Nutrition 2nd Exam PDF

CHAPTER 9 Water and the Body Water is essential for life and is the most important nutrient. The human body can only survive a few days without water. Water balance is the dynamic equilibrium of fluids within and around cells. The body regulates both intake and excretion to mainta...

CHAPTER 9 Water and the Body Water is essential for life and is the most important nutrient. The human body can only survive a few days without water. Water balance is the dynamic equilibrium of fluids within and around cells. The body regulates both intake and excretion to maintain this balance. Dehydration Dehydration occurs when the body loses more water than it takes in. It can happen quickly, and the thirst mechanism may not be sufficient to prevent it Older adults are more susceptible to dehydration as their thirst sensation diminishes. Signs of mild dehydration (less than 5% body weight loss): ○ Thirst ○ Sudden weight loss ○ Rough, dry skin ○ Dry mouth, throat, and body linings ○ Rapid pulse ○ Low blood pressure ○ Lack of energy and weakness ○ Reduced urine output; concentrated, dark yellow urine ○ Decreased mental and physical performance Signs of severe dehydration (more than 5% body weight loss): Pale skin Bluish lips and fingertips Confusion and disorientation Rapid, shallow breathing Weak, rapid, irregular pulse Thickening of blood Scant, brown-colored urine Shock, seizures Coma, death Water Intake Regulation Thirst is the primary regulator of water intake. When blood becomes too concentrated, the hypothalamus in the brain triggers thirst.  It's crucial to respond to thirst by drinking water as thirst alone doesn't remedy a water deficiency. Water Intoxication Water intoxication occurs when excessive water consumption overwhelms the kidneys' ability to excrete it. This can also occur with kidney disorders. Symptoms of water intoxication: ○ Severe headache ○ Confusion ○ Convulsions ○ Death (in extreme cases) Excessive water intake: can dilute blood sodium concentration, leading to hyponatremia. Water Excretion Regulation. The brain and kidneys regulate water excretion. Antidiuretic hormone (ADH): The hypothalamus stimulates the pituitary gland to release ADH when blood salt concentration is high, or blood volume or pressure is low. ADH prompts the kidneys to reabsorb water. Renin-angiotensin-aldosterone system: When blood pressure drops, the kidneys release renin, ultimately leading to aldosterone release, which also causes the kidneys to retain water. Minimum Water Needs and Balance The body needs to excrete at least 500 ml of urine daily to remove waste products. Water is lost through urine, sweat, breath, and feces. Intake includes: liquids, food, and metabolic water. Output includes: losses through kidneys, skin, lungs, and GI tract. Water Recommendations and Sources Water needs vary depending on factors like diet, environment, and activity level. The Adequate Intake (AI) for total water is: 3.7 liters for men and 2.7 liters for women, including water from beverages and food.  Pale yellow urine indicates adequate hydration. Dietary sources of water: Water and other beverages Fruits and vegetables (up to 95% water) Meats and cheeses (at least 50% water) Beverage Choices Water is the best choice for hydration as it's calorie-free. Other suitable options include tea, coffee, nonfat and low-fat milk, artificially sweetened beverages, fruit and vegetable juices, and sports drinks. Sugar-sweetened beverages provide empty calories and may displace more nutritious drinks. Caffeine-containing beverages contribute to daily water intake similar to non-caffeinated beverages. Alcohol acts as a diuretic and should not be relied upon for hydration. It also has negative health impacts. Electrolytes: are mineral salts that dissolve in water and separate into charged particles called ions. These ions can conduct electricity. This is why a salt that dissociates in water is called an electrolyte. Body fluids contain water and partly dissociated salts, which makes them electrolyte solutions. Electrolytes are essential for cell life and must be carefully regulated to maintain proper fluid distribution in the body. Major minerals create salts that dissolve in body fluids. Cells determine where these salts go, and the movement of salts dictates fluid flow. Water follows salt. Osmosis is the force cells use to move fluids across their membranes. Electrolytes help keep water in the compartments where it's needed. - For example, when