Ch. 12 Major Minerals

Question 1

Define bioavailability.

Answer 1

Rate and extent to which a nutrient is absorbed

Question 2

Explain the relationship between phytic acid, oxalic acid, and mineral bioavailability.

Answer 2

Phytic acid binds zinc, iron, calcium, magnesium, and copper.

Oxalic acid binds with calcium.

These are just 2 of the many factors that affect bioavailability of minerals.

Question 3

Identify food sources of phytic and oxalic acid.

Answer 3

Phytic acid: legumes, grains

Oxalic acid: rhubarb, spinach, chocolate

Question 4

Discuss terminology used for minerals. What are some general characteristics of minerals? What’s the difference between a major and trace mineral? Which minerals fall into which category?

Answer 4

Characteristics: inorganic elements, essential to nutrition of humans, essential to body function.

Fxn:

• Fluid/electrolyte balance
• Structural components (ex. bones)
• Help chemical reactions take place in cells
• Help skeletal/smooth muscles contract

Major minerals vs Trace Minerals:

• -major minerals are found in larger amounts in the body
• -trace minerals are found in smaller amounts in the body

Major Minerals:
–calcium, phosphorus, potassium, sulfur, sodium, chloride, magnesium

Trace Minerals:
–iron, zinc, copper, manganese, iodine, selenium

Question 5

Potassium

Answer 5

Fxn: maintain fluid balance, blood pressure regulation, transmit nerve impulses, muscle contractions
**opposes Na in fluid balance

Recommendations:

• -(AI) 4700mg/day
• -> low K = high BP

Deficiency: rare in healthy people

• Hypokalemia: low circulating K+ concentrations
• ->neuromuscular (muscle weakness, muscle fatigue), GI, and CV manifestations
• ->impaired kidney’s ability to concentrate the urine
• ->metabolic alkalosis (rise in blood pH)

Toxicity: rare for consuming too much food

• -Kidney disease
• -Tachycardia

Food Sources:
–rich (unprocessed): oranges, bananas, potatoes, tomatoes (fresh foods)

Question 6

Phosphorus

Answer 6

Fxn:

• regulator of energy metabolism (source of phosphate…ATP)
• major component of bones and teeth (second only to calcium in bones and teeth as far as content)
• genetic material (DNA and RNA)

Deficiency: rare in American diet

Toxicity: rare from excess dietary intake

• -excess can lower calcium in blood –> bone loss
• -kidney disease

Food Sources: meat, fish, poultry, milk, eggs

Question 7

Calcium

Answer 7

Fxn: build bones
–> Ca in bones= Calcium bank

Recommendations:

• -(AI) adolescents: 1300 mg/day
• -(AI) adults (ages 19-30): 1000 mg/day
• -TUL: 2500 mg/day

Deficiency:
–osteoporosis (at risk: elderly, women after menopause)

Toxicity:

• -hypercalcemia
• ->primarily results in kidney problems, can result in calcification of other organs in body

Food Sources: dairy/milk products, small fish with bones (ex: anchovies, sardines), several vegetables

Question 8

Sodium

Answer 8

Fxn: maintain fluid balance, regulate blood pressure, assist in nerve impulse transmission

Recommendations:

• -2300 mg/d
• -1500 mg/d for diabetics, people with high blood pressure

Deficiency: rare in our American diet

Toxicity: Yes. Edema, increased Ca excretion, and high blood pressure.

Food sources: processed foods (about 75% of sodium in diet), table salt (about 15% of sodium in diet)

Question 9

What is table salt?

Answer 9

It’s what we think of when we think of salt.

NaCl

Responsible for about 15% of sodium in diet

Question 10

What is sodium/salt sensitivity?

Answer 10

Response to a high salt intake with an increase in blood pressure or to a low intake with a decrease in blood pressure

Question 11

How is sodium/salt sensitivity determined?

Answer 11

Genetics, age, chronic diseases, high blood pressure

Question 12

Who is likely to be sodium/salt sensitive?

Answer 12

People whose parents had:
HTN
Chronic kidney diseases
Diabetes
African Americans
Overweight/obese
People over 50

Question 13

Where do you find sodium on the food label?

Answer 13

Under the sodium category

Question 14

How can you reduce your sodium intake?

Answer 14

Use fresh foods

Eliminate/decrease salt used in cooking

Add flavor with herbs and spices

Avoid using salt shaker

Read food labels

Question 15

What’s a calcium bank?

Answer 15

Calcium in bones=calcium bank

Question 16

How is blood calcium regulated?

Answer 16

Calcium balance:

• -if blood calcium too high –> excretion
• -if blood calcium too low –> breaking down bone

If blood calcium also too low:

• -intestines absorb more calcium (unless deficient in vitamin D)
• -bones release more calcium
• -kidneys excrete less calcium

Question 17

What factors enhance calcium absorption?

Answer 17

vitamin D

Lactose

Question 18

What factors inhibit calcium absorption?

Answer 18

vitamin D deficiency

High phosphorus intake

Phytates

Oxalates

Question 19

What factors enhance excretion of calcium?

Answer 19

ETOH

Caffeine

Question 20

What is potassium chloride?

Answer 20

• Used as a salt substitute
• Provides salty flavor and helps extend shelf-life
• Known to posses a bitter/metallic aftertaste
• Health risks involved with high intakes

Question 21

Sodium Sensitive vs. Insensitive HTN

Answer 21

Sodium Sensitivity:
-Strong dose-dependent response in BP (high dose=high BP increase)
-Most likely to be sodium sensitive…
•Familial history of HTN
•Chronic kidney disease
•African Americans
•Obese
•People over 50 

Sodium Insensitive HTN:
-Don’t necessarily respond to changes in sodium (may have other reasons for their HTN)