Vitamin B1 is a vital vitamin belonging to the family of B complex vitamins. Also known as thiamin, it is required for many crucial bodily functions. Though vitamin B1 deficiency is rare, it can affect the nervous system, heart, muscles and digestive system. Depression, anxiety, paleness, giddiness, lack of sleep, nervous system disorder, eating disorder & weight loss are some of the symptoms of this deficiency. Here are the top 5 food sources of vitamin B1/thiamin.