Macrominerals (Calcium, Phosphorus, Sodium, Chloride, and Potassium)

Question 1

Functions of Calcium

Answer 1

required for: vision, muscle contraction, nerve conduction, blood clotting, cell division, and the action of many enzymes and proteins

Question 2

How is calcium absorbed?

Answer 2

absorbed through:

• ATP regulated saturable carrier mediated mechanism that is vitamin D regulated
• paracellular (between intestinal cells) calcium transport which is nonsaturable

Question 3

What factors INCREASE calcium absorption?

Answer 3

vitamin D adequacy, calcium deficiency, phosphorus deficiency, pregnancy, lactation, increase PTC, growth, food/lactose

Question 4

What factors DECREASE calcium absorption

Answer 4

vitamin D deficiency, aging, menopause, decreased stomacy acid, rapid intestinal transit time, decreased estrogen

Question 5

How are blood calcium levels regulated?

Answer 5

When blood calcium levels drop, PTH is released from the PTH gland (activates Vitamin D in the kidney)

Active Vitamin D INCREASES:

• calcium absorption in the intestine
• calcium breakdown from bone
• reabsorption from kidney

Question 6

What happens if blood calcium levels get too high?

Answer 6

The thyroid gland releases calcitonin

calcitonin decreases

• calcium absorption
• calcium breakdown from bone

Question 7

What can increase urinary calcium excretion?

Answer 7

calcium, sodium, high protein diets, caffeine, high phosphorus intake, high zinc and magnesium intake

Question 8

What factors prevent osteoporosis?

Answer 8

• adequate diet (vitamin D and calcium intake)

- weight bearing exercise + adequate estrogen

Question 9

What factors increase risk for osteoporosis?

Answer 9

smoking, alcohol, poor diet, genetics, low body weight, caucasian and Asian background, female, past history of fractures, caffeine, medication use (steroids), menopause, loss of estrogen, and heavy sodium intake

Question 10

Functions of phosphorus

Answer 10

• involved in skeletal formation with calcium
• plays role in cell membrane formation (phospholipid membranes)
• Helps keep acid/base balance in the body

Question 11

Type of food contributing greatest to sodium intake

Answer 11

processed food

Question 12

Type of food associated with dietary potassium

Answer 12

unprocessed foods

Question 13

Relationship between sodium and hypertension

Answer 13

increased sodium increases blood pressure

Question 14

Relationship between potassium and hypertension

Answer 14

increased potassium decreases blood pressure

Question 15

Primary functions of Sodium

Answer 15

Ensures:

• adequate blood volume
• adequate arterial pressure
• adequate organ perfusion

helps with nerve transmission, impulse conduction, and muscle contraction

Question 16

Primary functions of Potassium

Answer 16

• Contractility of smooth, cardiac, and skeletal muscles
• excitability of nerve tissue
• maintaining pH and electrolyte balance

Question 17

How does renin-angiotensin-aldosterone system control blood volume?

Answer 17

Renin is converted to Angiotensin II

• low blood volume stimulates kidney to make renin
• renin converts angiotensinogen to angiotensin I
• angiotensin I converted to angiotensin II by ACE enzymes

Angiotensin II

• increases sympathetic nervous activity
• constricts blood vessels
• increases renal tubule reabsorption of Na- and Cl-
• stimulates ADH (anti-diuretic hormon) secretion from pituitary gland

Question 18

Dietary approach to manage hypertension

Answer 18

DASH diet (lowers blood pressure)

• foods rich in fruits, vegetables, whole grains, and low-fat dairy foods
• limited sugar-sweetened foods, red meats, and added fats