Thiamin, a B vitamin found in XFactor, is almost commonly known as Thiamine and vitamin B1. Thiamin is known to be involved in “several enzyme functions associated with the metabolism of carbohydrates, branched-chain amino acids, and fatty acids,” says MIC; a Micronutrient Information Center based out of Oregon State University.
Severe lack of Thiamin can lead to many organ system problems, mostly in a disease called beriberi, explains MIC. Being deficient in Thiamin has been shown to go hand and hand with Alzheimer's disease. Other problems of insufficient levels of Thiamin include psychosis, fatigue, nerve damage, and weakness. Severe lack of Thiamin can even cause brain damage, says NLM.
NLM (National Library of Medicine) says that the many foods that Thiamin is found in include “enriched, fortified, and whole grain products such as bread, cereals, rice, pasta, and flour, beef liver and pork, dried milk, egg, legumes and peas, nuts and seeds.”