salt is sprinkled on eggplant slices, the cellular water in the eggplant moves across each cell's membrane toward the higher concentration of dissolved particles on the surface, creating "sweat" beads. Proteins In the cell membranes control the movement of ions in and out of cells. These protein pumps usually concentrate sodium and chloride outside cells and potassium and other ions inside. Cells can regulate the precise amount of water inside and outside their boundaries by maintaining specific amounts of sodium outside and potassium inside. Healthy kidneys precisely regulate the body's sodium and water levels. The intestinal tract easily absorbs sodium, which then circulates freely in the blood. The kidneys filter out excess sodium. Although the kidneys filter all sodium from the blood, they return the exact amount the body needs to the bloodstream, keeping the body's total electrolytes constant. Urinary electrolytes fluctuate depending on dietary intake. In some cases, the body can't compensate for sudden, significant fluid and electrolyte losses due to events such as vomiting, diarrhea, heavy sweating, fever, burns, or wounds. These situations require medical intervention Major Minerals The major minerals are: calcium, chloride, magnesium, phosphorus, potassium, sodium, and sulfur The major minerals are present and needed in larger amounts in the body than trace minerals. Recommended intakes for the major minerals are in hundreds of milligrams or grams. Calcium and potassium are considered nutrients of public health concern because underconsumption is linked to chronic diseases. Sodium is overconsumed by most people. Roles of Major Minerals All major minerals influence the body's fluid balance. Sodium, chloride, and potassium are most noted for their role in fluid balance. Sodium, potassium, calcium, and magnesium are critical to nerve transmission and muscle contractions. Phosphorus and magnesium are involved in energy metabolism. Calcium, phosphorus, and magnesium contribute to bone structure. Sulfur helps determine the shape of proteins. Calcium and Phosphorus Calcium and phosphorus are the most prevalent minerals in the body. They are the chief minerals of bone. Importance The distinction between major and trace minerals does not mean one group is more important. A deficiency of either a major or trace mineral can be serious Calcium is the most abundant mineral in the body. 99% of the body's calcium is stored in bones and teeth. The other 1% of calcium circulates in body fluids as ionized calcium. Calcium has several roles in the body: It is a key component of bone structure. It acts as a reserve for calcium that can be used to maintain calcium levels in body fluids. It regulates ion transport across cell membranes. It is vital for nerve transmission. It helps maintain healthy blood pressure. It plays an essential role in blood clotting. It is essential for muscle contraction, including the heartbeat  It enables the secretion of hormones, digestive enzymes, and neurotransmitters. It activates cellular enzymes. Bone is a dynamic tissue that constantly undergoes remodeling. Remodeling involves the breakdown and formation of new bones. There are three phases of bone development: Active growth phase (from birth to about age 20) Peak bone mass development (between ages 12 and 30) Bone resorption exceeding formation (starting between ages 30 and 40 and continuing) Calcium balance is tightly regulated in the body. If blood calcium gets too high, hormones (including vitamin D) promote calcium deposition into bones. If blood calcium gets too low, the body increases blood calcium by: Increasing calcium absorption in the small intestine Releasing more calcium from bones Decreasing calcium excretion by the kidneys Even when there is a calcium deficiency, blood calcium levels are maintained at the expense of bone calcium. Osteoporosis: is a condition where bone loss is so severe that bones become fragile and easily fracture. About 25% of adults in the United States aged 50 and older have or are developing osteoporosis, mostly women. Risk factors for osteoporosis include: Nonmodifiable: Female sex Older age Small frame Caucasian, Asian, or Hispanic/Latino heritage Family history of osteoporosis or fractures Personal history of fractures Modifiable: Estrogen deficiency in women (amenorrhea or menopause, especially early or surgically induced); testosterone deficiency in men Sedentary lifestyle Diet inadequate in calcium and