Dear Mark: Carbs and Serum Saturated Fat, Fat and Polyphenols, and Avocado Oil for Searing

Dear_Mark_Inline_PhotoFor today’s edition of Dear Mark, I’m answering three questions from readers. All three questions come from last week’s saturated fat post. First, I explore the true reason for increases in serum palmitic acid—too many carbs. Second, I investigate whether dairy or saturated fat affect polyphenol absorption, and whether it actually matters. And finally, I discuss the merits of avocado oil for high heat cooking and searing.

Let’s go:

You didn’t mention that the level of palmitic acid in serum is controlled by dietary carbohydrate – this has been known since 1955 if not earlier, and more recently demonstrated in humans by Jeff Volek’s team.

Thanks, George. Great post, by the way. Love your stuff.

I did mention that “the only time we get a huge influx of pure palmitic acid is when we eat too many carbohydrates and our liver converts the excess into palmitic acid.” That’s de novo lipogenesis, the creation of (saturated) fat from glucose. It occurs in people with overstocked liver glycogen who eat too many calories and carbs and don’t move enough. There’s nowhere for the glucose to go, since glycogen stores are full. Conversion into palmitic acid, a relatively stable energy source with unlimited storage capacity, is the only other option.

Indeed, as shown in your link, diets high in fat and low in carbs tend to either reduce or maintain saturated fat levels in the serum.  They definitely don’t increase it, which is the opposite of what most people would think. Eat saturated fat and it shows up in your blood. Right? Not necessarily. Jeff Volek’s team showed that as dietary carbohydrate increases, so do saturated fatty acids in the blood.

Dr. Barry Sears, PhD, who authored the Zone and has a background with MIT, etc., has stated since his first book that Saturated Fatty Acids are inflammatory. He recently stated on his website, “Saturated fats are pro-inflammatory compounds and will antagonize the benefits of the polyphenols.” ( September 2017) So, what is the bottom line from science?

I tracked that statement down to a message on Sears’ Twitter account where he links to an article on Well and Good about optimizing your coffee. It’s a decent article, with helpful tips on choosing the best beans and roasts for polyphenol maximization. The last tip is to add healthy fats but limit dairy, as “cream and milk actually lower the amount of polyphenols.”

Is that true? Does dairy (or saturated fat) lower polyphenol absorption?

A polyphenol-rich carob drink in a “milk matrix” was effective at lowering inflammation and improving bowel function and lipids. The milk might have blocked  some of the polyphenols—there was no dairy-free control group to compare—but even if that was true, enough obviously got through to elicit beneficial effects.

Another study compared olive polyphenol-enhanced yogurt to plain yogurt. Both yogurts helped subjects lose weight, reduce weight circumference, and lower blood pressure, but subjects who ate the polyphenol-enhanced yogurt had lower LDL and higher antioxidant levels. Clearly, the polyphenols were making it through.

Another study found that in a simulated gastric environment—artificial stomach—cheese was an excellent vehicle for green tea polyphenols, protecting their viability and biological activity.

There have been studies where the presence of dairy seems to inhibit the absorption of polyphenols, but that was due to the proteins, not the fat.

Cocoa polyphenols work just fine in the presence of milk protein, lowering oxidized LDL and increasing HDL.

Maybe it does. None of these were perfectly controlled environments. Perhaps polyphenols work well with saturated dairy fat, but they’d work even better without it. We just don’t know.

We must also remember that polyphenols don’t have to be absorbed to help us. They’re also very effective in the gut, killing pathogens and serving as prebiotic fuel for our gut bacteria. If we aren’t absorbing them, they spend more time in the gut where the magic happens.

I’m still drinking coffee with cream though. If you like it, so should you.

Hi Mark,

With respect to smoke point, is it safe to pan sear a steak using avocado oil?

Avocado oil has one of the highest smoke points. It’s a great combination of stable fats, mostly monounsaturated, and natural antioxidants like vitamin E and other polyphenols that combine to present a united front against heat damage and oxidation and make avocado oil a great choice for searing steaks.

Compared to olive oil, which is no slouch in the heat tolerance department, avocado oil matches up well. “The stability of avocado oil was similar to that of olive oil.”

Adding avocado oil (and olive oil) to pork burger patties increased the oxidative stability of the burgers when cooked.

Avocado oil offers extra protection against oxidative damage by improving your glutathione status, at least if you’re a rat.

As you might have guessed, I didn’t just start selling the stuff for the hell of it. Olive oil is great, but there are dozens of great products already established and it doesn’t taste very good in mayo. The weight of the evidence convinced me it was the oil to use in my products. ]

That’s it for today, folks. Thanks for reading and be sure to chime in below with your own thoughts, questions, comments and concerns.


About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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4 thoughts on “Dear Mark: Carbs and Serum Saturated Fat, Fat and Polyphenols, and Avocado Oil for Searing”

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  1. I’ve been using avocado oil to sear meat and roast at high temps ever since I started reading about it here on MDA (and buying it from Primal Kitchen) Just yesterday I roasted tons of veggies at 400 that were very generously doused in avocado oil. Soooo good and I’m enjoying the leftovers right now. Glad to know I may be improving my glutathione status too 🙂

    1. I have a huge bottle of avocado oil from Costco in the fridge. I usually use it for salad dressing or mayo since I prefer to make my own. We mostly fry or sear meat in bacon fat but I agree that the oil does do a nice job with roasted veggies. Now that the Primal Kitchen brand appears to be available locally (at Whole Foods) I will give it a try.

  2. Re: saturated fat and carbohydrate. I am one of those people (possible my APoE 3/4 genetics) that gets a shockingly high risk of LDL/LDL-P/HDL/total cholesterol on low carb high sat fat diets. Carbs will somewhat mitigate this effect and increase my cholesterol metabolism. It’s important to use caution here because the exception can possibly be dangerous.

    1. Chris, you’re right that those with the APoE4 variant should take more care in individualizing their diet and lifestyle, as they’re more vulnerable to what I’ll call novel, modern stresses like sedentary living and toxin buildup. Some like Dr. William Davis, also theorize that people with this variant are more sensitive to dietary fats – particularly saturated fat – as well as carbs. If your genetic profile includes the APoE4 variant (and especially if you carry two copies), I suggest being more rigorous about an overall healthy lifestyle, monitoring your lipid panel in more detail, and adjusting your diet toward variations that show overall health as well as lipid benefits.