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Nutrition 4

Exam 4: Minerals, Energy Balance and Body Composition
STUDY
PLAY
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
iodine toxicity
infant can develop goiter; interferes with thyroid function and enlarge the gland
sources of iodine
iodized salt, seafood, bread, dairy products
1 lb body fat
3500 kcal eaten in excess
bomb calorimeter
instrument that measures heat energy released when foods burned
Calorie
the amount of heat energy required to raise temperature of 1ml of water 1°C
direct calorimetry
measures the amount of heat released
satiation
feeling of satisfaction, fullness that occurs during a meal; due to stomach receptors stretching, increased CCK
satiety
feeling of satisfaction that occurs after a meal and inhibits eating until next meal; determines how much time passes between meals
Most satiating
protein, high fiber, low energy density foods
basal metabolism
the energy needed to maintain life when a body is at complete digestive, physical, and emotional rest; 2/3 of total energy expenditure
BMR
basal metabolic rate; rate of energy use for metabolism under specified conditions
RMR
resting metabolic rate; slightly higher than BMR
BMR lowers with
increased age, more fat tissue, fasting/starvation, malnutrition, sleep
thermic effect of food (TEF)
an estimation of the energy required to process food (digest, absorb, transport, metabolize, and store ingested nutrients)
BMI equation
weight (lb)/ height (in)² * 703
underweight BMI
below 18.5
normal BMI
18.5-24.9
overweight BMI
25-29.9
Obese BMI
30-39.9
normal ranges of body fat
men: 13-21%; women: 23-31%
visceral fat
fat stored within the abdominal cavity in association with the internal abdominal organs
central obesity
excess fat around the trunk of the body; apple shaped; more common in men; increased risk of cardiovascular diseases, diabetes, hypertension, and some cancers
lower body fat
pear shape; more common in women
waist circumference
can predict risk of central obesity, heart disease, and diabetes; women > 35 inches, men > 40 inches