vitamin D  Diet excessive in sodium and caffeine Cigarette smoking Alcohol use disorder Low body weight Certain medications, such as glucocorticoids and anticonvulsants Adequate calcium intake during the growing years is crucial for building strong bones and reducing the risk of osteoporosis later in life. Physical activity, especially weight-bearing exercises like walking, running, dancing, and weight training, helps build and maintain bone density. Calcium recommendations vary by age and life stage: Adolescents (high bone growth): 1300 mg/day Adults aged 19 to 50: 1000 mg/day Women over age 50 and all adults over age 70: 1200 mg/day Many people in the US do not consume enough calcium. Dairy products are the richest sources of calcium. One cup of milk provides about 300 mg of calcium. Cheese also contains substantial amounts of calcium (one ounce is equivalent to about two-thirds of a cup of milk). Other good sources of calcium include: Calcium-fortified foods (juice, milk, cereals) Certain leafy green vegetables (beet greens, bok choy, broccoli, kale, mustard greens, rutabaga, turnip greens) Calcium-rich mineral water Spinach and Swiss chard, while appearing to be calcium-rich, contain binders that limit calcium absorption. Calcium absorption varies by age and physiological state: Infants and children: absorb up to 60% Pregnant women: absorb about 50% Other adults: absorb about 20-30% While supplements can help bridge the gap between dietary intake and recommendations, it is generally better to obtain calcium from food sources. Foods provide additional nutrients and may enhance calcium absorption. Some individuals absorb calcium more efficiently from dairy products than supplements. This study guide summarizes key information about calcium from your provided sources. Please note that this is a starting point, and you may need to consult additional resources to expand your understanding of this topic. Phosphorus The second most abundant mineral in the body. About 85% is found in bones and teeth, combined with calcium. Found in all body tissues as part of the body's buffer system (phosphoric acid). Part of DNA and RNA, so it is necessary for all growth. Key roles in the transfer of energy during cellular metabolism. Phosphorus-containing lipids (phospholipids) help transport other lipids in the blood. Phospholipids are also key parts of cell membranes. Dietary Sources of Phosphorus Animal protein is the best source of phosphorus. This is because animal cells are abundant in phosphorus. Milk and cheese are other rich sources. Diets with enough energy and protein also supply enough phosphorus. Dietary deficiencies are rare Magnesium Importance of Magnesium: Magnesium is a major mineral that plays a vital role in various bodily functions. Location of Magnesium in the Body: More than half of the magnesium in the body is found in the bones, acting as a reservoir. The rest is primarily in muscles, the heart, the liver, and other soft tissues, with only a small percentage in body fluids. Functions of Magnesium: Enzyme and Cellular Function: Magnesium is crucial for the proper functioning of hundreds of enzymes and other cellular processes. Protein Synthesis and Energy Release: It is involved in protein production and the release of energy within cells. Muscle Function: Magnesium works in conjunction with calcium to regulate muscle function. While calcium promotes muscle contraction, magnesium facilitates relaxation. Heart Health: Magnesium is essential for maintaining a healthy heart. Magnesium Deficiency:  Prevalence: Average magnesium intake often falls short of recommended levels. Health Risks: Chronic low intake may exacerbate inflammation and increase the risk of heart failure, stroke, hypertension, and diabetes. Causes of Acute Deficiency: Acute magnesium deficiency can arise from prolonged vomiting, diarrhea, excessive alcohol consumption, severe malnutrition, prolonged intravenous feeding with nutritionally incomplete fluids after surgery, and the use of diuretics. Symptoms of Deficiency: Symptoms include low blood calcium, muscle cramps, and seizures. Magnesium deficiency is also believed to contribute to hallucinations during alcohol withdrawal. Magnesium Toxicity: Rarity and Seriousness: Magnesium toxicity is uncommon but can be life-threatening. - Causes: It typically occurs due to high intakes from non-food sources, such as supplements or magnesium salts. Accidental poisoning can happen in children who have access