DHA: the crucial omega-3

Of the two omega-3 fatty acids that are best explored, EPA and DHA, it is likely DHA that exerts the most blood pressure- and heart rate-reducing effects. Here are the data of Mori et al in which 4000 mg of olive oil, purified EPA only, or purified DHA only were administered over 6 weeks:

□ indicates baseline SBP; ▪, postintervention SBP; ○, baseline DBP; •, postintervention DBP; ⋄, baseline HR; and ♦, postintervention HR.

In this group of 56 overweight men with normal starting blood pressures, only DHA reduced systolic BP by 5.8 mmHg, diastolic by 3.3 mmHg.

While each omega-3 fatty acid has important effects, it may be DHA that has an outsized benefit. So how can you get more DHA? Well, this observation from Schuchardt et al is important:

DHA in the triglyceride and phospholipid forms are 3-fold better absorbed, as compared to the ethyl ester form (compared by area-under-the-curve). In other words, fish oil that has been reconstituted to the naturally-occurring triglyceride form (i.e., the form found in fresh fish) provides 3-fold greater blood levels of DHA than the more common ethyl ester form found in most capsules. (The phospholipid form of DHA found in krill is also well-absorbed, but occurs in such small quantities that it is not a practical means of obtaining omega-3 fatty acids, putting aside the astaxanthin issue.)

So if the superior health effects of DHA are desired in a form that is absorbed, the ideal way to do this is either to eat fish or to supplement fish oil in the triglyceride, not ethyl ester, form. The most common and popular forms of fish oil sold are ethyl esters, including Sam's Club Triple-Strength, Costco, Nature Made, Nature's Bounty, as well as prescription Lovaza. (That's right: prescription fish oil, from this and several other perspectives, is an inferior product.)

What sources of triglyceride fish oil with greater DHA content/absorption are available to us? My favorites are, in this order:

Ascenta NutraSea
CEO and founder, Marc St. Onge, is a friend. Having visited his production facility in Nova Scotia, I was impressed with the meticulous methods of preparation. At every step of the way, every effort was made to limit any potential oxidation, including packaging in a vacuum environment. The Ascenta line of triglyceride fish oils are also richer in DHA content. Their NutraSea High DHA liquid, for instance, contains 500 mg EPA and 1000 mg DHA per teaspoon, a 1:2 EPA:DHA ratio, rather than the more typical 3:2 EPA:DHA ratio of ethyl ester forms.

Pharmax (now Seroyal) also has a fine product with a 1.4:1 EPA:DHA ratio.

Nordic Naturals has a fine liquid triglyceride product, though it is 2:1 EPA:DHA.

Comments (5) -

  • Jakub Polec

    5/22/2013 5:59:53 PM |

    In some DHA, or DHA+EPA supplements one can find additions with for lipase-enhanced digestion which support absorption of n-3 FA. Therefore any supplements with > 1g/d DHA+EPA (or purely DHA) should influence our health.

  • Susie

    5/30/2013 1:02:21 PM |

    Dr. Davis,

    Very happy to learn this distinction between forms of the fats. Are triglyceride and phospholipid two different forms or are they the same? Do you happen to know anything about the Swanson brand which has an EcoMarine trademark?

    Thank you,


  • john pop

    6/11/2013 12:33:21 AM |

    Dr Davis, what about Nordic Naturals DHA Xtra Strawberry softgels?

  • Annette

    6/11/2013 2:35:31 AM |

    I've been totally grain-free and dairy-free for over a yr.  My total chol is 177, HDL is 83, LDL is 88, Triglycerides are 30 and risk factor 2.7, but a 64-slice heart scan done in May 08 showed plaque to two coronary arteries.  I had a stroke in my 40's and lost the sight of one eye.  My dad died of a stroke at age 35.  My grandfather died at 68 of a heart attack.  I'm 70+.  On my insulin sensitivity score ranging from 0-100, I scored 1.  Dr Douglas Brown, Brookfield said, "I've never seen such a low score for insulin sensitivity or triglycerides.  My BP fluctuates wildly.  Some days I don't require any Lisinopril and other days I require 20+ mg.  He thinks I should have a heart cath, but with such great labs, I highly doubt that Medicare would approve.  I wish I knew what to do about the BP.  I do go to Pulmonary Rehab classes for bronchiectasis, but I'm chronically fatigued.  We've had both radon and mold remediation done at our home and a Naturopathic dr told me I have an extreme amt of lead toxicity.  I need advice.

    I have your book and your CD's.  Listening to the CD's is what made my husband decide to go off grains, other than a little rice occasionally.  He dropped 20lbs fairly quickly.

  • DDR

    6/23/2013 12:59:33 PM |

    I get very itchy skin when taking more that 2 capsules of Nordic naturals. Any reason for this? Advice?