Dear Mark: Soy-Fed Eggs, and Liver-Polluting, Body-Acifiying, Meditative State-Preventing Meat

EggsWe’ve got a two-parter for today’s edition of Dear Mark. First, I field a question from a reader who loves eggs, raises his own chickens on open pasture, and wants to know whether or not the soy he currently includes in their diets is going to affect him. Then I evade a silly question about the stagnating, putrefying qualities of rotting animal flesh and explore whether meat truly does raise uric acid levels, thereby interrupting our pursuit of satori and maybe giving us gout.

Let’s go:

Hi Mark,

I am currently doing about a dozen eggs per day (along with other primal friendly foods). We raise chickens and allow them to pasture happily and freely while also supplementing their diet with an organic soy based feed. Where my concern comes in is the soy content in the eggs. I hate not to use them since these chickens do produce pastured eggs. I am currently on the hunt for a soy free feed so this should no longer be an issue in short time to come. In the mean time, I have found another source of soy free pastured eggs; I use these and my family uses the eggs our chickens produce. Currently doing a dozen eggs per day, should I be worried about the the soy content in these eggs? I am not intolerant to soy just concerned about phytoestrogens I would be taking in on a daily basis. Thank you for your time really love and enjoy MDA!!


I have good news: you probably don’t have to worry about the phytoestrogens.

Sure, soy phytoestrogens show up in eggs from soy-fed chickens, but it’s a pretty small amount. A few years ago, a study (PDF) showed that while chickens fed supplementary soy phytoestrogens produced eggs with high levels of phytoestrogens in the yolks (nearly 1000 mcg/100 grams yolk), chickens on a standard 25% soy diet produced yolks with just 46 micrograms of phytoestrogens for every 100 grams of yolk. An egg yolk runs about 20 grams or so, so with your 12 yolk-a-day habit you’d be getting a little over 100 mcg of phytoestrogens. That pales in comparison with the amount of soy phytoestrogens (or isoflavones) in most soy supplements, which have about 50 milligrams of pure phytoestrogens per serving and are designed to elicit physiological effects. It also doesn’t really compare to the 15-50 mg/day phytoestrogen intake of people who actually eat soy, nor the even higher levels used in clinical trials. While it’s possible that you may be extremely sensitive to phytoestrogens, I’ll bet you can safely save your money and eat your own eggs without worrying about growing breasts.

That said, there is one bigger problem with soy-fed chickens and their eggs, and it rhymes with “Jomega Fix.”

Chickens are the kind of animal that incorporates the fatty acid profile of whatever it eats into its own tissues. Pigs and people are the same way. There’s some endogenous conversion of fats, but by and large if they and we eat a bunch of polyunsaturated fats our tissue fat will become more unsaturated. Ruminants, like cows, sheep, and bison, are different. They can eat omega-6 heavy grains and end up with fairly consistent levels of saturated, monounsaturated, and polyunsaturated fats in their milk and meat.

So, when a chicken eats a lot of soy or corn, the fatty acid breakdown of which is heavily weighted toward omega-6, they produce eggs that are also higher in omega-6 fats at the expense of monounsaturated fat. This is not a good thing. We are inundated with linoleic acid nowadays. We’re positively (but not literally) swimming in it (albeit laboriously, since it is a thick viscous oil). Plus, research shows that eating eggs from chickens fed a diet high in omega-6 can make your blood lipids more prone to oxidative damage, the progenitor of atherosclerosis and probably heart disease.

All that said, eggs are still good to eat. Their fat is still primarily saturated and monounsaturated (as long as the hen’s diet isn’t all soy). They still contain lots of micronutrients like vitamin A and choline and they’re still a great source of highly bioavailable protein. They’re no less delicious. And, being as that your chickens are pastured with some supplementary feed that contains some soy, you’re better off than almost everyone. For everyone else, I wouldn’t break the bank on regular eggs that happen to be soy-free. Instead, spend the money on pastured eggs, which may or may not have some soy in their diets. You’ll get far more bang for your buck.

Side note: I really enjoy the phrase “soy-fed eggs.” It conjures images of a farmer ever so softly cracking an egg and trying to slip soybeans through the crack.

Hi Mark,

My vegetarian yoga teacher says these things about eating meat. Can you respond? Thanks!

Meat is a concentrated animal protein. When an animal dies, its proteins coagulate within a few hours, releasing various toxins. These toxins can initially be absorbed by the liver, but eventually even the liver can’t handle them, and the body becomes polluted. Vegetable proteins, by comparison, do not undergo auto-putrefaction. Their main residue is cellulose, which is inert.

Meat is among the most acid-producing foods. It leaves a residue of uric acid in the bloodstream. Acidic blood is an ideal environment for the development of cancer. Uric acid is a toxin that makes it harder to reach the higher, clearer meditative states because it is an irritant in the bloodstream.


Your vegetarian yoga teacher doesn’t happen to be this guy, does he?

I’m not going to touch the first part of the question. Anytime I see words like “coagulate” or “toxins” or “polluted” or “putrefaction” coming from someone that’s anti-meat eating, my face goes numb and I disengage from the conversation. It’s not worth trying to refute, because people who use terms like that won’t ever change their minds. Believe me. It’s standard anti-omnivore propaganda. Next he’ll tell you that John Wayne (or was it Elvis) died with forty pounds of rotting meat lodged in his colon.

I will, however, discuss the uric acid question. Studies are fairly clear. Vegans, those folks who get all of their protein from plant sources and none from animal sources (except the spattered varmint blood and brain residues churned up by the grain thresher as it plowed through your vegan-friendly monoculture crop of choice), have the highest uric acid levels. Higher than meat eaters, fish eaters, and vegetarians (so I guess your teacher is able to hit those deep meditative states).

If he’s at least casually familiar with the literature, he’ll probably say “But purines!” And on the surface, he would appear to have a point. When dietary purines are broken down, we produce uric acid as a byproduct. What contains purines, you might wonder? Organ meats like sweetbreads, kidneys, liver, and brain; seafood like sardines, anchovies, herring, mackerel, scallops, and mussels; and wild game meat. In other words, the most prized Primal foods are high in the substance that produces uric acid in the body! Checkmate! Right?

No. In practice, eating purines actually increases uric acid excretion in order to maintain balance and keep excess uric acid down. It’s also worth noting that dietary protein has also been shown to increase uric acid excretion and lower serum uric acid. If eating meat – an infamously strong source of dietary protein and purines – increased uric acid levels, that wouldn’t be the case. Plus, low-purine diets for the treatment of gout (caused by an excess of uric acid in the blood) have been tried, and they don’t really work (PDF). Going on a zero-purine diet barely lowers uric acid levels by 1 or 2 mg/dL, and that reduction is short-lived. Meanwhile, a high-purine diet only raises uric acid levels by 1 or 2 mg/dL. That too is short-lived. You know what does work compared to a low-purine diet, according to researchers? A high-protein (and high-purine by extension), low-carbohydrate diet. 

Also, the Buddha ate meat, and I hear he was pretty successful with that meditation stuff.

TAGS:  dear mark

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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