Vitamin deficiency – the body is unable to absorb fat-soluble vitamins a, d, e, and k due to the incomplete absorption of fats. Vitamin b12 is essential for the proper functioning of the nervous system and the production of blood cells. This b 12 is synthesized and used by bacteria in the small intestine. The overgrowth of bacteria in the small intestine thus results in deficiency of vitamin b 12. This results in fatigue, weakness, numbness, and a tingling sensation in the hands and feet. The damage to the nervous system in severe cases may even be irreparable. Osteoporosis – damage to the small intestine due to bacterial overgrowth may result in weakened bones because of reduced calcium absorption. This ultimately leads to osteoporosis. Poor absorption of fats, proteins, and carbohydrates – overgrowth of bacteria in the small intestine may cause damage to the mucous lining of the intestine reducing the absorption of carbohydrates and proteins. The excess bacteria also break d...