Coeliac disease is a disorder in which the intestinal tract is damaged by the intake of gluten, a protein found in foods processed from wheat, barley, and rye. Symptoms can be broad and discomforting—bowel problems, weight loss, and fatigue—but can be alleviated by removing gluten from one's diet.

Diabetes is a disease characterized by high blood sugar levels. The three main types are due to either type 1 diabetes(deficiency in insulin production), type 2 diabetes (insulin resistance), or gestational diabetes, which effects previously undiagnosed pregnant women.

People's bodies respond to foods and other compounds with various chemical reactions. Allergies include antibody reactions. Food sensitivities cover a broader variety of reactions including lactose intolerance, fructose intolerance, coeliac disease and others.

Infections are the result of an invasion by disease-causing organisms, which often multiply and release toxins, negatively affecting the host. Symptoms are broad and depend on the particular infection but can include fatigue, bowel problems and fever. Many infections can be alleviated or treated upon diagnosis.

Irritable bowel syndrome (IBS) symptoms include diarrhea, constipation, and abdominal cramps. Though it is unknown what exactly causes IBS, effective treatments such as diet and lifestyle changes can help alleviate the symptoms.

Lyme disease is caused by a Borrelia burgdorferi bacterial infection transmitted by tick bites. A raised red border or bullseye pattern often surrounds the bite. Symptoms can be flu-like, including headaches, soreness, and fever. Borrelia infections are often accompanied by bacterial co-infections.