|A girl during the Nigerian Civil War of the late 1960s, shown suffering the effects of severe hunger and malnutrition.|
|Specialty||Critical care medicine|
Starvation is a severe deficiency in caloric energy intake, below the level needed to maintain an organism's life. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damageand eventually, death. The term inanition refers to the symptoms and effects of starvation. Starvation may also be used as a means of torture or execution.
Food energy is chemical energy that animals derive from food through the process of cellular respiration. Cellular respiration may either involve the chemical reaction of food molecules with molecular oxygen or the process of reorganizing the food molecules without additional oxygen.
Malnutrition is a condition that results from eating a diet in which one or more nutrients are either not enough or are too much such that the diet causes health problems. It may involve calories, protein, carbohydrates, vitamins or minerals. Not enough nutrients is called undernutrition or undernourishment while too much is called overnutrition. Malnutrition is often used to specifically refer to undernutrition where an individual is not getting enough calories, protein, or micronutrients. If undernutrition occurs during pregnancy, or before two years of age, it may result in permanent problems with physical and mental development. Extreme undernourishment, known as starvation, may have symptoms that include: a short height, thin body, very poor energy levels, and swollen legs and abdomen. People also often get infections and are frequently cold. The symptoms of micronutrient deficiencies depend on the micronutrient that is lacking.
Organs are groups of tissues with similar functions. Plant and animal life relies on many organs that coexist in organ systems.
According to the World Health Organization, hunger is the single gravest threat to the world's public health.The WHO also states that malnutrition is by far the biggest contributor to child mortality, present in half of all cases. Undernutrition is a contributory factor in the death of 3.1 million children under five every year. Figures on actual starvation are difficult to come by, but according to the Food and Agriculture Organization, the less severe condition of undernourishment currently affects about 842 million people, or about one in eight (12.5%) people in the world population.
The World Health Organization (WHO) is a specialized agency of the United Nations that is concerned with international public health. It was established on 7 April 1948, and is headquartered in Geneva, Switzerland. The WHO is a member of the United Nations Development Group. Its predecessor, the Health Organisation, was an agency of the League of Nations.
In politics, humanitarian aid, and social science, hunger is a condition in which a person, for a sustained period, is unable to eat sufficient food to meet basic nutritional needs. So in the field of hunger relief, the term hunger is used in a sense that goes beyond the common desire for food that all humans experience.
Child mortality, also known as child death, refers to the death of children under the age of 14 and encompasses national mortality, under-5 mortality, and mortality of children aged 5–14. Many child deaths go unreported for a variety of reasons, including lack of death registration and lack of data on child migrants. Without accurate data on child deaths, we cannot fully discover and combat the greatest risks to a child's life.
The bloated stomach represents a form of malnutrition called kwashiorkor. The exact pathogenesis of kwashiorkor is not clear, as initially it was thought to relate to diets high in carbohydrates (e.g. maize) but low in protein.While many patients have low albumin, this is thought to be a consequence of the condition. Possible causes such as alfatoxin poisoning, oxidative stress, immune dysregulation and altered gut microbiota have been suggested. Treatment can help mitigate symptoms such as the pictured weight loss and muscle wasting, however prevention is of utmost importance.
Kwashiorkor is a form of severe protein malnutrition characterized by edema, and an enlarged liver with fatty infiltrates. Sufficient calorie intake, but with insufficient protein consumption, distinguishes it from marasmus. Kwashiorkor cases occur in areas of famine or poor food supply. Cases in the developed world are rare.
Muscle is a soft tissue found in most animals. Muscle cells contain protein filaments of actin and myosin that slide past one another, producing a contraction that changes both the length and the shape of the cell. Muscles function to produce force and motion. They are primarily responsible for maintaining and changing posture, locomotion, as well as movement of internal organs, such as the contraction of the heart and the movement of food through the digestive system via peristalsis.
Early symptoms include impulsivity, irritability, and hyperactivity. Atrophy (wasting away) of the stomach weakens the perception of hunger, since the perception is controlled by the percentage of the stomach that is empty. Individuals experiencing starvation lose substantial fat (adipose tissue) and muscle mass as the body breaks down these tissues for energy.Catabolysis is the process of a body breaking down its own muscles and other tissues in order to keep vital systems such as the nervous system and heart muscle (myocardium) functioning . The energy deficiency inherent in starvation causes fatigue and renders the victim more apathetic over time. As the starving person becomes too weak to move or even eat, their interaction with the surrounding world diminishes. In females, menstruation ceases when the body fat percentage is too low to support a fetus.
Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations, poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, excessive amount of apoptosis of cells, and disuse or lack of exercise or disease intrinsic to the tissue itself. In medical practice, hormonal and nerve inputs that maintain an organ or body part are said to have trophic effects. A diminished muscular trophic condition is designated as atrophy. Atrophy is reduction in size of cell, organ or tissue, after attaining its normal mature growth. In contrast, hypoplasia is the reduction in size of a cell, organ, or tissue that has not attained normal maturity.
Fat is one of the three main macronutrients, along with carbohydrate and protein. Fats molecules consist of primarily carbon and hydrogen atoms, thus they are all hydrocarbon molecules. Examples include cholesterol, phospholipids and triglycerides.
In biology, adipose tissue, body fat, or simply fat is a loose connective tissue composed mostly of adipocytes. In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular endothelial cells and a variety of immune cells such as adipose tissue macrophages. Adipose tissue is derived from preadipocytes. Its main role is to store energy in the form of lipids, although it also cushions and insulates the body. Far from being hormonally inert, adipose tissue has, in recent years, been recognized as a major endocrine organ, as it produces hormones such as leptin, estrogen, resistin, and cytokine. The two types of adipose tissue are white adipose tissue (WAT), which stores energy, and brown adipose tissue (BAT), which generates body heat. The formation of adipose tissue appears to be controlled in part by the adipose gene. Adipose tissue – more specifically brown adipose tissue – was first identified by the Swiss naturalist Conrad Gessner in 1551.
Victims of starvation are often too weak to sense thirst, and therefore become dehydrated. All movements become painful due to muscle atrophy and dry, cracked skin that is caused by severe dehydration. With a weakened body, diseases are commonplace. Fungi, for example, often grow under the esophagus, making swallowing painful. Vitamin deficiency is also a common result of starvation, often leading to anemia, beriberi, pellagra, and scurvy. These diseases collectively can also cause diarrhea, skin rashes, edema, and heart failure. Individuals are often irritable and lethargic as a result.
The esophagus or oesophagus, commonly known as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about 25 centimetres long in adults, which travels behind the trachea and heart, passes through the diaphragm and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word oesophagus is the Greek word οἰσοφάγος oisophagos, meaning "gullet".
Vitamin deficiency is the condition of a long-term lack of a vitamin. When caused by not enough vitamin intake, it can be classified as a primary deficiency, whereas when due to an underlying disorder such as malabsorption, it is called a secondary deficiency. An underlying disorder may be metabolic – as in a genetic defect for converting tryptophan to niacin – or from lifestyle choices that increase vitamin needs, such as smoking or drinking alcohol. Governments guidelines on vitamin deficiencies advise certain intakes for healthy people, with specific values for women, men, babies, the elderly, and during pregnancy or breastfeeding. Many countries have mandated vitamin food fortification programs to prevent commonly occurring vitamin deficiencies.
Anemia is a decrease in the total amount of red blood cells (RBCs) or hemoglobin in the blood, or a lowered ability of the blood to carry oxygen. When anemia comes on slowly, the symptoms are often vague and may include feeling tired, weakness, shortness of breath or a poor ability to exercise. Anemia that comes on quickly often has greater symptoms, which may include confusion, feeling like one is going to pass out, loss of consciousness, or increased thirst. Anemia must be significant before a person becomes noticeably pale. Additional symptoms may occur depending on the underlying cause.
There is insufficient scientific data on exactly how long people can live without food.Although the length of time varies with an individual's percentage of body fat and general health, one medical study estimates that in adults complete starvation leads to death within 8 to 12 weeks. Starvation begins when an individual has lost about 30%, or about a third, of their normal body weight. Once the loss reaches 40% death is almost inevitable.