to medicine cabinets or in older adults who misuse magnesium-containing laxatives, antacids, and other medications. - Symptoms of Toxicity: Symptoms include diarrhea, abdominal cramps, and, in severe cases, acid-base imbalance and potassium depletion. Magnesium Recommendations and Sources: Recommendations: Recommendations for magnesium intake vary slightly across different adult age groups (refer to Appendix H for specific recommendations, which is not included in the provided sources). Water Contribution: “Hard” water, naturally containing calcium and magnesium, can significantly contribute to magnesium intake in certain regions. Food Sources: Magnesium-Rich Foods: Excellent sources include dark green, leafy vegetables; nuts; legumes; whole-grain breads and cereals; seafood; chocolate; and cocoa. Figure 9-6 (not provided) likely illustrates these sources. Food Processing Impact: Processing can lead to magnesium loss from foods, making unprocessed options preferable. Major Minerals Sodium Works with chloride and potassium to maintain fluid balance and acid-base balance. Important for nerve impulse transmission and muscle contraction. Deficiency symptoms: muscle cramps, mental apathy, loss of appetite. Toxicity symptoms: hypertension. - Sources: salt, soy sauce, processed foods. Chloride A component of hydrochloric acid in the stomach, which is needed for digestion. Deficiency does not occur under normal circumstances. Toxicity is normally harmless, although chlorine gas is poisonous. High intake can cause vomiting. Sources: salt, soy sauce, whole unprocessed foods (moderate quantities), processed foods (large quantities). Potassium Involved in protein production, fluid and electrolyte balance, cell integrity, nerve impulse transmission, and muscle contraction (including the heart). Moderate deficiency symptoms: elevated blood pressure, increased salt sensitivity, increased risk of kidney stones, increased bone turnover. Severe deficiency symptoms: cardiac arrhythmias, muscle weakness, glucose intolerance. Toxicity symptoms: muscular weakness, vomiting, can stop the heart if administered intravenously. Sources: all whole foods, including meats, milk, fruits, vegetables, grains, and legumes. Calcium The main mineral in bones and teeth. Involved in muscle contraction and relaxation, nerve functioning, blood clotting, blood pressure regulation, and immune defenses. Deficiency symptoms: stunted growth in children, adult bone loss (osteoporosis). Toxicity symptoms: constipation, increased risk of urinary stone formation and kidney dysfunction, interference with the absorption of other minerals. Sources: dairy products, oysters, small fish with bones, tofu, greens, and legumes. Phosphorus Important for bone and teeth mineralization.  Found in cells' genetic material, cell membranes (as phospholipids), energy transfer processes, and buffering systems. Deficiency is unknown. Toxicity symptoms: calcification of non-skeletal tissues, especially the kidneys. Sources: foods from animal sources such as meat, fish, poultry, eggs, and milk. Magnesium Involved in bone mineralization, protein production, enzyme activity, muscle contraction, and nerve impulse transmission. Critical to the function of hundreds of enzymes and other cellular functions. Deficiency symptoms: low blood calcium, muscle cramps, confusion, seizures (in severe cases), bizarre movements, hallucinations, difficulty swallowing, and growth failure in children. Toxicity is only from non-food sources and can cause diarrhea, nausea, abdominal cramps, acid-base imbalance, and potassium depletion. Sources: nuts, legumes, whole grains, dark green vegetables, seafood, chocolate, and cocoa. Sulfate The oxidized form of sulfur found in foods and water necessary for synthesizing important sulfur-containing compounds, such as sulfur-containing amino acids. Sulfur-containing amino acids are important for protein structure. Skin, hair, and nails contain rigid proteins with high sulfur content. A component of certain amino acids, the vitamins biotin and thiamin, and the hormone insulin. Stabilizes protein shape by forming sulfur-sulfur bridges. There is no recommended intake, and deficiencies are unknown Protein deficiency would likely occur before a sulfate deficiency. Toxicity would only occur from excess sulfur amino acid consumption, which can suppress growth. Sources: all protein-containing foods such as meat, fish, poultry, eggs, milk, legumes, and nuts. Key Concepts: Major minerals are needed in larger amounts than trace minerals. They play various roles in the body, including fluid balance, nerve function, muscle contraction, and bone health Both deficiencies and excesses of major minerals can cause health problems.  