Fish oil makes you happy: Psychological distress and omega-3 index

For another perspective on omega-3 blood levels, here's an interesting study in northern Quebec Inuits.

Traditionally, Inuits consumed large quantities of omega-3-rich seal, fish, caribou, and whale, even eating the fat. However, like the rest of the world, modern Inuits have increased consumption of store-bought foods, largely processed carbohydrates. Along with this trend has emerged more heart disease, diabetes, and depression.

A group from Laval University and University of Guelph, both in Canada, examined the relationship of plasma EPA + DHA levels and measures of psychological distress. This group had previously shown that Inuits older than 50 years had twice the plasma omega-3 levels (11.5%) compared to those younger than 50 years (6.5%), reflecting the shift away from the traditional diet.

Psychological distress was measured with The Psychological Distress Index Santé-Québec Survey (PDISQS-14): the higher the score, the greater the psychological distress. (In the graphs, tertile 1 is least distressed; tertile 5 is most distressed. Sorry about the small chart graphic--click on the graphic to make it bigger.)

From Lucas M et al 2009 (

"Our main finding was that women in the second and third tertiles of EPA+DHA concentrations in plasma PLs [phospholipids] had a 3 times lower risk of having a high-level PD [psychological distress] score than women in the lowest tertile."

While the relationship is stronger for women, you can see that, the higher the EPA + DHA plasma level, the lower the likelihood of psychological distress. Interestingly, the tertile with the greatest distress and lowest EPA + DHA levels had a plasma level of 7.0-7.5%--far higher than average Americans.

(Plasma levels of EPA + DHA were used in this study, which tend to reflect more recent omega-3 intake than the more stable and slower-to-change RBC Omega-3 Index that we use. Plasma levels also tend to run about 10-20% lower than RBC levels.)

Of course, there's more to psychological distress than omega-3 blood levels. After all, eating fish or taking fish oil capsules won't make money worries go away or heal an unhappy marriage. But it is one variable that can be easily and safely remedied.

Comments (24) -

  • Boris

    10/30/2009 1:31:07 PM |

    I think your are on to something, Dr. David. Every winter I get sad and depressed. After starting my omega-3 supplements, I noticed that I started feeling "better". I know that's very subjective. We set our clocks backwards 1 hour in a few days. I guess I will get a chance to test the "happy factor" of fish oil soon!

  • Rob McVey

    10/30/2009 2:14:08 PM |

    FYI, Laval is in Quebec, but Guelph is in Ontario (albeit both Canada). Perhaps you'd edit the post.
      --  Rob McVey, Markham, Ont.

  • Haggus

    10/30/2009 3:02:22 PM |

    Just to make it clear, the Univesity of Guelph is located in Ontario.

  • Jim Purdy

    10/30/2009 3:25:04 PM |

    I live in a high-rise apartment building where many of the residents are grouchy old ladies.

    Should I sneak fish oil into their food?

    Or should I move into a building with lots of happy old Inuits?

  • Deb

    10/30/2009 3:27:52 PM |

    I always enjoy and learn so much from you blog. Thank you.
    I have tried taking omega 3 fish oil capsules but they give me acid stomach and fish burps. Any solution to these problems? I have tried the enteric coated ones too.

  • William Trumbower

    10/30/2009 4:13:28 PM |

    I am not surprised at this data.  When I began taking adequate fish oil (7gm EPA+DHA) I noticed an improved mood, memory, and ability to organize my activities.

  • Dr. William Davis

    10/30/2009 5:00:07 PM |

    Rob and Haggus--

    Thanks for the correction.

  • Dr. William Davis

    10/30/2009 5:00:37 PM |

    Hi, Jim--

    Perhaps throw a fish oil party for the ladies!

  • Boris

    10/30/2009 6:13:55 PM |


    You are experiencing the effects of "cheap" fish oil that has a lot of other stuff in it besides Omega-3. I tried Walmart's Nature Made stuff and it made me feel sick. Now I am take Omapure 4x a day (one capsule each time) and I do not feel the same "fishy" burps.

  • Rich S

    10/30/2009 6:48:34 PM |


    Try lemon-flavored liquid form of EPA/DHA. Go with a high quality brand like Carlson, which a lot of us use.

    One tsp gives you 800EPA+500DHA (1300 total), and it actually tastes pretty good (it's not cod-liver oil).

    Buy it online, such as from i-Herb as an example:

    You won't have to swallow all those softgels, which used to bother me.  Also, a good quality distilled fish oil should not cause gastro distress, etc.


  • Nameless

    10/30/2009 7:24:58 PM |

    They have done Omega 3 depression studies. I believe they found EPA more important than DHA for improving depression scores. A lot of the 'mood' fish oil supplements tend to be EPA heavy too.

    I think they theorize that EPA helps the brain function, while DHA is primarily for structure (hence why it's important for children/babies).

