We’ve been bombarded for years with the evils of trans fat…
…and for once, the mainstream advice appears to be mostly correct. Trans fats cause coronary heart disease, they’re strongly associated with obesity, depression, infertility in women, and breast cancer, and they interfere with critical liver enzymes. (More.)
I’ve written about trans fats before: if you want to learn their basic chemistry—and more importantly, how to avoid them when shopping for food—read my article Eat More “Heart-Healthy” Trans Fats! (We hid them in plain sight).
“Help! There’s Trans Fat In My Grass-Fed Beef!”
However, an alert commenter (Steven) pointed out that beef contains a significant amount of trans fat. And while his estimate was a bit high, it is absolutely true that one ounce of beef fat (28.3g) usually contains 0.5g-1.4g of trans fat.
In fact, the meat and milk of ruminants contains a significant amount of trans fat—roughly 2-5% of the total. Even worse, grass-fed milk and meat contains even more trans fat than grain-fed milk and meat!
Journal of Dairy Science
Volume 82, Issue 10 , Pages 2146-2156, October 1999
Conjugated Linoleic Acid Content of Milk from Cows Fed Different Diets
T.R. Dhiman, G.R. Anand, L.D. Satter, M.W. Pariza“Cows grazing pasture and receiving no supplemental feed had 500% more conjugated linoleic acid in milk fat than cows fed typical dairy diets.”
What’s going on here?
Trans-Vaccenic Acid and the Conjugated Linoleic Acids
No, I haven’t just named an obscure prog rock band from the 1970s. I’ve named the culprits: vaccenic acid and rumenic acid (a conjugated linoleic acid). Though vaccenic acid comprises most of the total, our bodies convert vaccenic acid directly to rumenic acid (just as they convert stearic acid directly to oleic acid), so nutritionally, we only need to investigate the effects of rumenic acid.
(This conversion is not reflected in American nutritional labeling—which requires stearic acid to be counted as saturated fat and vaccenic acid to be counted as trans fat, despite the fact that our bodies immediately convert them to different forms.)
A Short Biochemistry Excursion
Rumenic acid is known formally as (9Z,11E)-octadeca-9,11-dienoic acid, and informally as cis-9, trans-11 18:2. Vaccenic acid is known formally as (E)-Octadec-11-enoic acid, and informally as 18:1 trans-11.
Interestingly, the enzyme that converts vaccenic acid to rumenic acid—delta-9-desaturase—is the same enzyme that converts stearic acid (a saturated fat, 18:0) to oleic acid (a monounsaturated fat, 18:1 cis-9). That’s because delta-9-desaturase creates a cis-handed double bond at the 9th position. If you look at their informal names (or their chemical structure), you’ll see that the difference between vaccenic and rumenic acid is a cis-9 double bond, just the same as the difference between stearic and oleic acid is a cis-9 double bond.
Rumenic acid is part of a family of fats known as conjugated linoleic acids. “Conjugated” means that it contains both cis- and trans- bonds, just as its name (cis-9, trans-11 18:2) says.
Where Do The Trans Fats In Beef and Milk Come From?
Multicellular animals create only cis-handed fats with their enzymes…so where do trans-rumenic and trans-vaccenic acid come from?
Answer: they come from bacteria.
Cows, and other ruminants, can’t digest grass any more than we can. However, they have extra “stomachs” that are basically big microbial fermentation vats, in which bacteria digest the grass for them. (Whereupon they burp it up again, “chew the cud”, and finally swallow it into the regular digestive system once the rumen bacteria are done working.) Trans-rumenic and trans-vaccenic acid are created by these rumen bacteria via biohydrogenation of polyunsaturated fats (link).
To learn more about the ruminant digestive system, click the picture.
When Trans Fats Are Good For You: Our Friend Rumenic Acid
As with most rules of thumb, “trans fats are bad” is an oversimplification. “Molecules found nowhere in real food are bad” is the correct statement. People have been eating ruminants for millions of years, so one might expect that our bodies might have a nutritional use for rumenic acid.
This is, in fact, the case. The health benefits of rumenic acid are well-established—to the point where conjugated linoleic acid supplements (usually labeled “CLA” in big letters) are found in every vitamin store!
