Loss of appetite and nausea are common symptoms that affect everyone at some point. The symptoms of lack of appetite and nausea are often non-specific can occur as a result of a variety of conditions. The most common causes of nausea and lack of appetite are conditions that affect the gastrointestinal tract, although systemic infections may also be the culprit.
Gastroenteritis is an infection of the gastrointestinal tract that may be caused by a bacterium or virus. The infectious organism that causes gastroenteritis is often transmitted through foods and infects the body when contaminated food is ingested. There are a number of organisms that can cause gastroenteritis, but symptoms of the infection are generally similar. These symptoms include abdominal cramps, abdominal pain, diarrhea, bloody stools, lack of appetite and nausea. Most cases of gastroenteritis go away on their own without medical intervention. It is important to stay hydrated during times of active symptoms to avoid dehydration.
Influenza is a viral infection that affects the respiratory system, which includes the nose, throat and lungs. Influenza is caused by the influenza virus and is usually transmitted through airborne droplets that are released when an infected person sneezes or coughs. According to the Centers for Disease Control and Prevention, the influenza virus can be spread from up to six feet away. When someone becomes infected with the influenza virus, she experiences fever, chills, sweats, headache, cough, muscle aches, nausea and lack of appetite. Because influenza is caused by a virus, there is no medical treatment. The infection usually goes away on its own, but it is recommended to get plenty of rest and increase fluid intake while symptoms persist.
The parathyroid glands are small glands in the front of the neck, on either side of the thyroid gland. The parathyroid glands are responsible for producing a hormone called the parathyroid hormone, which controls calcium levels in the blood. Hyperparathyroidism is a condition in which the parathyroid glands secrete too much parathyroid hormone. This results in abnormal blood calcium levels and can cause weakness, fatigue, depression, muscle aches, constipation, lack of appetite and nausea. According to the National Endocrine and Metabolic Diseases Information Service, most cases of hyperparathyroidism are treated with the surgical removal of the parathyroid glands.
Gallstones are small, hard stones that develop in the gallbladder, which stores bile. Gallstones develop when the bile in the gallbladder contains too much cholesterol, too many bile acids or not enough bile salts, according to the National Digestive Diseases Information Clearinghouse. When gallstones develop, they can cause abdominal pain, fever, chills, jaundice, abnormal colored stools, lack of appetite and nausea. Gallstones may be treated with the use of dissolving medications or surgical removal of the gallbladder.