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