7.3. Alcohol, Tobacco, Coffee and Tea Consumption
While chronic alcoholism is a recognized contributor to thiamine deficiency, the role of regular alcohol consumption, below the threshold of alcoholism, is underappreciated. Regardless of amount, the ethanol in alcohol blocks conversion of dietary thiamine into active thiamine [
156], reducing thiamine availability by as much as 54% [
157]. It is simply a matter of degree relative to chronicity that determines the rate of thiamine depletion. When consumed regularly, alcohol damages intestinal mucosa [
158], resulting in impaired absorption and dysbiosis [
159]. Dysbiosis, may be a cause or consequence of reduced thiamine, at least initially, but ultimately, becomes self-reinforcing if thiamine status is not corrected [
112,
116].
Nicotine in tobacco products, also inhibits thiamine availability via antagonism of a thiamine transporter in the pancreatic acinar cells by >40% [
160] and possibly in other tissues as well. This impairs insulin secretion [
161]. Nicotine use, in combination with alcohol ingestion, is implicated the development of pancreatitis [
162]. Inasmuch as both limit thiamine uptake, it is conceivable pancreatitis is an indirect manifestation of thiamine deficiency.
Finally, caffeic acid, chlorogenic acid, and tannic acid in coffee, tea, and energy drinks, oxidize the thiazole ring of the thiamine molecule, impairing its absorption, while the added sugars, flavors and other substances to enhance taste, increase thiamine demand. Sixty-two percent of Americans consume an average of three cups of coffee per day [
163], suggesting this popular food item may contribute more to TD than acknowledged.
