Solgar Vitamin B1 500Mg contains optimal levels of Thiamin (vitamin B1) in every tablet. This essential vitamin is part of the B complex group of nutrients and is present in many whole foods. The main function of B1 is to aid the body in converting blood sugar into energy. Good food sources of thiamine include whole-grain cereals, rye, whole-wheat flour and wheat germ. Unfortunately the modern diet tends to include refined cereals and flours, which do not contain this vitamin. Symptoms of Vitamin B deficiency include fatigue, irritability, loss of appetite, a disturbance in sleep patterns and poor memory. It is also required for a healthy heart and nervous system. Solgar Vitamin B1 500Mg is suitable for both vegans and vegetarians.