Vitamin B1 is essential for brain, nerve, and heart health, and deficiency can be dangerous

including:
Beriberi, which affects the nervous system and heart.
Wernicke encephalopathy, a brain disorder that can occur in severe deficiency.
Memory, balance, and coordination problems.
If someone is deficient in thiamine, getting enough Vitamin B1 can indeed prevent serious health problems.
However, for most people who already get adequate B1 from their diet, taking extra Vitamin B1 has not been shown to broadly “prevent loss” or dramatically protect the brain beyond normal nutritional needs.
Good Sources of Vitamin B1
Pork
Whole grains
Legumes (beans and lentils)
Nuts and seeds
Fortified cereals
Bottom Line
Vitamin B1 is essential for brain, nerve, and heart health, and deficiency can be dangerous. However, the statement is vague and exaggerates the benefit by implying that simply taking Vitamin B1 pills will broadly prevent major health problems for everyone. The real benefit is ensuring you meet your body’s normal thiamine requirements.