The Chemistry of Starvation Eating is essential for life, but what happens when the human body is deprived of food for an extended period of time? Food may not always be readily available, and when the human body fails to consume any food for more than a day or two, the body enters the process of starvation. The process of starvation is actually a series of different defense mechanisms at the disposal of the human body that have been crafted over the millions of years of our evolution; crafted so finely that the body can survive up to around seventy days without any food. Before delving into the effects of starvation, it is important to understand a general overview of how the human body uses the food it consumes. The three main nutrients
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During this stage, the body has consumed nearly all of its glycogen stores and must turn to alternative sources, as the meager remaining supply of glycogen must be preserved for use by the brain. On average, the brain consumes 120 grams of glucose a day. As for the rest of the body, it enters ketosis and resorts to its stores of fatty acids. The stored fatty acids are consumed by the body for energy, but fatty acids are incapable of crossing the blood-brain barrier (Dvorsky, 2012). Since the brain has consumed nearly all of the body’s glucose stores, it must find an alternative source of energy, lest death await only a short time away. This alternative energy source is the ketone body. Ketone bodies are short chain derivatives of fatty acids that are manufactured by first catalyzing the fatty acid acetyl-CoA with the enzyme thiolase. This reaction produces acetoacetyl-CoA which is further catalyzed with HMG-CoA synthase to form b-hydroxy-b-methylglutaryl-CoA. This molecule is once again catalyzed with HMG-CoA lyase to form acetoacetate which is finally reduced by b-hyroxybutyrate to form b-hydroxybutyrate dehydrogenase, the ketone body (Brandt, 2003). By day four, the brain receives approximately seventy percent of its energy from ketone bodies, and the brain’s glucose requirements drop to thirty grams. (Bushak, …show more content…
After so long without food, death is unavoidable, and it may come in various way. The earliest cause of death will likely be a disease from a germ that has taken advantage of the body’s severely weakened immune system. Without any vital vitamins and minerals to maintain the body’s immune system, the body is likely to become prey to a number of diseases (Dvorsky, 2012). If a person manages to avoid germ born disease and survives even longer, they will develop either marasmus or kwashiorkor. Marasmus is characterized by extremely low body weights and kwashiorkor by an edema and enlarged fatty liver. The final immediate causes of death are usually cardiac arrhythmia or a heart attack due to the sever autophagy of tissue (Gale, 2006). It is of course also possible that a person may recover from severe starvation. If the effects of starvation are not too severe, it is merely a matter of returning to a normal diet; although, for those near death, returning to a normal diet will not save them, as the intestines are not capable of absorbing adequate nutrients. To save such a starved person, their diet must consist of nutrients administered intravenously and later liquid food (Gale,
During this stage, the body has consumed nearly all of its glycogen stores and must turn to alternative sources, as the meager remaining supply of glycogen must be preserved for use by the brain. On average, the brain consumes 120 grams of glucose a day. As for the rest of the body, it enters ketosis and resorts to its stores of fatty acids. The stored fatty acids are consumed by the body for energy, but fatty acids are incapable of crossing the blood-brain barrier (Dvorsky, 2012). Since the brain has consumed nearly all of the body’s glucose stores, it must find an alternative source of energy, lest death await only a short time away. This alternative energy source is the ketone body. Ketone bodies are short chain derivatives of fatty acids that are manufactured by first catalyzing the fatty acid acetyl-CoA with the enzyme thiolase. This reaction produces acetoacetyl-CoA which is further catalyzed with HMG-CoA synthase to form b-hydroxy-b-methylglutaryl-CoA. This molecule is once again catalyzed with HMG-CoA lyase to form acetoacetate which is finally reduced by b-hyroxybutyrate to form b-hydroxybutyrate dehydrogenase, the ketone body (Brandt, 2003). By day four, the brain receives approximately seventy percent of its energy from ketone bodies, and the brain’s glucose requirements drop to thirty grams. (Bushak, …show more content…
After so long without food, death is unavoidable, and it may come in various way. The earliest cause of death will likely be a disease from a germ that has taken advantage of the body’s severely weakened immune system. Without any vital vitamins and minerals to maintain the body’s immune system, the body is likely to become prey to a number of diseases (Dvorsky, 2012). If a person manages to avoid germ born disease and survives even longer, they will develop either marasmus or kwashiorkor. Marasmus is characterized by extremely low body weights and kwashiorkor by an edema and enlarged fatty liver. The final immediate causes of death are usually cardiac arrhythmia or a heart attack due to the sever autophagy of tissue (Gale, 2006). It is of course also possible that a person may recover from severe starvation. If the effects of starvation are not too severe, it is merely a matter of returning to a normal diet; although, for those near death, returning to a normal diet will not save them, as the intestines are not capable of absorbing adequate nutrients. To save such a starved person, their diet must consist of nutrients administered intravenously and later liquid food (Gale,