Amidst all the debate  over how saturated fat and PUFAs differentially affect our health, we often forget about monounsaturated fats, or MUFAs. These are almost universally tolerated, if not loved. No one really maligns them. Vegans and carnivores alike consume them on a regular basis. You find ’em in nuts  and seeds alongside PUFAs . You find them in animal fats  alongside saturated fats. In most healthy diets, whether alternative (Primal, keto) or conventional (Mediterranean, AHA), monounsaturated fats feature prominently. They can’t really be avoided. But they’re an afterthought in hard core nutrition geek circles. Probably because no one really attacks them. Probably because they’re uncontroversial.
Let’s change that. Today, I’m going to explain why, in explicit detail, you should be eating more monounsaturated fat—if you aren’t already.
1. It’s surprisingly stable
Saturated , monounsaturated, and polyunsaturated  fats are defined by their molecular structure. When we talk about “oxidized fatty acids,” we’re talking about oxidation of the carbon atoms that lie between double bonds. PUFAs are highly unstable because they have two more double bonds; that’s two more weak spots vulnerable to oxidative damage. Saturated  fats are highly stable  because they have no double bonds, no weak spots. MUFAs, with their one double bond, are theoretically vulnerable to oxidation—but it rarely actually happens. The literature shows that MUFA-rich oils, like olive  and avocado , are highly resistant to heat damage during cooking .
2. It makes mitochondria function better
Mitochondria are (almost) everything. Cellular power plants whose design we co-opted from parasitic bacteria billions of years ago, mitochondria provide ATP—the basic energy currency. They regulate both individual cellular metabolism and, since we’re just collections of cells, overall metabolism. The more mitochondria we have and the better they work, the more energy we’re able to consume, utilize, and produce. They’re quite essential.
They’re also sensitive to oxidative stress if they’re not built with the right materials. Mitochondria whose membranes contain high levels of PUFAs are less stable, more prone to oxidative damage, and function worse than mitochondria with MUFA-rich membranes. We need our mitochondria to work if we’re to enjoy good health and a strong metabolism, and MUFAs make that possible.
3. It’s a primary constituent of many healthy foods
We eat foods, not nutrients, remember. And by choosing foods high in monounsaturated fat, in a roundabout way you’ll be choosing foods high in many important nutrients.
Consider the mac nut. Buttery, sweet, associated with many health benefits. A favorite treat of mine is salted, dry-roasted mac nuts in Greek yogurt with a drizzle of raw honey. “Salted”? Yep. Try it.
Consider the avocado. Everyone’s favorite “healthy fat.” A rich source of potassium, half an avocado can reduce the postprandial inflammatory load  of a big meal. I don’t mean to use scare quotes in a negative way—I love avocados. That everyone but Ray Peat embraces it amuses me, is all.
Consider the almond. A surprising source of prebiotic fiber  and repository for vital minerals, the almond is mostly known as a “bag of linoleic acid.” It has PUFAs, sure, but MUFAs are still the primary fatty acid present in the almond. Didn’t know that, did you? We forget.
Consider the olive, whose MUFA-rich oil reduces inflammation  in heart disease patients.
Consider the egg yolk. Easiest/tastiest source of choline around. Great source for folate, selenium, B12 , complete protein, dietary cholesterol (yes, it’s important ). Go pastured and it gets even better. Did you realize that MUFA is the predominant fatty acid in your average egg yolk ? It is.
Consider grass-fed beef. Who doesn’t love it? It’s higher in nutrients, lower in cruelty. Even vegans will begrudgingly admit it’s “better” and “slightly less murderous” than conventional beef. Turns out that the grass-fed stuff is higher in MUFAs (and stearic acid, a type of saturated fat that desaturates to MUFA  in the body).
4. It supports immune function
Research has established  the pivotal role of oleic acid in immune function: it improves wound healing, increases the elimination of pathogens, and is associated with protection against autoimmune diseases.
5. It protects against diabetes
Several lines of evidence point to a protective effect.
- Observational studies consistently show an inverse relationship between MUFA consumption and diabetes (and diabetes-related complications, like kidney damage ).
- Controlled trials find  that MUFA-rich diets improve glycemic control and lipid profiles in type 1 diabetics. In type 2 diabetics , they reduce insulin resistance  (especially compared to PUFA-rich diets).
- Animal trials show  that MUFA reverses the tendency of inflammatory cytokines to depress insulin production, making it vital for type 1 diabetics for whom depressed insulin production is a major issue.
Eat it up, diabetics.
6. It has anti-tumor mechanisms
Oleic acid plays a crucial role in the initiation of several anti-carcinogenic cellular processes . It even combines with bovine lactoferrin (a bioactive protein found in milk) to form a novel anti-tumor compound , and animal studies indicate  a number of anti-cancer properties inherent to oleic acid. Don’t go sticking raw milk  with olive oil  in your Vitamix and selling it as a cancer cure or anything, but that’s pretty cool.
7. It’s great for blood lipids
Even as controversy over the importance of the lipid profile rages across the nutritional world, one thing remains certain: whatever stance you take, monounsaturated fat has a neutral or positive effect. It increases HDL and reduces LDL. It reduces triglycerides and increases the all-important HDL:Total  ratio. It does this in healthy people and diabetics , in the overweight  and the heart disease-stricken. It does this without increasing LDL’s propensity to oxidize, as happens in high-PUFA diets .
8. It’s good for your joints
MUFA (and its constant companion, saturated fat) has been shown to increase the resilience of cartilage exposed to stressful conditions . Omega-6 PUFAs have the opposite effect. This may come down to oleic acid’s inhibitory effect on TNF-alpha , a cytokine involved in local joint inflammation .
9. It’s widely accepted
We like to flout conventional wisdom , but it’s important to only do that when it’s actually wrong. Sometimes conventional wisdom is correct. And when everyone agrees on something, take a closer look before discarding it.
It turns out that the pro-MUFA stance is not based on fluff or propaganda. Real legitimate science  shows that MUFAs are beneficial. The kind of science that your average vegan, paleo, and conventional cardiologist would all cite and find credible.
10. It’s found in the best mayo on the planet
Now, I have no idea what pure oleic acid tastes like. Not much, I’d imagine. But think about olives, bacon, beef, brie, and, oh, avocados . Foods that contain it tend to be delicious.
This is why I chose avocado oil  as the foundation for most of our Primal Kitchen products. Whether it’s mayo (chipotle lime  or regular ), dressing (Greek vinaigrette  or honey mustard ), or straight up avocado oil, MUFAs as they appear in the wild taste as good as they are good for you.
Oleic acid, the primary MUFA, isn’t magic. It’s not a “superfood.” It’s the work horse of the fatty acids. It’s the foundation. It’s the one constant amidst all healthy diets. Meat eaters get tons of it through animal fat. Lacto-ovo vegetarians get it through dairy and eggs. Vegans get it through nuts and oils. We all carry a lot of it in our adipose tissues, if not by weight then by percentage. Our bodies even convert certain saturated fats, like stearic acid, into oleic acid; that’s how much our bodies need it.
It’s time we pay closer attention to MUFAs. Don’t you agree?
What did I miss? What other health benefits do oleic acid and other MUFAs offer? What’s your favorite way to obtain them?
Thanks for reading, all!
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