The document provides a comprehensive overview of fat-soluble vitamins A, D, E, and K, explaining their essential roles in bodily functions, sources, and the consequences of deficiency. It details how vitamins are absorbed and utilized in the body, emphasizing the importance of diet and sunlight exposure for vitamins D and A. Additionally, it highlights the historical context of vitamin discovery and the biochemical aspects relating to vitamin health.

1. The Science Behind Health
With Doctor Bones (Don R. Mueller, Ph.D.)
The Funny Man of Health
Educator
Entertainer
J
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Scientist

2. A Science-Based Examination of the
Fat-soluble Vitamins ( A, D, E and K)

3. Vitamins are essential organic compounds, needed in small
amounts for normal functioning of the human body's metabolism,
growth and reproduction. A vitamin is called "essential" because
either we cannot make it in the body (called synthesis) or that we
produce too little of it for good health.
For example, humans cannot synthesize vitamin C. Therefore, we
must obtain it via our diet. On the other hand, we can synthesize
enough vitamin D in our skin if we receive sufficient exposure to
sunlight. If we are sun deficient, then we may also find ourselves
vitamin D deficient and must obtain vitamin D through our diet.

4. The 13 or so vitamins that we require all
play important roles in sustaining life.
The fat-soluble vitamins that we need
include vitamins A, D, E and K. Fat-
soluble vitamins dissolve in fat and
therefore can be stored in the fatty
tissues of the body. As a consequence,
we do not need to ingest fat-soluble
vitamins daily.
An assortment of B-vitamins and vitamin C are the water-soluble
vitamins that we require. Water-soluble vitamins dissolve in
water and not in fat and therefore cannot be stored in the fatty
tissues of the body. In order to avoid a deficiency, water-soluble
vitamins are needed on nearly a daily basis.

5. Did you know that the word vitamin comes from the word
"vitamine?" It's true! Vitamine, which means "vital amine," was
coined in 1911 by the Polish-American biochemist Casimir Funk
because it was thought at the time that these substances
contained amines, compounds that have nitrogen (N) as part of
their molecular structure.
The letter "e" in vitamine was later dropped when it was
determined that not all vitamins contained nitrogen. It was
Casimir Funk who discovered vitamin B1 (thiamine).

6. Fat-soluble Vitamins ( A, D, E and K)
Vitamin A (also called retinol) is fat-soluble, and as such, can
be found in the body’s fatty tissues, although the majority is
stored in the liver as retinyl palmitate. Vitamin A can be obtained
either directly from foods that are substantial in vitamin A (e.g.,
beef liver, fish liver oils, egg yolks and butter) or by converting a
substance called beta-carotene into vitamin A.
In 1913, the biochemist Elmer V. McCollum and his
colleagues conducted nutritional studies that led
to the discovery of vitamin A in butterfat and cod
liver oil. McCollum originally called it "fat-soluble
factor A" and then later "vitamine A."

7. An early sign of vitamin A deficiency is night
blindness. You've probably heard the saying,
“Carrots for good eyesight!" In truth,
carrots contain a substance called "beta-
carotene" (carotene, coming from carrots)
which the body can convert to vitamin A
when needed.
"Eat your carrots!”
Beta-carotene originates from compounds called "carotenoids."
These substances exhibit characteristic yellow and orange colors.
In addition to its role as a provitamin for vitamin A, beta-carotene
also functions as an important antioxidant compound, protecting
cells from the harmful effects of free radicals.

8. Vitamin A has many Important Functions:
 Plays an important role in vision, especially night vision.
 Helps regulate cell development.
 Promotes the proper growth of bones and teeth.
 Boosts the body's immune system helping to increase our
resistance to infectious diseases.
 Vital in the formation and maintenance of healthy hair,
skin and mucous membranes.
 Vitamin A holds an important place in sexual reproduction.

9. Vitamin D - "The Sun Vitamin"
Vitamin D3 is synthesized in the body when
ultraviolet light (mostly UV-B radiation) strikes our
skin. Fair-skinned people need 20 to 30 minutes a
day in bright sunlight to meet their vitamin D
needs. The darker your skin the longer you need to
be in the sun in order to make enough vitamin D.
Overcast skies, smog, clothing and sunscreens all decrease your
exposure to UV-B radiation and hence decrease the amount
vitamin D you can produce from sunlight. Fortunately, we can also
meet our vitamin D needs with vitamin D fortified foods (milk, for
example is one such item) and vitamin D supplements.

