Thiamine enhances circulation and assists in blood formation, carbohydrate metabolism, and in the production of hydrochloric acid, which is important for proper digestion. Thiamine also optimizes cognitive activity and brain function. It has a positive effect on energy, growth, normal appetite, and learning capacity, and is needed for proper muscle tone of the intestines, stomach and heart. Thiamine also acts as an anti-oxidant, protecting the body from the degenerative effects of aging, alcohol consumption, and smoking.  

Beriberi, a nervous system disease that is rare in developed nations, is caused by a deficiency of thiamine. Other symptoms that can result from thiamine deficiency include constipation,  edema, enlarged liver, fatigue, forgetfulness, gastrointestinal disturbances, heart changes,  irritability, labored breathing, loss of appetite, muscle atrophy, nervousness, numbness of the hands and feet, pain and sensitivity, poor coordination, tingling sensations, weak and sore  muscles, general weakness, and severe weight loss.