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Is Wheat Addictive?

Posted By Mark Sisson On July 18, 2012 @ 8:00 am In Nutrition | 381 Comments

Within the Primal/paleo community and elsewhere, it’s often stated offhandedly that wheat is addictive. And absolutely, wheat for many people feels like something they could never give up. I hear it all the time: “I couldn’t live without bread.” “What would I do without cereal, dinner rolls, toast, {insert your favorite grain-based food item here}.” And wheat is often the main culprit in the sugar/insulin rollercoaster that drives sugar-burners’ [7] need to eat (more wheat) every few waking hours. But is wheat addictive in a different sense – as an opiate like heroin and other drugs? Today I take a look at the research and attempt to separate fact from fiction. What do we really know about wheat as an opiate? Let’s find out…

Humans and other animals have something called an opioidergic system – an evolutionarily-preserved way for an organism to modulate behavior, addiction, and reward. When you exercise, for example, a lot of the euphoria you feel comes from endogenous (produced in-house) opioids interacting with your opiate receptors. This is the body’s way of dealing with a stressful experience (physical exertion), reducing pain, and it also has the effect of reinforcing a behavior that is positive, healthy, and in the organism’s best interest. The opioidergic system also interacts with the immune [8], endocrine, and central nervous systems (in other words, this is physiology, so it’s all interrelated), but we won’t get too much into that today. Now, it’s not just endogenous opioids interacting with our receptors; certain substances, like heroin and other opiate drugs, act as exogenous (produced out-of-house) opioids, thereby hijacking and “supercharging” our physiology. Cocaine [9], alcohol [10], and tobacco [11] also interact with opioid receptors. The addictiveness of these substances is infamous, so these interactions exist shouldn’t surprise you.

However, there are other exogenous opioid peptides, also known as exorphins (exogenous morphine), found in substances that we don’t normally consider to be repositories of potentially addictive morphine-analogs. Like wheat.

Some of the most extensively studied food-based exorphins – gluten exorphins, from gluten [12], and gliadorphins, from gliadin – are derived from wheat. In a previous post [13], I raised the possibility of a wheat addiction. But are these exorphins actually problematic? Do they really interact with your opioid receptors to make you crave another “hit”? Well, an early 1979 paper (PDF [14]) on the topic suggests that in order for them to actually function as in vivo [15] opioid exorphins in our bodies, wheat exorphins must appear in our gastrointestinal tract after ingestion and during digestion, they have to survive degradation by intestinal enzymes into constituent amino acids, they have to be absorbed – intact – into the bloodstream, and they must pass the blood-brain barrier.

Do they satisfy those requirements? Let’s take a look.

When wheat is applied to conditions designed to simulate the human gut (complete with physiological amounts and proportions of stomach acid and digestive enzymes), exorphins are produced. This suggests that applying wheat to actual human stomachs (by eating it) should also produce wheat exorphins. Satisfied.

There’s also evidence that gluten exorphins do show up in the bloodstream after ingestion of wheat, at least in subjects with celiac disease (PDF [16]). But let’s temper our conclusions; remember that celiac disease is usually characterized by a severely-compromised intestinal lining, and that the subjects who had exorphins in their blood tended to have the most intestinal damage. It remains to be seen if wheat has the same effect on people with healthy, intact intestinal linings. Satisfied and satisfied.

I was unable to find hard evidence of wheat opioids crossing the blood-brain barrier. There is this rat study [17], which found that gluten exorphins stimulate the secretion of prolactin (an excess of which can lead to loss of libido in both sexes) by interacting with opioid receptors located outside of the blood-brain barrier, but not inside it. On the other hand, Dr. Emily Deans says [18] that exorphins “definitely end up in the body and brain of rats fed gluten orally.” She also uses low-dose naltrexone (an opiate blocker) to treat celiac patients who can’t seem to give up wheat, which would suggest that something’s getting through to interact with those receptors. Still, not completely satisfied.

We’ve all had people tell us “but I could never give up bread!” In my experience, and from talking to hundreds upon hundreds of newcomers and sharing emails with many more, this is common in folks going Primal. Your pastas, your breads, your pizzas, your pastries, your muffins, your cookies are the foods that people have trouble giving up and the foods that, once expunged from the diet, have the greatest tendency to cause “relapses” if eaten again. Part of it is cultural conditioning, I’m sure – the whole “staff of life” thing, the inundation from birth with the message that whole grains represent the pinnacle of healthy eating, the bread basket at dinner, the pancakes on Saturday morning, the birthday cake that you’re practically excommunicated for refusing – and part of it is the fact that wheat flour goes well with vegetable fat, refined sugar, and low prices, but I wouldn’t be surprised if wheat has addictive properties mediated through its unique exorphins.

