I just listened to an interview of Dr. Cordain. He mentions that Huntington Chorea seems to be an autoimmune disease. I have Huntington Chorea in my family. So obviously I’d like to know more about your or his findings. Could you please explain if there is any study showing this and what foods one should eliminate from the diet? I’d be so grateful.
Dr. Cordain’s Response:
Huntington’s Chorea or Huntington’s Disease (HD) results from lesions (alpha synuclein crosslinks) occurring in the brain which cause the characteristic symptoms (tremors and paralysis) of HD. It is well documented that a genetic basis underlies the development of HD. HD patients inherit a specific gene which causes increased expression of a protein called mutant huntingtin protein (mHTT). Whereas people without HD have inherited a gene which expresses the normal version of this protein, simply called, huntingtin protein (HTT). The over expression of mHTT at the expense of HTT is thought to cause the brain lesions of HD.
So, can diet have anything to do with whether or not a person with the mHTT genetic makeup goes on to develop the disease? Yes, and let me explain the underlying rationale. The imbalance in the mHTT to HTT ratio that occurs in HD patients requires the inheritance of the mHTT gene, however the gene cannot make its product without the presence of an enzyme called transglutaminase (TG). Transglutaminase is a post-translational enzyme (meaning that it is required to produce the gene product after the gene has been translated within a cell’s nucleus). TG is a ubiquitous post translational enzyme that is found throughout the body’s tissues, particularly in the gut, nervous tissue and brain. Without the presence of adequate concentrations of TG in the brain, mHTT cannot be produced in sufficient quantity to imbalance the mHtt to HHT ratio that results in HD.
So the $64,000 question in HD: what is the environmental trigger that causes over expression of TG in the brain? Plain and simple, it is wheat. More specifically, a storage protein in wheat called Gliadin. Unlike other dietary proteins, Gliadin is an unusual protein because it is resistant to the enzymes in the human gut (proteases) which normally degrade proteins into their constituent amino acids. Consequently, Gliadin arrives in the small intestine intact where it has recently been shown to bind a gut receptor (the CRX2 chemokine receptor). When Gliadin from wheat binds CRX2 it causes the intestinal cells to release a recently discovered enzyme known as zonulin. Zonulin release by gut cells causes the gut to become “leaky” and allow passage of intact proteins across the gut barrier — including Gliadin itself.
Once Gliadin bypasses the gut barrier, it is immediately catalyzed by transglutaminase (TG) which is expressed by local intestinal cells. When you eat wheat on a daily basis, there is so much dietary Gliadin bypassing the gut barrier that it overwhelms the ability of the intestinal cells to produce the enzyme (TG) to catalyze the substrate (Gliadin). Intestinal cells as well as all other cells in the body react to this overload of circulating Gliadin by up-regulating (increasing) TG production.
The proof of the pudding lies in the experimental evidence. Unfortunately no randomized controlled trials of Gliadin free diets in HD patients have been examined to date. Having said this, I am aware of a single HD patient in S. California who was a member of a local CrossFit Gym, and who had been diagnosed with HD by a group of University neurologists employing MRI technology to detect the characteristic brain lesions. After approximately 8 months following adoption of a Paleo Diet (Gliadin free), this patient experienced a dramatic reduction in disease symptoms and subsequent MRI evaluation indicated a reduction in lesion volume. In addition to HD, numerous ataxia patients respond favorably to Gliadin free diets.