If you are experiencing a loss of appetite, the cause may be traced to a problem in your gastrointestinal tract. Problems in the gastrointestinal tract, or GI tract, can lead to iron-deficiency anemia, which is linked to low vitamin D levels. See your doctor if your appetite has decreased, though, since there are many other conditions that cause a loss of appetite.
Lower GI Anemia
The GI tract consists of the upper and lower portions. The lower GI includes most of the small intestine and large intestine, which includes the colon, rectum and anus. The upper GI includes the first part of the small intestine, as well as the stomach and the esophagus, which is the tube that runs from your mouth to your stomach. Bleeding in the GI tract can cause anemia. Anemia is when your red blood cell count is low. There are mild and serious reasons why your GI tract bleeds. Hemorrhoids or anal fissures can cause bleeding in the lower GI tract. More serious causes include cancer in the small intestine, colon or stomach.
GI bleeding can cause iron deficiency anemia. It is the leading cause of iron deficiency anemia in post-menopausal women and men over 50 years of age. Gradual blood in the GI tract, ongoing blood loss -- such as during menstruation -- a lack of iron in the diet and difficulty absorbing iron are the main causes of iron deficiency anemia for all ages. Your body needs iron to be healthy. All of your red bloods cells contain iron. This mineral is critical for the production of red blood cells and you need red blood cells to carry oxygen throughout your body. Therefore, if you are lacking iron your body cannot make enough red blood cells, which in turn means less oxygen is able to reach your cells and they cannot function properly.
Vitamin D Deficiency
A vitamin D deficiency can lead to unhealthy teeth, osteomalacia and rickets. Osteomalacia is a condition that causes weak bones in adults and rickets is a similar condition seen in children. An iron deficiency correlates with a higher risk of vitamin D deficiency -- a study published in the "American Journal of Clinical Nutrition" in September 1992 found that most of the participants with iron-deficiency anemia also had low levels of vitamin D in their blood. Researchers suggested an iron deficiency impairs the body's ability to absorb vitamin D, which leads to a deficiency.
Loss of Appetite
Loss of appetite is a symptom of an iron deficiency, along with weakness, fatigue, irritability, pale skin and dizziness. The loss of appetite can further contribute to an iron deficiency if you then eat fewer iron-rich foods, such as fish, lean meats, egg yolks, green leafy vegetables, nuts and whole-grain products. Loss of appetite is not a common symptom of vitamin D deficiency, but a decreased appetite from an iron deficiency could contribute to a vitamin D deficiency if you consume fewer vitamin D foods. Vitamin D is found in sardines, salmon, herring, tuna, cod liver oil and dairy products.