Is omega 3 the same as fish oil? Not always. Read on for the proper way to categorise your omega-3s, and learn how each affects your heart health.
Key Takeaways
- Omega-3 and fish oil need not be referring to the same thing. That’s because “omega-3” could be referring to either plant-based or marine sources.
- Neither plant-based nor marine omega-3 supplements reliably lower LDL-cholesterol at standard doses, but one type does show a consistent benefit for triglycerides, another cardiovascular risk factor.
- Both plant-based and marine omega-3s consistently lower chronic inflammation, an independent risk factor for heart disease.
- When it comes to the risk of developing or dying from heart disease, whole food sources of omega-3s consistently outperform supplements, and a Singapore study points to why combining both types matters.
- The way you cook your fish changes whether it protects or harms your heart. Find out how to get the most from fatty fish, and when a high-quality supplement is worth adding.
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Omega 3 vs Fish Oil: What’s the Actual Difference?
Is Omega 3 the Same as Fish Oil?
Most people use these terms interchangeably. But they need not always mean the same thing.
Fish oil is a supplement containing two specific types of omega-3: EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). These are marine omega-3s since their sources are fatty fish.
However, there is a second family of omega-3s that is plant-based. This refers to ALA (alpha-linolenic acid), which is an essential fatty acid that we must obtain from our diet, and is found in foods such as flaxseeds, chia seeds, and walnuts. As such, flaxseed oil supplements are technically omega-3s too, but they are not fish oil.
Your body can convert ALA into EPA and DHA. But the conversion rate is very low. Research suggests that your body converts only around 5 to 15% of dietary ALA to EPA, and less than 1% to DHA.
So when someone says that they’re taking an omega-3 supplement, it’s worth asking: “which type?”
Takeaway: Fish oil contains EPA and DHA. Plant-based omega-3 supplements contain ALA. Your body converts ALA into EPA/DHA, but not efficiently enough to treat them as being equal.
Omega-3 Supplements, LDL-Cholesterol, and Heart Health
The most comprehensive evidence comes from a 2020 Cochrane review that pooled data from 86 randomised controlled trials.
Increasing EPA/DHA supplementation had no effect on reducing the risk of suffering from cardiovascular events like heart attacks and strokes. However, there was an 8% reduction in the risk of dying from a cardiovascular disease, in particular coronary events.
The clearest benefit though was for triglycerides, that is the fats in your blood that also raise heart disease risk. EPA/DHA supplements reduced triglycerides by around 0.24 mmol/L, or roughly 15%.
ALA supplementation, on the other hand, had no effect on the risk of developing or dying from any heart disease.
At the same time, the review found that neither EPA/DHA nor ALA had any meaningful effect on LDL-cholesterol.
That said, both EPA/DHA and ALA do show consistent benefit for chronic inflammation.
A 2019 meta-analysis of 20 randomised controlled trials found that EPA reduced CRP by 0.56 mg/L and DHA by 0.5 mg/L. CRP, or C-reactive protein, is a key marker of chronic inflammation, which is an independent risk factor for heart disease.
Another 2023 meta-analysis of 19 randomised controlled trials found that ALA supplementation also reduced CRP by 0.38 mg/L.
Takeaway: Neither EPA/DHA nor ALA supplements reliably lower LDL-cholesterol. Both reduce CRP, a marker of chronic inflammation. EPA/DHA supplements were also found to lower triglycerides by around 15%.
Why Do Whole Foods Outperform Omega-3 Supplements?
Here’s where the benefits of omega-3s become more compelling.
A 2016 pooled analysis looked at circulating biomarkers of ALA, EPA, and DHA across 19 cohort studies and more than 45,000 participants. Higher levels of each type were independently associated with 9 to 10% lower risks of dying from coronary heart disease, or heart disease caused by blocked arteries.
This is a biomarker study, meaning that it measures the actual omega-3s in the blood and tissues. This is a more reliable signal of how much omega-3 the body is absorbing and using, compared to using food diaries or participants’ ability to recall what they ate.
