It’s time for yet another edition of Dear Mark , and this time I’m covering some interesting topics. First up is the phenomenon of sleepiness following a meal of chicken with the skin on. Far from being an unwelcome, foggy sort of fatigue, this particular brand of sleepiness is pleasing. Could it be something in the chicken? Next, I discuss whether or not the proteins in bone broth are irreparably alerted – in a bad way – upon microwave exposure. I don’t come to an ironclad conclusion, but I do try to give some perspective on the issue. Finally, I try to decide on the “safest” CAFO meat to order when you’re unable to procure grass-fed or pastured. Let’s go:
Hey Mark, I love eating chicken, especially baked. I have noticed that after eating chicken meat with the skin I often feel pleasantly sleepy afterward. This is not a brain fog, food coma kind of tired. Just a nice tiredness. Do you know of anything about chicken that would cause this? Or is it just an association? Thanks! Sarah
As much as we criticize chicken for containing too many PUFAs  – which is a valid point, especially if you rely on chicken for the bulk of your animal calories – chicken fat is actually quite high in oleic acid, the primary monounsaturated fat and the same one found and championed in olive oil , ranging from 37% to 56% of total fat. In fact, it’s the primary fatty acid in chicken fat. In the body, oleic acid can be converted into oleamide, a fatty acid amide. Fatty acid amides are formed when a fatty acid combines with an amine, and they are used in chemical signaling within the body. Oleamide in particular has been fingered as a potent sleep-inducer:
- During sleep deprivation, oleamide accumulates in the cerebrospinal fluid .
- Both acute and sub-chronic administration of oleate increases REM sleep in rats . May they sleep well and dream of large blocks of cheese (points to whomever gets that reference).
- Oleamide has been detected in humans , not just lab animals, and low oleic acid intake has been linked to sleep disorders  among the depressed.
Beyond helping to regulate sleep, oleamide likely has other physiological roles. For one, it appears to inhibit the inflammatory effects  of lipopolysaccharide, the toxin released by certain gut flora. For a real nice sleep, try chicken soup. The glycine in gelatinous  broth links up (in your body) with the oleic acid in chicken to form n-oleoylglycine, a bioactive precursor to oleamide with “chill-out” properties of its own . It’s not quite so simple as “eat chicken fat, make more oleamide,” but having more oleic acid in your diet should provide more substrate for oleamide synthesis, and thus inducement of sleep. Either way, it appears to be having an immediate effect on you. Even if my educated guess isn’t correct, enjoy the sleep! You know, I’ve noticed this myself. Not just with chicken, but with pretty much any animal fat , which makes sense when you realize that animal fat almost invariably comes along with plenty of oleic acid. Beef fat? About 50% oleic. Pork fat? About 50% oleic. Lamb  fat? Around 45% oleic. I wonder if olive oil (mostly oleic) will work, too, or if it’s something else in the animal fat that works in concert with the oleic acid. Interesting stuff. To find out the truth, just eat some animal fat before bed! Seth Roberts has had similar experiences with animal fat (specifically pork fat) and sleep , for what it’s worth. Speaking of broth…
Mark, I just read your 4/24 post on how much protein should you eat . I followed a link from that to an article on the Weston A. Price site (Why Broth is Beautiful: Essential Roles for Proline, Glycine and Gelatin ). One part of the article said that microwaving bone broth changes the proline in it from the trans to the cis form. This in turn causes ‘structural, functional and immunological changes’ in the body and can be nephrotoxic, and heptatotoxic. So, is this true?? Do you use a microwave to reheat broth? I have been, should I stop? Kitty
That’s a great article, overall, which is why I linked to it, but I’m not very convinced on the dangers of microwaved bone broth . Let’s assume microwaving turns the L-proline into D-proline. Should we be worried about D-proline? Is it truly toxic to the kidneys and liver? There have been a number of animal studies examining the effects of the various proline isomers , and there are conflicting results. In chickens, L-proline induced amnesia, while D-proline did not. L-proline destroyed more hippocampal neurons than D-proline. Among chicks, L-proline caused more pecking than D-proline. Pecking is often used as a marker of depression in chickens kept in close quarters with other chickens. Now that I think of it, though, I’m not so sure “increased tolerance of inhumane crowding” is such a good or normal thing. Depression appears to be warranted in the chicken’s situation! When injected into a chicken’s heart, D-proline produced convulsions and death, while L-proline did not. D-proline produced liver and kidney damage in rats, while L-proline did not. There are also a few human studies, not on the effect of dietary D-proline, but rather highlighting the constant presence of D-proline in our guts and in our saliva: Both D-proline and L-proline are found in human gastric juice . Furthermore, patients with gastric cancer and H. pylori infections tended to have higher levels of L-proline, but not D-proline, in their guts. It’s also present in our saliva  independent of our dietary