Dietary calcium

Question 1

1. Describe the role of calcium in bone health and identify at least two stages of life when inadequate dietary calcium may lead to increased risk of metabolic bone disease.

A. how much where is it stored how often turned over?
B. physiology, absorption, what helps it and hurts its absorbtion
C.critical times in development or who is at risk?

Answer 1

A. Most abundant mineral in the body; average adult male contains ~1200-1500 g, 99% is in the skeleton;
bone Ca turns over ~ every 5-6 yr

B. Metabolism and Homeostasis:

• PTH, 1,25(OH)2D, and Calcitonin;
• Serum Ca maintained in very tight range at all costs
• Absorbed in duodenum, jejunum, ileum; Active transport occurs in the duodenum
• Enhancers of Absorption: Vitamin D; physiological demand; lactose; Gastric Acidity; protein
• Impair Absorption: Vitamin D deficiency, Steatorrhea, Oxalic and Phytic Acid, Gastric Alkalinity

C. Critical times in the life cycle for Ca++ intake:

• Premature infants: 3rd trimester period of rapid bone mineral accretion; preterm infants at risk for “osteopenia of prematurity”
• Adolescence: hormonal milieu during puberty favors calcium absorption and bone deposition; ~ 50% of total adult bone mineral mass is accrued during adolescence.
• peri-menopause: high requirements, increased losses, and frequently with low intake
• Pregnancy and lactation: women return to eucalcemia post pregnancy
• Post-Bariatric Surgery

Question 2

2. Identify dietary and lifestyle factors that may adversely impact bone health.

Answer 2

A. Nutritional/dietary factors:
a )low calcium intake: low dairy
d) low Vitamin D
f) high Sodium intake – high Na++ intake → increased urine Ca++ excretion

B. Behaviors/lifestyle

b) Smoking
c) Alcohol - depresses osteoblasts

Question 3

3. Discuss strategies to optimize bone density, including “whole diet” approaches, lifestyle modification, and supplementation.

Answer 3

1. Weight bearing activity
2. Maintain good calcium intake over lifetime
3. Avoid excessive alcohol and tobacco
4. healthy diet DASH diet: .
5. Supplement (only) when necessary
   - Ca supplementation (w/o Vit D) associated with increased risk of myocardial infarction

Question 4

4. Identify food sources of calcium; discuss role of supplements for bone health.

Answer 4

Dietary sources

• Dairy products contribute ~70% of Ca diet
• Tofu
• Salmon, canned, w/ bones,
• Soy milk, fortified,
• Collard greens,
• Beans,

Supplements
Ca-Carbonate: 
- best absorbed w/ meals; has least lead, esp manufactured (vs bone meal, oyster shell, dolomite);
CaCitrate: 
- better absorbed w/o meals

Question 5

5. Describe quick assessment of patient’s risk for low bone mineral density (dietary, behavioral, and additional factors).

Answer 5

• low calcium intake
• smoking/ alcohol
• limited weight bearing activity
• BMI
• family hx, ethnicity
• menstrual history
• medical hx, meds