UNIT 3 SEMINAR HW 205

Unit Outcomes  Understand the purpose and benefits of fat soluble vitamins.  Be able to identify Food Sources, Deficiencies, RDA/Dosage and Forms of the fat soluble vitamins.  Understand the Safety/Precautions, and Spectrum of Age Issues, for each of the vitamins discussed.  Course Outcome: Identify the most commonly used vitamins, their benefits, dosage, precautions and contraindications, as well as their recommended daily value and optimal forms of ingestion.

Office of Dietary Supplements

Fat Soluble Vitamins  What are fat soluble vitamins and why are they important?  A, D, E, K  Closely associated with body lipids  Functions usually related to structural activities

Vitamin A  Retinol, retinal, retinoic acid  Insoluble in water, relatively stable in cooking  Preformed vitamin A – natural form, found in animal sources  Liver  Kidneys, lungs, adipose  Fat portion of dairy foods, egg yolk, fish

Vitamin A (continued)  Provitamin A (Beta Carotene) – carotenoids, produced by plants  Eaten by animals and converted to Vitamin A  Humans can eat the animal sources or the plant sources and it will be converted in the body  Yellow and orange pigments in vegetables and fruits Carrots, broccoli, spinach, cantaloupe tomato juice, apricots Red palm oil

Vitamin A: Absorption  What is needed?  Bile salts – help transport Vit A and associated fats into intestinal wall for further breakdown Bile duct obstructions can lead to inhibited Vit A absorption  Pancreatic Lipase – fat splitting enzyme for hydrolysis of emulsions containing Vit A.  Dietary Fat – At least 10g fat is needed per day to stimulate release of bile salts

Vitamin A: Transport & Absorption  Beta carotene and Vitamin A are transported along with fat  Intestinal mucosa Retinol and carotenoids are absorbed and enter the bloodstream via the lymph system. Are carried to the liver and stored or distributed to tissues Liver stores about 85% of body’s Vit A, and can prevent deficiency for up to 4 years!

Vitamin A: Functions  Vision  Integrity of body coverings and linings  Growth  Immunity  Reproductive function

Vitamin A: RDA & Signs of Toxicity  Men 19+: 900mcg  Women 19+: 700mcg  Pregnancy: 770mcg  Lactation: 1300mcg  Signs of Toxicity:  Vomiting  Headache  Joint pain  Thickening of long bones  Hair Loss, jaundice, liver injury

Vitamin D  Not actually a vitamin!  A Prohormone  Functions as a hormone  A sterol with precursor 7-dehydrocholesterol  Two forms:  Ergocalciferol (D2)  Cholcalciferol (D3) Made from ultraviolet rays acting on 7-dehydrocholesterol Found naturally in fish liver oils Fortifed dairy, cereals, juice

Vitamin D: Absorption  Absorbed in small intestine  Malabsorption occurs with celiac disease, cystic fibrosis, Crohn’s disease, or Pancreatic insufficiency  Synthesis:  Skin or dietary sources  Travels to liver and converted to 25- hydroxycholecalciferol  Travels to kidneys and combines with an enzyme to make calcitriol (its active form)

Vitamin D: Functions  Controls calcium levels and phosphorus levels in bone and blood  Optimum calcium and vit D intake levels promote maintenance of blood calcium and phosphorus, and prevent mobilization of parathyroid hormone and bone calcium  Also plays a roll in cell growth rate and muscle metabolism (and strength and contraction)  Also improves immune function, insulin levels, and blood pressure

Vitamin D: RDA and Toxicity  Age 6mo-50yrs: 200IU  Age 51-70yrs: 400IU  Age 71+: 600IU  Controversial:  Many experts recommend 1000IU per day to prevent deficiency  Symptoms of Toxicity:  Progressive weakness, bone pain, hypercalcemia  For children: failure to thrive, calcium deposits in soft tissue

Vitamin D: Sources and Deficiency  Sources:  Fortified foods  Sunlight  D2 only in yeast  D3 in fish liver oils, small amount in mackerel and salmon, and egg yolks  Signs of Deficiency:  Poor calcium absorption, more falls (in elderly)  Musculoskeletal pain  depression

Vitamin E  Tocopherol – related to reproduction  A pale yellow oil, stable to acids and heat, insoluble in water  Important role as antioxidant

Vitamin E: Absorption, Transport, Storage  Absorbed in micelles with aid of bile  Transported out of intestinal wall into lymph, and then to general circulation  It is stored in the liver and adipose tissue in liquid droplets  It is very slowly mobilized

Vitamin E: Functions  Antioxidant  Partner with selenium  Prevention of age-related change and chronic disease  Helps counteract side effects and toxicity of chemotherapy

Vitamin E: RDA and Sources  Age 14+: 15mg per day (not met!)  Sources  Vegetable oils  Peanut butter, nuts, sardines, kidney beans  Fortifed cereals  Tomato sauce, spinach

Vitamin E: Deficiency & Toxicity  Deficiency:  Premature infants: anemia  Disrupts myelin (sheath on nerves that passes messages to muscles)  Toxicity:  Unknown

Vitamin K  Found in plants and animals, named phylloquinone and menaquinone  A water soluble analog, menadione, can be absorbed directly into the blood  Functions  Blood clotting  Bone metabolism

Vitamin K: Absorption, Transport, Storage  Requires pancreatic lipase and bile salts for absorption  Travel via the lymph system and then portal blood to the liver  Stored in small amounts in the liver

Vitamin K: AI & Deficiency  AI (Why not RDA?)  Men 19+: 120mcg  Women 19+: 90mcg  Deficiency  Neonatal issues  Malabsorption – prolonged clotting time  Prolonged antibiotics (cystic fibrosis)  Obstructed bile duct  Drug side effects

Vitamin K: Sources  Dark green veg, leafy greens  Liver  Milk, meat and certain cheeses (menaquinones)  Canned tuna  Spaghetti sauce  Synthesized in intestines by bacteria