Conjugated linoleic acids (CLA) are a group of positional and geometric isomers of linoleic acid with proven beneficial influence on health. They show e.g. anticarcinogenic, antiobesity, and antiatherogenic effect. Milk, dairy products and meat of poligastric animals are their most valuable dietary sources, with cis-9, trans-11 CLA (RA – rumenic acid) being the predominant isomer.
…
This group of fatty acids has been extensively studied for recent years, in both in vivo and in vitro models, because of their beneficial biological effects: protection against cancer [7-10], prevention of atherosclerosis [11-14], reduction of obesity [15-17] and hypertension [18].
–Bialek et.al.
Since vaccenic acid (which becomes rumenic acid) and rumenic acid comprise 2-5% of beef and milk fat, this gives us yet another excellent reason to consume fatty meat and butter. Sign me up!
CLA Supplements: Not The Same As Real Food
It’s easy to get trapped in “nutritionism”: the idea that we can eat whatever junk we want, and take supplements to replace the nutrients we’re not getting from our food. This rarely works…and in the case of CLA supplements, we know why.
Recall that “conjugated linoleic acid” can mean a whole host of different fats, depending on the positions of the double bonds. Most CLA supplements are derived from safflower oil—
—and they contain equal parts rumenic acid (cis-9, trans-11 18:2) and an unnamed trans-10, cis-12 18:2 isomer. In other words, half of a CLA supplement is an entirely different chemical than what you’re getting from meat and butter.
Unfortunately, trans-10, cis-12 doesn’t have all the same beneficial effects. While it still seems to have anti-cancer properties in mice, it doesn’t have the same effects on human metabolism as rumenic acid:
Circulation. 2002; 106: 1925-1929
Supplementation With Conjugated Linoleic Acid Causes Isomer-Dependent Oxidative Stress and Elevated C-Reactive Protein: A Potential Link to Fatty Acid-Induced Insulin Resistance
Ulf Risérus, MMed; Samar Basu, PhD; Stefan Jovinge, MD, PhD; Gunilla Nordin Fredrikson, PhD; Johan Ärnlöv, MD; Bengt Vessby, MD, PhD“The significant increase from baseline in 8-iso-PGF2α, 15-K-DH-PGF2α and CRP after t10c12 CLA was 1.04±0.7 (578%), 0.30±0.31 (77%), and 2.89±3.66 (110%), respectively.
…
This randomized, double-blind, placebo-controlled trial demonstrates that dietary supplementation with t10c12CLA causes isomer-specific oxidative stress that is related to induced insulin resistance.”Diabetes Care September 2002 vol. 25 no. 9 1516-1521
Treatment With Dietary trans10cis12 Conjugated Linoleic Acid Causes Isomer-Specific Insulin Resistance in Obese Men With the Metabolic Syndrome
Ulf Risérus, MMED1, Peter Arner, MD, PHD2, Kerstin Brismar, MD, PHD3 and Bengt Vessby, MD, PHD1“This randomized placebo-controlled trial has revealed unexpected metabolic actions by conjugated fatty acids in humans—actions that seem isomer-specific. The t10c12 CLA isomer, but not a CLA mixture, significantly increased insulin resistance, fasting glucose, and dyslipdemia in abdominally obese men.”
[I can’t resist an editorial comment at this point: why did neither study test rumenic acid alone, the way it occurs in real food? Might it have actually reduced oxidative stress and decreased insulin resistance, when not forced to fight equal amounts of the imposter t10c12?]
It’s important to note that many of the studies that claim benefits for t10c12 are on mice or rats. As Risérus et.al. note:
“Conjugated linoleic acid (CLA) is a group of dietary fatty acids with antiobesity and antidiabetic effects in some animals. The trans10cis12 (t10c12) CLA isomer seems to cause these effects, including improved insulin sensitivity.”
Unfortunately, as their experiment proved, the safflower-derived t10c12 doesn’t have the same benefits for humans as it does for rodents. And perhaps we shouldn’t be surprised that ingesting a chemically extracted fraction of a seed oil doesn’t produce the same benefit as eating real food.
Conclusion: Keep Eating Like a Predator, Keep Eating Real Food
Our conclusions should be obvious, but I’ll restate them:
- If we’ve eaten something for millions of years, the odds are very good that we’re adapted to eating it.
- Be skeptical of studies that feed fat to mice—herbivores that naturally subsist on plants and seeds.
- Whenever possible, eat real food, not supplements. You might not be getting the same benefits…or even the same nutrients.
