Did you realize that thiamin deficiency can be caused by your environment? In the old days, beriberi was associated with the consumption of white rice. Nowadays, refined foods are an unlikely cause of thiamin deficiency because they are fortified. We associate deficiency syndromes such as Wernicke’s encephalopathy and Korsakoff’s psychosis primarily with chronic alcoholism. Yet there are regional outbreaks of thiamin deficiency among wildlife attributed to poorly characterized thiamin antagonists in the environment. Thiamin-destroying amoebas can pollute water, thiamin-destroying bacteria have been isolated from human feces, and thiamin-destroying fungi have also been identified. Could toxic indoor molds and systemic infections play a role as well? Thiamin deficiency is overwhelmingly neurological in nature and hurts the metabolism of carbohydrate much more than fat. Indeed, preliminary evidence suggests thiamin supplementation can help mitigate glucose intolerance. Ketogenic diets are the diets that maximally spare thiamin and are best characterized as treatments for neurological disorders. Anecdotally, ketogenic diet-responsive neurological problems sometimes arise as a result of infection. Could ketogenic diets be treating problems with thiamin or thiamin-dependent enzymes? One must exercise caution here: fat contains little thiamin, and ketogenic diets can actually cause thiamin deficiency if they don’t contain added B vitamins. The relationships between thiamin, glucose metabolism, and neurological health are remarkable and desperately need our attention. For the full lesson, go to chrismasterjohnphd.com/mwm/2/14 Sign up for MWM Pro for early access to content, enhanced keyword searching, self-pacing tools, downloadable audio and transcripts, a rich array of hyperlinked further reading suggestions, and a community with a forum for each lesson.