Nutrition Exam 4: Chapter 14

Solutes

-The fluid in these compartments is not pure water; it also contains dissolved substances known as solutes.

Isotonic Solution

An isotonic (normal) concentration a concentration of ions outside the cell equal to that inside the cell results in a typically shaped red blood cell.

Sweetened Beverages

-Supply few micronutrients in contrast to micronutrient rich milk and fruit juice.

Water in Foods

Water also is abundant in fruits and vegetables, which typically are 75 to 95% water by weight. other sources that fall between 50 to 75% water are potatoes, chicken, and steak. Foods that are less than 35% water include jam, honey, crackers, and butter and margarine. Vegetable oils contain no water.

Functions of Sodium

- Helps absorption of glucose and some amino acids in the small intestine -Required for normal muscle and nerve function -Aids in water balance

Sodium Needs

-1200 mg/day to 2400 mg/day recommended intake, lower intakes recommended for older adults and those with medical conditions such as hypertension. -Healthy adults should consume no more than 2300 mg/day

Sodium Absorption, Transport, Storage, and Excretion

-Absorbed in intestinal tract -absorbed like potassium and chloride ions through active transport in both the small and large intestines. -Most sodium found in extracellular fluid compartment, where it is tightly regulated. When sodium intake is high, excess sodium is excreted by kidneys. Conversely, when the concentration of sodium in the blood is low, the hormone aldosterone inhibits sodium excretion by the kidneys -Sodium is also lost via feces and perspiration

Chloride Needs

-Adequate Intake is 2300 mg -Based on 40:60 ratio of sodium to chloride in salt

Chlorine in Foods

-Almost all chlorine in diet is from table salt

Absorption, Transport, Storage, and Excretion of Chloride

-Almost completely absorbed in small and large intestines like sodium and potassium -Allows a balance of electrical charges beween the negatively charged chloride ion and the positively charged sodium -Most chloride is found in the extracellular fluid, where it is associated with sodium. Like Sodium and potassium, the excretion of chloride occurs mainly through the kidneys

Sodium

-Best source is inland salt deposit created by ancient seas or produced by the evaporation of sea water. -Salt is 40% sodium and 60% chloride -Average intake 4243 mg men and 2980 mg women in U.S.

Potassium Absorption

-Body absorbs 90% of potassium consumed -Mostly absorbed in small and large intestines. -Balance achieved by excretion through kidney

Bone development and Maintenance

-Bones consists of a network of protein fibers, primarily collagen, and minerals. -Calcium and phosphorus obtained from the diet are the main minerals in bone. -Calcium and phosphorus form the lattice like crystal hydroxyapatite which binds to the collagen fibers. -Outer dense shell of bone is compact bone (cortical bone): makes up 75% of skeletal mass -Remainder spongy bone (trabecular bone), a hard, spongy network of rods, plates, and needlelike spines that adds strength without much weight.

Calcium-Alkali Syndrome

-Characterized by hypercalcemia or high levels of calcium and the calcification of coronary arteries. Negligible when kept under 1.5 g.day of calcium supplements

Water output

-Consists of sensible and insensible water losses. Sensible water losses, or those we notice, are urine output and heavy perspiration. Most of the sensible water loss is urine (typically 1000 to 2000 m/day). Insensible water losses, or those we do not normally notice, include water lost through the skin, lungs, and feces.

Chloride Deficiency

-Generally unlikely because intake is so high -Frequent vomiting and bouts of vomiting can result in chloride deficiency

Functions of Water: Temperature Regulation

-Helps enzymes to function normally. -Water has a high heat capacity or specific heat. That means water resists temperature changes, so its temperature rises slowly when it is heated. This is because large amount of heat is required to break attraction between water molecules.

Parathyroid Hormones

-Helps increase calcium absorption indirectly by promoting the synthesis of calcitriol in the kidney. In addition, parathyroid hormone often works in conjunction with calcitriol to release calcium from bones, a rich nutrient reserve for both calcium and phosphorus.

Regulation of Water Balance

-Kidneys are the main regulators, but the brain, lungs, and liver also have important roles in maintaining water balance. -When water intake is too low to replace losses, the blood becomes more concentrated (the osmotic pressure of the extracellular fluid increases) and blood pressure falls. These changes signal the body that there is a shortage of water and trigger a series of fluid conservation measures. In response to increased osmotic pressure, the pituitary gland releases antidiuretic hormone (ADH). ADH signals the kidneys to retain water, thus reducing urine output. At the same time, falling blood pressure initiates another sequence of events - highly sensitive pressure receptors in the kidneys trigger the release of the enzyme renin. -Renin, in turn, activates angiotensinogen forming angiotensin I. Aldosterone signals the kidneys to retain more sodium and chloride, and therefore more water (Water always follows electrolytes). Thus, low blood pressure, through this roundabout sequence, causes the kidneys to increase water conservation in the body. There is, however, a limit to how concentrated urine can become.

