Vitamins and Dietary Supplements Flashcards
What are vitamins?
Vitamins are organic compounds that people need in small quantities. Most vitamins need to come from food because the body either does not produce them or produces very little.
- Not an energy source
- Individual units rather than long chains
- Essential for normal functioning, growth, and maintenance of the body
Vitamin Content in food depend on (3)? How is this different in plants (4)?
- Source
- Packaging and storage
- Levels of processing
- For plants: Sunlight, moisture, growing conditions, maturity at harvest
Which Vitamins are Fat Soluble, and which are water soluble?
Fat Soluble A-E-D-K
Water Soluble B-C
How are fat-soluble (AEDK) vitamins and water-soluble vitamins(BC) digested?
Fat Soluble
In the mouth to break foods into smaller pieces to release vitamins.
In the stomach, digestive enzymes work to release vitamins from food.
Bile is required to emulsify fat and aid digestion and absorption.
Water Soluble
In the mouth to break down food to release vitamins.
In the stomach, digestive enzymes work to release vitamins from food.
How are fat-soluble (AEDK) vitamins and water-soluble vitamins(BC) absorbed?
Fat Soluble
Occurs in the small intestine. Inside the intestinal cell, they are packaged in chylomicrons and move to lymphatic circulation before being transported by the blood.
Water soluble
Occurs in small intestine, similar to glucose and amino acids, directly into blood.
How are fat-soluble (AEDK) vitamins and water-soluble vitamins(BC) transported?
Fat Soluble
Transported by protein carriers (lipoprotein) through watery compartments of the body
Water Soluble
Travel freely in watery compartments of the body
How are fat-soluble (AEDK) vitamins and water-soluble vitamins(BC) stored?
FAT SOLUBLE
Liver or fatty tissue such as adipose tissue
Provitamins must be activated for example beta carotene to vitamin A
Water soluble
Not stored in the body, with exception to vitamin B12 in the liver
What is the dietary requirement difference in fat-soluble and water-soluble vitamins?
Fat Soluble
Daily intake is not required because of body storage
Water soluble
Regular intake is required and varies by vitamin because the body does not usually store large amounts.
Which type of vitamin is vulnerable to cooking?
Water-soluble vitamins are Vulnerable to cooking
Boiling 35-60%
Frying 7-10%
What are the active forms (retinoids) and precursors of Vitamin A?
Active forms (retinoids)
Retinol, Retinal, Retinoic Acid
Found in animal source
Precursors (Carotenoids) Plant Pigments Act as antioxidant Beta-carotene and lycopene Body absorbs 20 - 40% of carotenoids, dietary fat, protein, vitamin E, quick cooking enhance absorption
Where is Vitamin A stored?
Liver stores 90% of vitamin A
Can store up to a year’s supply
Retinol Binding protein carries retinol released by the liver
What is the function of Vitamin A?
Vision: changes incoming light to visual images, forms rhodopsin which signals electrical information to the brain.
Bone Health: Needed for bone growth and remodelling
Reproduction: Sperm production, female fertility
Immune Function
What is the source of Vitamin A? RDI?
Animal source 70-90%: Retinoids
Plant Source 9-22%: provitamin A carotenoids
In small interesting carotenoids → Retinol → Transported by chylomicrons to the lymphatic system → storage in liver
Dietary intake: 800-680 microgram retinol for men or women
What is vitamin D? What are the two different type
Similar to hormone
D2 ergocalciferol, cheap
D3 cholecalciferol, more effective
What is the Function of Vitamin D?
Functions: Regulation of osteoblast and osteoclast equilibrium Regulation of cell differentiation Prevention of cancer cell division Anti Inflammatory properties Regulation of insulin production
What is the source of Vitamin D?
Provitamin D3 in the skin (a cholesterol) became active through UV light
Vitamin D3 and D2 are absorbed with fats, incorporated with chylomicrons to the lymphatic system to the liver, where it is stored as calcidiol
Parathyroid hormone activates calcidiol to calcitriol.
What medical illnesses are associated with vitamin D Malnutrition?
Rickets and osteomalacia and osteoporosis
Hypercalcemia
Characteristics of Vitamin E? Absorption, Storage, Function, RDI, Sources?
Alpha-tocopherol Absorption: GI tract (20-80%) Storage: Adipose tissue Functions: Antioxidant RDA (15mg/day) Sources: Nuts, seeds, vegetable oil, whole grain, wheat germ oil, fruit, vegetables. Deficiency and toxicity are rare
Characteristics of Vitamin K? Absorption, Storage, Function, RDI, Sources?
Quinones Absorption GI Tract Storage Liver Functions: Promotes Blood clotting RDA 120 - 90 Sources: leafy greens and intestinal bacteria Deficiencies and toxicities are rare
What is the function of Vitamin B12 (Cobalamin)?
Functions:
DNA and red blood cell synthesis
Maintains myelin sheath around nerves
How is Vitamin B12 absorbed?
R-protein from salivary glands
Intrinsic Factor from stomach cells
B12+R-protein complex in the stomach
Pancreatic enzymes degrade R-protein in the small intestine: B12 is released and can bind with the intrinsic factor (B12+IF complex)
B12+IF complex binds to intestinal cell receptor and absorbed in the ileum
Requires adequate stomach acid and intrinsic factor
The only water-soluble vitamin that can be stored in the liver
What are the sources of Vitamin B12?
Only animal foods
Animals obtain it from bacteria on their food or from their intestinal bacteria
Fortified Foods, such as cereal, milk substitutes and some soy products.
How is long is Vitamin B12 stored in the body?
Enough Vitamin B12 to last 2 years
Symptoms of deficiency may not appear till 12 years later
Most deficiency is caused by inadequate intake or impaired absorption
What is Pernicious Anemia?
A form of anaemia from an autoimmune disorder that damages cells lining the stomach (IF reduced) and inhibits vitamin B12 absorption
Characteristics of Vitamin C? Function, Source, RDI, Deficiency?
Function Antioxidant and reducing agent Collagen function Enhances absorption of nonheme iron in plant foods Source: 75mg/day Fruits and vegetables Deficiency: Scurvy: reopening of wounds, bleeding gums, bone pain
Which population require dietary supplements?
Women of childbearing age who may become pregnant Pregnant and breastfeeding women Women with heavy menstrual losses Children Infants People with severe food restrictions Strict Vegetarians Old people
What is megadosing? Where is it used? What is the drawback?
Megadoses High levels of supplementation Uses in limited and specific cases: example malabsorption syndromes such as pernicious anemia Achieving the optimal nutrition level Drawbacks of megadoses Can act as a drug Can create deficits of other nutrients Can interfere with absorption of others