We just can’t say that yet, not definitively. It may be addictive, but not to everyone. If your gut is permeable enough to allow passage of opioid peptides into your blood, I could see it causing problems. If your gut is healthy and intact, maybe it’s not such an issue. More research is clearly required. Still, until this all gets sorted out, I’d suggest people continue to avoid wheat and other gluten-containing grains (and heck, all grains [19] for that matter). And if you’re going to mention the opioid stuff to any skeptics or interested parties, don’t sound too authoritative. Admit that while evidence for wheat’s addictiveness exists, it’s far from conclusive.

Besides, wheat’s not the only food whose proteins are degraded into opioid peptides (PDF [20]):

Casein [21], a dairy [22] protein, can also be cleaved to form exorphins. Human milk [23] even contains a number of dairy exorphins, most notably beta-casomorphin (casein morphine). In fact, beta-casomorphin levels are highest in colostrum [24], the highly nutritious “first milk” that infants get from their mothers. Perhaps that’s a way to get babies hooked on the sweet, nutritious, essential breastmilk right off the bat? The old “bait and switch,” where you slip the customer the pure stuff, get them hooked on it, and subsequently sell them the stuff that’s been cut with filler? We don’t know for sure, but I would assume that the most nutritious, perfectly “designed” food for human infants contains opioid peptides for a very important reason.

Hemorphins, a class of opioid peptides, come from hemoglobin [25], a protein found in the red blood cells of vertebrates. If you like your steak bloody rare, you’re likely consuming hemoglobin, and your stomach is probably cleaving the hemoglobin up into hemorphins. Of course, since hemorphins already appear naturally in your cerebrospinal fluid, brain, and plasma, I wouldn’t necessarily worry about becoming addicted to blood sausage.

Other food compounds can act as exorphins, too. Flavonoids, those bioactive plant compounds with antioxidant properties, may interact with opioid receptors [26]. Epicatechin, a flavonoid found in green tea and chocolate, can act like an exorphin [27], at least in mice. Its cardioprotective effects are even thought to be mediated through its opioid activity.

Interestingly, even spinach contains an exorphin which, along with a gluten exorphin variant, has actually been shown to improve the learning ability of rodents [28].

That doesn’t mean you should pound spinach and wheat gluten before finals week and hope for a miracle. It also doesn’t mean that you should avoid chocolate [29] and give your baby formula instead of breastmilk because you’re worried about addiction. It simply means that the effects of food exorphins aren’t clear-cut. They aren’t necessarily “bad.”

I’m definitely anti-wheat. I think people eat way too much of it, and it appears to perpetuate its own consumption. I wish I could say definitively whether wheat is addictive as an opiate or not – but I can’t. Not yet.

What say you, folks? Were you addicted to wheat? Are you? What about any of the other foods that break down into opioid exorphins – any spinach addicts out there?

Thanks for reading.


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[8] immune: http://www.marksdailyapple.com/why-grains-are-unhealthy/#axzz20wj7689C

[9] Cocaine: http://www.ncbi.nlm.nih.gov/pubmed/11458541

[10] alcohol: http://www.ncbi.nlm.nih.gov/pubmed/19630722

[11] tobacco: http://www.behavioralandbrainfunctions.com/content/2/1/28/

[12] gluten: http://www.marksdailyapple.com/gluten-celiac-disease/

[13] post: http://www.marksdailyapple.com/8-reasons-why-you-act-against-your-own-better-judgment/#axzz20uEGJRbx

[14] PDF: http://www.jbc.org/content/254/7/2446.full.pdf+html

[15] in vivo: http://en.wikipedia.org/wiki/In_vivo

[16] PDF: http://www.benthamscience.com/open/tospecj/articles/V001/9TOSPECJ.pdf

[17] rat study: http://www.ncbi.nlm.nih.gov/pubmed/15698850

[18] says: http://evolutionarypsychiatry.blogspot.com/2010/06/wheat-and-schizophrenia.html

[19] grains: http://www.marksdailyapple.com/why-grains-are-unhealthy/

[20] PDF: http://xa.yimg.com/kq/groups/18630837/685088275/name/Exorphins.pdf

[21] Casein: http://www.marksdailyapple.com/whey-egg-white-casein-pea-hemp-rice-protein-powder-supplement/

[22] dairy: http://www.marksdailyapple.com/dairy-intolerance/

[23] milk: http://www.marksdailyapple.com/milk-dairy-human-diet/

[24] highest in colostrum: http://www.ncbi.nlm.nih.gov/pubmed/17869380

[25] come from hemoglobin: http://www.ncbi.nlm.nih.gov/pubmed/9216251

[26] may interact with opioid receptors: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2265593/

[27] act like an exorphin: http://www.ncbi.nlm.nih.gov/pubmed/20833967

[28] shown to improve the learning ability of rodents: http://www.ncbi.nlm.nih.gov/pubmed/12769740

[29] chocolate: http://www.marksdailyapple.com/why-you-should-eat-and-drink-high-cacao-dark-chocolate/

[30] Primal Blueprint Books: http://www.primalblueprint.com/category/Books_and_Media?utm_source=mda_sidebar&utm_medium=banner&utm_campaign=sidebar_like_article_books

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