Did you know…

Thiamine deficiency is not a disease of the past, of the tropics, or of alcoholism. It is documented in psychiatric patients, pregnant women, emergency department patients, obese individuals, dialysis patients, heart failure patients on diuretics, the elderly, people with chronic illness, and children raised on ultra-processed products. And no developed country has current data on how prevalent it actually is, because thiamine is almost never measured.

The claim, in the words of a Nutrients review

A 2021 review in the journal Nutrients carries a title that names the situation directly: “Hiding in Plain Sight: Modern Thiamine Deficiency.” Its opening premise is the sentence that a public-health apparatus should read carefully:

“TD is believed to be rare in developed, food-secure countries. […] As a result of this perception, thiamine is not consistently assessed in healthcare practice or in the nutritional surveys that guide policy.”

— Nutrients, 2021

The same review, having examined the case literature, concluded on the population question:

“The number and variety of symptomatic thiamine-deficient adults identified in this review demonstrates that thiamine deficiency is not exclusive to LMICs and, in high-income settings, is not exclusive to alcoholic patients.”

— Nutrients, 2021

The carbohydrate paradox

Thiamine is the limiting cofactor of three fundamental enzymes of energy metabolism: pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and transketolase. The higher the diet in refined carbohydrates, the greater the thiamine requirement. Ultra-processed foods are both poor in B1 and heavy consumers of B1. The overweight metabolism, running compensatory hyperinsulinemia and continuous lipid recycling, is thiamine-hungry in a way that eating white bread only reproduces episodically. Metformin, diuretics, proton pump inhibitors, and coffee all lower thiamine stores further.

Why the standard test does not help

Serum thiamine poorly reflects tissue stores and can remain normal despite functional deficiency. Whole-blood thiamine diphosphate (TDP) is more relevant but is not standardised, and functional assays like ETKAC have their own limitations. In practice, several review authors conclude that when the clinical picture is compatible, it is often rational to supplement empirically, since thiamine is very safe and inexpensive.

This entry is a companion to Right to Optimal Thiamine (Vitamin B1) Status.