Upper GI dysfunctions include low stomach acid, bacterial infections such as H.pylori or malabsorption. The Upper GI dysfunction can lead to decreased absorption of minerals (calcium and iron) and vitamins (B12). Long term or frequent use of antibiotics and antacids blocks the action of HCL in the stomach. Low stomach acid interfere with digestion of protein and can inhibit further digestion and absorption of food and nutrients in the small intestine.