Fat Soluble Vitamins

Where is vitamin A found?

-In animal products or supplements -Plant foods (orange foods like cantaloupe, carrots, sweet potatoes) -Plants contain precursor to vitamin A (beta-carotene) -Animal products contain preformed Vitamin A (cheese, milk, animal liver, eggs)

What does vitamin A do?

-In cell differentiation... -Young cells are undifferentiated (they can become different types of cells, like stem cells that can be any type of cell) -Vitamin A ensures that this process happens properly -In epithelial tissue... -They are tissues on surface of the body (skin, lungs, etc) -Vitamin A ensures these cells differentiate properly -Immune system, needed to make healthy cells that will keep infections out -Production of sperm and fertilization

What is Beta-Carotene and where is it found?

-It has a yellow-orange pigment -It is a carotenoid -It is a pro-vitamin (our body can convert it to vitamin A)

What does beta-carotene do?

-It is an antioxidant -Protects cell membranes -Prevents cancer, heart disease, cataracts, macular degeneration

What are the functions of vitamin E?

-It is an antioxidant -Works in lipid environments -Stored as triglycerides

What does vitamin D do for bone health?

-It is important for calcium balance -Helps absorb, retain, and regulate blood levels of calcium

What happens when you have a vitamin E deficiency?

-It is rare -Causes nerve damage, impaired vision, speech, movement, leg cramps -Hemolytic anemia (breaking of blood cells) -20-40% of North Americans have low vitamin E levels -Greater chance of heart disease

What is the link between vitamin E and CVD?

-It reduces oxidized LDLs -(This is a good thing) -Reduces inflammation of blood vessels which can lead to plaque flaking off -Reduces blood clotting

What happens if you have too much vitamin A?

-Loss of appetite -Blurred vision -Pain, nausea -Liver, and other organ damage -Birth defects in pregnant women -Possible to overdose from food sources alone (preformed vitamin A) -UL is 2000 RAE

What can a vitamin A deficiency cause?

-Night blindness -Dry eyes (xerophthalmia) -Blindness -Immune compromises -Severe cases, death

When is vitamin D toxic?

-Not possible from sun exposure (once you have enough your body stops making it) -Toxicity would be from supplements (but it is rare) -May cause high blood calcium levels (hypercalcemia) -Excess is stored in fat tissue

Where do we find vitamin D naturally in foods?

-Oily fish such as wild salmon (1000 IU in 3oz serving), herring, trout, mackerel (farmed salmon has 1/4 vitamin D wild salmon does) -Fortified milk and margarine -Sometimes yogurt -NOT cheese

What is vitamin E destroyed by?

-Oxygen -Light -High heat cooking -Keep oils in a cool, dark place, uncooked oils contain most vitamin E -Deep frying usually kills all vitamin E

What kind of people absorb less vitamin D?

-People with darker skin -People who live far from the equator -In Edmonton, people synthesize NO vitamin D between October and May -97% of Canadians have inadequate vitamin D levels during the winter/spring -The elderly -People wearing sunscreen, cover their skin, or stay indoors

What happens if you don't get enough vitamin D?

-Rickets (soft bones) -Common during industrial revolution due to pollution blocking sunlight -Rich kids were sent to the country

What is vitamin A needed for?

-Sight -Cell differentiation -Maintenance of epithelial tissue

What is osteomalacia?

-Soft bones due to vitamin D deficiency -Causes bowed legs, aching joints, higher risk of fractures

What is oxidation?

-Stealing of electrons by free radicals -Molecules containing oxygen are usually electron stealers -Examples include superoxide, hydroxyl radicals, nitric oxide, and reactive oxygen species (ROS)

What is the link between vitamin D and cancer?

-Study showed taking supplement lowered risk of cancer by 60% -Others say too much can increase risk of cancer -Moderate intake is still recommended

How do we get enough vitamin D?

-Synthesize if from a form of cholesterol in our skin (need UV light) -Converted in kidneys

What happens when some fatty acids are oxidized more easily than others?

-The more double bonds a fatty acid has, the easier the oxidation reaction (polyunsaturated fatty acids are a problem) -Why saturated and trans fats have a longer shelf life -Why old fish smells bad and frying in oil smells bad

What happens as you increase PUFA intake?

-The more vitamin E you need to protect those fats from oxidation -Usually, foods that contain PUFA also have vitamin E

What happens when we have a vitamin A deficiency?

-Threat to children around the world -Caused by insufficient intake of vitamin A, protein or zinc

When can vitamin E be toxic?

-Uncommon, usually only seen in supplements -Doses would have to be over 50 times the RDA -Causes nausea

How much vitamin A do we need?

-900 RAE for men -700 RAE for women -In Canada, half our vitamin A comes from preformed vitamin A (animal products) -Other half from beta-carotene

What is vitamin D?

-Also called calcitriol (active form) -Also considered a hormone (chemical messenger in the body) -It is conditionally essential, we can make it ourselves if we have enough sunlight -Or we can get it from foods

What is vitamin E?

-Also known as alpha-tocopherol -Fat soluble (non polar) -Can be absorbed better when eaten with fat -Absorbed in intestines -Transported in blood via lipoproteins -Stored in adipose tissue

What are the characteristics of fat soluble vitamins?

-Consist of vitamins A, D, E and K - Absorbed with fat in micelles -Transported in lipoproteins or with protein transporters -Stored in fat cells -Deficiency takes and while, and toxicity is possible

What are the characteristics of water soluble vitamins?

-Consist of vitamins B and C -Absorbed with facilitated or active transport -Not stored in the body and toxicity is unlikely -Deficiencies are common

What is vitamin A?

-Consists of retinol, retinal, and retanoic -It is absorbed in micelles (small intestine) with fat -It is stored in the liver and in fat cells (why liver has tons of vitamin A) -Measured in Retinal Activity Equivalents (RAE) -1 RAE = 1 microgram of retinol or 12 micrograms of beta carotene -Plays a key role in night vision, growth regulation

Where do you find vitamin E?

-Food sources that also have PUFA -Avocados, nuts, canola oil, olive oil, spinach

When should you take a vitamin D supplement?

-If you are over 50 -In the winter -If you don't eat milk or fatty fish -If you stay indoors or wear sunscreen -Supplements should contain 600-800 IUs

What are the other roles of vitamin D?

-Important for cell differentiation -Potential role in cancer prevention -Helps immune system by fighting off viruses and infections