Non sequiter dietary fats

Tl;dr: SFA and DHA

Essential fatty acids?  Well, there’s really only one, DHA, and we really only need a gram or two.  In other words, our entire requirement for dietary fat can be met by about 2% of total calories (plus a few extra grams to accommodate fat-soluble vitamins) (plus DHA is never the sole fat in a food, so you’d be getting a few more grams of other fats, too).  But still, a very low fat diet!  But impractical and probably not very palatable or healthy.

On average, dietary fat comprises about a third of calories, roughly equally divided between SFA, MUFA, and PUFA (slightly less PUFA).

Major sources of SFA are pizza and desserts – no wonder SFA gets a bad rap!

 

cheese-crust-pizza

 

 

Of the PUFAs, 15-20 grams are n6 linoleic acid and <2 grams are n3 linolenic acid.  This is why the n6/n3 ratio is so out of whack: WAY too much linoleic, ie, vegetable oil.  No bueno.

 

Books: Omega-6/Omega-3 Fatty Acid Ratio: The Scientific Evidence & Fatty Acids: Physiological and Behavioral Functions

 




 

Honestly, I don’t care much for these two fatty acids, but should really get way less linoleic.  And a bit more linolenic wouldn’t hurt… primarily to block n6 conversion; not really to push n3 conversion because it’s dismally low: 5% of 4g = 200 mg of the estimated 1g requirement.  Sure, some women with low n6 and high n3 intake could theoretically meet the DHA requirement via n3 conversion, but much easier to eat a serving of seafood.

 




 

Salmon is ~1% DHA by weight, so 100g serving of salmon would be enough by itself, but in practice would need less because there are other sources of DHA in your diet.  But with DHA, my advice leans toward “more is better” if it’s from whole foods because: 1) “need < optimal;” and 2) it’s difficult to get too much DHA from whole foods (if “too much DHA” even exists)…

 

salmon

 

For people following high fat diets, I think SFA should be the biggest contributor for a couple reasons.  From a lipid peroxidation and hepatoprotective perspective, SFA are the safest bet.  Cook with coconut oil, cocoa butter, and butter or ghee.  Avocados and olive oil are good sources of MUFA, which I largely view as health-neutral.  And n6 PUFAs should be minimized especially on high fat diets.

Coconut oil: has MCTs, which are cool: cheaper boost in ketones than ketone supps (albeit more calories).

 

dark-chocolate

 

Tl;dr: SFA and DHA

 

calories proper

 

 

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  • Tuck

    Nice post.

    There’s some evidence that coastal Eskimos get too much DHA, and have genetic adaptions as a result. But unless you’re eating all fish, all the time, I don’t think it’s really a concern.

    Fish oil and alcohol are a bad combination, however, so I’d avoid that!

    • TechnoTriticale

      For some perspective, 1g DHA/day would be 2 or 3 small cans of sardines per day.

      re: But unless you’re eating all fish, all the time, I don’t think it’s really a concern.

      What could be a concern, even for 1g/day, is going higher than bait fish in the marine food chain, due to a long list of modern environmental toxins.

      re: Fish oil and alcohol are a bad combination…

      Got a pointer to more info on that?

    • “Fish oil and alcohol are a bad combination, however, so I’d avoid that!”

      pre-game with some dark chocolate 🙂

  • Man

    There’s another angle for men: the effect of diet on testosterone levels. Foods like fatty fish, eggs, olives and whole fat dairy should be quite good in that respect. Other foods like flaxseeds, soy beans and sunflower seeds are not exactly good: some mimic estrogen while others boost aromatisation of T and can lead to estrogen dominance. Foods like mushrooms, celery stems, broccoli, chia seeds, zinc rich items like oysters, etc, are all good: some will help testies, others will clear excess estrogen or even inhibit aromatisation of T. In general, for men, eating some fat is quite important, but if all you eat is burgers and crappo cheese, then it won’t cut it.

  • Raymund Edwards

    So are nuts a healthy choice as a component of a ketogenic diet ?
    esp ones with more PUFA like almonds ?

    IN a keto context would not a lot of the PUFA end up as ketones !

    I agree that SAT and MONO are the fuels the body seems to really like and it is revealing that body FAT is in the main a good mix of those with PUFA content of body FAT (o6) very reliant on past dietary makeup !

    • “So are nuts a healthy choice as a component of a ketogenic diet? esp ones with more PUFA…?”

      well, yes, just don’t eat “ALL THE NUTZ!” 🙂

      “IN a keto context would not a lot of the PUFA end up as ketones?”

      PUFAs are relatively more ketogenic than other LC fats, but I wouldn’t up the PUFAs for this reason. If ketones are the *goal,* I’d opt for coconut oil.

  • MUFA is neutural? My lipids normalized and are in excellent ranges after making walnuts, almonds and olive a staple of my diet. Say it ain’t so Bill.

  • Erik Arnesen

    SFA vs. PUFA and liver fat: What do you think of Riserus et al’s RCT’s on this? See for example “Overfeeding Polyunsaturated and Saturated Fat Causes Distinct Effects on Liver and Visceral Fat Accumulation in Humans” here: http://diabetes.diabetesjournals.org/content/63/7/2356.

    Or the HEPFAT study: http://ajcn.nutrition.org/content/95/5/1003.abstract, which found that n-6 PUFA reduce liver fat compared with SFA.

    A recent review (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4245577/) concludes:

    “On the basis of the small amount of studies undertaken it would seem logical to recommend an iso-caloric diet (if weight loss is not a goal) of moderate total fat intake and low (<10%TE) in SFA to lower the risk of NAFLD development."

    • in general, long-chain saturated fat tends to store better than other fats, but this shouldn’t be a problem if in energy balance or weight loss.

      As to the HEPFAT study, I’d rather have slightly more liver fat if it was less susceptible to damage (ie, more saturated). But if n3’s were increased in the SFA group, might’ve seen higher oxidation via PPAR activation, attenuating the difference between n6 & SFA group.

      Lastly, this topic in general is more important for LCHF dieters because those n6 PUFAs can add up fast when you go from avg fat to high fat.

  • bearowsley

    I am concerned about the price of salmon and about the heavy metal content of fish.

    The tissue with the most dha seems to be .. eyes, followed by brain tissue. Cannot find anything on pork eyes, but even land animals brains and eyes seem to be rich in them (as these organs need them the most).

    brains:
    http://nutritiondata.self.com/facts/beef-products/3463/2

    on eyes, I only found something on human eyes. but i guess there is not that much difference to other land mammals?!
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3322172/

    To me, that seems to be the most economic way to get enogh DHA (haven’t tried eyeballs yet, but brains can be quite tasty. In my country, brains with eggs was once a staple food)

  • Nick Waring

    I’m under the impression that both arachidonic acid and DHA are essential. This is a very good article by Chris Masterjohn:
    http://www.westonaprice.org/know-your-fats/precious-yet-perilous/