Daffodil International University
Faculty of Allied Health Sciences => Nutrition and Food Engineering => Topic started by: nfe fouzia on November 09, 2013, 07:11:27 PM
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Electrolytes play a vital role in maintaining homeostasis within the body. They help to regulate myocardial and neurological function, fluid balance, oxygen delivery, acid-base balance and much more. Electrolyte imbalances can develop by the following mechanisms: excessive ingestion; diminished elimination of an electrolyte; diminished ingestion or excessive elimination of an electrolyte. The most common cause of electrolyte disturbances is renal failure.
The most serious electrolyte disturbances involve abnormalities in the levels of sodium, potassium, and/or calcium. Other electrolyte imbalances are less common, and often occur in conjunction with major electrolyte changes. Chronic laxative abuse or severe diarrhoea or vomiting (Gastroenteritis) can lead to electrolyte disturbances along with dehydration. People suffering from bulimia or anorexia nervosa are at especially high risk for an electrolyte imbalance.
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Electrolytes are important because they are what cells (especially nerve, heart, muscle) use to maintain voltages across their cell membranes and to carry electrical impulses (nerve impulses, muscle contractions) across themselves and to other cells. Kidneys work to keep the electrolyte concentrations in blood constant despite changes in your body. For example, during heavy exercise, electrolytes are lost in sweat, particularly sodium and potassium. These electrolytes must be replaced to keep the electrolyte concentrations of the body fluids constant.
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We also need to learn about the following terms a little---
- Acidosis
- Alkalosis
- Dehydration
- Malnutrition
- Starvation
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Acidosis is an increased acidity in the blood and other body tissue (i.e. an increased hydrogen ion concentration). If not further qualified, it usually refers to acidity of the blood plasma.
Acidosis is said to occur when arterial pH falls below 7.35 (except in the fetus - see below), while its counterpart (alkalosis) occurs at a pH over 7.45. Arterial blood gas analysis and other tests are required to separate the main causes.
The term acidemia describes the state of low blood pH, while acidosis is used to describe the processes leading to these states. Nevertheless, the terms are sometimes used interchangeably. The distinction may be relevant where a patient has factors causing both acidosis and alkalosis, wherein the relative severity of both determines whether the result is a high or a low pH.
The rate of cellular metabolic activity affects and, at the same time, is affected by the pH of the body fluids. In mammals, the normal pH of arterial blood lies between 7.35 and 7.50 depending on the species (e.g. healthy human-arterial blood pH varies between 7.35 and 7.45). Blood pH values compatible with life in mammals are limited to a pH range between 6.8 and 7.8. Changes in the pH of arterial blood (and therefore the extracellular fluid) outside this range result in irreversible cell damage.
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Alkalosis refers to a condition reducing hydrogen ion concentration of arterial blood plasma (alkalemia). Generally, alkalosis is said to occur when pH of the blood exceeds 7.45. The opposite condition is acidosis (when pH falls below 7.35).
Causes
The main cause of respiratory alkalosis is hyperventilation, resulting in a loss of carbon dioxide. Compensatory mechanisms for this would include increased dissociation of the carbonic acid buffering intermediate into hydrogen ions, and the related excretion of bicarbonate, both of which lower blood pH.
Metabolic alkalosis can be caused by prolonged vomiting, resulting in a loss of hydrochloric acid with the stomach content. Severe dehydration, and the consumption of alkali are other causes. It can also be caused by administration of diuretics and endocrine disorders such as Cushing's syndrome. Compensatory mechanism for metabolic alkalosis involve slowed breathing by the lungs to increase serum carbon dioxide, a condition leaning toward respiratory acidosis. As respiratory acidosis often accompanies the compensation for metabolic alkalosis, and viceversa, a delicate balance is created between these two conditions.
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Alkalosis can refer to:
Respiratory alkalosis
Metabolic alkalosis
Complications:
Metabolic alkalosis is usually accompanied with hypokalemia, causing, e.g., muscular weakness, myalgia, and muscle cramps (from disturbed function of the skeletal muscles), and muscle spasms (from disturbed function of smooth muscles).
It may also cause hypocalcemia. As the pH of blood increases, blood transport proteins, such as albumin, become more ionised into anions. This causes the free calcium present in blood to bind more strongly with albumin. If severe, it may cause tetany (alkalotic tetany).
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Dehydration is the excessive loss of body water, with an accompanying disruption of metabolic processes. It is literally the removal of water (Ancient Greek: ὕδωρ hýdōr) from an object; however, in physiological terms, it entails a deficiency of fluid within an organism. Dehydration of skin and mucous membranes can be called medical dryness.