Starvation is an imbalance between energy intake and energy expenditure. The body expends more energy than it takes in. This imbalance can arise from one or more medical conditions or circumstantial situations, which can include:
With a typical high-carbohydrate diet, the human body relies on free blood glucose as its primary energy source. The level of blood sugar is tightly regulated; as blood glucose is consumed, the pancreas releases glucagon, a hormone that stimulates the liver to convert stored glycogen into glucose. The glycogen stores are ordinarily replenished after every meal, but if the store is depleted before it can be replenished, the body enters hypoglycemia, and begins the starvation response.[ citation needed ]
After the exhaustion of the glycogen reserve, and for the next 2–3 days, fatty acids become the principal metabolic fuel. At first, the brain continues to use glucose. If a non-brain tissue is using fatty acids as its metabolic fuel, the use of glucose in the same tissue is switched off. Thus, when fatty acids are being broken down for energy, all of the remaining glucose is made available for use by the brain.[ citation needed ]
After 2 or 3 days of fasting, the liver begins to synthesize ketone bodies from precursors obtained from fatty acid breakdown. The brain uses these ketone bodies as fuel, thus cutting its requirement for glucose. After fasting for 3 days, the brain gets 30% of its energy from ketone bodies. After 4 days, this may go upwards to 70% or more.Thus, the production of ketone bodies cuts the brain's glucose requirement from 80 g per day to 30 g per day, about 35% of normal, with 65% derived from ketone bodies. But of the brain's remaining 30 g requirement, 20 g per day can be produced by the liver from glycerol (itself a product of fat breakdown). But this still leaves a deficit of about 10 g of glucose per day that must be supplied from some other source. This other source will be the body's own proteins.
After exhaustion of fat stores, the cells in the body begin to break down protein. This releases alanine and lactate produced from pyruvate into the bloodstream, which can be converted into glucose by the liver. Since much of human muscle mass is protein, this phenomenon is responsible for the wasting away of muscle mass seen in starvation. However, the body is able to selectively decide which cells will break down protein and which will not. About 2–3 g of protein has to be broken down to synthesize 1 g of glucose; about 20–30 g of protein is broken down each day to make 10 g of glucose to keep the brain alive. However, this number may decrease the longer the fasting period is continued in order to conserve protein.
Starvation ensues when the fat reserves are completely exhausted and protein is the only fuel source available to the body. Thus, after periods of starvation, the loss of body protein affects the function of important organs, and death results, even if there are still fat reserves left unused. (In a leaner person, the fat reserves are depleted faster, the protein depletion occurs sooner, and therefore death occurs sooner.[ citation needed ]) The ultimate cause of death is, in general[ further explanation needed ], cardiac arrhythmia or cardiac arrest brought on by tissue degradation and electrolyte imbalances. Alternatively, things like metabolic acidosis may also cause death in starving people.
Starvation can be caused by factors, other than illness, outside of the control of the individual. The Rome Declaration on World Food Security outlines several policies aimed at increasing food securityand, consequently, preventing starvation. These include:
Supporting farmers in areas of food insecurity through such measures as free or subsidized fertilizers and seeds increases food harvest and reduces food prices.
Starving patients can be treated, but this must be done cautiously to avoid refeeding syndrome.Rest and warmth must be provided and maintained. Small sips of water mixed with glucose should be given in regular intervals. Fruit juices can also be given. Later, food can be given gradually in small quantities. The quantity of food can be increased over time. Proteins may be administered intravenously to raise the level of serum proteins.
Many organizations have been highly effective at reducing starvation in different regions. Aid agencies give direct assistance to individuals, while political organizations pressure political leaders to enact more macro-scale policies that will reduce famine and provide aid.
According to estimates by the Food and Agriculture Organization there were 925 million under- or malnourished people in the world in 2010. [ citation needed ]This was a decrease from an estimate of roughly 1 billion malnourished people in 2009. In 2007, 923 million people were reported as being undernourished, an increase of 80 million since 1990-92. It has also been recorded that the world already produces enough food to support the world's population.
As the definitions of starving and malnourished people are different, the number of starving people is different from that of malnourished. Generally, far fewer people are starving, than are malnourished.
The proportion of malnourished and of starving people in the world has been more or less continually decreasing for at least several centuries.This is due to an increasing supply of food and to overall gains in economic efficiency. In 40 years, the proportion of malnourished people in the developing world has been more than halved. The proportion of starving people has decreased even faster.
|Proportion of undernourished people in the less-developed world||37 %||28 %||20 %||16 %||17 %||16 %|
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Historically, starvation has been used as a death sentence. From the beginning of civilization to the Middle Ages, people were immured, or walled in, and would die for want of food.
In ancient Greco-Roman societies, starvation was sometimes used to dispose of guilty upper class citizens, especially erring female members of patrician families. For instance, in the year 31, Livilla, the niece and daughter-in-law of Tiberius, was discreetly starved to death by her mother for her adulterous relationship with Sejanus and for her complicity in the murder of her own husband, Drusus the Younger.
Another daughter-in-law of Tiberius, named Agrippina the Elder (a granddaughter of Augustus and the mother of Caligula), also died of starvation, in 33 AD. (However, it is not clear whether her starvation was self-inflicted.)
