Starvation is a very serious form of malnutrition characterized by a deficiency in nutrients, vitamins, and energy. People can experience this as a result of food deprivation or because of diseases which cause disorders of metabolism which interfere with the ability to absorb nutrients. If the underlying cause is not corrected, starvation can lead to death. Historically, this issue has been a significant problem in many human cultures and it continues to be one today in some regions of the world.
People can experience this crisis because of war, famine, and other social and political factors which make it difficult to access food. Disorders such as marasmus, in which people do not ingest enough energy sources, or kwashiorkor, in which there is a deficiency in protein, can develop into starvation. These conditions are common when food supplies are disrupted, forcing people to eat a diet which is not very diverse and may also be limited in terms of overall volume as well.
Anorexia nervosa, a psychiatric condition, leads to a person starving because the patient stops eating with the goal of losing weight. A number of other medical conditions can also cause starvation by disrupting the body's ability to absorb nutrients, vitamins, and energy. In these cases someone may be eating a diverse diet, but still starve because the body is experiencing few nutritional benefits. Some congenital conditions lead to this type of nutritional deficiency, with patients developing slowly as children and experiencing learning delays and other problems related to their inability to absorb nutrients.
In the long term, starvation can cause stunted growth and organ damage as the body slowly turns to reserves of stored energy in the fat and muscles. The patient becomes weak and anemic and neurological deficits may develop. Patients can also develop signs such as stomachs swollen with edema, a complication of some forms of starvation. Malnutrition in general also increases susceptibility to infection because the body's immune defenses are weakened. Ultimately, the patient will die of lack of food, an infection, or complications related to the nutritional deprivation.
People can live without food for a surprisingly long amount of time, such as weeks, as long as they have access to water. The precise length of survival varies depending on factors such as overall health before a period of starvation and activity levels. Even a short period of starvation of this kind can cause permanent damage to the body, however. Deprivation of both water and food can lead to death within a matter of days because the body cannot survive without adequate water supplies.