Some authors have reported three types of dehydration based on serum sodium levels: hypotonic or hyponatremic (referring to this as primarily a loss of electrolytes, sodium in particular), hypertonic or hypernatremic (referring to this as primarily a loss of water), and isotonic or isonatremic (referring to this as equal loss of water and electrolytes). In reality however, it emerges that by "hyponatremic" and "eunatremic" dehydration these authors are actually referring to "hypovolemia" (see definition below). In humans, it is thought that the most commonly seen type of dehydration by far is isotonic (isonatraemic) dehydration, but this effectively refers to hypovolemia. "Dehydration", is thus a term that has loosely been used to mean loss of water, regardless of whether it is as water and solutes (mainly sodium) or free water. Those who refer to hypotonic dehydration therefore refer to solute loss and thus loss of intravascular volume but in the presence of exaggerated intravascular volume depletion for a given amount of total body water gain. It is true that neurological complications can occur in hypotonic and hypertonic states. The former can lead to seizures, while the latter can lead to osmotic cerebral edema upon rapid rehydration. It is thus important to distinguish "dehydration" from "hypovolemia" and maybe limit the term "dehydration" to states of "hypernatremia" and call all other usage "hypovolemia" as that would greatly facilitate management.
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Malnutrition is the condition that results from eating a diet in which certain nutrients are lacking, in excess (too high in intake), or in the wrong proportions. The verb form is "malnourish"; "malnourishment" is sometimes used instead of "malnutrition". A number of different nutrition disorders may arise, depending on which nutrients are under- or over-abundant in the diet. In most of the world, malnutrition is present in the form of under-nutrition, which is caused by a diet lacking adequate calories and protein—not enough food, and of poor quality. Extreme undernourishment is starvation, and its symptoms and effects are inanition. While malnutrition is more common in less-developed countries, it is also present in industrialized countries. In wealthier nations it is more likely to be caused by unhealthy diets with excess energy, fats, and refined carbohydrates. A growing trend of obesity is now a major public health concern in lower socio-economic levels and in developing countries as well.
The World Health Organization have reported hunger and related malnutrition as the greatest single threat to the world's public health. Improving nutrition is widely regarded as the most effective form of aid. Nutrition-specific interventions, which address the immediate causes of undernutrition, have been proven to deliver among the best value for money of all development interventions. Emergency measures include providing deficient micronutrients through fortified sachet powders or directly through supplements.WHO, UNICEF, and the UN World Food Programme recommend community management of severe acute malnutrition with ready-to-use therapeutic foods, which have been shown to cause weight gain in emergency settings. The famine relief model increasingly used by aid groups calls for giving cash or cash vouchers to the hungry to pay local farmers instead of buying food from donor countries, often required by law, to prevent dumping from hurting local farmers.
Long term measures include fostering nutritionally dense agriculture by increasing yields, while making sure negative consequences affecting yields in the future are minimized. Recent efforts include aid to farmers. However, World Bank strictures restrict government subsidies for farmers, while the spread of fertilizer use may adversely affect ecosystems and human health and is hampered by various civil society groups.
Malnutrition has shown to be an important concern in women, children, and the elderly. Because of pregnancies and breastfeeding, women have additional nutrient requirements. Children can be at risk for malnutrition even before birth, as their nutrition levels are directly tied to the nutrition of their mothers. Breastfeeding can reduce rates of malnutrition and mortality in children, and educational programs for mothers could have a large impact on these rates. The elderly have a large risk of malnutrition because of unique complications such as changes in appetite and energy level, and chewing and swallowing problems. Adequate elderly care is essential for preventing malnutrition, especially when the elderly cannot care for themselves.
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Starvation is a severe deficiency in caloric energy, nutrient, and vitamin intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death. The term inanition refers to the symptoms and effects of starvation.
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 bloated stomach, as seen in the picture to the right, represents a form of malnutrition called kwashiorkor which is caused by insufficient protein despite a sufficient caloric intake. Children are more vulnerable to kwashiorkor whose advanced symptoms include weight loss and muscle wasting.
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Why is Fluid and Electrolyte Balance so Important?
Electrolytes are minerals in your body that have an electric charge. They are in your blood, urine and body fluids. Maintaining the right balance of electrolytes helps your body's blood chemistry, muscle action and other processes. Sodium, calcium, potassium, chlorine, phosphate and magnesium are all electrolytes. You get them from the foods you eat and the fluids you drink.
Levels of electrolytes in your body can become too low or too high. That can happen when the amount of water in your body changes, causing dehydration or overhydration. Causes include some medicines, vomiting, diarrhea, sweating or kidney problems. Problems most often occur with levels of sodium, potassium or calcium.
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How we can maintain Fluid and Electrolyte Balance in our body?
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We should make initiatives to do so.