A son and daughter of Agrippina were also executed by starvation for political reasons; Drusus Caesar, her second son, was put in prison in 33 AD, and starved to death by orders of Tiberius (he managed to stay alive for nine days by chewing the stuffing of his bed); Agrippina's youngest daughter, Julia Livilla, was exiled on an island in 41 by her uncle, Emperor Claudius, and subsequently her death by starvation was arranged by the empress Messalina.
It is also possible that Vestal Virgins were starved when found guilty of breaking their vows of celibacy.
Ugolino della Gherardesca, his sons and other members of his family were immured in the Muda, a tower of Pisa, and starved to death in the thirteenth century. Dante, his contemporary, wrote about Gherardesca in his masterpiece The Divine Comedy .
In Sweden in 1317, King Birger of Sweden imprisoned his two brothers for a coup they had staged several years earlier (Nyköping Banquet). According to legend they died of starvation a few weeks later, since their brother had thrown the prison key in the castle moat.
In Cornwall in the UK in 1671, John Trehenban from St Columb Major was condemned to be starved to death in a cage at Castle An Dinas for the murder of two girls. The Makah, a Native American tribe inhabiting the Pacific Northwest near the modern border of Canada and the United States, practiced death by starvation as a punishment for slaves.
Many of the prisoners died in the Nazi concentration camps through deliberate maltreatment, disease, starvation, and overwork, or were executed as unfit for labor. Many occupants of ghettos in eastern Europe also starved to death, most notoriously in the Warsaw ghetto. Prisoners were transported in inhumane conditions by rail freight cars, in which many died before reaching their destination. The prisoners were confined to the cattle cars for days or even weeks, with little or no food or water. Many died of dehydration in the intense heat of summer or froze to death in winter. Nazi concentration camps in Europe from 1933 to 1945 deliberately underfed prisoners, who were at the same time forced to perform heavy labour. The diet was restricted to watery vegetable soup and a little bread, with little or no dietary fats, proteins or other essential nutrients. Such treatment led to loss of body tissues, and prisoners became skeletal, the so-called Muselmann who were murdered by gas or bullet when examined by camp doctors.
Starvation was also used as a punishment where victims were locked into a small cell until dead, a process which could take many days. Saint Maximilian Kolbe, a martyred Polish friar, underwent a sentence of starvation in Auschwitz concentration camp in 1941. Ten prisoners had been condemned to death by starvation in the wake of a successful escape from the camp. Kolbe volunteered to take the place of a man with a wife and children. After two weeks of starvation, Kolbe and three other inmates remained alive; they were then executed with injections of phenol.
The following is a glossary of diabetes which explains terms connected with diabetes.
Ketone bodies are the water-soluble molecules containing the ketone group that are produced by the liver from fatty acids during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise, alcoholism or in untreated type 1 diabetes mellitus. Ketone bodies are readily transported into tissues outside the liver and converted into acetyl-CoA, which then enters the citric acid cycle and is oxidized in the mitochondria for energy. In the brain, ketone bodies are also used to make acetyl-CoA into long-chain fatty acids.
Ketosis is a metabolic state in which some of the body's energy supply comes from ketone bodies in the blood, in contrast to a state of glycolysis in which blood glucose provides energy. Generally, ketosis occurs when the liver is metabolizing fatty acids or ethanol at a high rate in the absence of glucose and converting the product acetyl-CoA into ketone bodies. The first ketone body to be produced is acetoacetate, followed by enzymatic reduction by beta-hydroxybutyrate dehydrogenase to beta-hydroxybutyrate with NADH and a proton as a cofactor, or loss of a carbon dioxide molecule to form acetone. As the liver itself lacks the metabolic machinery required to utilize them, the product ketone bodies are entirely released into the blood for use by the rest of the body.
Human nutrition deals with the provision of essential nutrients in food that are necessary to support human life and health. Poor nutrition is a chronic problem often linked to poverty, food security or a poor understanding of nutrition and dietary practices. Malnutrition and its consequences are large contributors to deaths and disabilities worldwide. Good nutrition is necessary for children to grow physically, and for normal human biological development.
Famine relief is an organized effort to reduce starvation in a region in which there is famine. A famine is a phenomenon in which a large proportion of the population of a region or country are so undernourished that death by starvation becomes increasingly common. In spite of the much greater technological and economic resources of the modern world, famine still strikes many parts of the world, mostly in the developing nations.