- Most importantly: keep eating delicious fatty red meat and butter!
Spend money on vitamins...
...or prime rib?
Live in freedom, live in beauty.
JS
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So, if you're doing it right already … don't worry about the details. For those inquisitive individuals who enjoy the detail it was good to see the distinction.
“… keep eating delicious fatty red meat and butter!” … will do 🙂
Your blog is one of those things that makes me appreciate living in Bulgaria, although the Bulgarian dream is to move out of the country and to a more “civilized” place.
It’s a weird looking place and I love it: you can see a horse-drawn cart in the street, next to a BMW X5.
It’s a place where it’s OK to be a bit wild. Did I mention most meat is grass-fed because it’s easier that way?
So I live here: the purchasing power parity is ridiculously low in developed country standards, but I get what I need, and more. I can reach good education and trinkets of civilization, and I can be a wild thing, too.
Come and visit if you wish!
I’m glad to see your emphasis on grass-fed meat. The health of the animals we eat is intrinsic to our health.
Aspiring Gnolls should also frequent themselves with the highly nutritious (and cheaper) cuts of meat such as tongue and liver.
Use of a slow-cooker to extract nutrients from bones by way of a stock, is also recommended – and superior to a vitamin pill.
Asclepius,
I love putting marrow bones, knuckles, what have you in my slow cooker with other meat and vegetables and letting it crank for hours on end. It tastes great, and you and I know how healthy all those dissolved minerals are, esp. in combination with the leached gelatin and fat. I’ll take slow-cooked soul food over a supplement any day (except vitamin D, I’ll still pop a pill for that one). Oh, and tongue is surprisingly fabulous – I was expecting tough meat, but it was the most tender cut I’ve yet eaten.
I have a grass fed beef tongue waiting in me freezer. I need to figure out how to cook that thing…
A long time back I pointed (http://praguestepchild.blogspot.com/2010/10/kiwi-cows-now-with-built-in-crisco.html) to an article about New Zealand cows having increased trans fat–palmitelaidic acid–from being fed palm kernel cake. I’m not sure if this is a bad thing or not, I think you totally nailed it about natural trans fats vs the artificial kind. But my preference would be to eat cows that are not eating seeds of any kind.
Dave – boil it. Then skin it an chop, shred or slice it. Really, it’s that easy, and it tastes like a beef roast.
@Greg – pretty much as Jan suggested:
1. Put the tongue in a pan and cover with cold water.
2. Bring to the boil.
3. Remove pan from stove, drain off the water and refill the pan with cold water.
4. Bring to boil once again.
5. Once boiling, turn the heat down to allow the pan to simmer.
Periodically stick a fork in to the tongue and if the fork slides easily in and out of the tongue it is ready. The outer skin of the tongue turns white with cooking and you have to peel it off – which is strangely satisfying.
Once cooked I usually dice it and put it in the fridge (I have to dice it as the though of biting into something tongue shaped is something I cannot get my head around!).
It makes a great snack when eaten cold, can be added to soups or simply used as the ‘meat portion’ of an evening meal (serve with steamed cabbage and diced potatoes – all covered in butter).
I am not sure if mice are obligate herbivores. I can’t really find anything definitive, but Paul says in the following message that rats love pork. Peter’s rat does eat lard, and I expect some meat.
http://high-fat-nutrition.blogspot.com/2011/03/ratty-at-year.html?showComment=1299010990361#c7686429462279399815
Rabbits on the other hand are obligate herbivores.
yeah i don’t think mice are obligate herbivores. i had pet mice as a child and they loved bugs, i know because i fed them bugs when the time of year was right.
(so not winter pretty much)
otherwise great update, i did wonder about CLA when bought as a supplement as clearly it would be unlikely to come from beef due to cost, mass produced from seed oils though i can readily believe.
I was going to mention the trans fats produced when cows are fed palm kernel expeller also. I’ve got links in this post:
http://paleozonenutrition.wordpress.com/2010/10/02/new-zealand-cows-fed-palm-kernel-expeller-producing-a-new-type-of-trans-fat-is-it-safe/
Great post – thanks JS
@anand, rats are more omnivorous than mice. They’re not all that similar in diet or behavior really, just appearance.
Mice definitely do eat bugs, though.
Now I want a giagantic prime rib. Thanks a lot JS.
