❝ Key Takeaways
The form of omega-3 matters as much as the dose. Fish oil in a supplement can be in many chemical forms including phospholipid form, triglyceride form and ethyl ester (EE). Generally, phospholipid or krill absorption and TG absorb well in a fasted state. While EE and TG absorb well with a high fat meal.
Testing provides important context: If you are low, supplementing will be beneficial. After 3-6months, retesting will tell you if your supplement is working.
The Omega-3 Index blood test tells you whether you actually need fish oil at all. Aim for above 8% and this results in >30% reduction in all cause mortality.
Pay attention to the label: The label “high strength” or “1,000 mg fish oil” is misleading. What matters is the EPA+DHA per capsule, not the total fish oil weight.
Want to understand the science behind these? Keep reading below 👇
📑 In This Issue
Catch up on the rest of the series: Welcome to Pareto Life · Issue 01 — Are Omega-3s good for everyone’s heart? · Issue 02 — Do Omega-3s reduce risk of dementia? · Issue 03 — Does fish oil really help arthritis, dry eyes or AMD?
Most fish oil on store shelves in multiple chemical forms. The list includes esterified esters (EE), triglycerides(TG) and phospholipids (Krill oil). The absorption changes depending on the chemical form of the fish oil. Krill oil and TG fish oil absorb better on empty stomach however with a high fat meal EE and TG absorb better. Surprisingly, krill oil absorption declines significantly with a high fat meal. When taken with a low fat meal absorption of all three chemical forms are relatively similar.
A comprehensive review the literature has demonstrated that although absorption or bioavailability can be significantly different, multi-week studies in which patients were taking fish oil in EE, TG and phospholipid forms, there was minimal difference omega-3 index. The key is to be consistent.
Simply stated. Buy a supplement that makes sense for your lifestyle.
Full fat meal: TG and EE and avoid krill oil
Low fat meal: TG, EE and krill oil
Fasting: TG and Krill oil
This issue covers what actually matters when you’re choosing a fish oil supplement: when to take it (and when not to) and how to know whether you need it at all. We’ve spent the last three issues digging into who benefits most for heart, brain, and inflammation. This is the practical guide to acting on that knowledge.
When Should You Actually Take Omega-3?
The honest answer: not everyone needs to supplement. Daily fish oil makes sense for specific people, not as a universal habit.
The evidence was covered on prior newsletters.
Heart health
Evidence suggests individuals who have a significant risk cardiovascular risk factors (prior heart attack/stroke, established atherosclerotic disease, statin therapy with elevated triglycerides, high coronary calcium score) benefit from prescription strength EPA or EPA dominant formula
high dose EPA reduces risk of major cardiovascular events by 25%
prescription strength pure EPA called Vascepa was used in the REDUCE-IT trial and is available for $22/month
If you have no risk factors, an Omega-3 Index below 5% suggests supplementing is beneficial
Raising your Omega 3 index to >8% lowers risk of all-cause mortality by 34% and lowers risk of cardiovascular disease by 39%
Remember, genetics affects absorption. Different doses work for different people.
Dementia risk
Individuals who have a genetic testing confirming they are APOE e4 carriers benefit supplementation early in life
If you have no risk factors, an Omega-3 Index below 5% suggests supplementing is beneficial
Arthritis
Although the mechanism of action can be explained on how omega-3s reduce inflammation, the clinical impact is modest and inconsistent. There is mild potential benefit in patients with rheumatoid arthritis.
The reduction in inflammatory markers like C- reactive protein (CRP), IL-6 are statistically significant but small (unlikely clinically significant).
Dry eyes
Large randomized controlled clinical trials found no benefit with Omega-3s. However, the Academy of Ophthalmology recommends considering Omega-3s since smaller studies have demonstrated improvement in tear osmolarity (tear salt concentration) and tear volume.
Age-related macular degeneration
Randomized controlled clinical trials found no benefit. Observational studies have demonstrated lower AMD risk however these studies were based on blood levels and dietary intake.
The Omega-3 Index: When to Test and How to Read It
The Omega-3 Index is a simple finger-prick blood test that measures EPA+DHA as a percentage of red blood cell fatty acids. It’s the single most useful number for deciding whether you need to supplement and whether your supplement is working.
When to test: before starting supplementation if you’re healthy and unsure whether you need it; 3-6 months after starting supplementation, to confirm your levels are rising.
How to read it:
Below 4% is high risk is strongly associated with elevated cardiovascular mortality.
Between 4–8% is intermediate suggest there is room for meaningful improvement.
The 8–11% target range is associated with the lowest cardiovascular disease incidence.