It's important to consume a balanced diet that provides adequate amounts of all the essential minerals. Iron Function: Iron is a component of hemoglobin in red blood cells and myoglobin in muscle cells. It helps these proteins carry and release oxygen. Iron is also vital for energy production, cell growth, and the synthesis of amino acids, hormones, and neurotransmitters. Absorption and Regulation: The body tightly regulates iron absorption and storage to ensure adequate levels while preventing toxicity. Special proteins transport and store iron, and the hormone hepcidin plays a central role in maintaining iron balance. Iron Deficiency: Iron deficiency is the most common nutrient deficiency worldwide. It is particularly prevalent in preschool children, pregnant women, toddlers, adolescent females, and women of childbearing age. - Causes: The main cause of iron deficiency is inadequate intake from iron-poor food choices or blood loss. Stages and Assessment:Iron deficiency develops in three stages, which can be assessed using laboratory tests: - Stage 1: Depleted iron stores, reflected by low serum ferritin levels. - Stage 2: Decreased transport iron, with low serum iron and high transferrin levels. - Stage 3: Limited hemoglobin production, leading to low hemoglobin and hematocrit values and accumulation of erythrocyte protoporphyrin. iron-Deficiency Anemia: Iron-deficiency anemia occurs when severe iron depletion results in low hemoglobin concentration. This leads to fatigue, weakness, headaches, apathy, pallor, and poor cold tolerance. Pica: Some iron-deficient individuals, particularly women and children in low-income households, exhibit pica, a craving for nonfood substances like ice, chalk, starch, and clay. Self-Diagnosis Caution: It is crucial to consult a physician for diagnosis rather than self-diagnosing iron deficiency and taking supplements, as iron deficiency can mask underlying medical conditions.  Iron Overload: Iron overload, often caused by hemochromatosis , a genetic disorder, can lead to tissue damage, infections, and increased risks of diabetes, liver cancer, heart disease, and arthritis. Iron Poisoning: Rapid ingestion of large amounts of iron, particularly from supplements, can be fatal, especially in young children. Keep iron supplements out of reach of children. Recommendations: Iron needs vary depending on age and gender. Women of childbearing age have higher iron needs (18 mg/day) than men (8 mg/day). Food Sources: - Heme Iron: Found in meat, poultry, and fish, it is more absorbable than non heme iron. - Nonheme Iron: Found in both plant and animal foods. - Factors Affecting Absorption: MFP factor (found in meat, fish, and poultry) and vitamin C enhance iron absorption, while tannins, calcium, and phytates inhibit it. Zinc Function: Zinc is essential for the activation of over 2700 enzymes involved in various bodily functions, including growth, immune function, wound healing, taste perception, and reproduction. Absorption and Transport: Zinc absorption is regulated by the body's needs. Albumin is the main transport protein for zinc in the blood. Zinc Deficiency: Zinc deficiency can lead to growth retardation, impaired immune function, loss of appetite, and developmental problems during pregnancy. Zinc Toxicity: Excessive zinc intake can interfere with copper absorption, leading to copper-deficiency anemia. High doses of zinc can cause gastrointestinal distress, headaches, and other symptoms. Recommendations and Food Sources: Most people in the United States meet their zinc requirements. Good sources include protein-rich foods like shellfish, meats, poultry, milk products, legumes, and whole grains.  