Nutrition 4

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Exam 4: Minerals, Energy Balance and Body Composition

In what region of the body is the storage of excess body fat associated with the highest risks for cardiovascular disease and diabetes?

abdomen

What is the main explanation for the difference in basal metabolic rates between males and females of the same body weight?

Males have a higher percentage of lean body mass

What are known side effects of having insufficient fat stores?

Infertility, clinical depression, abnormal hunger regulation

What group has the highest metabolic rate?

younger individuals

Jim is a 45 year old who eats fast food at least 3 times a week and smokes a pack of cigarettes each day. He just had a physical examination and was told that his body mass index is 24. In what category would Jim's BMI be classified?

Healthy weight

Jackie, who has a sedentary lifestyle, is 5'5" tall and weighs 165 lbs. She calculated her BMI to be 27.5. She recognizes that her body weight is unhealthy and vows to improve her eating habits and begin a regular program of physical fitness. Her goal is to achieve a BMI of 22. Approximately how much weight (lbs) must she lose?

33

A graph of the relationship between mortality (left axis) and body mass index is shaped like a(n)

J

What percentage of adult body weight is water?

60%; ³/₄ Lean tissue is water; Less than ¹/₄ fat tissue is water

main role of water

to maintain an appropriate water balance to support vital functions

roles of water in the body

1. Transports nutrients and wasted products
2. Maintains structure of large molecules
3. Participates in metabolic reactions
4. Solvent for minerals, vitamins, amino acids, glucose and others
5. Lubricant and cushion around joints, inside eyes, spinal cord, and amniotic fluid
6. Regulate body temperature
7. Maintains blood volume

ICF

Intracellular fluid; a cell and it's associated fluids, inside cells ²/₃ of body water

ECF

extracellular fluid; outside cells

interstitial fluid

fluid in the spaces between cells

intravascular

within blood vessels

hypothalamus

a brain center that controls activities such as maintenance of water balance, regulation of body temperature, and control of appetite

dehydration

water output> water input

water intoxication

excessive water contents in all body fluid compartments, rare, occurs mostly in endurance athletes; can lead to hyponatremia and death

AI for total water

men: 3.7 L/day; women: 2.7 L/day; ~7-11 cups a day

obligatory water excretion

500mL (about 2 c or a pint)

What organ regulates blood volume and blood pressure?

kidneys

nephron

working unit of the kidney; more than 1 million in each kidney

renin

enzyme released by kidney cells when blood pressure is low; kidneys reabsorb Na → H₂O; leads to the production of angiotensin II

ADH

stimulates the kidneys to reabsorb water; antidiuretic hormone

angiotensin II

constricts blood vessels and stimulates the release of aldosterone and ADH

aldosterone

regulates potassium and sodium levels

electrolytes

salts that dissolve in water and dissociate into charged particles called ions; enable body to move fluids

cations

positively charged ions

anions

negatively charged ions

NaCl

salt dissolves in water into ions → Na+ Cl-

Osmosis

movement of water across a cell membrane toward more concentrated solutes

protein regulation

regulate the flow of fluids and ions

transport proteins

regulate passage of positive ions (NaK ATPase pump)

vascoconstrictor

a substance that constricts or narrows the blood vessels

What are the two sites of regulation of fluid and electrolyte balance

GI tract and kidneys

kidneys maintain fluid balance using

ADH

kidneys maintain electrolyte balance using

aldosterone

effects of fluid and electrolyte imbalance

vomiting and diarrhea, lose sodium; uncontrolled diabetes, lose glucose; can occur with vomiting, diarrhea, heavy sweating, burns, traumatic wounds

normal pH ranges of blood

7.35-7.45

pH value

the concentration of hydrogen atoms; unit of measure expressing a substance's acidity or alkalinity

the lower the pH

the higher the H+ ion concentration and stronger the acid

bicarbonate

an alkaline compound with that formula HCO₃, it is produced in all cell fluids from the dissociation of carbonic acid to help maintain the body's acid-base balance; it is also secreted from the pancreas during digestion as part of the pancreatic juice

buffers

regulate pH in the body; weak acids or bases that can react with strong acids or bases to prevent sharp sudden changes in pH

regulation of acid-base balance in the lungs

respiration speeds up and slows down as needed

regulation of acid-base balance by the kidneys

selects which ions to retain and which to excrete; urine's acidity level fluctuates; long term control

bicarbonate-carbonic acid buffer system

If increase in H+, equation would shift to left and generate CO₂ and increase respiration; if pH increases, more CO₂ would combine with H₂O to form H+ ions to decrease pH

the major minerals

sodium (Na+), chloride (Cl-), potassium (K+), calcium (Ca²+), phosphorous (P), magnesium (Mg), sulfur (S); also called macrominerals, essential mineral nutrients the human body requires in relatively larger amounts (greater than 100mg per day)