Above 11% you hit diminishing returns and a theoretical bleeding-risk concern at extreme levels.
Where to Order an Omega 3 Index
At home testing is available through Carlson labs, Fullsscript, OmegaQuant, etc. In addition, Labcorp can perform the test for approximately $75.
Where to Order an ApoE Genetic Test
ApoE is a one time genetic test. Knowing your ApoE status helps determine whether you are among those at higher risk of dementia and need a higher or more targeted supplementation. Labcorp can perform the ApoE genotype test for approximately $125.
How to Read a Fish Oil Label Without Getting Fooled
The most common label trick: front-of-bottle “1,000 mg” or “high strength” refers to the total fish oil weight per capsule, not the omega-3 content. The omega-3 numbers are on the back, in smaller text.
In patients who high risk for cardiovascular disease, consider generic vascepa. This was the medicine that was used in the REDUCE-IT trial that demonstrated significant reduction in cardiovascular deaths. The generic prescription strength high dose 2gm/day EPA can be found at Costplusdrugs.com for $23/month. It should be taken with fatty meal to maximize absorption.
In patients who have no cardiac risk factors, a combination of EPA/DHA fish oil is likely fine. However read the label and identify the chemical form (EE, TG or krill oil). To achieve a minimum daily 1gm dose and make sure the EPA and DHA should add up to 1gm.
Quality and Purity: The Third-Party Seals That Matter
Fish oil is a particularly easy supplement to mess up because it can oxidize (go rancid), accumulate heavy metals from contaminated fish, and degrade in storage. Manufacturer self-claims of purity mean little. Third-party testing is what counts.
Seals to look for:
IFOS (International Fish Oil Standards) is the gold standard for fish oil specifically — tests for heavy metals, PCBs, oxidation, dose accuracy.
USP Verified is a strong general supplement quality seal.
NSF Certified (especially “NSF Certified for Sport”) has strict heavy metal and contaminant standards.
Red flags: no third-party testing seal at all. A few indications that the oil may have become oxidized include an unpleasant odor: fishy smell, rancid or bitter, sour/metallic taste.
Fishy burps is normal with fresh non-oxidized fish oil, especially when the dose is high.
So When and How — A Practical Buying Guide
If you’ve decided you need to supplement based on the criteria above, the practical path:
Test your Omega-3 Index before buying anything. If it’s already above 8%, you may not need supplementation at all.
Choose the form:
Trigylceride form absorbs with or without food
Krill oil absorbs the best on an empty stomach.
Ethyl ester absorbs best with fatty meal.
Match the EPA:DHA ratio to your goal.
Look for IFOS, USP, or NSF seals on the bottle.
Retest your Omega-3 Index at 3 months to confirm your level is rising. If it isn’t, consider increasing dose, switching to a better-absorbed form, or using a different company.
Don’t overshoot. An Omega-3 Index above 11% is generally not pursued — diminishing returns and theoretical bleeding risk.
❝ ✅ The Bottom Line
Test your Omega-3 Index before and 3 months after starting. Aim for above 8%.
Read the label for EPA+DHA per serving, not total fish oil weight. “High strength” on the front of the bottle is usually marketing.
Look for IFOS, USP, or NSF third-party seals. Skip products without one.
Match your EPA:DHA ratio to your goal: EPA-dominant for cardiovascular, balanced or DHA-containing for brain.
This closes out the fish oil series. Next week: Urinary tract infections, vaginal health and the role of vaginal estrogen, cranberry, D-mannose and oral vs vaginal probiotics.
If you’re new to the series, start here: Welcome to Pareto Life. Then catch up on Issue 01 — Are Omega-3s good for everyone’s heart?, Issue 02 — Do Omega-3s reduce risk of dementia?, and Issue 03 — Does fish oil really help arthritis, dry eyes or AMD?.
References
Dyerberg et al., Prostaglandins Leukot Essent Fatty Acids 2010 | Schuchardt & Hahn, Prostaglandins Leukot Essent Fatty Acids 2013 | Neubronner et al., Eur J Clin Nutr 2011 | Köhler et al., Lipids 2017 | Lawson & Hughes, Biochem Biophys Res Commun 1988 | Davidson et al., J Clin Lipidol 2012 | Harris & von Schacky, Prev Med 2004 (Omega-3 Index original) | von Schacky, Nutrients 2021 | Sheppard et al., JACC Adv 2025 | Bhatt et al., N Engl J Med 2019 (REDUCE-IT) | Yokoyama et al., Lancet 2007 (JELIS) | IFOS testing standards | USP-NF Dietary Supplements