dietary calcium

Question 1

Ca is the most abundant mineral in the body; average adult male contains _____

Answer 1

~1200-1500 g (1.7% of total body weight); 99% is in the skeleton;

Question 2

Key hormonal regulators that effect Ca Homeostasis are:

Answer 2

PTH, 1,25(OH)2D, and Calcitonin

Question 3

Absorption of calcium occurs passively in duodenum, jejunum, ileum; Active transport (effected by habitual intake via vitamin D) occurs in the ______

Answer 3

duodenum

Question 4

What are the Enhancers of Ca Absorption:

Answer 4

Vitamin D; 
physiological demand; 
lactose; 
Gastric Acidity; 
protein

Question 5

What can Impair Ca Absorption:

Answer 5

Vitamin D deficiency,
Steatorrhea,
Oxalic and Phytic Acid,
Gastric Alkalinity

Question 6

What are Critical times in the life cycle for Ca++ intake:

Answer 6

a. Premature infants: 3rd trimester period of rapid bone mineral accretion; preterm infants at risk for “osteopenia of prematurity”
b. Adolescence: hormonal milieu during puberty favors calcium absorption and bone deposition; ~ 50% of total adult bone mineral mass is accrued during adolescence.
c. After skeletal “maturity,” esp. peri-menopause: associated with relatively high requirements, increased losses, and frequently with low intake
d. Pregnancy and lactation: physiologic responses compensate for increased Ca demand so dietary requirements are not increased
e. Post-Bariatric Surgery

Question 7

60-80% of variance in peak bone mass attributable to ____ .

Answer 7

heritable factors

Question 8

what is the target vitamin D serum level to reap skeletal benefits?

Answer 8

Target serum 25(OH)D level >30 ng/ml

Question 9

why is Vitamin K important in bone health

Answer 9

co-factor w/ osteocalcin & other bone forming proteins

Question 10

How does Sodium intake affect bone health?

Answer 10

high Na++ intake -> increased urine Ca++ excretion

Question 11

What are Behaviors/lifestyle that affect bone health

Answer 11

a) Exercise: weight-bearing;
- muscle mass directly related to bone mass
- Mechano-sensors in bone stimulate osteoblasts
b) Smoking
c) Alcohol - depresses osteoblasts

Question 12

what is the RDA for Ca in Men 51-70 yr

Answer 12

1000 mg/d

Question 13

what is the RDA for Ca in Women: 51-70 yr

Answer 13

1200 mg/d

Question 14

RDA of Ca in Children 1-3 yr?

Answer 14

700 mg/d

Question 15

RDA for Ca in 4-8 year olds?

Answer 15

100 mg/d

Question 16

RDA for Ca in Adolescents (9-18 yr)?

Answer 16

1300 mg/d;

Question 17

Results of meta-analysis supports benefits of calcium supplementation ± Vit D supplementation on fracture reduction and reduced bone loss in Which subjects?

Answer 17

> 50 yr.

Question 18

Ca supplementation (w/o Vit D) associated with increased risk of ______

Answer 18

myocardial infarction