Fat-Soluble Vitamins

Fat-soluble versus Water-Soluble: How are they absorbed?

-Fat-soluble require bile, enter via lymph and then the blood -Water-soluble enter directly into the blood

Fat-soluble versus Water-Soluble: In regards to storage

-Fat-soluble vitamins are stored in adipose cells and the liver -Water-soluble vitamins have minimal storage

Fat-soluble versus Water-Soluble: In regards to excretion?

-Fat-soluble vitamins tend to remain stored -Excess Water-soluble vitamins are excrete in the urine.

Fat-soluble versus Water-Soluble: What are their requirements?

-Fat-soluble: Consume weekly or even monthly -Water-soluble: Consume every few days

Fat-soluble versus Water-Soluble: In regards to toxicity?

-Fat-soluble: Toxicity can occur with supplement overuse with Vitamins A and D, even at modest levels -Water-soluble: Toxicity is possible with supplements at very high levels

Fat-soluble versus Water-Soluble: How are they transported?

-Many Fat-soluble vitamins require protein carriers -Water-soluble vitamins are circulated freely through the blood

Vitamin A is a family of retinoids with three active forms. What are these active forms?

-Retinol -Retinal -Retinoic acid

What are specific rich food sources for Carotenoids?

-Spinach and other dark green leafy vegetables (chlorophyll pigment masks the color) -Deep orange fruits like apricots and cantaloupe -Deep orange vegetables like squash, carrots, sweet potatoes, and pumpkin

How does Vitamin K work with the blood clotting process?

-We have some precursors (proteins) that assist in the eventual formation of a clot -What's important with vitamin K, is that it is very important early on. These precursors rely on having enough vitamin K as a coenzyme to allow this process of blood clotting to occur

Compare plant and animal sources of vitamin A. Is milk a good source of vitamin A?

-You can get vitamin A through consumption of plant foods (the orange vegetables) because this is a source of Beta-Carotene which is a precursor to Vitamin A. -You can also get Vitamin A directly via animal products which have vitamin A naturally occuring -So yes, milk is a good source, along with dairy products because this falls within animal foods

Summarize the process of how vitamin D is synthesized in the body:

1. The precursor Vitamin D is made in the liver and it travels to the skin, so right under the skin is where we hold this precursor molecule to vitamin D 2. The precursor sits there and as we are exposed to UV rays, a conversion happens to actually convert that precursor molecule in our skin to an inactive form of vitamin D 3. Enzymes in the liver and kidneys are what convert the inactive from of vitamin D to an active form of vitamin D (This consists of two activation steps and this entire process would be useless without these last two steps)

What is Vitamin D as 125 Dihydroxy Vitamin d?

125 Dihydroxy is the active form of vitamin D

How many target tissues does 125 Dihydroxy Vitamin D have??

125 dihydroxy vitamin D has 3 target tissues

What is the upper limit for Vitamin A?

3000 ug

How much sunshine weekly and to how much skin surface would you recommend to people who consume little or no dairy products?

5-10 minutes per day, 2-3 times per week on the hands, face and arms

How are fat-soluble vitamins absorbed in the body?

Absorbed in the body with the help of bile

Some vitamin K is from a non-dietary source. Explain

An absorbable form of Vitamin K is made by bacteria in the GI tract.

What kind of foods are sources of Vitamin A?

Animal Products! -provide retinoids (pre-formed vitamin A)

What is the exception to water-soluble vitamins being excreted?

B12 and folate are excreted via urine and bile

Why are we talking about these carotenoids with vitamin A?

Because they are precursors to formation of vitamin A in the body!!! (Specifically beta-carotene) -so not only do we have actual vitamin A that we can get naturally occurring in animal products -but we also have that beta-carotene as a precursor that can assist in the formation of vitamin A

What are Carotenoids?

Carotenoids are plant pigments that produce the yellow or orange colors of many fruits and vegetables (Vitamin A precursors)

What is the other way to get vitamin D?

Directly through fortified Milk

What should think of when we think of where the epithelial cells are in the body and how Vitamin A helps maintain these cells?

Epithelial cells are cells of the skin, surface of your eye, respiratory, urinary and intestinal tracts - we have these mucus membranes that are very strong as part of our immune system. Vitamin A in the form of retinoic acid is actually responsible for keeping these membranes healthy!

What are factors that can cause one to have a Vitamin K deficiency?

Fat malabsorption, rare genetic liver disease, long-term use of antibiotics, newborns

What are food sources of vitamin d?

Fortified foods such a milk and margarine

What are specific rich food sources for Vitamin A?

Fortified milk, cheese, cream, butter, fortified margarine, and eggs.

Whenever cells use oxygen they produce harmful by-products called free radicals. What are free radicals?

Free radicals are compounds with unpaired electrons. This means that have an odd number of electrons. They are not stable.

High levels of Vitamin a (as retinoids) in the body can result in what?

High levels of vitamin A (as retinoids) in the body result in hypervitaminosis A.

What factors create higher risk of vitamin D deficiency? How does this recommendation change with these kinds of people?

High risk: elderly, dark-skinned individuals, those who wear clothes over most of body, people living in cold climates. They may need to go further than just sunlight to receive adequate amounts of vitamin D. 2 cups milk per day if you aren't getting recommended sun exposure

Vitamin D has been described as both a vitamin and a hormone. Explain your answer.