  • Anonymous

    10/30/2009 8:32:51 PM |

    I think this is an important study, but I have to wonder if low omega-3 might also indicate difficult in fiding adequate food, which would clearly be stressful.  It's a chicken and egg argument so to speak.  Without verying that total nutrition other than omega-3 was adequate, I'm no sure a real conclusion can be made.

  • JD

    10/30/2009 10:37:58 PM |

    The question would be is it the Omega 3's or the fact that those who eat carbs get more depressed?

  • AuntWie

    10/31/2009 4:36:55 AM |

    I've battled depression on and off for most of my life.  Meds help.  Fish oil and lots of vitamin D help even more.  I increase my intake of both whenever my exposure to sunlight is limited (including when the summer heat keeps me indoors a lot.)

  • Anonymous

    10/31/2009 11:41:10 AM |

    So what would be the typical EPA+DHA daily dose (not the oil) to reach these heights of happiness...or plasma levels?

  • Dr Matti Tolonen

    10/31/2009 12:20:06 PM |

    Another recent report from Laval University suggests that highly purified ethyl-eicosapentaenoic acid (E-EPA) may relieve psychological distress in middle-aged women.
    The daily dosage was about 1gram.
    E-EPA is a very popular omega-3 supplement in Europe and Japan.

  • Dr. William Davis

    10/31/2009 1:32:40 PM |

    In response to several comments--

    Taken in the context of other studies, this study simply adds to the notion that omega-3 intake is associated with mood status.

    While omega-3 plasma levels may also serve as a surrogate for other phenomena, such as vitamin D intake (also rich in fish, though not fish oil), the experience as a whole do indeed show a strong relationship between omega-3 levels and depression/mood/"psychological distress."

  • Red Sphynx

    11/1/2009 2:24:01 PM |

    I'm skeptical of this study.  Look, I expect that, eventually, research will show a strong relationship between mood and LC ω-3.  But this study ain't it.

    First off, this is an observational study.  When observational studies turn up order-of-magnitude differences, they point to cause-and-effect relationships.  But when they turn up relationships that barely pass the statistical significance test (p ~ .05) they are more likely measuring the shared influence of some other cause.

    And what might this cause be?  Well, the authors point out (a) seafood consumption varies upwards with wealth and income.  (b) Happiness varies upwards with wealth and income. (c) They really would have liked to have controlled for wealth and income but they couldn't because the Inuits wouldn't fill out the wealth and income portion of the questionnaire.  

    So their study was underpowered to measure one of the most obvious non-physiological explanations of the (weak) correlation they found.

    This study would have us believe (a) Inuits have much higher ω-3 levels that other Quebec citizens.  (b) The suicide rate among Inuit in 1987–1994 was 6.5 times higher than in the rest of Québec, and the rate in the younger age group (15–
    24 years) was 20 times higher. (!!) (c) ω-3 is associated with better mood.

    Something is pretty discordant there.

    I'll wait for an intervention study.

  • Dr. William Davis

    11/1/2009 9:38:06 PM |

    Hi, Red-

    That's right.

    This study, taken in isolation, proves nothing. It only adds to the other observations that suggest that omega-3 may exert an effect on ADHD, bipolar illness, depression, etc.

    The fact that there appears to be concordance across different populations, though with differing frequencies of depession, is the argument of importance.

  • Dr. William Davis

    11/1/2009 9:38:13 PM |

    Hi, Red-

    That's right.

    This study, taken in isolation, proves nothing. It only adds to the other observations that suggest that omega-3 may exert an effect on ADHD, bipolar illness, depression, etc.

    The fact that there appears to be concordance across different populations, though with differing frequencies of depession, is the argument of importance.

  • Razwell

    1/26/2010 6:40:33 PM |

    Fish oil makes me depressed and nauseous and tired . I do not  know what all the fuss is about.

    I use a supposedly good type too, Carlson's.

  • buy jeans

    11/3/2010 10:03:25 PM |

    A group from Laval University and University of Guelph, both in Canada, examined the relationship of plasma EPA + DHA levels and measures of psychological distress. This group had previously shown that Inuits older than 50 years had twice the plasma omega-3 levels (11.5%) compared to those younger than 50 years (6.5%), reflecting the shift away from the traditional diet.

  • Lisa

    5/16/2011 9:13:39 AM |

    Omega-3 is geally great. Improves memory , I'm loosing pounds and I don't feel hungry or depressed (and when I'm depressed I eat soooo much!).  I prefer flax oil of flax seed as a sourse of omega-3.  My body seems to reject fish oil and I think it's not for nothing. The mercury pollution won't do any good.

Cath lab energy costs

Cath lab energy costs

In honor of Earth Day, I thought I'd highlight the unexpectedly high carbon costs of activities in hospitals, specifically the cardiac catheterization laboratory.

