Omega-3 fatty acids and blood pressure

Blood Pressure CuffIt was recognized many years ago that fish oil has a dose-dependent effect on lowering blood pressure (1). So how does it do it? There are a lot of different ways.

The first is the ability of the omega-3 fatty acids in fish oil to alter the levels of a group of hormones known as eicosanoids (2,3). These are the hormones that cause blood vessels to contract, thereby increasing the pressure needed to pump blood through the arteries. The omega-3 fatty acids, especially eicosapentaenoic acid (EPA), inhibit both the synthesis and release of the omega-6 fatty acid arachidonic acid (AA) that is the molecular building block necessary to produce those eicosanoids that cause constriction of blood vessels.

The second way that fish oil helps reduce blood pressure is to accelerate weight loss. When you lose excess weight, blood pressure invariably decreases. A recent trial has indicated that when you add fish oil to a calorie-restricted diet, there is greater weight loss (4). This study was followed by an additional trial that indicated when adding fish oil to a weight-reduction diet, there was a further effect on lowering blood pressure (5). So how does fish oil help you lose excess weight? The answer lies in the ability of the omega-3 fatty acids in fish oil to reduce cellular inflammation in the fat cells (6). It's that cellular inflammation that makes you fat and keeps you fat. Reducing that cellular inflammation in the fat cells is the key to weight loss.

Finally another cause of increased blood pressure is increased stress. It was shown in 2003 that high levels of fish oil reduce the rise of blood pressure induced by mental stress (7).

Of course, the best way to reduce blood pressure is to follow an anti-inflammatory diet rich in omega-3 fatty acids. That means a diet rich in fruits and vegetables with adequate levels of low-fat protein and low levels of omega-6 and saturated fats. It's also commonly known as the Zone diet.


  1. Morris MC, Sacks F, and Rosner B. “Does fish oil lower blood pressure? A meta-analysis of controlled trials.” Circulation 88: 523-533 (1993)
  2. Sears B. “The Zone.” Regan Books. New York, NY (1995)
  3. Sears B. “The OmegaRx Zone.” Regan Books. New York, NY (2002)
  4. Thorsdottir I, Tomasson H, Gunnarsdottir I, Gisladottir E, Kiely M, Parra MD, Bandarra NM, Schaafsma G, and Martinez JA. “Randomized trial of weight-loss diets for young adults varying in fish and fish oil content.” Int J Obes 31: 1560-1566 (2007)
  5. Ramel A, Martinez JA, Kiely M, Bandarra NM, and Thorsdottir I. “Moderate consumption of fatty fish reduces diastolic blood pressure in overweight and obese European young adults during energy restriction.” Nutrition 26: 168-174 (2010)
  6. Sears B. “Toxic Fat.” Thomas Nelson. Nashville, TN (2008)
  7. Delarue J, Matzinger O, Binnert C, Schneiter P, Chiolero R, and Tappy L. “Fish oil prevents the adrenal activation elicited by mental stress in healthy men.” Diabetes Metab 29: 289-295 (2003)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

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About Dr. Barry Sears

Dr. Barry Sears is a leading authority on the impact of the diet on hormonal response, genetic expression, and inflammation. A former research scientist at the Boston University School of Medicine and the Massachusetts Institute of Technology, Dr. Sears has dedicated his research efforts over the past 30 years to the study of lipids. He has published more than 30 scientific articles and holds 13 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 13 books, including the New York Times #1 best-seller "The Zone". These books have sold more than 5 million copies in the U.S. and have been translated into 22 different languages.

40 thoughts on “Omega-3 fatty acids and blood pressure

  1. Are paleo eaters “archevorists”? Curious new term by Dr Kurt Harris.

    Everyday I am more intriguing with the primal concept of only having 2-3 meals a day, ‘dont grazing like a herbivore’, as Harris says. Because of originally Zone Diet recommended 5 meals a day. I go on recommending 2-3 meals a day with a couple of snacks, but I am tempted to modify slightly my point of view.

