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Rebekah S. Marsh, PhD.
Kaplan University
Objectives
What will we be learning about tonight?
Vitamin A
Vitamin E
Vitamin D
Vitamin K
Vitamin A
http://upload.wikimedia.org/wikipedia/commons/0/0e/Vitamin-A-Synthese.png
Vitamin A: Dietary Recommendations
Diet recommendations Recommended Dietary
Allowance (RDA):
 Adult males 1000 ug Retinyl Equivalents (RE)/d
 Adult females, 800 ug RE/d
Deficiency of Vitamin A
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Deficiency of Vitamin A (cont.)
How much vitamin A do you think is currently
given to children in developing countries in a
single dose?
Toxicity of Vitamin A
Acute intake of extremely high doses of vitamin A
(>200 mg RE in adult humans)
Can cause nausea, vomiting, headache, and
increased cerebrospinal pressure.

Symptoms are generally transient.
Chronic high intakes (e.g., >10x RDA) can cause
hair loss, bone and muscle pain, headache, liver
damage, and increased blood lipid concentrations.
 A particular danger in pregnant women is
teratogenesis (birth defects).

On the other hand, carotenoids as a source of vitamin A
are not toxic, even with very high intakes.
Carotenoids
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There are over 600 carotenoids in nature.
Carotenoids generally contain a conjugated
polyene structure which is efficient at
absorbing light, and are the major yellow and
red pigments in many fruits and vegetables.
Beta-carotene and alpha-carotene are
responsible for the orange color of carrots,
and lycopene for the red color of tomatoes;
astaxanthin imparts a red or pink color to
lobsters and salmon.
Major storage sites:
 Because the carotenoids are fat-soluble, they
are found in fatty tissues in the body and are
transported in blood by lipoproteins.
 The predominant carotenoids found in human
tissues are beta-carotene, alpha-carotene,
lycopene, lutein, zeaxanthin, and betacryptoxanthin; their relative abundance
depends on dietary intake.
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Functions:
Carotenoids
 In animals some carotenoids serve as
dietary precursors to vitamin A, and
many of them may function as fatsoluble antioxidants.

In plants they serve as antioxidants to protect
the highly reactive photosystems and also act
as accessory photopigments.
 Increased consumption of foods rich in
carotenoids is associated with decreased
risk of some degenerative diseases, and
there is some evidence also for their role
in improving immune function.
What foods contain Carotenoids?
Diet recommendations:
 No formal diet recommendation for
carotenoids has yet been established but
some experts suggest intakes of 5 to 6
mg daily (about twice the average daily
American intake).
http://aginglongevity.com/wp-content/uploads/2009/06/carotenoid.jpg
Carotenoids
Deficiency
 One study has found that
carotenoid deficiency is
associated with skin changes
(including acne and dermatitis).
o
These changes were detrimental but not
life-threatening.
 This effect should be confirmed
by additional studies before
making dietary recommendations.
Toxicity
 The carotenoids are remarkably
devoid of toxicity, and serve as
good nontoxic sources of vitamin
A.
 Massive overconsumption of
carotenoids can result in
yellowing of the skin, especially
of the hand and ears , but has no
adverse health effects.
 The color disappears within a
week or so after reducing intake
of carotene-rich foods.
Vitamin E
Vitamin E: Dietary Recommendations
The Recommended Dietary Allowance (RDA) for vitamin E is based
primarily on customary intakes from US food sources.
The current RDA for males is 10 mg and 8 mg for
females.
However, the requirement for vitamin E increases with higher
intakes of polyunsaturated fatty acids (PUFA).
The recommended ratio of E/PUFA is 0.4 mg d-a-tocopherol per
gram of PUFA.
In defining the ideal intake, factors to consider are
intake of other antioxidants, age, environmental
pollutants, and physical activity
Deficiency of Vitamin E
 The main signs of severe deficiency in animals are
reproductive failure, nutritional "muscular
dystrophy," hemolytic anemia, and neurological
and immunological abnormalities.
 The last three processes also have been identified
in humans.
 However, vitamin E deficiency occurs rarely in
humans, having been reported in only two
situations: premature infants with very low birth
weight and patients who fail to absorb fat.
Toxicity of Vitamin E
 Vitamin E is relatively safe compared to the fat-
soluble vitamins.
 Few side effects from high intakes of this
vitamin have been reported, even at doses as
high as 3200 mg daily.
 However, high vitamin E supplementation
may be contraindicated when a coagulation
defect is present due to vitamin K deficiency
or in individuals receiving anticoagulant
drugs.
Synthesis of Vitamin D
http://rickets.stanford.edu/images/vitamin_D_diagram004-300.jpg
1. 7-dehydrocholesterol is absorbed
through the skin generating vitamin D3
(cholecalciferol).
2. Within the liver, cholecalciferal is
hydroxylated to 25hydroxycholecalciferol
by the enzyme 25-hydroxyvitamin D31-hydroxylase enzyme
3. Within the kidney, 25-hydroxyvitamin
D serves as a substrate for 1-ahydroxylase, yielding 1,25dihydroxyvitamin D (calcitriol,
1alpha,25-dihydroxyvitamin D]—the
most potent form of vitamin D.
4. The active form of vitamin D can then
aid in bone formation/breakdown
Vitamin D: Dietary Recommendations
The IOM concluded that it was not possible to determine a recommended
dietary allowance (RDA) for vitamin D from the literature but rather to
recommend an adequate intake (AI).
 Based on the available literature and assuming
some exposure to sunlight:
Ages 0 - 50 years was set at 200 IU (5 mg)/day.
Adults 51 - 70 years as 400 IU (10 mg)/day
Adults > 71 years, 600 IU (15 mg)/day.
No
increase for pregnancy or lactation.
A Tolerable Upper Limit level for vitamin D for ages 0 - 12
months was set at a limit of 1,000 IU (25 mg)/day.
For older children and adults, including pregnant and lactating
women, the UL was set at 2,000 IU (50 mmg)/day.
Deficiency of Vitamin D
 In children leading problem