intake. Does this mean broth should be microwaved in order to convert it into gut-protective D-proline? Does it mean that it should never be microwaved in order to protect us from liver lesioning D-proline? Of course not! I just wanted to highlight how depending on what research you use you could claim that D-proline is dangerous, deadly stuff that should be avoided at all costs, or you could call it neuro-protective and anti-depressant (at least for baby chicks). Look, D-proline may be problematic. I really don’t know. And microwaving your broth may alter the proteins to make them dangerous. I don’t know. I don’t think it’s likely to cause severe issues in the way we consume broth. I mean, how often are you drinking broth, let alone broth that’s been heated in a microwave? Daily? Couple times a week? A tablespoon of gelatin, which contains just under a gram of proline, will gelatinize two cups of water, so you’ll be getting about that much (of potentially converted D-proline) every time you consume a couple cups of properly set broth. I find that I don’t use the microwave all that often for broth, but that’s mainly because I like to add stuff to it and stir it in as it heats on the stove. I’ll usually throw in some sea salt, black pepper , and turmeric  (and maybe some egg yolks ) as it heats. And if I cook with broth, say to make a reduction. My latest kick is sautéing some garlic, shallots, and ginger in butter, adding a splash of white wine, reducing that, adding a cup of real broth to the pan, reducing that, and then add chopped pastured chicken livers to the mix until it forms a nice, livery (yet mild) gravy. Excellent, nutritious, and no chance of creating harmful amino acids. I wouldn’t worry too much about microwaved  broth, especially if that’s your only reliable way to get it. Whatever you do, don’t inject microwaved broth into your ventricles (either of them).
Dear Mark, If I have to choose among CAFO beef, chicken, or pork, which is the least of the “evils”? I try to get grass-fed/pastured whenever possible, but that’s not always possible. Thanks! Goldie
“Cleanliness,” or the presence of various agricultural and/or industrial toxins in the meat.
CAFO animals eat industrially-produced feed, which means exposure to a fair amount of pesticides and other toxins. Do these show up in the actual meat, though? Let’s take a look at some average findings, according to the What’s on my Food?  website. Beef fat  samples contained 10 pesticide residues, including significant amounts of DDE and dieldrin. DDE is a metabolite of DDT, and it’s been linked to impaired neurodevelopment in children , lower birth size , and chronic kidney disease , among other conditions. Dieldrin is an organochlorine insecticide banned in the US since 1987 that still manages to display remarkable persistence in the food supply, even biomagnifying – become more concentrated – as it moves up the food chain. 33% of samples contained DDE and 15% of samples contained dieldrin. Beef muscle meat and liver , however, were absent of pesticide residue. Poultry fat contained no residues, whereas poultry thigh and breast both have been shown to contain detectable levels of eight and seven pesticides, respectively, though at a far lower rate than beef fat. Residues from three pesticides have been found in pork meat, while pork fat has been shown to contain up to eight pesticides. Winner: Lean beef or beef liver.
Fatty acid composition.
Since the ruminant is pretty resistant to dietary influence of its fatty acids, CAFO beef fat contains just 4% PUFA, with the rest being saturated and monounsaturated fat. That’s pretty solid. Too bad you’re missing out on the CLA  content found in grass-fed beef , though. Pork fat is decent in theory, but in practice – which includes the feeding of soy, corn, and related oils to pigs – the PUFA content of pork fat can get as high as 32% . Chicken fat is PUFA-rich, and it’s getting even richer. Since 1980, the average linoleic acid content in chicken has increased by 2.6 times, while the omega-3 content has dropped even further. Nowadays, CAFO chicken fat is a bit like tasty vegetable oil. Winner: Beef.
A new report  found antibiotic resistant bacteria  in 81% of ground turkey, 69% of raw pork chops, 55% of raw ground beef, and 39% of raw chicken parts. I know how much you all love your rare turkey burgers and medium rare chicken thighs, but it’s just not worth it. Beef seems to be the most risky here, for two reasons: grinding beef increases the surface area and spreads the bacteria evenly throughout; beef is often eaten rare, which keeps the bacteria alive. Sure, you’ve got the occasional crazy who demands his chicken thigh pink, but that’s pretty rare. Winner: Chicken, which has the least resistant bacteria and tends to be well-cooked.
Quality of life.
While no CAFO animal lives a “good life,” some have it worse than others. Chickens live in crowded warehouses with tens of thousands of other chickens with no access to fresh air. Pigs live on concrete slabs, oftentimes in pens too small to turn around. Cows, on the other hand, typically start out on pasture before being transferred to feedlots. All animals suffer stress, but it seems obvious that cows suffer “less” than the others. Winner: Beef, although I’m hesitant to call it a winner. Overall? I’d say go for the lean CAFO steak. But if you don’t make this sort of thing a habit, go for whatever you want and enjoy it. Thanks for reading, folks. Take care.