10. For humans, the two most important forms of vitamin D are
vitamin D2 and vitamin D3. Vitamin D2 (ergocalciferol) is derived
from plants and irradiated yeast and fungi. Vitamin D3
(cholecalciferol) as discussed previously, is synthesized in the
body when we are exposed to sunlight and can be obtained from
foods such as milk, fortified cereals, tuna, salmon and fish oils.
Vitamin D2 and vitamin D3 have equal biological
activity. Both can be converted, first to
calcifediol (a transport form of vitamin D) in the
liver and then to the bioactive form of vitamin D,
calcitriol (1,25-dihydroxycholecalciferol) in the
kidneys. Calcitriol is then transported via a
carrier protein to the various sites in the body
where it is needed.

11. Some of the many useful functions of Vitamin D
 Vitamin D aids in the absorption of calcium and phosphorus
from the small intestine for the normal mineralization of bone.
 Vitamin D helps regulate calcium levels in the blood, ensuring
that nerves and muscles function properly, as calcium is vital for
nerve cell transmissions and muscle fiber contractions.
 There is evidence that vitamin D (specifically, vitamin D3) is
involved in regulation of the body's immune system.
 Vitamin D is essential for normal insulin secretion by the
pancreas and therefore control of blood sugar levels.
 The bioactive form of vitamin D3, (calcitriol) is believed to play
an important role in the regulation of the genes involved in cell
growth, differentiation and proliferation.

12. Vitamin E - The Antioxidant Vitamin
The fat-soluble Vitamin E, is actually a family of eight different
vitamin E molecules. Four of the eight vitamin E molecules are
called the tocopherols (alpha, beta, gamma and delta).
Foods containing significant amounts of tocopherols include a
number of oils (corn, safflower, soybean, cottonseed and canola),
nuts (almonds, hazelnuts, and walnuts), wheat germ and
vegetables like spinach, kale, sweet potatoes and yams.

13. The remaining four Vitamin E molecules are known as
tocotrienols (alpha, beta, gamma and delta). Sources of
tocotrienols include: oils from palm, rice bran and annatto beans.
In foods, alpha-tocopherol is in the form of d-alpha-tocopherol
(the vitamin E isomer preferred by the body), which is found in a
number of oils, including safflower and sunflower. It is also found
in wheat germ. “Trienol” refers to three C=C double bonds.
C=C double bonds

14. Some of the Important Functions of Vitamin E
 Vitamin E in the form of d-alpha-tocopherol is an important
fat-soluble antioxidant, scavenging oxygen free radicals: lipid
peroxy radicals and singlet oxygen molecules before these
various radicals can do further harm to cells.
 Vitamin E helps maintain the structural integrity of cell
membranes throughout the body.
 The isomer, d-alpha-tocopherol has been shown to inhibit the
aggregation or "clumping" of blood platelets, hence, helping to
reduce the risk of heart attack and stroke.
 Studies show that d-alpha-tocopherol protects the fat
component in low-density lipoproteins (LDLs) from oxidation and
exhibits moderate cholesterol-lowering capabilities.

15. Vitamin K - The Anti-Hemorrhagic Vitamin
Vitamin K, was first isolated in 1939 by the Danish biochemist
Henrik Carl Peter Dam, later winning the Nobel Prize in Medicine
in 1943, for his work involving vitamin K.
A decade earlier, it was shown that this fat-soluble substance
(present in green leafy vegetables) was required for normal
coagulation of the blood.
The "K" comes from the German word "koagulation.” Vitamin K
is essential for the functioning of several proteins involved in
normal blood clotting. Vitamin K is needed to make four blood
coagulation factors, including: prothrombin (factor II),
proconvertin (factor VII), Christmas factor (factor IX) and the
Stuart-Power factor (factor X).

16. Vitamin K1 is the major dietary source of vitamin K and is found
in green leafy vegetables like lettuce, kale, parsley, spinach and
various greens (turnip, beet and mustard). Broccoli is also a
good source of vitamin K1 as are certain vegetable oils (soybean,
cottonseed, canola, and olive).
Vitamin K1 (phylloquinone)
There are three basic forms of vitamin K, namely:

17. Vitamin K2, which is the most biologically active form of vitamin
K, is found in egg yolks, butter, liver, cheddar cheese and yogurt.
Vitamin K2 is also produced by certain "friendly" intestinal
bacteria in humans and it has been suggested that products
yogurt, kefir and acidophilus milk (fermented milk) may help to
increase the functioning of these useful bacteria.
Vitamin K2
(menaquinone)

18. Important Functions for Vitamin K
 The primary role for Vitamin K in human health is in the
regulation of normal blood clotting.
 Vitamin K has been shown to improve bone health, particularly
for those at risk for osteoporosis.
 Used to reduce the hazard of bleeding in liver disease.
Vitamin K3 or "menadione" is a fat-
soluble synthetic (man-made) vitamin
K compound, used mainly in animal
feed and pet foods. Although vitamin
K3 is converted to vitamin K2 in the
body, it is generally not recommended
for use in humans.
Vitamin K3