  2. I’m grateful for the Zone information; since last fall, I’ve applied it diligently but not soon enough to avoid open heart by-pass surgery. Fortunately my cardiologist is encouraging me to continue the daily 10ml of Zone Omega 3 oil [I get it by the bottle] along with SeaHealth, Micronutrients and Bone Health; and he is generally supportive of the Zone diet although I’m not sure how much he is familar with it. My cardio-surgeon was certainly all for going home on such a diet – immediately after surgery, he put me on a diabetic diet complete with insulin [I'm not diabetic] because low/normal blood sugar levels promote tissue healing. With the Zone nutritional plan my blood sugar is fine. Thank you for your continuing work that reverses past, present and future dietary-caused disasters. I’ve noticed since my surgery, that a 1 block snack or a 2 block meal is all that I want or can handle; I don’t “graze” but sometimes eat again 3 hours later when I start to feel hungry.

      • Can you please translate 2.5 grams of EPA/DHA per day as to “number of” capsules? I currently take 4 capsules (the large ones) of EicoRX and 1 capful of the Sea Health Plus in the morning with breakfast. Thanks.

  3. Why does everyone always rag on saturated fats? They are certainly preferable to polyunsaturated fats, which have a high change of oxidation. That’s also why too much omega-6 isn’t good either. They are about the highest of the polyunsaturated fats, but they have good qualities other polys don’t. Normal saturated fats should NOT be lumped with trans fats, which is what is usually done. Bad! Bad! Bad!

    • I consider omega-6 fatty acids to be the most inflammatory of all fatty acids because of their conversion into arachidonic. Saturated will have lower inflammatory impact than omega-6 fatty acids, but they exert their influence by binding to TLR-4 to activated NF-kappaB. Monounsaturated fats are neuter in regard to inflammation, whereas omega-3 fatty acids are anti-inflammatory fatty acids.

  4. Again, thank you for giving us the science in a way the non-scientist can understand. I’ve been to the website–and am able to fully understand very little–it’s definitely written for scientists. What I definitely understand is the ‘urgency’ these scientists communicate regarding the imbalance of omega 3 to omega 6 in our diet. Dr. Sears also discusses this with the same urgency. The scientists that are part of the NIH specifically state excessive omega-6 eicosanoid actions occur during thrombosis and arrhythmia of heart attacks and inflammatory/immune processes of atherosclerosis, arthritis, asthma, and tumor development; just as Dr. Sears has communicated through his blogs, books, websites, interviews, etc. They (NIH) state that two dietary imbalances lead to these conditions; excess food energy intake over expenditure and excess intake of omega 6 intake over omega 3 intake. They stress that each imbalance can be prevented. “The issue is the tissue” . . .is something you’ll hear them refer to when you watch some of the video presentations. The excess food intake coupled with the fatty acid imbalance, sets the stage (in the tissue) for the majority of our chronic, debilitating diseases. In my experience, the best ways to prevent the imbalances they refer to, are following The Zone Diet, and supplementing with a high quality omega-3. Thank you Dr. Sears, for your research in this area and more importantly, for communicating it in a way that’s understandable and doable. You’re giving us the tools to use so we can hope to live a long, energetic, disability-free life. I’ve been following the Zone lifestyle for 9 years and have never felt better. . . .when you consider that I’m in my mid 50′s, that’s truly saying something.

  5. I’ve been on a paleo diet for the last 3 months (no grains, no dairy) and am consuming about 5-6 grams of EPA/DHA daily. I was about 145 at the start of this process and am now at about 136. Is it conceivable that all my fish oil is causing me to lose additional weight, even though I wasn’t overweight to begin with? My blood pressure has usually been around 105/60 and continues to be about that even after the increase in Omega 3. Or is my weight loss more likely to attributed to a considerable decrease in grain-based carbs and much less snacking?


    • Mark,
      I’m not trying to be sarcastic here, but basically you just asked if you lost weight because you began restricting your caloric intake (no snacking), more specifically you restricted your carb intake (Paleo)…. My experience with the Paleo diet and the Zone diet is I wasn’t hungry enough to maintain my current weight. I found myself needing to remember to eat in order to maintain my weight.

      If you are trying to gain weight, don’t cut your carb blocks.

