nutrition exam 4 part 2

Question 0

Calcium functions

Answer 0

Provides structure for bones and teeth
Assists with acid−base balance
Transmission of nerve impulses
Assists in muscle contraction
Maintains healthy blood pressure

Question 1

Nutrients for Bone health

Answer 1

Calcium is the most recognized nutrient associated with bone health
Also essential for bone health:
◦Vitamins D and K
◦Phosphorus
◦Magnesium
◦Fluoride

Question 2

Calcium

Answer 2

Calcium absorption
◦Is enhanced in an acid environment
◦Requires 1,25-dihydroxyvitamin D
Bioavailability: body’s ability to absorb and utilize calcium depends on
◦Individual’s age and calcium need
◦Dietary calcium and vitamin D
◦Binding factors (phytates, oxalates) in foods

Question 3

Excess calcium

Answer 3

Excess dietary calcium is excreted in feces
Mineral imbalances from supplements
Hypercalcemia (high blood calcium)
◦Cause: cancer or parathyroid hormone (PTH) overproduction
◦Symptoms: fatigue, appetite loss, constipation, mental confusion, calcium deposits in soft tissues

Question 4

Calcium deficiency

Answer 4

Osteoporosis from long-term calcium deficiency
Hypocalcemia (low blood calcium)
◦Causes: kidney disease, vitamin D deficiency, or diseases that inhibit the production of PTH
◦Symptoms: muscle spasms and convulsions

Question 5

Vitamin D

Answer 5

Fat-soluble vitamin
◦Excess is stored in liver, adipose tissue
Can be synthesized by the body from exposure to UV rays from the sun
Considered a hormone
◦Synthesized in one location and regulates activities in other parts of the body

Question 6

Functions of vitamin D

Answer 6

Regulates blood calcium levels
◦Regulates Ca and P absorption
Stimulates osteoclasts
◦When Ca is needed elsewhere in the body
Required for bone calcification

Question 7

Adequacy of vitamin D

Answer 7

Recommendations assume sun exposure is inadequate
Factors that impact synthesis in skin
◦Darker skin
◦Melanin reduces the penetration of sunlight
◦Inadequate sun in the winter
◦Latitude of more than 40°N or more than 40°S
◦People >65 years
◦Reduced skin thickness
◦Obesity
◦Negative effect on metabolism and storage
Other considerations
◦Sunscreen

Question 8

Sources of vitamin D

Answer 8

Ergocalciferol (D2)
◦Plants, supplements
Cholecalciferol (D3)
◦Animal foods, sun
Most foods contain very little vitamin D
◦Primary source: fortified foods (e.g. milk*)
◦Natural sources: cod liver oil & fatty fish

Question 9

Too much vitamin D

Answer 9

◦Results in hypercalcemia

Question 10

Not enough vitamin D

Answer 10

◦Loss of bone mass
◦From fat malabsorption
◦Softening of bones
◦Rickets (children)
◦Osteomalacia (adults): softening of bone
Medications alter vitamin D metabolism and activity
◦Glucocorticoids, phenobarbital
Vitamin D impacts ability to absorb calcium

Question 11

Vitamin K

Answer 11

Fat-soluble vitamin, stored in the liver
Phylloquinone
◦Plant form of vitamin K
Menaquinone
◦Animal form of vitamin K produced by bacteria in the large intestine

Question 12

“Gla” protein production

Answer 12

◦Osteocalcin:
◦secreted by osteoblasts (bone remodeling)
◦Matrix Gla protein:
◦in protein matrix of bone, cartilage, blood vessel walls, soft tissues

Question 13

Sources of vitamin K

Answer 13

◦Synthesized by bacteria in the large intestine

◦Green leafy vegetables, vegetable oils

Question 14

Vitamin k consumption

Answer 14

What if you consume too much?
◦No known side effects from large quantities
What if you don’t consume enough?
◦Reduced blood clotting, excessive bleeding
◦Fat malabsorption (celiac disease, Crohn’s disease, and cystic fibrosis)

Question 15

Phosphorous

Answer 15

Phosphorus
Phosphorus is the major intracellular negatively charged electrolyte
An essential component of all cells, found in both plants and animals

Question 16

Functions of phosphorus

Answer 16

◦Critical in bone formation
◦Required for proper fluid balance
◦Component of ATP, DNA, membranes

Question 17

Sources of phosphorous

Answer 17

High in protein-containing foods such as milk, meats, eggs
In processed foods as a food additive: smoothness, binding, and moisture retention
In soft drinks as phosphoric acid (milk-displacement effect) : drink too much soda, not enough milk, not enough calcium

Question 18

Too much phosphorous

Answer 18

◦Excessive vitamin D supplements or phosphorus-containing antacids can cause high phosphorus levels (muscle spasms and convulsions)

Question 19

Not enough phosphorous

Answer 19

◦Deficiencies are rare in healthy adults

◦Can occur in alcohol abuse, premature infants, and elderly people with poor diets

Question 20

Magnesium

Answer 20

Kidneys regulate blood magnesium levels

Question 21

Functions of magnesium

Answer 21

◦Mineral found in bone structure
◦Cofactor for over 300 enzyme systems
◦Required for ATP, DNA, and proteins
◦Supports vitamin D metabolism, muscle contraction, and blood clotting

Question 22

Sources of magnesium

Answer 22

◦Green leafy vegetables, whole grains, seeds, nuts, seafood, beans, some dairy products
◦Dietary protein enhances absorption and retention

Question 23

Too much magnesium

Answer 23

◦Excess supplements cause diarrhea, nausea, cramps, dehydration, acid–base imbalances
◦Hypermagnesemia occurs in individuals with impaired kidney function (antacid)

Question 24

Too little magnesium

Answer 24

◦Hypomagnesemia: results in hypocalcemia; associated with osteoporosis, heart disease, high blood pressure, type 2 diabetes

Question 25

Functions of fluoride

Answer 25

Trace mineral Stored in teeth and bones ◦Develop and maintain teeth and bones ◦Combines with calcium and phosphorus to protect teeth from bacteria

Question 26

Fluoride toxicity and deficiency

Answer 26

too much? ◦Fluorosis (excess fluoride) increases the protein content of tooth enamel and makes teeth porous; teeth become stained and pitted don't consume enough? ◦ Dental caries (cavities)