Thiamine deficiency (beriberi) results when your body does not have enough of the vitamin thiamine. Your body requires thiamine to help it break down different types of sugar.Without enough thiamine, you may experience a variety of symptoms that can be serious.Because many foods are supplemented with thiamine, thiamine deficiency is rare in the United States.owever, thiamine deficiency is possible in some people with rare genetic conditions, in people who eat very unbalanced diets, in alcoholics, and in some people with kidney disease. Depending on the level of thiamine deficiency, symptoms can vary greatly.