The Definitive Guide to Saturated Fatty Acids

January 30, 2020

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I’ve written guides to fat in general, animal fats in particular, and edible oils as well. I’ve written a definitive guide to saturated fat. But what are these fats, exactly? Today, I’m writing the Definitive Guide to Saturated Fatty Acids—a guide to all the individual fatty acids that make up the saturated fats we eat, store, and burn.

I won’t cover every single saturated fatty acid in existence. Some of them don’t play any significant role in human health or diet. Like cerotic acid, which appears mainly in beeswax. Or arachidic acid, which you can get by hydrogenating arachidonic acid or eating a ton of durian. There are a few more that aren’t very relevant.

I will instead cover the most important ones.

But First, a Word about Saturated Fatty Acids…

Saturated fats have all available carbon bonds paired with hydrogen atoms, making them highly stable and resistant to oxidation and rancidity—even when heated. That’s why our bodies tend to build cellular membranes with a significant portion of saturated fats. They provide stability and a strong foundation.

Caproic Acid, Caprylic Acid and Capric Acid

I included these together because their names come from the Latin word for “goat,” and all three are found most famously in goat milk—they run about 15% of goat milk fat. Capric acid is also found in coconut oil (10% of coconut fat) and palm oil (4% of palm fat).

The “goat” fats are what give goat milk its distinctive “goaty” odors. Come to think of it, I’ve had coconut oil that had a “funk” to it, and I bet the capric/caprylic acid was to blame. But if you can get past the goatiness, there are benefits to these fatty acids.

Capric acid has been used to inhibit seizures in people with epilepsy, and if you combine it with caprylic acid, the anti-seizure effect seems to increase.
As medium-chain triglycerides, the goat fatty acids increase ketone production. In fact, caprylic acid is the most ketogenic medium-chain triglyceride of all.
Capric acid has anti-fungal properties, showing particular efficacy against Candida, while all three are effective against oral bacteria.

Best sources: goat milk, coconut oil, palm oil.

Lauric Acid

Another medium-chain triglyceride, lauric acid is the primary fatty acid in coconut fat (40-50% lauric acid) and palm kernel fat. It also appears in human breast milk (about 6.2% of total fat).

Lauric acid is anti-microbial. That’s why it appears in breast milk—to help infants ward off pathogens while their immune systems are still developing. And it’s probably why people report getting rid of foot and toenail fungus by smearing their feet with coconut oil at night.
Lauric acid reduces hunger. In one study, people who had lauric acid shot directly into their guts ate less food than the people who had oleic acid shot in.
When you consume lauric acid, some of it is converted into monolaurin, a more potent compound (both coconut oil and breast milk also contain some monolaurin directly) with anti-viral, anti-microbial, and anti-fungal properties.
Lauric acid is not as directly ketogenic as the “goaty” medium-chain triglycerides.

Best sources: coconut fat, palm kernel fat, breast milk.

Myristic Acid

Myristic acid is a perplexing one. Some studies find that its presence in the blood indicates metabolic issues, whereas, as you’ll see below, in the diet it can have some good effects and play some important roles.

The odor of myristic acid draws the newborn to the breast and helps trigger the appetite for mother’s milk.
Myristic acid in milk also possesses anti-listeria activity.
Eating 1-2% of calories as myristic acid—about what you’d get from including a little coconut or moderate amounts of full-fat dairy in your daily diet—improves red blood cell membrane fluidity and lipid profile. Eating that much also improves omega-3 status.
High-fat dairy is consistently linked to better cardiovascular health despite being one of the best sources of myristic acid.
The Tokelau islanders ate a coconut-based diet that was very high in myristic acid; they had excellent cardiovascular health.

What’s happening? Why the discrepancies?

Some in the diet is way better than none. Too much more than 1-2% of calories (about 10% of calories from dairy fat), and the benefits start dropping and even reversing. However, that “1-2%” limit was in the context of a higher-carb diet. If you’re lower carb, you can probably benefit from higher intakes.
Myristic acid in the blood isn’t so much “dangerous” as it is indicative of metabolic dysfunction. For instance, the most reliable way to reduce blood levels of myristic acid is to reduce your carbohydrate intake.

Best sources: nutmeg butter (don’t eat that and go driving, though; nutmeg is downright psychoactive), coconut fat, palm kernel oil, milk fat, breast milk.

Stearic Acid

Stearic acid is enjoying a bit of a renaissance lately. People are mixing isolated stearic acid into clarified butter to create a “super-stearic butter.” Why?

Stearic acid is one of the saturated fats that even SFA-phobes admit has a neutral effect on cholesterol levels. If anything it boosts HDL.
Dietary stearic acid appears to cause “fusing” of our mitochondria—the power plants of our cells—and increase fatty acid oxidation shortly after consumption. In other words, it’s a potent boost to our ability to generate energy.
Diets based on either red meat or cheese—two foods high in stearic acid—improve metabolic and blood markers.

