If you do not have enough thiamine (vitamin B1), you may develop a disorder called beriberi. This is a serious condition, and in severe cases, it can lead to lasting damage to the nervous system and heart. There are two main types of beriberi: wet beriberi and dry beriberi. While wet beriberi primarily affects the cardiovascular system, dry beriberi mainly affects the nervous system. Beriberi symptoms vary depending on which type you have.