Waste Product Removal By Water

-Liver metabolism converts some fat-soluble compounds, such as certain medications and potential cancer causing substances, into water-soluble compounds that can be excreted in the urine. -Typical urine output is 4 1/4 to 8 1/2 cups daily can easily change in response to fluid, protein, and sodium intake. The minimum output required to excrete usual amounts of urea and sodium waste is 2 1/2 cups per day. If urine output is this low frequently, its heavy ion concentration may increase the risk of kidney stone formation in susceptible people, especially men. Kidney stones are minerals and other substances that have precipitated out of the urine and accumulated in kidney tissues.

Hypokalemia

-Low blood potassium is a life threatening problem.

Functions of Chloride

-Main anion in the extrecellular fluid, where its negatively charge balances the positively charge from the sodium ion. Together, sodium and chloride help maintain extracellular fluid volume and balance. -Aid in transmission of nerve impulses. -Electrolyte -Component of HCI produced in the stomach -Helps maintain acid-base balance and dispose of carbon dioxide by way of exhaled air.

Functions of Water

-Maintenance of blood volume and the transport of nutrients and oxygen throughout the body depend on water. Water is the basis for the fluids synthesized throughout the body, such as saliva, bile, and amniotic fluid, the fluid that surrounds a fetus growing in a woman's uterus. Water is incompressible, so it helps form lubricants in the knees and other joints. Water also serves as a solvent in many metabolic processes and actively participates as a reactant in numerous chemical reactions.

Potassium (K)

-Majority through fruit and vegetables -adequate intake is 4700 mg per day. -Average intake of American woman in 2408 mg/day and 3172 mg in men

Overview of Minerals

-Minerals are essential inorganic elements needed in small amounts in the diet for the normal function, growth, and maintenance of body tissues. -Indispensable in human diet, cannot be synthesized in the body -Divided into major minerals and trace minerals depending on the amount needed each day.

Calcium Transportation, Storage, Regulation, and Excretion

-Occurs along length of intestinal Tract -Most efficiently absorbed in the upper part of the small intestine because its slight acidic pH helps keep the calcium dissolved in its ionic form. -Intestinal contents become more alkaline as they pass through the intestine; thus, calcium absorption decreases at the terminal end of the small intestine and colon, although some still occurs via passive diffusion.

Calcium Needs

-RDA 1000 mg.day for adults, 1200 mg/day for women over age 50 and men over age 70. 1300 mg/day for adolescents

Major Mineral

-Required 100 mg or more of a mineral daily

Dehydration

-Results from a variety of conditions. -They include those related to medical conditions such as diarrhea, vomiting, fever, inability to consume sufficient fluid, poorly controlled diabetes mellitus, and burns. -In the healthy, can occur as a result of heavy exercise, hot weather, dry environments, high altitudes (more rapid breathing causes increased fluid loss from the lungs), or even just ignoring feelings feelings of thirst. In all cases of dehydration, fluid intake does not match fluid always work well during intense exercise, illness, infancy, and old age. Sick children- especially those with fever, vomiting, diarrhea, and increased perspiration- and older person often need to be reminded to drink plenty of fluids. -Athletes working outside in warm, humid environments are at extra risk of dehydration -Prolonged activity, sweat loss = 3 to 8 cups an hour.

Signs of Dehydration

-Signs of mild to moderate dehydration include dry mouth and skin, fatigue, and muscle weakness, decreased urine output, deep yellow (concentrated) urine, headache, and dizziness. As dehydration progresses, solute concentrations in the blood rise, blood pressure decreases, and heart rate increases due to low blood volume. -Only treatment for dehydration is to replace the lost fluids. -In cases of severe dehydration, fluid replacement should be done under medical supervision. Left unchecked, severe dehydration can progress to death

Chloride

-Strong oxidant widely used to purify water, disinfect swimming pools, bleach fabrics, and produce many products -Chlorine and chlorine gas is toxic

Electrolytes

-The most abundant solutes are electrolytes that form when salts, such as sodium chloride or potassium phosphate, dissociate in solution and form ions. -The major positively charged electrolytes (cations) and the negatively charged electrolytes (anions) found in each fluid compartment vary. Intracellular fluid contains primarily potassium and magnesium cations, along with negatively charged phosphate anions. In extracellular fluid, positively charged sodium cations and negatively charged chloride anions, along with bicarbonate

Water toxicity

-Too much is as dangerous as too little. -Water intoxication develops when the kidneys cannot remove water fast enough to keep pace with water intake. -As a result, water accumulates in the blood and dilutes the sodium in the serum, a condition known as hyponatremia.

