Poor Digestion Can Lead To Poor Nutrition Absorption

It has been well documented that physical disease can lead to weight loss. Disease may limit dietary intake or may alter physiological processes, resulting in decreased nutrient digestion or absorption, increased nutrient excretion, or increased nutrient requirements.

Prescription drugs may interfere with nutrient absorption, digestion, metabolism, utilization, or excretion. Similarly, both nutritional status and diet can affect the action of drugs by altering their metabolism and function, and various dietary components can have pharmacologic activity under certain circumstances.

Drugs may act centrally or peripherally to decrease appetite or may reduce appetite as a result of side effects. Drugs that act centrally include catecholaminergics, dopaminergics such as levodopa for Parkinson's disease, serotoninergics, and endorphin modulators such as naloxone. Peripherally acting agents include those that inhibit gastric emptying, and bulking agents.

The emetic centre, located in the brain stem, is easily stimulated by the action of many drugs. Almost all drugs have the potential to alter gastrointestinal function, causing nausea, vomiting, diarrhea, and constipation. Any drug causing nausea, especially alcohol, can decrease appetite. For instance, it has been well documented that digitalis toxicity leads to anorexia, nausea, weight loss, and wasting. Narcotics, analgesics, and clofibrate are also commonly associated with nausea and vomiting. Cancer chemotherapeutic drugs such as methotrexate have a strong anoretic effect and can cause gastroenterologic toxicity.

In addition, drugs may alter nutritional status, which in turn can result in anorexia and weight loss. High doses of aluminum or magnesium hydroxide antacids can cause phosphate depletion, leading to muscle weakness, anorexia, and even congestive heart failure. Thiazide and furosemide diuretics can cause sodium, potassium, and magnesium depletion, resulting in anorexia and muscle weakness. Commonly used folate antagonists include methotrexate, a cancer chemotherapeutic agent; triamterene, a diuretic; trimethoprim, an antibacterial agent; phenytoin, an anticonvulsant; and sulphasalazine, an anti-inflammatory agent. Sulphasalazine and phenytoin are competitive inhibitors of folate transport in addition to being folate antagonists. Folate deficiency can lead to weight loss and anorexia. Penicillamine induces zinc depletion, which may cause a loss of taste acuity and possibly decreased food intake. Alcohol abuse also commonly results in deficiencies of thiamin, folate, vitamin B6, vitamin A, and zinc. [Fischer, J., and Johnson, M.A. Department of Foods and Nutrition, College of Family and Consumer Sciences, University of Georgia, Athens, Georgia.]

Cancer is the most frequently cited cause of involuntary weight loss, and weight loss may occur during early stages of tumour growth before other symptoms emerge. The anorexia of malignancy has been related to taste alterations; changes in gastrointestinal tract contraction and secretion; metabolic disturbances resulting in changes of circulating glucose, amino acid, fatty acid, or lactic acid levels; changes in hypothalamic function; and weakness leading to decreased motor activity.

Cancer patients frequently have problems getting enough nutrition. Malnutrition is a major cause of illness and death in cancer patients. Malnutrition occurs when too little food is eaten to continue the body's functions. Progressive wasting, weakness, exhaustion, lower resistance to infection, problems tolerating cancer therapy, and finally, death may result.

Many malnutrition problems are caused directly by the tumor. Tumors growing in the stomach, esophagus, or intestines can cause blockage, nausea and vomiting, poor digestion, slow movement through the digestive system, or poor absorption of nutrients. Cancer of the ovaries or genital and urinary organs can cause ascites (excess fluid in the abdomen), leading to feelings of early fullness, worsening malnutrition, or fluid and electrolyte imbalances. Pain caused by the tumor can result in severe anorexia and a decrease in the amount of foods and liquids consumed. Central nervous system tumors (such as brain cancer) can cause confusion or sleepiness; patients may lose interest in food or forget to eat.

Changes in the body's metabolism can also cause nutritional problems. Tumor cells often convert nutrients to energy in different, less efficient ways than do other cells.

Tumors may produce chemicals or other products that can cause anorexia and cachexia. For example, tumors can produce a substance that changes a person's sense of taste, so that the patient does not want to eat. Tumors can affect the receptors in the brain that tell the stomach if it is full. Tumors can also produce hormone substances, which can change the amount of nutrients eaten, the way they are absorbed, and the way they are used by the body.

Manganese is necessary for the use of biotin, B1 and C, by the body. It can help eliminate fatigue, improve memory, reduce nervous irritability and assure the proper digestion and utilization of food. A deficiency can cause poor reproductive performance, growth retardation, abnormal formation of bone and cartilage, and an impaired glucose tolerance.

The nutrients mentioned above reflect the major nutritional supplements that may help the condition. Please do remember however that nutritional supplementation is an adjunct to medical treatment and in no way replaces medical treatment.

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