    • The fish oil is improve the burning of stored fat by increasing the secretion of adiponectin from the fat cells that lowers insulin resistance as well as decreasing any cellular inflammation in the fat cells. Any time you decrease grain-based carbs you will also decrease insulin levels resulting in a decrease of retained water. This is why I prefer to look at percentage of body fat instead of total weight.

  6. I would like to ask a question in terms of extremes so that I know what each component does why they are so important. OK here goes: If we did not take in any omega 6 fatty acids but only omega 3′s, how would that effect our health? Is there a minimum quantity that we need in omega 6′s? I know you emphasize the omega 3′s and I agree, but I would like to know if omega 3′s or omega 6′s can become rancid or oxidize easily and lead to problems if we do not also balance this intake with enough anti-oxidants even if we do take in the minimum amounts of both types of fatty acids and our omega 6 to omega 3 ratio is say 3:1? Also, why is krill oil which has a much lower content of DHA and EPA than regular cold fish oils, better to take and does this involve huge differences in bioavailability of these oils in krill or what? Thank you.

    • All nutrition is about balance. The data suggests that 1% of total calories as omega-6 is more than sufficient to supply your dietary needs. Unfortunately Americans currently consume nearly 8% of total calories as omega-6 fatty acids. The intake of both omega-6 and omega-3 fatty acids have to be balanced with anti-oxidants with polyphenols being the most powerful. I generally recommend 8,000 ORAC units for every 2.5 grams of omega-3 fatty acids since they are more prone to oxidation than are omega-6 fatty acids.

      I would take the krill oil story with a grain of salt. It is not a fish oil per se, but composed of phospholipids. They have a slightly better absorption rate that triglycerides or ethyl esters, but our preliminary testing indicates they may contain high levels of chloroform as that is the solvent used to extract them from the tiny shrimp (i.e. krill).

    • This is obviously a self-serving statement, but I would say no. They are less purified relative to PCBs levels, they have a very concentration of EPA and DHA, they are far more expensive per gram of EPA and DHA, and our preliminary data indicates they appear to have some solvent contaminants.

      I could only find four studies in Pub Med using krill oil in humans compared to more than 8,000 using fish oil. I believe there is more marketing hype on krill oil than science but I always keep an open mind.

  7. Don’t try and substitute krill oil for a highly refined, molecularly distilled fish oil–it will cost a fortune! Using the Dr. Sears omega, you’re spending about $0.06 or $0.07 per 100 mg. EPA/DHA. Krill oil costs from $0.30 to $0.60 per 100 mg. EPA/DHA.

  8. I have been in the zone diet for more than ten years and suddenly i observed my weight machine was fooling me for i don’t know how long, so i went to a more careful watched diet to loose 6 kilos (around 12 pounds) in six weeks, taking a dose of 2.5 gr Omega 3 per day. Everything fine and easy, which makes me more happy yet to be a zone diet follower.
    Now, I have incurred in an arrithmic problem in my heart, with sudden early bits, which tend to occur much more often than before. Then, my question is if the Omega 3 or the diet could have anything to do with this.

    • It is highly unlikely, but try stopping the omega-3 fatty acids for a month to see if there is any change. If not, then I would check with your physician.

  9. Can you please translate 2.5 grams of EPA/DHA per day as to “number of” capsules? I currently take 4 capsules (the large ones) of EicoRX and 1 capful of the Sea Health Plus in the morning with breakfast. Thanks.

  10. Dr. Sears,
    I think Mark Sisson does good work , just as I think you do. Both of you have goals of improving our health and reducing inflammation in our bodies. I know you have concerns with AA in egg yolks (and I’ve turned to eating mostly egg whites), but I’d like to hear your take on Mark’s article here – . Is he right, partly right, not right, or??