Hormone because it targets organs and it helps maintain healthy levels of calcium and phosphorus (these are minerals)

What do you see when one has rickets?

If a child has vitamin D deficiency, once the child starts walking, it can actually find a bowing of the legs because these bones aren't formed properly.

What has been done in the U.S. to alleviate this problem?

Infants are given an injection of vitamin K right at birth just in case, say they have some internal bleeding for some reason, ect. So until they are able to synthesize that GI bacteria (which may take the first few months to get to a good level) they will have that vitamin K that was injected at birth

What is Xerophthalmia?

It is a severe vitamin A deficiency and can result in permanent blindness (stage II), this is a result of the production of keratin.

What foods are rich in vitamin K?

Leafy green vegetables, cabbage-type vegetables and milk

What is the first symptom of Vitamin a deficiency?

Night Blindness

What is night blindness and why does low vitamin A status cause it?

Night blindness results when there is not enough retinal to recycle rhodopsin

Is Xerophthalmia reversible?

No! :(

Are Carotenoids toxic?

No, but can result in the discoloration of skin. (Turns your skin orange) Only possibly in extreme, excess amounts of Carotenoids.

Do supplements of Vitamin E help reduce LDL oxidation?

No, just dietary sources!

What are characteristics of adults that lead to increased risk of osteoporosis?

Older adults have decreased synthesis of vitamin D, milk consumption and exposure to sunlight, all factors leading to increased risk of osteoporosis.

What is Vitamin D's role, overall?

Overall: vitamin D's role is to control blood calcium levels to optimize bone growth & maintenance.

What kind of foods are sources of Carotenoids?

Plant foods! -provide vitamin A precursors in the form of carotenoids (beta-carotene)

What is a retinoid?

Pre-formed vitamin A coming from animal sources

What is the function of Retinal?

Retinal is needed for vision

What is the function of Retinoic Acid?

Retinoic Acid functions in growth, cell differentiation and immunity

What is the function of Retinol?

Retinol supports reporduction

What is the difference between Rickets and Osteomalacia/Osteoporosis?

Rickets occurs when there is a vitamin D deficiency in children and Osteomalacia/osteoporosis occurs when there is a vitamin D deficiency in adults.

What is severe vitamin A deficiency called?

Severe vitamin A deficiency is called xerophthalmia

What are these 3 target tissues?

The 3 target tissues are the small intestine, kidney and bone

What is the reason why most of us do not have trouble getting adequate levels of vitamin E?

The reason most of us have no trouble getting adequate levels of vitamin E is because so much of our food supply is made with vegetable oils!

What are the effects / risks that come with hypervitaminosis A ?

Toxicity: Birth defects Liver abnormalities Decreased bone mineral density

What are the dietary sources of Vitamin E?

Vegetable oils, seeds, nuts, and green leafy vegetables

Vitamin A is a family of what?

Vitamin A is a family of retinoids with three active forms

What does Vitamin A maintain?

Vitamin A maintains the epithelial cells of the skin and the mucus membranes lining the surface of your eye, respiratory, urinary, and intestinal tracts.

What are the fat-soluble vitamins?

Vitamin A, vitamin E, vitamin D and vitamin K

What can Vitamin D deficiency result in?

Vitamin D deficiency can result in rickets and osteomalacia/osteoporosis.

How is Vitamin D made?

Vitamin D is made in the body after the skin is exposed to UV rays from sunlight. Vitamin D is actually synthesized in the body and is able to occur due to UV rays from sunlight that we are exposed to.

What is Vitamin D's function in the body?

Vitamin D maintains normal blood levels of calcium (Ca) and phosphorus.

How does living north of 40° latitude (including central Pennsylvania) impact vitamin D needs throughout the year?

Vitamin D synthesis decreases. Vitamin D synthesis essentially ceases for four months of winter.

What is the role of Vitamin E in the body?

Vitamin E, with it's antioxidant properties, has been shown to reduce oxidation of LDL. This may slow damage to arteries and decrease risk of developing atherosclerosis.

Why is Vitamin K deficiency rare?

Vitamin K deficiency is rare because vitamin K is made by bacteria in the GI tract and is present in many foods

What is Vitamin K's function?

Vitamin K functions as a coenzyme, which activates proteins required for the blood clotting process. It is also essential for the formation of proteins that bind minerals in bone

What is the exception to water-soluble vitamins being stored?

Vitamins B12 and B6

What are examples of the antioxidant vitamins?

Vitamins E, C and A

Now describe what the physiological response is when calcium is low in the blood and vitamin D is activated.

When calcium is low, vitamin D is telling the small intestine to increase the calcium binding proteins which allows for more absorption. Vitamin D is telling the kidney to excrete less or retain more vitamin d. Vitamin D is telling the bone to release calcium from the bone, back into the bone!

Can night blindness be reversed?

Yes

Is there risk of low vitamin K status in any human populations in the U.S.? Explain

Yes, Newborns. New born babies are born with a sterol GI tract (which means they don't have any of that healthy gut bacteria yet)

To meet ones need for vitamin a, rich sources of carotenoid-containing vegetables only need to be consumed a few times each month. Why?

You don't need to consume Vitamin A in high amounts or frequently because we have stores for them