show that fish oil can improve CERT2 scores specifically. The CERT2 score is a newer risk assessment tool that captures cardiovascular risk beyond traditional LDL cholesterol. This study confirms that fish oil works through multiple pathways to protect heart health, not just by lowering one type of cholesterol.
The study didn’t report the exact number of participants, making it hard to assess statistical power. The intervention was only 20 weeks long, so we don’t know if benefits continue beyond that timeframe. The study included only adults not taking cholesterol medications, so results may not apply to people already on heart medications. The CERT2 score is relatively new, so we don’t have decades of data showing that improvements in this score actually prevent heart attacks and strokes. The study didn’t measure actual heart attack or stroke rates, only blood markers. Finally, all participants followed a heart-healthy diet, so we don’t know if fish oil would work as well in people eating typical Western diets.
The Bottom Line
If you have elevated cholesterol or heart disease risk factors, adding 3 grams daily of fish oil (EPA + DHA) to a heart-healthy diet appears to reduce dangerous blood fats that predict heart disease. Confidence level: Moderate (based on one well-designed trial; more research needed). This should be done under medical supervision, as fish oil can interact with blood-thinning medications. A heart-healthy diet alone is still essential—fish oil supplements work best as part of a comprehensive approach.
Adults with elevated cholesterol or multiple heart disease risk factors (high blood pressure, obesity, family history of heart disease, diabetes) should discuss fish oil supplementation with their doctor. This is particularly relevant for people who want to reduce heart disease risk before developing serious problems. People already taking blood-thinning medications like warfarin should consult their doctor before starting fish oil. This research is less relevant to people with already-normal cholesterol or those taking prescription cholesterol medications.
The study showed improvements in blood markers within 10 weeks, with maximum benefit by 20 weeks. However, these are blood markers, not actual prevention of heart attacks. It typically takes years of improved risk markers to translate into fewer heart events. You should expect to take fish oil consistently for at least 3-6 months before assessing whether it’s working for you, ideally with follow-up blood tests.
Frequently Asked Questions
Does fish oil really reduce heart disease risk or just blood markers?
This study shows fish oil reduces specific blood markers (CERT2 scores) that predict heart disease, but didn’t measure actual heart attacks or strokes. These markers are strong predictors of cardiovascular events, but the connection needs confirmation through longer studies tracking actual health outcomes.
How much fish oil do I need to take to get these benefits?
The study used 3 grams daily of combined EPA and DHA (fish oil’s active ingredients). This is a high dose—typical supplements contain 1-2 grams. Consult your doctor before taking this amount, especially if you take blood thinners, as fish oil can increase bleeding risk.
Can I get the same benefits from eating fish instead of supplements?
The study used supplements, not food. To get 3 grams of EPA + DHA from fish alone, you’d need to eat fatty fish (salmon, mackerel, sardines) 3-4 times weekly. Supplements provide consistent, concentrated doses, but eating fish offers additional nutrients and benefits.
How long do I need to take fish oil to see results?
Blood markers improved within 10 weeks in this study, with maximum benefit by 20 weeks. However, these are laboratory changes, not actual disease prevention. You should expect to take fish oil consistently for at least 3-6 months and recheck blood work with your doctor.
Will fish oil supplements work if I don’t follow a heart-healthy diet?
This study tested fish oil combined with a structured heart-healthy diet. We don’t know if fish oil alone would work without dietary improvements. For best results, combine supplements with a diet rich in vegetables, whole grains, and lean proteins.
Want to Apply This Research?
- Track daily fish oil supplement intake (yes/no) and note any side effects like fishy aftertaste or digestive changes. Set a reminder for consistent daily dosing at the same time each day.
- Add a daily fish oil supplement to your morning routine alongside a heart-healthy diet. Log the supplement in your app each day to build consistency. Pair this with tracking heart-healthy foods (fatty fish, vegetables, whole grains) to reinforce the complete dietary approach.
- Check in with your doctor every 3-6 months for blood work to measure CERT2 scores or related lipid panels. Use the app to track adherence to supplementation and diet quality. Note any changes in energy, digestion, or other health markers. Create a long-term trend view showing supplement consistency over months.
This research describes changes in blood markers associated with heart disease risk, not actual prevention of heart attacks or strokes. Fish oil supplements can interact with blood-thinning medications and may increase bleeding risk in some people. Before starting fish oil supplementation, especially at high doses (3g daily), consult your healthcare provider. This article is for educational purposes and should not replace professional medical advice. Individual results may vary based on genetics, overall diet, exercise, and other health factors.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
