Jun 3, 2021 • In this video I explain the reasons why I believe that thiamine (vitamin B1) is the most underrated and overlooked B vitamin deficiency in the Western world. Excess consumption of refined carbohydrates, along with several other factors sets the stage for chronic thiamine insufficiency. This condition is so difficult to spot because it is known to manifest in a variety of different ways for each individual, and so it is often mistaken for other health conditions and not treated.