Diseases of the Digestive System

Lactose intolerance 

People with lactose intolerance have a reduced ability to digest lactose, a sugar found in milk and dairy products. This usually happens for one of two reasons - either the cells lining the small intestine do not secrete enough lactase, the enzyme that breaks down lactose into glucose and galactose, or the lactase does not work properly.

Cause: The body naturally makes less lactase after age 2 years, as a child eats other foods and becomes less dependent on their mother’s milk or formula. Sometimes the body produces too little lactase enzyme. Lactose intolerance can also be a genetic problem that is inherited in a person’s genes, or caused by an injury to the small intestine from an illness. An allergic reaction or a side effect of chemotherapy can also cause lactase deficiency.

Symptoms: Most people with lactose intolerance develop symptoms within 30 minutes to 2 hours of eating dairy products. Symptoms may include nausea, stomachache, bloating, gas, and diarrhea.

Treatment: People can modify their diet to only eat dairy products mixed with other food, eat less dairy, or eat lactose-free dairy products. To aid in digestion, over-the-counter pills of the enzyme lactase can also be taken with meals. 

Viral Gastroenteritis

This illness of the digestive tract is the second most common contagious illness in the United States. It is an inflammation of the stomach and small intestine, which results in diarrhea. Most people mistake viral gastroenteritis for the common flu. 

Cause: Viral gastroenteritis can be caused by one of four different viruses (rotavirus, adenovirus, norovirus or astrovirus) that are most commonly transmitted by unwashed hands or sharing food or drink with someone carrying the active virus. People may still be contagious 2 weeks after their symptoms have disappeared.

Symptoms: Most people experience vomiting and diarrhea within 4 to 48 hours after contracting the virus. Other symptoms can include headache, fever, chills, dehydration, and a stomachache.

Treatment: Viral gastroenteritis will usually go away on its own as the body fights the infection. Symptoms usually last only 1 to 2 days, but may persist for longer periods of time. People infected with this virus should drink lots of water to prevent dehydration. Eating easy-to-digest foods, like chicken broth or toast, and avoiding dairy products can help ease symptoms.