Excess Sodium and Upper Level

-Upper level is 2300 mg a day -Sodium intake greater than 2g per day also increase calcium loss in the urine and are of potential concern for the loss of calcium from bones

Function of Minerals

-Water balance requires sodium, potassium, calcium, and phosphorus. Sodium, potassium, and calcium aid in the transmission of nerve impulses throughout the body. Some minerals, such as magnesium, copper, and selenium, function as cofactors and enable enzymes to carry out chemical reactions. Minerals also are components of many body compounds. For example, iron is a component of hemoglobin in red blood cells. Body growth and development also depend on certain minerals, such as calcium, and phosphorus. At all levels- cellular, tissue, organ, and whole body minerals play important roles in maintaining body functions.

Water in the body: Intracellular and extracellular fluid

-Water is the largest component of the human body, making up to 50% to 75% of body weight, depending on age and body fat content. -55% of an adult's body weight is water- about 10 gallons in a person weighing 160 lbs. -Lean individuals have a greater percentage of body water than those who are obese because lean tissue contains about 73% water, whereas adipose tissue is only 20% water. -Body water is found in intracellular, extracellular compartment, and interstitial + intravascular fluid

Water Needs

-Water needs vary with factors such as body size, physical activity, environmental conditions, and dietary intake. Despite this variability, an adequate intake has been set to provide guidance to individuals for water intake. The adequate intake for total water intake per day is 15 cups for adult men and 11 cups for adult women.

Functions of Potassium

-major cation inside cell and performs many of the same functions as sodium. Both are involved in maintaining fluid balance, transmitting nerve impulses, and contracting muscle. -Influences the excretion of calcium in that it declines with the intake of potassium increases. -Helps keep blood pressure normal.

Hypertonic Solution

A hypertonic solution has a high ion concentration, which causes shrinkage of the red blood cell as water moves out of the cell and into the concentrated solution

Hypotonic Solution

A hypotonic (dilute solution) has a low ion concentration, which results in swelling and subsequent rupture (puff of red in the lower left part of the cell) of a red blood cell places into the solution.

Osteocytes

Biochemically active; they can take up calcium from the blood and release it back into the blood, as well as help bone become more dense, if needed.

Intracellular Compartment

Body water inside cells

Extracellular Compartment

Body water outside cells. -Almost two-thirds of body water is found in the intracellular fluid compartment, the rest is in extracellular fluid. -Extracellular fluid is divided into interstitial fluid, the fluid between cells, and intravascular fluid, the fluid in the blood and lymph.

Remodeling

Bone is continually being build, broken down, and reshaped. Remodeling is vital for bone health because it allows bones to grow normally and to repair and replace damaged or brittle areas. -Permits calcium and phosphorus to be withdrawn and used for other functions when dietary intake is insufficient. -Bone cells function in bone growth and remodeling: osteoblasts, osteocytes, osteoclasts

Unleavened Bread

Bread that does not contain leavening agents, such as yeast or baking powder. Leavening agents, such as yeast or baking powder. Leavening agents cause bread dough to rise. Flat breads, such as pita bread and tortillas, are unleavened. French and Italian bread, biscuits, and muffins are leavened breads.

Mineral Deficiencies

Calcium is a major mineral that is likely to be deficient in some diets. Starting in their teen years, most females are unlikely to meet calcium intake recommendations, especially when they do not use calcium supplements. Potassium and magnesium intakes also fall short of DRI recommendations. Of the trace minerals, iron, zinc, and iodine are most likely to be deficient in diets.

Hyperparathyroidism

Can cause persistently elevated blood calcium.

Osteoclasts

Cells on the bone surface that dissolve bone (bone resorption) by releasing acid and enzymes. -Activity is stimulated by parathyroid hormone, often in conjunction with Vitamin D. Osteoclasts are very active when a diet is deficient in calcium - they release calcium from the bone so that is can enter the blood. Remember, a supply of calcium is vital to all cells, not just to bone cells.

