27 January 18

Do YOU need a DHA supplement?


Docosahexaenoic acid EXPELLIARMUS!


No, that’s not a Harry Potter spell (ok, the second half was, but not first).


Eicosapentaenoic acid and docosahexaenoic acid, EPA and DHA, respectively, are the two major “fish oil” fatty acids. And it’s important to have high levels in your body. Here’s why:

Association of marine omega-3 fatty acid levels with telomeric aging in patients with coronary heart disease (Farzaneh-Far et al., 2010)

Telomere length is believed to be a biomarker of aging: the shorter your telomeres, the faster you’re aging. In this study, they measured telomere length in white blood cells and EPA+DHA in whole blood at baseline and again 5 years later.

 

Quartile 1: EPA+DHA = 2.3% of the fatty acids in whole blood.

Quartile 2: 3.3%

Quartile 3: 4.3%

Quartile 4: 7.3%

 

How much DHA do you need to get into that 4th quartile?

Hold my beer.

Factors influencing EPA+DHA levels in red blood cells in Japan (Itomura et al., 2008)

 

Salmon is roughly 1-2% EPA+DHA by weight, so a standard ~3 ounce  portion has approximately 1-2 grams. Doing this regularly puts you significantly ahead of the curve.

 

The impact of age, BMI, and fish intake on the EPA and DHA content of human erythrocytes (Sands et al., 2005)

 

Omega-3 index in this population: was 4.9% and it increased by ~0.24 units with each additional monthly serving of fatty fish. Thus, mathematically, to get from 4.9% to 8% would require 13 additional servings per month. However, biology is not mathematics, and from the figure below it appears that less might be able to do the same.

>3 servings per week

 

Reminder: why is this important?  

 

1) Recall the association of Omega-3 Index with telomere length from above.

 

2) Also, Inverse association between docosahexaenoic acid and mortality in patients on hemodialysis over 10 years (Terashima et al., 2014).

 

After adjusting for a plethora of confounding factors, patients with red blood cell phospholipid DHA > 8.1% had a significantly lower risk of all-cause mortality than those with DHA < 7.2%. No effect of EPA.

 

3) Blood  EPA and DHA Independently Predict All-Cause Mortality in Patients with  Stable Coronary Heart Disease (Pottala et al., 2010)

 

27% decreased risk of all-cause mortality in those with total blood levels of EPA+DHA above 3.6% compared to those below it. 3.6%? According to the data above, this amounts to only 2 servings/week!

4) DHA supplementation improved both memory and reaction time in young adults: a randomized controlled trial (Stonehouse et al., 2013)



Seafood vs. fish oil supps

 

Comparison  of the effects of fish and fish-oil capsules on the n-3 fatty acid  content of blood cells and plasma phospholipids (Harris et al., 2007)

 

Participants were assigned to get 485 mg EPA+DHA per day, on average, from either 2 servings salmon or tuna per week or from 1-2 capsules/day.

 

In red blood cell membranes, DHA increased by 50% in the fish group and 46% with supps. In plasma phospholipids, DHA increased by 64% in  the fish group and 60% with supps. This basically confirms one of the aspects of why seafood is a little better than supps: greater bioavailability of DHA in seafood. It’s not a huge difference, but the whole food is also greater than the sum of its parts: seafood comes with additional benefits not found in supps (eg, iodine, selenium, other micronutrients, etc.).

 

That said, the supplements work. Period.

 

Why genetic testing is important

 

Maybe I just have a grim view of humanity, but I think just about no one is in that 4th quartile. The conversion of omega-3 precursor fatty acids like linolenic acid (found in flaxseeds, for example) into DHA is relatively low. This is controlled, in part, at the genetic level.

There are two enzymes, fatty acid desaturases 1 and 2 (FADS1 and 2), that largely impact how much DHA you can make (eg, Glaser et al., 2011). The genes which code for those enzymes have multiple SNPs which explain a large proportion of the variability in DHA status (eg, Harslof et al., 2013). Long story short, you want to be in that 4th quartile and if you have any low activity SNPs in FADS 1 or 2, then the only way you're going to get there is with DHA supplementation or massively increasing your seafood intake.

 

That’s where WE come in. We can analyze your SNPs and determine if you need fish oil supplements and if so, how much and how frequently.


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