I recently attended a lecture by Dr. Bill Harris on Omega-3s and athletes - I am a dietitian that specializes in longevity for professional athletes - and here are my key takeaways!
You gotta measure.
Dr. Harris has hundreds of research papers dedicated to omega-3 fatty acids. He is one of the most well respected scientists in this field and actually created a measurement tool - the Omega 3 Index (O3I) - that researchers and providers like me around the world use today to document client health progress. The O3I is a measurement of the EPA and DHA present in the membranes of your red blood cells. The total fatty acids are measured, and then the percentage of those fatty acids that are EPA and DHA are given as a percentage on your Omega 3 Index report. The goal is 8-12% and even higher. Red blood cells turn over about every 120 days, so the O3I is a great measurement of what has been going on in your body for the last several months, not just what you ate last week. Monitoring your O3I can be done in 4 month intervals, and once you get your level up into that 8+ range, annually.
Both EPA and DHA are important.
Both Dr. Bill Harris and his daughter, nutrition scientist and dietitian Dr. Kristina Harris Jackson both mention that there are lots of ways to argue for high EPA or high DHA. There is evidence to support both in many different applications. They said what was more important is that you have both. Wild fish present their omega-3 fatty acids in phospholipid form with both EPA and DHA together. So eating fish rich in omega-3s is key, and if supplementing, find one in a triglyceride (TG) or ethyl ester (EE) form that shows both EPA and DHA listed separately on the nutrition facts label. I like Nordic Naturals, Pure Encapsulations, or Quell.
Chase the Japanese
The Japanese eat a lot of fish. Weekly for sure, most likely daily, and in some cases, every few hours! Due to their high fish intake, studies show the Japanese have an average O3I over 8%. Meanwhile, here in the US we are struggling to hit 4%. In Seattle where I am from we are struggling even more down at 3%! Raising a low Omega-3 Index is a reasonable goal on its own terms. Worth being careful with the longevity framing, though: the research linking a higher Index to longer life is observational, so it shows the two travel together rather than proving that raising your Index adds years.
Omega-3s preserve muscle mass.
After an injury, surgery, or even a large weight loss, lean body mass begins to drop. A number of studies suggest omega-3s help preserve muscle mass during recovery, though the literature is not uniform. Notably, there was no effect on increasing muscle mass, or on speeding wound or bone healing — the finding is about holding on to what you have, not building more. They also do their best work when they are already on board, so you’ll want to be at that 8%+ range before you ever do get injured or are in a position where you may lose muscle mass over time.
Consistency is key.
In a flow chart slide from the presentation, on each outcome and regardless of status, one of the actionable recommendations was “recommend consistent intake of multiple omega-3 rich meals per week.”
On the specific number, the authoritative guidance is two to three servings a week: the American Heart Association recommends two servings of about 3 ounces cooked, and the FDA and EPA advise two to three 4-ounce servings a week from their Best Choices list. Note that a few species carry their own weekly limits under that advice — albacore among them, at one serving a week.
Mixing in salmon, tuna, shellfish and lean white fish makes a great rotation for variety and flavour.
Do your math correctly.
The biggest question everyone has is “how much?” Now that we know omega-3s are so important, how do we get them and how much do we need to eat? The therapeutic goal from this lecture (the amount needed to see significant benefit) was 1.5-2.2 grams (that's 1500-2200 mg) every day! They recommend both eating fish three times a week and supplementing with a fish oil supplement that has both EPA and DHA. For food, a 4 oz cooked piece of wild Alaskan king salmon provides roughly 2 grams (2000 mg) of EPA and DHA on USDA figures, which covers two days of that target. Eating wild Alaskan king salmon a couple of times a week gets you most of the way there. On a supplement bottle, you have to be sure to do your math correctly… Dr. Harris and Dr. Jackson said to ignore the “total omega-3” number on the bottle and instead take the listed mg of EPA and add it to the listed mg of DHA, and that is your accurate intake amount. Make sure you check the serving size!
Fish + Supplements are the most efficient.
According to a study, the most efficient way to improve your O3I is to eat fish three times a week and supplement with a fish oil rich in EPA + DHA. Eating fish 3x/week got people to about 7.1% O3I; but just a little extra kick with supplementation put people over the 8% goal.
Omega-3s and bleeding — what the evidence actually shows.
This is the question that comes up most, so it is worth setting out carefully and with sources you can check.
Dr. Harris has argued this case in the peer-reviewed literature. In a 2014 review in the British Journal of Nutrition — titled, precisely, "n-3 Fatty acids affect haemostasis but do not increase the risk of bleeding" — he and his co-authors concluded that the evidence offers no support for discontinuing omega-3 before invasive procedures or when it is taken alongside other agents that affect bleeding. Note the distinction in that title: omega-3s do measurably affect how platelets behave. What the trials have not found is an increase in clinically significant bleeding.
The evidence has moved in his direction since. In the OPERA trial, more than 1,500 cardiac surgery patients received omega-3 before surgery, and it did not increase perioperative bleeding — a dedicated analysis of that trial found fewer transfusions, and that higher blood omega-3 levels on the morning of surgery were associated with less bleeding. A 2024 meta-analysis of 11 trials and over 120,000 patients found no increase in overall or serious bleeding. And the Society for Perioperative Assessment and Quality Improvement, which recommends stopping most dietary supplements about two weeks before surgery, makes fish oil an explicit exception and recommends continuing it.
Two things we are not going to leave out. The FDA-approved label for prescription icosapent ethyl at 4 g/day does list an increased risk of bleeding events, and the label for prescription omega-3 ethyl esters notes prolonged bleeding time while stating that it has not produced clinically significant bleeding episodes. High-dose omega-3 also carries a small increased risk of atrial fibrillation, which European regulators added to prescription omega-3 product information in 2023.
And the practical point, which Dr. Harris makes himself: follow your surgeon. Stopping for a few days will not meaningfully move your Omega-3 Index, and it is not worth an argument. Tell your surgical team what you are taking and do what they tell you.
Source: Sports Nutrition Symposium 5.0, Bill Harris, PhD & Kristina Harris Jackson, PhD, RD, "Omega-3 Fatty Acids Overview," Monday, June 20th 2022. This article is a first-person account of a live lecture, and the symposium was not recorded, so the summaries of what was said cannot be checked against a transcript. Where this piece makes a claim about safety or dosing we have anchored it on published, citable sources instead — linked inline above.