Beri beri may not be the most common health affliction, but it can have serious and even deadly consequences. Simply put, beri beri is a deficiency in vitamin B1, also known as thiamine. This particular vitamin is important for cardiovascular and central nervous system health. This deficiency can be caused by breastfeeding, hypothyroidism, alcoholism or a poor diet. Brown rice, however, is rich in vitamin B1 and is considered the most concentrated form available in a standard diet. Be sure to avoid dehusked or polished rice, as the vitamin B1 content is significantly reduced.