Hello, everyone! Thanks for your patience in waiting for my responses: I'm bumping up against the limits of my time and ability.
Paul:
Absolutely. If I find data that requires me to dramatically revise my recommendations, I'll do so and let everyone know. Meanwhile, I find it interesting to know why things work as they do — and Steven had a legitimate question about why there's so much trans fat in beef.
Hipparchia:
I hope I will someday have the opportunity to accept your generous offer!
Asclepius:
Liver especially: it's nature's vitamin pill. There's a reason carnivores eat it first. Someday I'll write another article on quick and dirty meat preparation.
Greg:
Bison tongue was highly prized by Native Americans, who in times of plenty would occasionally kill a bison for the tongue, nose (also fatty AFAIK), and visceral fat, and leave the rest to the wolves.
Dave:
What Jan said. Or you can just slice it thinly and flash-fry it, Korean BBQ style. Anyone ever made carpaccio from tongue?
Sean, Julianne:
I suspect palmiteliadic acid is just as Not Good as other trans fats, since it's a) not a conjugated fat (TRA has both a cis- and trans- bond) and b) it's nowhere in our evolutionary history.
Jan:
It's surprising how normal beef tongue tastes.
Asclepius:
That's the traditional way. And you raise a good point about changing the water.
Anand, eddie:
Mice are herbivores, unlike rats. Though you're correct that they're not obligate herbivores: they do eat insect larvae. I'll revise to reflect that.
Uncephalized:
Exactly. Analogy: mice are to rats as pigeons are to crows.
Chris:
The question is: when DON'T you want a prime rib?
Fortunately they're the easiest thing in the world to cook so long as you have the old-school Taylor meat thermometers that go down to 105 degrees. Just stick them in a 260 degree oven and wait until the temperature hits 110-130, depending on how done you like it. (I think 115 is about right.) Warning: the government says you'll die if you cook them to anything less than 135.
JS
stanton: Warning: the government says you’ll die if you cook them to anything less than 135.
this made me lol at work!
also not meaning to be picky, but if mice eat bugs surely they are omnivores with a heavy leaning towards more vegetable matter.
kind of like we are omnivores with a heavy leaning towards meat consumption. (certainly with regards to caloric split anyway)
eddie:
Deer are theoretically obligate herbivores, but here's video of one eating a dead goose:
http://www.youtube.com/watch?v=lqdfgfZvV10
And here's one killing and eating a live bird:
So, strictly speaking, deer are omnivores too!
Note that I can't find any good figures on the percentage that insect larvae make of the mouse diet — and apparently it differs between species of mouse, with some being strict herbivores and some willing to snack on insects. But I generally see mice classified as herbivores (example).
More importantly, they're very well adapted to eating grass seeds, which humans are not.
JS
actually i remember years ago an elephant in london zoo ate a keeper so you have a good point!!
J. Stanton said:
Chris:
Ha ha, best quote ever: “the government says you'll die if you cook them to anything less than 135.”
I guess I have more lives than a cat. I always order bleu for tender/flavorful cuts and hardly ever like anything past rare. Guess I'm going to die soon. Though I generally get my meat from trusted sources.
Chris:
If you look at actual deaths from foodborne illnesses, far more people die from fruits and veggies than from meat. Example: 21 people died this year from cantaloupes, one from strawberries, and one from Cargill ground turkey.
And if you look at the deadliest outbreaks throughout history:
https://secure.wikimedia.org/wikipedia/en/wiki/Deadliest_foodborne_illness_incidents
Far more people have died from shady Mexican cheese, bean sprouts, cantaloupe, and onions than have died from meat of any kind…and the meat deaths are from things like “cold cuts” and hot dogs. Even store-bought hamburger doesn't make the list, let alone actual cuts of beef.
I eat everything good bleu rare, too.
JS
Ray Peat:
'When meat is grilled at a high temperature, the normally spaced double bonds in PUFA migrate towards each other, becoming more stable, so that linoleic acid is turned into “conjugated linoleic acid.” This analog of the “essential” linoleic acid competes against the linoleic acid in tissues, and protects against cancer, atherosclerosis, inflammation and other effects of the normal PUFA.' (link)
(I am quite surprised)
Natalia:
That particular statement about linoleic acid converting to CLA
in the presence of grill heat is a) not footnoted and b) seems bogus to
me. In that case, well-used deep-fryer seed oil ought to be full of
CLA, since the source oil is full of LA — but I haven't seen any
indication that this is the case.
