#314 Is Fish Oil Still Good for the Heart and Longevity?

Is Fish Oil Still Good for the Heart and Longevity?

Is fish oil still good for the heart? Ten or 20 years ago I would have said most definitely for the heart and possibly for longevity. Now, I’m not so sure.

Six Reasons Why I Took Fish Oil in the Past

1. Fish Oil May Lower Blood Pressure 1-2 Points

Studies show that fish oil may have a slight blood pressure-lowering effect in the range of 1-2 mmHg. And as my long-time readers know, the goal blood pressure to prevent heart disease and to optimize for longevity seems to be about 110/70 mmHg. To put this blood pressure-lowering effect of fish oil into perspective, you could get this same 1-2 mmHg blood pressure reduction from losing just 2-4 pounds.

2. Fish Oil Lowers Triglycerides

High levels of triglycerides in the blood can cause all sorts of damage to your vascular system. And fish oil has long been proven to lower triglycerides. However, whatever benefit you may gain in triglyceride-lowering from fish oil, simply eliminating all added sugars and flour may lower your triglycerides even more!

3. Fish Oil May Keep Inflammation Levels Lower

Once again, long-term readers know that keeping inflammation levels low may be the secret to avoiding cardiovascular disease, including atrial fibrillation, and optimizing for longevity. And science suggests that fish oil may help to reduce inflammation levels. As my personal goal is to have a C-reactive protein (CRP) lab value of zero despite having a history of an autoimmune condition, this provided an additional reason for me to take fish oil. For those not familiar with the CRP blood test, a CRP reading of zero indicates no significant inflammation going on anywhere in the body.

4. Fish Oil May Promote Longevity

Although the data is weak, some studies report a longevity benefit from fish oil. For example, in this study, fish oil helps to prevent the telomere shortening that comes with aging. While many studies report that higher blood levels of omega-3’s are associated with an increased lifespan, it isn’t clear to me if this is from fish oil or from eating real fish.

5. Fish Oil May Help with Weight Loss

Once again, the data here is weak but yes, there are studies reporting that fish oil helps with weight loss. Indeed, some studies report that fish oil may reduce hunger and enhance metabolism. As one who has struggled to keep my weight in check, I was eager for any help I could get. Sadly, I didn’t notice any reduction in my hunger or an increased calorie burn with fish oil.

6. Fish Oil May Help with Dry Eyes and Dry Skin

Yes, fish oil has been shown to help with dry eyes and dry skin. And given that I live in the very dry state of Utah, my hope was that fish oil would help me better tolerate contact lenses and help to moisturize my skin. But with many of the other possible fish oil benefits, it didn’t really seem to help my dry eyes or my dry skin.

Fish Oil Doesn’t Seem to Prevent Heart Disease and Cancer

With all of the above reasons to take fish oil, one would hope that fish oil prevents heart disease and cancer. So in the biggest and most rigorous study to date, the recently completed VITAL Trial randomized nearly 26,000 patients to approximately 1 gram/day of fish oil or placebo for over 5 years. Sadly, faithfully taking fish oil for over 5 years didn’t prevent heart disease nor did it prevent cancer.

Fish Oil May Increase Your Risk of Atrial Fibrillation

While fish oil didn’t seem to impact heart disease risk, a just-published sub-study of the VITAL Trial showed a non-statistical trend toward an increased risk of atrial fibrillation from taking 1 gram/day of fish oil. To put this finding in perspective, a study using 2 grams/day of fish oil also showed a non-statistically significant increased risk of atrial fibrillation. And at the high dose of 4 grams/day of fish oil, two studies showed a statistically significant risk of atrial fibrillation. Taken together, these studies raise the possibility that there just might be an atrial fibrillation risk from taking fish oil and this potential risk may be dose-related.

Does Fish Oil Increase Your Bleeding Risk?

One area of controversy is whether or not fish oil increases your bleeding risk. Indeed, there are many studies reporting that fish oil increases your bleeding risk, especially when combined with other blood thinners, whereas other studies say there is no increased risk.

The bottom line is if you have been prescribed a blood thinner, please discuss the possibility of an even higher bleeding risk with your cardiologist or EP should you choose to take fish oil. Also, please remember that fish oil has never been proven to prevent AFib strokes.

Fish Oil in China’s Longevity Village

As you know from our best-selling book, The Longevity Plan, the centenarians we studied in China’s Longevity Village didn’t take fish oil supplements. Rather, they kept their omega 3 levels high from eating small oily fish that they caught from the river running through the village one to two times a week. And eating small oily fish is ideal for maximizing the benefit of omega 3’s to the mercury and PCBs. In general, the smaller the fish the lower the mercury/PCB dose.

Is Dr. Day Still Taking Fish Oil?

Rather than keep you in suspense any longer, let me answer this question. While I took fish oil in the past for the six reasons I’ve listed above, I no longer take it.

The reason is that, now that several studies have reported an increased risk of atrial fibrillation from this supplement, I started to experience palpitations every time I took it. I didn’t used to get palpitations before, but now I do when I take this supplement. Perhaps it was just a nocebo effect, where I started to experience side effects because I was worried this supplement might be harming me. So, while omega 3s are still important, I now get them naturally from wild salmon, whole flax seeds, and chia seeds.

Dr. Day’s 5 Thoughts on Fish Oil

1. Based on my review of the medical literature, I still believe that fish oil may help lower triglycerides, inflammation, and possibly blood pressure.

2. The data for fish oil promoting longevity and weight loss is so weak that I don’t feel there is much of a benefit in these two categories.

3. While fish oil may lower your triglycerides, inflammation, and blood pressure, it probably won’t prevent a heart attack, heart failure, etc.

4. Fish oil may increase your atrial fibrillation risk which is why I’ve significantly reduced the dose of fish oil that I take.

5. Based on the potential AFib risk, it may be better to get your omega 3’s naturally from wild fish low in mercury/PCBs or from plant-based sources like flax seeds, chia seeds, or walnuts.


While fish oil has been widely studied and is commonly used as a dietary supplement, individual responses may vary. It’s important to note that the information provided in this blog is for educational purposes only and should not be considered medical advice. Before starting any new supplement regimen, including fish oil, readers are encouraged to consult with their healthcare provider to determine if it is safe and appropriate for their individual health needs and medical history.

About the Photo

Also, if you liked the photo attached to this article, it is a picture we took on one of our daily runs in the summer at 10,000 feet overlooking beautiful Park City, Utah.

Disclaimer Policy: This website is intended to give general information and does not provide medical advice. This website does not create a doctor-patient relationship between you and Dr. John Day. If you have a medical problem, immediately contact your healthcare provider. Information on this website is not intended to diagnose or treat any condition. Dr. John Day is not responsible for any losses, damages or claims that may result from your medical decisions.

  1. Keep on running, Dr. Day. 10,000 feet in the Wasatch Range is a great place to enjoy life during ANY season. Thankyou for how your skills have blessed my life.

  2. I am taking 750mg of Omega3 but its not fish oil.
    Says “emulsified dry” cant find any info on what
    that means. What is that? Should I go back to full
    fish oil?
    Thanks in advance,

  3. Thanks for this information. I heard a Doctor talking about fish oil and A fib on the radio in Australia but only caught the tail end of the comment.I then asked my electrophysiologist and cardiologist and they had not heard of this. It was 6 months ago.
    I did pull back on my fish oil dosage- at that time I was taking 3 grams daily to 1 gram daily and have been looking for more information since.

    Your article has answered all my questions, thank you so much