Vitamins
Vitamin A toxicity
Toxicity is a real concern
Most toxic form: Preformed vitamin A (from animal sources, fortified foods, and supplements)
Children are most vulnerable
Risk: Bone defects
Match these:
1. Affects children, causes bones bend
2. Reduced ability to activate and make vitamin D
3. Fractures often result in calcium loss from bones
4. Affects adults, poor mineralization causes soft, brittle bones
With these:
• Osteomalacia
• Osteoporosis
• Rickets
• The elderly
1. Affects children, causes bones bend = Rickets
2. Reduced ability to activate and make vitamin D = The elderly
3. Fractures often result from calcium loss from bones = Osteoporosis
4. Affects adults, poor mineralization causes soft, brittle bones = Osteomalacia
Vitamin K roles in the body
Primary action: blood clotting
− Prothrombin
• Metabolism of bone proteins
− Osteocalcin
− Low bone density
• Other possible roles of vitamin K in the body
blindness, kidney failure, cardiovascular disease, neuorological disorders
Biotin B7
Coenzyme that carries activated carbon dioxide
− Critical in TCA cycle
▪ Delivers carbon to pyruvate to form oxaloacetate
− Gluconeogenesis and fatty acid synthesis
− Breakdown of fatty acids and amino acids
• Widespread in food sources
• Toxicity
− No UL
- Vital role in metabolism
- Breaks down carbs, fats, and proteins to produce energy
- RDA - not established, but the institute of medicine recommends 30mg a day
- 2 primary sources -> egg yolk, organ meats, nut seeds, some vegetables
Vitamin D roles
Active form is a hormone
Essential for making and maintaining bones
Assists in absorption of calcium and phosphorus
Brain and nerve cells
Protects against cognitive decline
Regulates adipose cells to influence obesity development
Almost 10% of Americans are vitamin D deficient
Vitamin E as an antioxidant
Two subgroups: tocopherols and tocotrienols
− Each contains four compounds: alpha, beta, gamma, and
delta
▪ Position of methyl group
− Only alpha-tocopherol maintained in the body
• Antioxidant
− Stops chain reaction of free radicals
▪ Protects cells and their membranes
▪ Heart disease and protection of LDLs
Vitamin K deficiency
Deficiency
− Primary: Inadequate dietary intake
▪ Rare
− Secondary: Antibodies kills off vitamin K-producing bacteria
▪ Failure of bile production
− Infants: Sterile gut, no vitamin K-producing bacteria
What intolerance does type 2 diabetes have
Carbohydrates intolerance - can't tplerate carbs
List 4 factors that contribute to the deficiency
Dark skin, breastfeeding without supplementation, lack of sunlight, not consuming fortified milk
A vitamin D deficiency subsequently causes a calcium deficiency.
Vitamin E deficiency
Primary deficiency is rare
• Secondary deficiency
− Fat malabsorption
• Effects of deficiency
− Red blood cells break open
▪ Erythrocyte hemolysis
− Neuromuscular dysfunction
• Other conditions and vitamin E treatment
Vitamin K toxicity
Toxicity
− Not common
▪ No adverse effects with high intakes
− No UL
− High doses can reduce effectiveness of anticoagulant drugs
What happens in the muscle with type 2 diabetes
When insulin tries to go into the muscle, there is a blockage, so Glut4 can't go up and be used for ATP
Vitamin D deficiency
Production of calbindin slows when deficient. May result in:
• Rickets
− Rare in U.S. but can affect more than half of the children
in some countries
− Bones fail to calcify normally
• Osteomalacia
− Bones become soft, flexible, brittle, and deformed
• Osteoporosis
− Can result in fractures
• Deficiency especially likely in elderly
Vitamin E toxicity
Liver regulates vitamin E concentrations
− Toxicity is rare
• UL is 65 times greater than recommended intake for adults
• Extremely high doses of vitamin E
− May interfere with vitamin K activity
− Hemorrhage
Vitamin D toxicity
Most likely of the vitamins to have toxic effects
− When consumed in excessive amounts
• Raises blood calcium concentrations
− Forms stones in soft tissues
− May harden blood vessels
− Can cause death
• Supplements
• Vitamin D found in multivitamin-mineral supplements,
high-dose single supplements
• Commonly available
• More effective than vitamin D2
Vitamin E reccomendations
The RDA is based on the alpha-tocopherol form only.
• Vitamin E is widespread in foods. Much of dietary vitamin E
comes from vegetable oils or foods containing them.
• Vitamin E is destroyed by oxidation and heat, therefore
fresh foods are preferable sources