A particularly relevant finding comes from the Singapore Chinese Health Study in 2015. Among over 63,000 Singaporean Chinese adults, the highest combined dietary intake of ALA and EPA/DHA was associated with a 33% lower risk of cardiovascular death compared to the lowest intake.
When analysed separately, dietary EPA/DHA alone was associated with a 14% lower risk of dying from heart disease, and dietary ALA alone was associated with a 19% lower risk.
Takeaway: Both biomarker data and dietary intake studies of omega-3s point in the same direction. Getting omega-3s from both plant-based and marine whole food sources is consistently associated with meaningfully lower risk of dying from heart disease, with the greatest benefit seen when whole foods provide good amounts of both ALA and EPA/DHA.
The Food Matrix: Why Supplements Can’t Do It All
Why do whole foods appear to outperform supplements when it comes to heart health? The most plausible explanation is the food matrix.
When you eat fatty fish, you’re not just getting EPA and DHA. You’re also getting vitamin D, B12, selenium, and iodine.
When you eat ground flaxseed or walnuts, you’re getting fiber, lignans, antioxidant minerals, vitamin E, and polyphenols.
None of these come together in a supplement capsule that has been concentrated to the omega-3 oil. And these nutrients likely work together in ways that an isolated supplement cannot replicate.
Takeaway: Omega-3 supplements offer real support for inflammation and triglyceride reduction. But whole foods with their food matrix do the heavy lifting to deliver actual heart health outcomes.
How to Get More (of the Right) Omega-3s Daily: Four Practical Tips
Tip 1: Eat Fatty Fish at Least Twice a Week
Most dietary guidelines, including Singapore’s, recommend two servings of fatty fish per week for better heart health.
Good options include salmon, saba (mackerel), and canned sardines, which are especially convenient. If you have access to a Japanese supermarket, grilled eel (unagi) and smelt (shishamo) are excellent choices as well.
Tip 2: Don’t Deep-Fry Your Fish
Cooking method makes a difference. A 2023 meta-analysis found that higher intake of fatty fish was associated with an 11% lower risk of heart disease. However, higher intake of fried fish increased that risk by 3%.
Deep-frying not only degrades omega-3 content, but also adds fat and calories. Steaming, grilling, baking, or pan-frying are all better options.
Tip 3: Consider a High-Quality EPA/DHA Supplement If You Don’t Eat Fish Regularly
Your body converts less than 10% of ALA to EPA, and less than 1% to DHA. A flaxseed oil capsule is therefore not a functional substitute for fish oil.
If you don’t eat fatty fish regularly, look for a high-quality fish oil supplement. But check the label, and look for a product where EPA and DHA together make up at least 80% of the total fat content.
For those interested, this is a fish oil that I often use with my clients.
[This is an affiliate link. If you make a purchase through the link, I may earn a small commission at no extra cost to you.]
If you’re vegan, look for a high-quality algae oil with the same criteria. Fun fact: algae is actually the original source that fatty fish get their EPA and DHA from.
Tip 4: Combine ALA and EPA/DHA from Whole Foods
The 2015 Singapore study found that the biggest reduction in the risk of dying from heart disease came from combined intake of both plant-based and marine omega-3s.
So, besides eating two servings of fatty fish, keep up the habits from the Portfolio Diet. Soak chia seeds together with your overnight oats; stir ground flaxseed into your cooked pearl barley or rye; and have a small handful of walnuts for an afternoon snack.
Bottom Line: Is Omega 3 the Same as Fish Oil?
Not always. Omega-3 is a broader category, with fish oil as a specific marine source of EPA and DHA, and ALA as the other main version from plant-based sources.
For LDL-cholesterol, neither type of supplement reliably moves the needle. Both reduce chronic inflammation, and EPA/DHA also lowers triglycerides by around 15%.
Where omega-3s really show their impact is in their whole food forms, with compelling data from the Singapore population study: Combining fatty fish with ALA-rich plant foods was associated with a 33% lower risk of dying from heart disease when compared to the lowest intake.
So, have the best of both worlds. Eat fatty fish at least twice a week, and also add flaxseeds, chia seeds, and walnuts to your daily routine.
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