carbonic acid

H₂CO₃; compound that results from the combination of carbon dioxide and water; of particular importance in maintain the body's acid-base balance

inorganic elements

always retain their chemical identity; cannot be destroyed by heat, air, acid or mixing

phytates

found in legumes and grains; a binder that can combine chemically with minerals and prevent absorption

oxalates

found in spinach and rhubarb; a binder that can combine chemically with minerals and prevent absorption

high sodium intake

causes excretion of both itself and calcium

sodium, potassium, and chloride

function in fluid balance

calcium, phosphorus, and magnesium

function in bone growth and health

chief roles of sodium

maintains normal fluid and electrolyte balance--principle extracellular cation; assists in nerve impulse transmission and muscle contraction

recommendations for sodium

<2300mg daily; <1500mg for elderly, black people, and people with high blood pressure

sodium food sources

table salt, moderate amount in meats, milks, breads, vegetables, and large amounts in processed foods

salt sensitivity

a characteristic of individuals who respond to a high salt intake with an increase in blood pressure or to a low salt intake with a decrease in blood pressure

DASH diet

dietary approaches to stop hypertension; diet emphasizes consumption of addition fruits and veggies per day, fat-free or low fat milk and dairy products, inclusion of whole grains, nuts and beans, reduced intake of red meat, butter, and high fat foods

sodium deficiency

hyponatremia; lost with vomiting diarrhea, heavy sweating; symptoms: muscle cramps and mental apathy

sodium toxicity

acute: edema, acute hypertension; prolonged: hypertension

functions of chloride

maintains fluid and electrolyte balance; major anion of extracellular fluids; mostly associated with sodium; part of hydrochloric acid found in stomach, necessary for proper digestion

chloride food sources

processed foods, table salt, soy sauce, meats, milk, and eggs

functions of potassium

body's principle intracellular cation; maintains normal fluid and electrolyte balance; facilitates many reactions; supports cell integrity; assists in nerve impulse transmission and muscle contractions (steady heartbeat)

potassium deficiency

increase in blood pressure, irregular heartbeat, muscular weakness, glucose intolerance, salt sensitivity, kidney stones, bone turnover

toxicity

muscular weakness, vomiting, if given into a vein it can stop the heart; kidneys will accelerate excretion

calcium

most abundant mineral in the body; 99% in bones and teeth; 1% in blood

hydroxyapatite

crystals made of calcium and phosphorus

mineralization

process in which calcium, phosphorus and other minerals crystallize on collagen matrix of growing bone, hardening it

calcium in body fluids

regulates muscle contractions; transmission of nerve impulses; role in mediating constriction and relaxation of blood vessels

calmodulin

a protein that calcium binds with and activates; one role is to activate the enzymes involved in breaking down glycogen, which releases energy for muscle contractions

calcium and disease prevention

may prevent against hypertension; play role in maintaining healthy body weight

organs involved in calcium balance

kidneys, intestines, bone

calcitonin

a hormone secreted by the thyroid gland that regulates blood calcium by lowering it when levels rise too high

parathyroid hormone

a hormone from the parathyroid glands that regulates blood calcium by raising it when levels fall too low; also known as parathormone

calcium rigor

hardness or stiffness of the muscles caused by high blood calcium concentrations

calcium tetany

intermittent spasm of the extremities due to nervous and muscular excitability caused by low blood calcium concentrations

factors that enhance calcium absorption

vitamin D, stomach acid, lactose (in infants only)

factors that inhibit calcium absorption

lack of stomach acid, vitamin D deficiency, high phosphorus intake, phytates and oxalates

peak bone mass

the highest attainable bone density for an individual, developed during the first three decades of life

calcium-binding protein

a protein in the intestinal cells, made with the help of Vitamin D, that facilitates calcium absorption

calcium food sources

milk, milk products; some brands of tofu, nuts and seeds, corn tortilla, mustard and turnip greens, bok choy, broccoli, kale

calcium deficiency

stunted growth in children; bone loss in adults (osteoporosis)

calcium toxicity

constipation; increased risk of urinary stone formation and kidney dysfunction; interference with absorption of other minerals

chief functions of calcium in the body

mineralization of bones and teeth; also involved in muscle contraction and relaxation, nerve functioning, blood clotting, blood pressure

Phosphorus

second most abundant mineral in the body

chief functions of phosphorus

mineralization of bones and teeth; part of every cell; important in genetic material, part of phospholipids, used in energy transfer and in buffer systems that maintain acid-base balance

food sources of phosphorus

all animal tissues

magnesium

¹/₂ is found in bones; rest is in muscles and soft tissue

chief functions of magnesium in the body

bone mineralization, building of protein, enzyme action, normal muscle contraction, nerve impulse transmission, maintenance of teeth, and functioning of immune system

food sources of magnesium

nuts, legumes, whole grains, dark vegetables, seafood, chocolate, cocoa

osteoporosis

a disease characterized by porous and fragile bones

cortical bone

the very dense bone tissue that forms the outer shell surrounding trabecular bone and comprises the shaft of a long bone

trabecular bone

the lacy inner structure of calcium crystals that supports the bone's structure and provides a calcium storage bank; sensitive to hormones; losses become significant in the 30s

bone density

a measure of bone strength

Which of the following foods provides the greatest amount of iron per serving?

pinto beans

What type of anemia results from iron deficiency?