A patient enters the cath lab. The groin is shaved using a plastic disposable razor, the site cleaned with a plastic sponge, then the site draped with an 8 ft by 5 ft composite paper and plastic material (to replace the old-fashioned, reusable cloth drapes). A multitude of plastic supplies are loaded onto the utility table, including plastic sheaths to insert into the femoral artery (which comes equipped with a plastic inner cannula and plastic stopcock), a multi-stopcock manifold that allows selective entry or removal of fluids through the sheath, a plastic syringe to inject x-ray dye, plastic tubing to connect all the devices (total of about 5 feet), and multiple plastic catheters (3 for a standard diagnostic catheterization, more if unusual arterial anatomy is encountered).

All these various pieces come packed in elaborate plastic (polyethylene terephthalate or other polymers) containers, which also come encased in cardboard packaging.

Should angioplasty, stenting, or similar procedure be undertaken, then more catheters are required, such as the plastic "guide" catheters that contain a larger internal lumen to allow passage of angioplasty equipment. An additional quantity of tubing is added to the manifold and stopcock apparatus, as well as a plastic Tuohy-Borst valve to permit rapid entry and exit of various devices into the sheath.

Several new packages of cardboard and plastic are opened which contain the angioplasty balloon, packaging which is usually about 4 feet in length. The stent likewise comes packaged in an 18-inch or so long package with its own elaborate cardboard and plastic housing.

At the conclusion of the procedure, another cardboard/plastic package is opened, this one containing the closure device consisting of several pieces of plastic tubes and tabs.

If the procedure is complicated, the number of catheters and devices used can quickly multiply several-fold.

By the conclusion of the procedure, there are usually two large, industrial-sized trash bins packed full of cardboard, plastic packaging, and discarded tubing and catheters. The trash is so plentiful that it is emptied following each and every procedure. None of it is recycled, given the contamination with human body fluids.

That's just one procedure. The amount of trash generated by these procedures is staggering, much of it plastic. I don't know how much of the U.S.'s annual plastic trash burden of 62 billion pounds (source: EPA) originates from the the cath lab, but I suspect it is a big number in total.

So if you are truly interested in reducing your carbon footprint and doing your part to be "green," avoid a trip (or many) to the cath lab.

Comments (6) -

  • Anonymous

    4/23/2009 8:05:00 AM |

    Dr. Davis,
    Isn't a catheter used for an angiogram?  I thought an angiogram is a necessity before surgery for an aortic abdominal aneurysm?  What are the other alternatives if catheters make so much rubbish?  Just wondering since my mother is considering having surgery for her AAA and needs to have an angiogram first.
    Josephine Keliipio

  • Anonymous

    4/23/2009 2:19:00 PM |

    Dr. Davis doesn't answer questions posted to his blog any longer. He announced this some time ago.

    I think the point of his little story about being green is to avoid having to have such a procedure done in the first place. I don't believe he is suggesting that you ask the Hospital to recycle all the left over rubbish from such a procedure. At the rate of pay of those people, they'd probably have to charge you a couple of hundred dollars to sort everything out that could be recycled..  Frown

    I am only a lay person but I believe there is no alternative (less rubbish producing that is) to the procedure your Mom needs done. Don't worry about the trash and focus on your Mom's outcome instead.

    Good luck with your Mom's procedure.

  • Anonymous

    4/23/2009 5:10:00 PM |

    Catheter angiogram is no longer needed to demonstrate arteries, especially arterial anatomy in the abdomen, extremities,head and neck, including, carotids and intracerebral arteries, arteries in the arm or legs. There is now, an alternative, non-invasive. This consist of CT, CTA, or even better, without radiation an MRI,MRA. The only indication for catheter angiogram is if there is plan for angioplasty, or placement of a stent.
    No one or nobody should be subjected, to a catheter angiogram, in this day and age.
    I hope this helps.

  • Jonathan Selwood

    4/23/2009 5:55:00 PM |

    Dr. Davis,

    Much obliged for the post.  It provides me with a wonderful counter to claims that a grain-based diet has less of an environmental impact.

    Wheat=Heart Disease=Medical Waste


  • Anonymous

    4/24/2009 9:41:00 AM |

    Anonymous #2,
    Thanks for your comment about angiograms. I am still learning about this procedure and am glad to know that there may be other alternatives. My mom had no plans for a stent or an angioplasty but it seems that angiograms are the standard for elderly patients electing to fix AAAs. Anyway, lots of questions to ask the cardiologist when we see him again in a few weeks. Josephine

  • jean

    4/25/2009 5:53:00 PM |

    Mmmm...stay out of the surgical ICU also, if you can help it. We generated on average 3-4 large cans of waste per room (14) per shift (12hr) per day. Efforts to separate out recyclables were futile. And let's not even get into hand washing. This was in 2000. I hope things have improved.