Is Wheat Addictive?by
Mark Sisson Recently by Mark Sisson: The Definitive Guide to Stress, Cortisol, and the Adrenals: When ‘Fight or Flight’ Meets the Modern World
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' 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, 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, alcohol, and tobacco 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, and gliadorphins, from gliadin – are derived from wheat. In a previous post, 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) on the topic suggests that in order for them to actually function as in vivo 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). 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, 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 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. Listen to Lew's recent podcast with Mark Sisson July 20, 2012 Copyright © 2012 Mark's Daily Apple
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