| Vitamin A types and sources | 1 Retinoids
- retinol, retinal, retinoic acid
animal foods, milk fortification
2 Carotenoids
- beta-carotene
plants
vitamin A precursor |
| Vitamin A Functions | 1 Visual pigment (rhodopsin)
2 Maintenance of epithelial cells (keratin protein synthesis)
3 Bone and Immune System Development |
| Vitamin D
1 Dietary sources
2 Skin | 1 animal foods, fortified milk
2 cholesterol + sunlight
- Vitamin D3
- 5-10 minutes, arms and legs, mid-day sun
Liver & Kidney for activation |
| Vitamin D: Functions | Helps regulate blood calcium levels
When blood calcium levels are low, vitamin D (and other hormones):
1 Increases dietary calcium absorption
2 Decreases urinary calcium excretion
3 Increases bone calcium mobilization |
| Vitamin D: Deficiency will cause __ | 1 Rickets - bone deformities in children
2 Osteomalacia
- weak bones due to low calcium content
- Vitamin D deficiency
- Calcium deficiency
- multiple pregnancies |
| Vitamin D: Toxicity
5 times the RDA chronically: __ | calcification of soft tissue
toxicity due to excessive vitamin supplementation |
| Calcium Functions | 1 Bone Structure (99%)
2 Regulator of Metabolism (1%)
- nerve impulse transmission
- muscle contraction
- blood clotting
3 Regulation of Blood Calcium |
| abnormal muscle cramping
nerve irritation | hypocalcemia & hypercalcemia |
| Brittle, weak bones due to loss of total bone mass (minerals and protein) | Osteoporosis |
| Osteoporosis risk factors | 1 Genetics
Caucasian > Asian > Blacks
2 Chronic Calcium Deficiency
3 Lack of Exercise
4 Gender
- associated with declines in estrogen production
- post-menopause
- anorexia, female athletes |
| Prevention of Osteoporosis | 1 Exercise
2 Dietary Calcium
300 mg/d from plant sources
300 mg/d from each serving of dairy |
| Calcium Supplements | 1 Calcium carbonate - cheap
2 Calcium citrate/malate (CCM) - expensive
3 Adequate amounts of vitamin D
4 Hormonal replacement in high risk women |
| Folic acid
1 DRI (RDA): 1998 __
2 Typical folate intake
3 FUNCTIONS | 1 600 ug/d pregnancy (400)
2) 200 ug/d
3 “single carbon metabolism”
- DNA synthesis (cell division)
- other reactions |
| 1 Functions
“single carbon metabolism”
2 Typical folate intake
3 DRI (RDA): 1998 | 1 Folic Acid
2) 200 ug/d
3 600 ug/d pregnancy (400) |
| Folic Acid Deficiency leads to __ | 1 Megaloblastic Anemia
2 Elevated blood homocysteine
3 Neural Tube Defects |
| 1 large abnormal red blood cells
2 CHD risk factor | 1 Megaloblastic Anemia
2 Elevated blood homocysteine |
| Vitamin B-12
1 DRI (1998):
2 Dietary sources
3 Function: __ | 1) 2.4 ug/d (old 2 ug/d)
2 animal foods
fortified cereals
3 “single carbon isomerization”
- synthesis of DNA (folate interaction)
- nerve fiber sheath synthesis |
| 1 Vitamin B-12 Deficiency __
2 Digestion and Absorption | 1 Pernicious Anemia
- megaloblastic anemia
- nerve injury
- peripheral weakness and numbness
- progressive degeneration to death
- concern among the elderly
2 Requires functioning stomach
“intrinsic factor protein”
acid production |
