While there is more to wheat's adverse effects on human health than celiac disease, studying celiac disease provides important insights into why and how wheat--the gluten component of wheat, in this case--is so destructive to human health.
Modern wheat, in particular, is capable of causing "celiac disease" without intestinal symptoms---no cramping or diarrhea--but instead shows itself as brain injury (ataxia, dementia), peripheral nervous system damage (peripheral neuropathy), joint and muscle inflammation (rheumatoid arthritis, polymyalgia rheumatica and others), and gastrointestinal cancers.
One neurological manifestation of wheat's effect on the human brain is a condition called cerebellar ataxia. This is a condition that can affect adults (average age 48 years) and children and consists of incoordination, falls, and incontinence.
Because brain tissue has limited capacity for healing and regeneration, symptoms of cerebellar ataxia usually improve slowly and modestly with meticulous elimination of wheat and other gluten sources.
Such observations are relevant even to people without celiac disease. Celiac disease sufferers are more susceptible to such extra-intestinal phenomena, but it can also happen in people without positive celiac antibodies.
A total of 72 patients with biopsy proven celiac disease (CD) (mean age 51 +/- 15 years, mean disease duration 8 +/- 11 years) were recruited through advertisements. All participants adhered to a gluten-free diet. Patients were interviewed following a standard questionnaire and examined clinically for neurological symptoms. Medical history revealed neurological disorders such as migraine (28%), carpal tunnel syndrome (20%), vestibular dysfunction (8%), seizures (6%), and myelitis (3%). Interestingly, 35% of patients with CD reported of a history of psychiatric disease including depression, personality changes, or even psychosis. Physical examination yielded stance and gait problems in about one third of patients that could be attributed to afferent ataxia in 26%, vestibular dysfunction in 6%, and cerebellar ataxia in 6%. Other motor features such as basal ganglia symptoms, pyramidal tract signs, tics, and myoclonus were infrequent. 35% of patients with CD showed deep sensory loss and reduced ankle reflexes in 14%. Gait disturbances in CD do not only result from cerebellar ataxia but also from proprioceptive or vestibular impairment.
Two hundred and twenty-four patients with various causes of ataxia from North Trent (59 familial and/or positive testing for spinocerebellar ataxias 1, 2, 3, 6 and 7, and Friedreich's ataxia, 132 sporadic idiopathic and 33 clinically probable cerebellar variant of multiple system atrophy MSA-C) and 44 patients with sporadic idiopathic ataxia from The Institute of Neurology, London, were screened for the presence of antigliadin antibodies. A total of 1200 volunteers were screened as normal controls. The prevalence of antigliadin antibodies in the familial group was eight out of 59 (14%), 54 out of 132 (41%) in the sporadic idiopathic group, five out of 33 (15%) in the MSA-C group and 149 out of 1200 (12%) in the normal controls. The prevalence in the sporadic idiopathic group from London was 14 out of 44 (32%). The difference in prevalence between the idiopathic sporadic groups and the other groups was highly significant (P < 0.0001 and P < 0.003, respectively). The clinical characteristics of 68 patients with gluten ataxia were as follows: the mean age at onset of the ataxia was 48 years (range 14-81 years) with a mean duration of the ataxia of 9.7 years (range 1-40 years). Ocular signs were observed in 84% and dysarthria in 66%. Upper limb ataxia was evident in 75%, lower limb ataxia in 90% and gait ataxia in 100% of patients. Gastrointestinal symptoms were present in only 13%. MRI revealed atrophy of the cerebellum in 79% and white matter hyperintensities in 19%. Forty-five percent of patients had neurophysiological evidence of a sensorimotor axonal neuropathy. Gluten-sensitive enteropathy was found in 24%. HLA DQ2 was present in 72% of patients. Gluten ataxia is therefore the single most common cause of sporadic idiopathic ataxia.