Angiotensin II

Compound, produced from angiotensin I, that increases blood vessel constriction and triggers production of the hormone aldosterone

Phytic Acid (phytate)

Constituent of plant fibers that binds positives ions (zinc as Zn^2) to its multiple phosphate groups and decreases their bioavailability.

Bioavailability

Degree to which the amount of an ingested nutrient is absorbed and is available in the body -Mineral bio-availability also is strongly affected by nonmineral substances in the diet, Phytic acid (phytate) in wheat grain and legume fiber can limit the absorption of some minerals by chemically binding them and preventing their release during digestion. -Fiber intake greatly above the adequate intake of 25 to 38 g/day can adversely affect mineral status. However, if grains are leavened with yeast, enzymes produced by the yeast can break some of the chemical bonds between phytic acid and minerals. Breaking these bonds increases the bioavailability of the minerals. The Zinc deficiencies found among some Middle Eastern populations are attributed partly to their heavy reliance on unleavened breads, resulting in low bioavailability of dietary zinc. -Oxalic acid (oxalate) found in leafy green plants also binds minerals and makes them less bioavailable. Spinach, for example, contains plenty of calcium, but only about 5% of it can be absorbed because of the vegetable's high concentration of oxalic acid. On the other hand, about 32% of the dietary calcium is absorbed from miilk and milk products. -Polyphenols are a group of compounds containing at least 2 ring structures that each have at least 1 hydroxyl group attached. Polyphenols also can lower the bioavailability of minerals, especially iron and calcium. Many polyphenols occur naturally in plants, such as tea, dark chocolate (cacao beans), and wine (grapes). Some types of polyphenols, such as flavonoids and tannins, may help prevent cancer and heart disease. -Mineral bioavailability can be enhanced by some vitamins. Vitamin C can improve iron absorption when both are consumed in the same meal. The Vitamin D hormone calcitriol improves calcium, phosphorus, and magnesium absorption. -Gastric Acidity Promotes the bioavailability of many minerals. -

Functions of Calcium

Developing and maintaining bones and teeth are calcium's major functions in the body. Calcium also is required for blood clotting, the transmission of nerve impulses, muscle contraction, and cell metabolism

Renin

Enzyme formed in the kidneys and released in response to low blood pressure. It acts on a blood protein called angiotensinogen to produce angiotensin I.

Mineral Toxicity.

Excess mineral intake can be toxic, particularly trace minerals, such as iron and zinc. The use of mineral supplements, especially if intake will exceed the Upper Level, is best considered after consulation with a registered dietitian or physician. -High intakes of 1 mineral can hinder the absorption of others -

Excretion of Minerals

Excretion of the major minerals takes place primarily through the urine. However, some trace minerals, such as copper, are secreted by the liver into the bile for excretion in the feces. When kidney function fails, mineral intake must be controlled to avoid mineral toxicity, such as phosphorus and potassium.

Hyperkalemia

High potassium levels in the blood

Antidiuretic Hormones (ADH)

Hormone secreted by the pituitary gland that signals the kidneys to decrease water excretion; also called arginine vasopressin

Aldosterone

Hormone, produced in the adrenal glands, the acts on the kidneys, causing them to retain sodium and therefore water

Transport and Storage of Minerals

Once absorbed, minerals travel in the blood, either in a free form or bound to proteins. For example, calcium ions can be found free in the blood or bound to the blood protein albumin. Trace minerals in their free form are often highly reactive and are toxic if not bound. Thus, many trace minerals have specific binding proteins that transport them in the blood stream. Many also are bound by specific cellular proteins once they are taken up by cells. -Minerals stores provide a ready source of the mineral when dietary intake is lacking. Mineral storage in the body varies tremendously. Some minerals are stored in large quantities; for example, calcium and phosphorous are stockpiled in bones and teeth. Other minerals, such as iron stored in the liver and bone marrow, are stored in smaller amounts. The human body has extremely small stores of many trace and ultratrace minerals.

Oxalic Acid

Organic Acid, found in spinach, rhubarb, and other leafy green vegetables, that can depress the absorption of certain minerals present in the food.

Sodium Deficiency

Rare because of abundance in food supply -Only when perspiration weight loss is beyond 2% of total body weight or 5-6 lbs should sodium losses be concerned.

Upper Level for Chloride

The upper level for chloride is 3600 mg/day

Nephrotic Syndrome

Type of kidney disease that results from damage to the kidney, often caused by another disease, such as diabetes. The symptoms include fluid retention, weight gain, and high blood pressure.