Supplementation: Zinc supplements are generally not recommended unless prescribed for a diagnosed deficiency. Selenium Function: Selenium functions as an antioxidant nutrient, primarily as part of glutathione peroxidase enzymes, which work with vitamin E to protect cells from free radical damage. Selenium and Cancer: While adequate selenium intake is associated with lower cancer risks, supplementation has not been shown to provide additional benefits in populations with sufficient selenium intake. selenium Deficiency: Deficiency is rare but has been linked to Keshan disease, a heart condition prevalent in selenium-deficient regions of China. Selenium Toxicity: Excessive selenium intake can cause gastrointestinal problems, hair and nail loss, and nervous system damage. Recommendations and Food Sources: A varied diet of unprocessed foods generally provides adequate selenium. Good sources include meats, shellfish, vegetables, and grains grown in selenium-rich soil. Iodine Function: iodine is a crucial component of thyroid hormones, which regulate metabolism, growth, development, and various bodily functions. Iodine Deficiency: Iodine deficiency can lead to goiter (enlarged thyroid gland) and impaired cognitive function. During pregnancy, severe deficiency can cause cretinism, characterized by irreversible intellectual disabilities and physical stunting. Iodine Toxicity: Excessive iodine intake can also cause thyroid enlargement. Food Sources: The ocean is the primary source of iodine. Iodized salt, seafood, and foods grown in iodine-rich soil are good dietary sources. Copper Function: Copper is a component of various enzymes involved in iron absorption and utilization, collagen synthesis, wound healing, and nerve function.  Copper Deficiency: Deficiency is rare but can occur in premature infants, malnourished infants, and individuals with high zinc intakes. Copper Toxicity: Copper toxicity is usually associated with genetic disorders. Recommendations and Food Sources:** Organ meats, legumes, whole grains, seafood, nuts, and seeds are good sources of copper. Manganese Function:Manganese acts as a cofactor for numerous enzymes involved in various metabolic processes, including bone formation. Manganese Deficiency:Manganese deficiency is rare in humans. Manganese Toxicity: Toxicity can occur from inhaling manganese dust, primarily affecting the nervous system. Food Sources: Nuts, whole grains, leafy green vegetables, and tea are good sources of manganese. Fluoride Function: Fluoride is essential for the mineralization of bones and teeth. It helps form fluorapatite, which strengthens teeth and makes them resistant to decay. Fluoride Deficiency: Deficiency increases the risk of dental caries (tooth decay). Fluoride Toxicity: Excessive fluoride intake, especially during tooth development, can cause fluorosis, resulting in white specks or staining on teeth. Food Sources: Drinking water (fluoridated or naturally containing fluoride), processed beverages made with fluoridated water, fluoride toothpastes, and certain foods like fish and tea are sources of fluoride. Chromium Function: Chromium enhances insulin action and plays a role in carbohydrate and lipid metabolism. Chromium Deficiency: Deficiency is unlikely but can lead to impaired glucose tolerance and a diabetes-like condition.  food Sources: Unrefined foods like liver, brewer's yeast, whole grains, nuts, and cheeses are good sources of chromium. Other Trace Minerals Molybdenum: An essential trace mineral that functions as part of several enzymes. Deficiencies and toxicities are unknown. Other Trace Minerals: Nickel, silicon, cobalt, and boron are known or suspected to play roles in various bodily functions. Vitamin and Mineral Supplements General Considerations: While most healthy individuals can obtain sufficient nutrients from a balanced diet, supplements may be beneficial for certain populations, such as those with nutrient deficiencies, low energy intakes, or specific dietary restrictions. Arguments Against Supplementation Toxicity Risk: Supplements can cause nutrient imbalances and toxicities, especially at high doses. Contamination and Regulation: Some supplements may contain unapproved ingredients or contaminants. Delaying Medical Treatment: Reliance on supplements may delay seeking appropriate medical care for underlying health conditions. Absorption Interference: supplements can interfere with the absorption of nutrients from food and other supplements. Recommendations for Supplement Use: Consult a healthcare professional for guidance on appropriate supplementation. Choose single, balanced supplements with nutrient levels close to the RDA. Avoid high doses, "organic" or "natural" claims, and unneeded ingredients. Supplement Labeling: Supplement labels must include a "Supplement Facts" panel listing nutrient content and may include nutrient claims, health claims, and structure-function claims. However, the FDA does not require pre-market approval for supplements, making it crucial to choose products from reputable sources.