It’s getting really tough to deny the benefits of stearic acid.

Best sources: cocoa butter, beef fat (steer/stearic), dairy, lard.

Palmitic Acid

Palmitic acid gets a terrible rap. In study after study, we find palmitic acid doing bad things to our cells and our health markers. And when you douse cells in pure palmitic acid, they tend to suffer and even die. This looks really bad.

For instance, palmitic acid lowers expression of the LDL receptor gene. Less LDL receptor activity, more time for LDL to hang around in the bloodstream and cause trouble. That’s not good.

Or the fact that palmitic acid is toxic to skeletal muscle cells, impairing glucose uptake and increasing insulin resistance.

Or that palmitic acid induces inflammation and disrupts insulin signaling, suggestive of diabetes. We don’t want diabetes, we don’t want heart disease, and we like our muscle cells to function, so we should probably stop eating any palmitic acid, right?

Except a modicum of oleic acid stimulates LDL receptor activity. And arachidonic acid, a polyunsaturated fat found in animal products often alongside palmitic acid, prevents cell toxicity. And finally, if you throw in a little oleic acid alongside that “inflammatory” palmitic acid, you obliterate the inflammation.

Okay, but what about serum palmitic acid being a harbinger of metabolic disorder? Easy. When you overeat sugar and there’s nowhere to put it and you can’t burn it, the liver converts any extra into palmitic acid to be stored. Elevated palmitic acid is a marker of eating too many carbohydrates (and food in general).

Best sources: dairy fat, ruminant fat, palm oil.

What does it all mean?

Even though today’s post was about the individual saturated fatty acids, we very rarely eat individual fatty acids. Instead, we’re eating fats that contain a half dozen fatty acids or more, or foods that contain fats that contain a half dozen fatty acids. We aren’t cooking with lauric acid or sprinkling pure palmitic acid in the pan. We’re eating foods. And, as part of the food matrix, all the saturated fatty acids I’ve examined have important and valid roles to play.

If you want to avoid palmitic acid but welcome stearic acid, guess what? You’re gonna have to craft some Frankenstein-fat. Foods that contain stearic acid also contain palmitic acid. The best sources of lauric acid are also pretty high in stearic, palmitic, and myristic acid. And so it goes. You can’t avoid palmitic acid and only eat lauric and stearic acid while eating actual food.

If you have any questions, drop them down below.

Thanks for reading, everyone!

References

Wlaz P, Socala K, Nieoczym D, et al. Acute anticonvulsant effects of capric acid in seizure tests in mice. Prog Neuropsychopharmacol Biol Psychiatry. 2015;57:110-6.

Huang CB, Alimova Y, Myers TM, Ebersole JL. Short- and medium-chain fatty acids exhibit antimicrobial activity for oral microorganisms. Arch Oral Biol. 2011;56(7):650-4.

Feltrin KL, Little TJ, Meyer JH, et al. Comparative effects of intraduodenal infusions of lauric and oleic acids on antropyloroduodenal motility, plasma cholecystokinin and peptide YY, appetite, and energy intake in healthy men. Am J Clin Nutr. 2008;87(5):1181-7.

Intorre F, Venneria E, Finotti E, et al. Fatty acid content of serum lipid fractions and blood lipids in normolipidaemic volunteers fed two types of cheese having different fat compositions: a pilot study. Int J Food Sci Nutr. 2013;64(2):185-93.

Gutiérrez-garcía AG, Contreras CM, Díaz-marte C. Myristic acid in amniotic fluid produces appetitive responses in human newborns. Early Hum Dev. 2017;115:32-37.

Chen X, Zhao X, Deng Y, Bu X, Ye H, Guo N. Antimicrobial potential of myristic acid against Listeria monocytogenes in milk. J Antibiot. 2019;72(5):298-305.

Prior IA, Davidson F, Salmond CE, Czochanska Z. Cholesterol, coconuts, and diet on Polynesian atolls: a natural experiment: the Pukapuka and Tokelau island studies. Am J Clin Nutr. 1981;34(8):1552-61.

Hunter JE, Zhang J, Kris-etherton PM. Cardiovascular disease risk of dietary stearic acid compared with trans, other saturated, and unsaturated fatty acids: a systematic review. Am J Clin Nutr. 2010;91(1):46-63.

Thorning TK, Raziani F, Bendsen NT, Astrup A, Tholstrup T, Raben A. Diets with high-fat cheese, high-fat meat, or carbohydrate on cardiovascular risk markers in overweight postmenopausal women: a randomized crossover trial. Am J Clin Nutr. 2015;102(3):573-81.