First, oil mostly oxidizes (burns) on the grill AFAIK.
Second, the number of possible configurations of 18:2 (linoleic acid) is quite large, and even if isomerization occurred, it seems like the odds of heat randomly happening to produce the one single isomer that we can use (trans-rumenic acid) are relatively low.
I'm open to correction on this issue…but it seems highly fishy to me.
JS
That’s why I’m surprised…
It would be too easy for us.
I believe bacteria sences dangerous PUFA and makes it safe…for itself.
[…] levels of CLA, a healthy naturally occurring trans fat. Grass fed dairy also has more of the beneficial trans fats. Grass fed beef has plenty of healthy fats, distributed more evenly throughout the animal’s […]
It is wrong!!!!….CLA Supplements:……….2nd paragraph. Safflower oil das not contain CLA. This statment is opposite to the fact that only ruminant produce CLA and Vaccenic acid
Lilia:
Safflower oil doesn't contain CLA itself: the CLA is produced chemically, via alteration of the linoleic acid it contains. That's why I said “Most CLA supplements are derived from safflower oil,” and that statement is correct.
The reason safflower oil is usually used to make CLA supplements is that it's both cheap and very high in linoleic acid. However, other oils, such as soybean or corn oil, are occasionally used.
JS
[…] However, it may surprise you to learn that many of the foods recommended on a Paleo or whole foods diet contain trans fats as well. Dairy fat and meats from grass eating “ruminant” animals contain significant amounts of trans fatty acids, and grass-fed animals actually have higher levels of these trans fats than grain fed animals. (1) In fact, your grass-fed steak contains about 0.5g-1.4g of trans fat per ounce (28.3g) of total fat. (2) […]
[…] However, it may surprise you to learn that many of the foods recommended on a Paleo or whole foods diet contain trans fats as well. Dairy fat and meats from grass eating “ruminant” animals contain significant amounts of trans fatty acids, and grass-fed animals actually have higher levels of these trans fats than grain fed animals. (1) In fact, your grass-fed steak contains about 0.5g-1.4g of trans fat per ounce (28.3g) of total fat. (2) […]
[…] However, it may surprise you to learn that many of the foods recommended on a Paleo or whole foods diet contain trans fats as well. Dairy fat and meats from grass eating “ruminant” animals contain significant amounts of trans fatty acids, and grass-fed animals actually have higherlevels of these trans fats than grain fed animals. (1) In fact, your grass-fed steak contains about 0.5g-1.4g of trans fat per ounce (28.3g) of total fat. (2) […]
[…] “Trans fat is good for you, but only if it’s from meat and butter” from gnolls.org This entry was posted in Workout of the Day by Todd. Bookmark the permalink. […]
[…] Trans Fat Is Good For You, But Only If It’s From Meat and Butter: Vaccenic Acid and the Conjug… My chocolatey Primal journey Unusual food recipes (plus chocolate) blog Reply With Quote […]
Check out how it’s effecting the climate and our bodies http://www.upworthy.com/a-world-gone-mad-for-cows-bad-beef-bacteria-and-cow-poo-climate-change?c=tkp1
Sara:
If grazing animals caused global warming, the planet would have drowned tens of millions of years ago. There were somewhere between 20 and 80 million bison on the Great Plains alone before the white man colonized America…and the entire Pleistocene was a major cooling trend, culminating in the Ice Ages.
Also, did you know that rice paddies produce at least as much methane as cow burps or farts? (Estimates vary, but they're of similar magnitude.)
Yes, factory farming is destructive for other reasons, and I oppose it too: corn isn't the natural diet of cattle any more than it's the natural diet of humans. But propaganda videos aren't a valid argument.
JS
I think we need to understand that we have only had spears and fire for the last 400,000 years and before then would have eaten little to no animal foods. I ask you to really think about it and look in the mirror and ask ourselves how could i have possibly caught and eaten animal foods before then? You, yes YOU are a herbivore in every way shape and form!
Clint:
We've used sharp rocks to obtain meat for at least 3.4 million years, and made our own sharp rocks for at least 2.6 million years. And chimpanzees hunt and eat monkeys without using any tools at all.
JS
Hey there, thanks for the post. I love the content I’m getting.