By OmegaQuant
Groundbreaking research presented at the American College of Cardiology (ACC) 2020 Scientific Session has reshaped how scientists understand the heart-protective effects of omega-3s. According to new findings from the REDUCE-IT study, it’s not the reduction in triglycerides that drives cardiovascular benefits — it’s the blood levels of EPA, one of the most powerful omega-3 fatty acids.
A Closer Look at the REDUCE-IT Study
The REDUCE-IT trial, led by Dr. Deepak L. Bhatt of Brigham and Women’s Hospital and Harvard Medical School, investigated icosapent ethyl (Vascepa) — a purified form of EPA developed by Amarin. The study enrolled more than 8,000 patients across 11 countries who were already on statin therapy but remained at elevated cardiovascular risk.
Over a five-year period, participants taking high-dose icosapent ethyl experienced a:
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25% reduction in major cardiovascular events
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30% reduction in total cardiovascular incidents (including repeat events)
These results were considered historic — yet until recently, experts assumed that the drug worked primarily by lowering triglycerides.
Why Blood EPA Levels Matter More Than Triglycerides
The new ACC analysis revealed that higher achieved blood EPA levels, not triglyceride reductions, were the strongest predictors of benefit. Dr. Bhatt explained that while changes in markers like LDL, HDL, ApoB, and CRP contributed minimally, EPA concentration in the blood was the true driver behind the sharp decline in cardiovascular risk.
In simple terms:
“The higher the EPA levels in the blood, the lower the risk of heart attack, stroke, and death,” said Dr. Bhatt.
This discovery marks a shift in thinking about omega-3 therapy, much like the early days of statins revolutionized cholesterol treatment.
How EPA Works to Protect the Heart
The REDUCE-IT data revealed that participants with the highest EPA blood levels had significantly lower risks of:
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Cardiovascular events
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Heart attacks and strokes
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Sudden cardiac death and cardiac arrest
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Hospitalization for new heart failure
Interestingly, while EPA levels rose by 386%, levels of DHA — another major omega-3 — slightly declined (by about 3%). This distinction suggests that EPA alone was responsible for the observed cardiovascular protection, not DHA.
Why EPA Levels Differ Between Individuals
One of the lingering questions is why some people achieve higher blood EPA levels than others, even on the same dose of icosapent ethyl. Researchers speculate that metabolism, genetics, body size, and other individual factors may play a role. More research is needed to uncover why certain people respond more robustly than others.
What About Fish and Supplements?
Dr. Bhatt noted that the EPA concentrations achieved in REDUCE-IT far exceed what can be reached through diet or standard fish oil supplements. Achieving similar blood levels through food alone would require consuming enormous quantities of oily fish — something not practical for most people.
Likewise, reaching REDUCE-IT-level EPA through supplements could require 20–30 capsules per day, depending on formulation and purity. Additionally, many supplements contain DHA, which may counteract some of EPA’s effects.
Still, for those who are not candidates for prescription omega-3 drugs, dietary sources and high-quality omega-3 supplements remain essential for supporting overall heart, brain, and eye health.
Understanding the Omega-3 Index: Measuring What Matters
While REDUCE-IT focused on serum EPA levels, the Omega-3 Index provides a simple, standardized way to assess long-term omega-3 status. Developed by Dr. Bill Harris and Dr. Clemens von Schacky, this test measures EPA and DHA in red blood cell membranes and categorizes results into three risk zones:
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High risk: <4%
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Intermediate: 4–8%
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Low (optimal): >8%
An Omega-3 Index above 8% has been consistently linked to lower cardiovascular risk and better heart health outcomes.
How Much Omega-3 Do You Need to Reach Optimal Levels?
In a study published by OmegaQuant’s Dr. Bill Harris and Dr. Kristina Harris Jackson, researchers estimated that to reach an Omega-3 Index of 8%, individuals may need 1–2 grams of EPA and DHA daily, depending on their starting point and the supplement form used.
As Dr. Jackson explained:
“Low doses make studies confusing — they may show no effect simply because participants never reached adequate omega-3 levels.”
This insight underscores the importance of dose and measurement. Without knowing your baseline omega-3 level, you can’t tailor your intake effectively.
The Takeaway: Blood Levels Are the Future of Omega-3 Therapy
The REDUCE-IT findings highlight a crucial point — omega-3 benefits are dose- and level-dependent. For prescription users, icosapent ethyl provides a proven clinical benefit through dramatically elevated EPA levels. For others, monitoring and optimizing omega-3 intake through diet, supplementation, and Omega-3 Index testing can still play a powerful role in preventive health.
As research continues, one thing is clear: omega-3 status in your blood — not just your diet — is what truly matters for your heart.