    • I have spent 30 years studying eicosanoids so I have some perspective on the subject. Both EPA and AA (as well as DGLA) compete for the COX and LOX enzymes in the production of eicosanoids. The AA/EPA ratio is an indicator of that competition. You need a balance of both types of eicosanoids as I would like to think that I clearly explained in my first book, The Zone. I feel the ideal ratio of AA/EPA in the blood is between 1.5 and 3 as it is in the Japanese population. The AA/EPA ratio in Americans is currently 20 indicative of a greater competitive edge of AA for production of pro-inflammatory eicosanoids. The recent JELIS study (the largest cardiovascular study ever undertaken) has indicated when the AA/EPA ratio is reduced from 1.6 to 0.8 in Japanese cardiovascular patients there is an additional 20% reduction in cardiovascular events. My own published studies indicated that as the AA/EPA ratio is reduced in children with ADHD, there is significant improvement in their behavior.

      All anti-inflammatory drugs seek to inhibit the conversion of arachidonic acid into pro-inflammatory eicosanoids. I could go on, but I have written 12 books and published serveral scientific articles on this subject which can be explored in more detail on

      Bottom line, he is off target and has significantly misrepresented the great body of published research (more than 120,000 articles) on eicosanoids.

  11. I had a Holman Omega 3 Test done about a year ago and as I’ve mentioned before to you, my AA/EPA ratio was 2.41. At that time, I was probably consuming 15 whole eggs per week. I haven’t tested it since going on paleo about 4 months ago and eat mostly egg whites now. (also boosted my fish oil intake to about 6.5g of DHA/EPA.

    Since 2.41 seems to fall in that ideal range, how did I get there, eating that many whole eggs? I took Lovaza during that period as I recall, but even so, I would think the eggs if they truly are inflammatory would have pushed that level up higher. (I have RA and take methotrexate 20mg/week). Eating paleo has reduced my fasting blood sugars to below 100 and rarely now do they go about 120 during the day. I would guess if my level was 2.41 a year ago that it is in the 1.0-1.5 range by now considering my diet and increased consumption of fish oil and near avoidance of egg yolks.

    Thoughts on how that level was so low a year ago considering my consumption of egg yolks?


    • That’s why you measure the blood and not keep a food dietary. The primary source of arachidonic acid is the liver. If you are not eating a diet very rich in linoleic acid and one that doesn’t generate a lot of insulin secretion, then there will be little driving force to make more arachidonic acid. However, the data suggests that a ketogenic diet rich in arachidonic acid will increase blood levels of arachidonic acid, whereas a non-ketogeneic diet, such as the Zone diet, will not.

  12. Dear Doctor Sears ,
    I enjoyed readin your article and found it at the right time. I am currently taking fish oil and am experiencing extremely low blood presssure and / or blod sugar attacks. I have had them for a few days now and have experienced this severly before. I stopped taking omega three oils before my pregnancy and starte up again when the baby was borne 10 months ago. During the period of no omega Ididn’t suffer from these attacks. My main issue here is that it has not only helped me with post pardom depression but the fish oils have also contributed to some weight loss. I don’t want to have to stop taking these. I alternate with a EFA in the form of GLA , omega 6.
    Any suggestions? Love my fish oil but not the dizzy spells etc.

  13. I forgot to say how much I am taking between 1000 mg and 2000mg of Omega three and alternating with 1000 milligrams of GLA. I have been taking this for about 10 weeks and it has made a world of difference for my mood.
    Thanks for your time,

  14. I just went off my statin (pravastatin), which was making my Achilles tendons very painful (my doctor didn’t believe me and thought I had somehow injured my tendons – both of them! — but the pain has been going on since last August, about two weeks after I started the statin, so I found that instructive…). I have purchased your fish oil (liquid form, not capsules) and have started to take 1 tsp a day, as the bottle recommends. My question is, should I be taking more daily — perhaps as much as 2 tsp. a day? I have started the Zone diet, feel great on it, and I have about 100 pounds to lose. I have moderate HBP (usually around 135-140 over 80) and am taking Norvasc for that, and take levothroid for low thyroid.

    • A realistic amount of weight loss on the Zone diet is about 1-2 pounds per week. That may be slower since you have a low thyroid. You might wish to consider more omega-3 fatty acids and use your blood pressure as an indicator of their efficacy in lowering the blood pressure.

  15. Pingback: Your Questions About Omega 3′s Foods — Benefits of Fish Oil Pills

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