Write a Short Essay Describing the Role of Nutrition in Maintaining Homeostasis

The process of digestion seems deceptively simple, matter moves into the body and continues down a conveyer belt like chain of organs that break it down completely before it leaves the body. However, the maintenance of such a system is complex and relies on a balance of pH and helpful bacteria to maintain homeostasis. Both acidic and basic pH’s are required at various points in digestion to maintain balance during the process. Saliva in the mouth, the starting point of digestion, is only mildly acidic for the purpose of initially breaking down the food without damaging the teeth or delicate throat tissue. The stomach, on the other hand, needs to be highly acidic to jump-start the breakdown process as well as act as a defense for the body against any harmful bacteria or other intruders. To balance things out on the basic side, it is important that the small intestine has a high pH, because most of the enzymes used in digestion can't function properly in an acidic environment.

Helpful bacteria also are integral to maintaining homeostasis in the digestive system. It is estimated that the average human has around 500 species of helpful bacteria, also known as intestinal microflora, in the digestive tract, mostly concentrated in the large intestine. These bacteria aid in digestion, help produce vitamins, help formulate excrement and guard against harmful bacteria. When the bacteria population in a digestive tract is thrown off or decimated, the host will notice a change in the pace and quality of digestion. Microflora species have such a positive effect on their host that there are many products available, mostly yogurts, that contain material that supports intestinal microflora's growth and health.

Homeostasis is a condition by which the biological / physical body is not lacking any nutrients and all needed nutritional components are readily available in their proper forms and amounts so every biological function can operate unimpeded. When various nutrients are lacking, some bodily functions will be undernourished. The essential bodily functions will receive their proper nutrients first so life can continue. Non-essential bodily functions will then suffer due to lack of all nutrients needed for their full function. Examples of non-essential bodily functions are: hair, skin, sexual function, muscles, tendons, vertebral discs, etc. Examples of essential bodily functions are: heart, lungs, kidneys, liver, etc. After the body has received all the nutrients it needs for the essential bodily functions, then the non-essential complaint receives its needed nutritional components and those complaints will usually resolve on their own.

Water is essential to life and nutritional health. Humans can live for several weeks without food, but can survive only a few days without water. Water makes up a large percentage of the body, in muscles, fat cells, blood and even bones.

Every cell, tissue and organ requires water to function properly. Water transports nutrients and oxygen to the cells, provides a medium for chemical reactions to take place, helps to flush out waste products, aids in maintaining a constant body temperature, and keeps the tissues in the skin, mouth, eyes, and nose moist.

The body does not store excess water like it does with other nutrients. With physical exertion, water requirements increase; therefore, fluid replacement during exercise is critical. The longer the duration and the more physical exertion athletes put into their exercise, the more fluid they lose during workouts. To keep the body working at its best, it is essential to replenish lost fluid after workouts, and to stay well hydrated during exercise.
The body can accommodate extreme changes in water intake when the brain and kidneys are functioning normally. It is usually possible for a person to consume enough water to maintain blood volume and electrolyte balance in the blood. However, if a person is unable to consume enough water to equal excessive water loss, dehydration may result.

The body works to maintain water balance through mechanisms such as the thirst sensation. When the body requires more water, the brain stimulates nerve centers in the brain to encourage a person to drink in order to replenish the water stores.
The kidneys are responsible for maintaining homeostasis of the body water through the elimination of waste products and excess water. Water is primarily absorbed through the gastrointestinal tract and excreted by the kidneys as urine. Water intake can vary widely on a daily basis and is influenced by such factors as: access to water, thirst, habit, and cultural factors. The variation in water volume ingested is dependent on the ability of kidneys to dilute and concentrate the urine as needed. There is a reservoir of water outside of the bloodstream that can replace or absorb excess water in the blood when necessary.
The following conditions increase water consumption needs. However, the amount of water necessary depends on body size, age, climate, and exertion level.
Water needs are increased by; Exercise, High altitudes, Prescription drugs, Dieting and Illness. Individuals should not wait until they are thirsty to replenish water stores. By the time the thirst mechanism signals the brain to encourage a person to drink water, already 1–3% of the body fluids are lost and an individual is mildly dehydrated.