Wednesday, January 5, 2011

Dr. Davis Versus The New York Times

"Can You Be Addicted To Foods?" the NYT asks.  They then present a bunch of near-useless pseudo-scientific blather from a psychiatrist.  Gary Taubes could have answered this question, but Dr. Davis does an even better job:

"So what do morphine-blocking drugs have to do with weight loss?

"An odd series of clinical studies conducted over the past 40 years has demonstrated that foods can have opiate-like properties. Opiate blockers, like naloxone, can thereby block appetite. One such study demonstrated 28% reduction in caloric intake after naloxone administration. But opiate blocking drugs don't block desire for all foods, just some.

"What food is known to be broken down into opiate-like polypeptides?

"Wheat. On digestion in the gastrointestinal tract, wheat gluten is broken down into a collection of polypeptides that are released into the bloodstream. These gluten-derived polypeptides are able to cross the blood-brain barrier and enter the brain. Their binding to brain cells can be blocked by naloxone or naltrexone administration. These polypeptides have been named exorphins, since they exert morphine-like activity on the brain. While you may not be 'high,' many people experience a subtle reward, a low-grade pleasure or euphoria.

"For the same reasons, 30% of people who stop consuming wheat experience withdrawal, i.e., sadness, mental fog, and fatigue...."
Dr. Davis has an older post on the topic as well.

And in poking around for this post I came across this:

"The effect of exogenous opioid peptides, gluten exorphins A5 and B5, which were isolated from the enzymatic digest of wheat gluten, on the postprandial insulin level were examined in rats. The oral administration of gluten exorphin A5 at a dose of 30 mg/kg w. potentiated the postprandial plasma insulin level and the effect was reversed by naloxone. The administration of gluten exorphin B5 showed a similar effect at a higher dose (300 mg/kg w). Furthermore, intravenous administration of gluten exorphin A5 at a dose of 30 mg/kg w. also stimulated the postprandial insulin release. The fact that orally and intravenously administered gluten exorphin A5 stimulates insulin release suggests that it modulates pancreatic endocrine function by the action after the absorption rather than within the the gastrointestinal tract."


So, in a nutshell, wheat gluten causes an insulin response, which naloxone blocks.  Gluten causing an insulin response, even if isolated from the carbohydrates in wheat, would certainly explain wheat's tendency to lead to obesity...  If insulin spikes, the body clears the blood of glucose, which leaves you with a state of low blood sugar, and that leaves you hungry for more carbs. 

Wonderful.

In my own experience wheat definitely acts on me like a drug, and a fast-acting one.  I can feel the rush from even inadvertent wheat ingestion in minutes, if not seconds.  If I have too much, I get light-headed and have to lie down for a while.