Ketoacidosis is a metabolic state associated with high concentrations of ketone bodies, formed by the breakdown of fatty acids and the deamination of amino acids. The two common ketone bodies produced in humans are acetoacetic acid and β-hydroxybutyrate.
Marasmus is a form of severe malnutrition characterized by energy deficiency. It can occur in anyone with severe malnutrition but usually occurs in children. A child with marasmus looks emaciated. Body weight is reduced to less than 62% of the normal (expected) body weight for the age. Marasmus occurrence increases prior to age 1, whereas kwashiorkor occurrence increases after 18 months. It can be distinguished from kwashiorkor in that kwashiorkor is protein deficiency with adequate energy intake whereas marasmus is inadequate energy intake in all forms, including protein. This clear-cut separation of marasmus and kwashiorkor is however not always clinically evident as kwashiorkor is often seen in a context of insufficient caloric intake, and mixed clinical pictures, called marasmic kwashiorkor, are possible. Protein wasting in kwashiorkor generally leads to edema and ascites, while muscular wasting and loss of subcutaneous fat are the main clinical signs of marasmus.
Emaciation is defined as extreme weight loss and unnatural thinness due to a loss of subcutaneous fat and muscle throughout the body. It affects human beings and animals; one who is emaciated could be described as "wasting away" or being "gaunt." Emaciation is caused by severe malnourishment and starvation. Emaciation is a predominant symptom of malnourishment, a basic component of poverty and famine that also occurs with diseases that interfere with the digestive system and appetite, other systems, and eating disorders. These include nutrient deficiency disorders, diseases with prolonged fever and infection, malignant diseases, parasitic infections that can result from contamination, anorexia nervosa and other conditions. The malnourishment associated with emaciation has been referred to as "inanition", while infection by parasites has been described as "adulteration". Treatment of emaciation includes gradual renourishment with a slow increase of daily caloric intake to help rebuild tissues and regain weight. Rest, and emotional and psychological therapy and support may be included.
Protein–energy malnutrition (PEM) is a form of malnutrition that is defined as a range of pathological conditions arising from coincident lack of dietary protein and/or energy (calories) in varying proportions. The condition has mild, moderate, and severe degrees.
Refeeding syndrome is a syndrome consisting of metabolic disturbances that occur as a result of reinstitution of nutrition to patients who are starved, severely malnourished or metabolically stressed due to severe illness. When too much food and/or liquid nutrition supplement is consumed during the initial four to seven days of refeeding, this triggers synthesis of glycogen, fat and protein in cells, to the detriment of serum (blood) concentrations of potassium, magnesium, and phosphorus. Cardiac, pulmonary and neurological symptoms can be signs of refeeding syndrome. The low serum minerals, if severe enough, can be fatal.
Starvation response in animals is a set of adaptive biochemical and physiological changes that reduce metabolism in response to a lack of food.
GLUT1 deficiency syndrome, also known as GLUT1-DS, De Vivo disease or Glucose transporter type 1 deficiency syndrome, is an autosomal dominant, genetic metabolic disorder associated with a deficiency of GLUT1, the protein that transports glucose across the blood brain barrier. Glucose Transporter Type 1 Deficiency Syndrome has an estimated birth incidence of 1 in 90,000. This birth incidence translates to an estimated prevalence of 3,000 to 7,000 in the U.S.
The Randle cycle, also known as the glucose fatty-acid cycle, is a metabolic process involving the competition of glucose and fatty acids for substrates. It is theorized to play a role in explaining type 2 diabetes and insulin resistance.
Catabolysis is a biological process in which the body breaks down fat and muscle tissue in order to stay alive. Catabolysis occurs only when there is no longer any source of protein, carbohydrate, or vitamin nourishment feeding all body systems; it is the most severe type of malnutrition.
There were 795 million undernourished people in the world in 2014, a decrease of 216 million since 1990, despite the fact that the world already produces enough food to feed everyone—7 billion people—and could feed more than that—12 billion people.
Malnutrition in children is common globally and may result in both short and long term irreversible negative health outcomes. The World Health Organization (WHO) estimates that malnutrition accounts for 54 percent of child mortality worldwide, about 1 million children. Another estimate also by WHO states that childhood underweight is the cause for about 35% of all deaths of children under the age of five years worldwide.
In the early months of 2017, parts of South Sudan experienced a famine following several years of instability in the country's food supply caused by war and drought. The famine, largely focused in the northern part of the country, affected an estimated five million people. In May 2017, the famine was officially declared to have weakened to a state of severe food insecurity.
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