Microcytic hypochromic

Iron overload is also known as:

hemochromatosis

An enzyme in which zinc is an integral part of its structure is classified as a(n)

metalloenzyme

Which of the following nutrients enhances iron absorption from the intestinal tract?

Vitamin C

Which of the following represents the most reliable source of dietary zinc?

Meats and whole grain cereals

What is the function of the MFP factor?

Enhances iron absorption

Goiter is caused primarily by a deficiency of

iodine

What iron-containing compound carries oxygen in the bloodstream?

Hemoglobin

What is the normal body fat content for normal-weight men?

13-21%

What instrument is used to measure the energy content of foods?

bomb calorimeter

An index of a person's weight in relation to height is called

body mass index

Waist circumference can best be used to assess

abdominal fat stores

Eating an additional ______ kcalories (above needs) will result in a 1 pound weight gain

3500

Which of the following is a feature of the basal metabolic rate (BMR)?

Fever decreases the BMR

After consuming a very large meal, the desire to eat a slice of chocolate cake is an example of behavior known as

satiety

What term is given to the condition of a female athlete who has an eating disorder and develops amenorrhea and osteoporosis?

Female athlete triad

Among the following groups, which has the highest metabolic rate?

Younger individuals

44 million have low bone mass

osteopenia

DEXA scan

dual-energy X-ray absorpiometry test that assesses risk of bone fractures

three major risk factors for osteoporosis

age, gender, physical activity

upper limit for calcium

2500mg/d

calcium carbonate

best absorbed with food; 40% calcium

calcium citrate

can be taken any time; 21% calcium

calcium lactate

13% calcium

How do you increase bone mineral density?

take in adequate calcium and vitamin D; strength training helps to build strong bones

Food sources of trace minerals

dependent on soil and water composition; food processing; interactions with other trace minerals

trace mineral deficiencies

mild-easily overlooked; severe- mostly seen in children resulting in failure to grow and thrive

Hemoglobin

iron found in red blood cells; carries O₂ in blood

myglobin

iron found in muscle cells; makes O₂ available to muscles

ferritin

iron storage protein

transferrin

iron transport protein

MFP factor

meat, fish, poultry: promotes absorption of nonheme iron from other foods in that meal

other iron absorption-enhancing factors

vitamin C, citric acid and lactic acid from foods, HCl acid from stomach

iron absorption inhibiting factors

phytates and fiber, oxalates, calcium and phosphorus, EDTA, tannic acid (tea and coffee)

surplus of iron is stored

in bone marrow, spleen, and liver

hemosideron

storage protein used when concentrations of iron are extremely high

iron

can act as a free radical

iron deficiency

most common worldwide nutrient deficiency; vulnerable stages of life; blood losses

microcytic hypochromic anemia

small cell, too little color; fatigue, weakness, apathy; iron deficiency anemia

Pica

the habit of eating ice, clay paste, or other non food substance; generally seen in women and children from low-income groups

iron toxicity

hemochromatosis; more common in men; toxicities may be caused by repeated blood transfusions or massive doses of supplements

food sources of iron

red meats, fish, poultry, shellfish, eggs, legumes

contamination iron

found in foods as a result of contamination by inorganic iron salts from iron cookware or iron containing soils

ferrous sulfate or iron chelate

best absorbable supplements

roles of zinc in the body

supports work of many metalloenzymes; involved in growth, development and immune system; sperm and fetal development

absorption of zinc

dependent on status in body; vulnerable to phytates

metallothionein

special protein that holds zinc in storage

albumin

zinc is transported by this protein

zinc deficiency symptoms

growth retardation, delayed sexual maturation, impaired immune function, hair loss

zinc food sources

red meat, shellfish, poultry, legumes; can be bound by phytates and fiber in diet (although rare)

What converts iodine to iodide?

GI tract

Iodide function in body

part of thyroid hormones; regulate body temperature, metabolic rate, reproduction, growth, blood cell production, nerve and muscle function

iodine deficiency

reduction in thyroid hormone; thyroid gland cells enlarge, visible lump in neck; Goiter

cretinism

severe iodine deficiency during pregnancy that causes extreme and irreversible mental and physical retardation

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