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
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is rickets
In adults leading problem is
osteomalacia
What is the difference
between the two?
Who is at risk for deficiency?
Other deficiency symptoms

muscle weakness, bony
deformities, neuromuscular
irritability causing muscle
spasms of the larynx and hands,
generalized convulsions and
tetany
Toxicity of Vitamin D
Excessive quantities of vitamin D (in excess of
5,000-10,000 IU/day) can cause:
Hypercalcemia
Hypercalciuria
kidney stones
soft tissue calcifications
Vitamin K
 Vitamin K is a coenzyme for a microsomal enzyme that
catalyzes the conversion of specific glutamyl residues
to gamma-carboxyglutamyl (Gla) residues in a small
number of proteins.
 Several of the Gla-proteins are essential for blood
clotting and its regulation.
 Others have a role in the regulation of tissue
mineralization and cell proliferation.
 Phylloquinone from plants and a series of bacterial
menaquinones are natural forms of the vitamin.
Blood Clotting
Four main steps:
1. Vasoconstriction- limiting blood flow
to the injured area
2. Platelet activation/adhesion/
aggregation- forms a platelet plug
3. Fibrin meshwork (clot)- binds blood
cells together; forms hemostatic plug
4. Fibrinolysis (clot dissolution)removes clots during wound healing
http://www.biosbcc.net/doohan/sample/images/blood%20cells/clottingcascade.jpg
Vitamin K: Dietary Recommended Daily Allowances
RDAs (µg/day) are:
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5 at age 0-6 months,
10 for 6-12 months,
15 for 1-3 years,
20 for 4-6 years,
30 for 7-10 years
45 for 11-14 years
55 for females 15-18 years, 60 for females 19-24 years, 65 for females 25
years and older, pregnant and lactating women and males 15-18; 70 for
males 19-24 years
80 for males 25 years and older.
Most Americans obtain almost no menaquinones with their
diet, but it is likely that some vitamin K (menaquinones)
from bacterial production in the lower intestines is
absorbed, the amounts appear to be much less than what is
usually available from dietary sources.
Deficiency of Vitamin K
 Historically, vitamin K deficiency has been defined as a disruption of
blood clotting
 Infants are at risk for severe cerebral hemorrhage during the first 3-4
months
 impaired fat absorption in conjunction with a low vitamin intake from breastfeeding.
(Human milk contains much less vitamin K than infant formulas).
 In the US and many other countries newborn infants routinely receive vitamin K.
 Bleeding due to the lack of vitamin K is very rare in older children and
adults
 Oral antibiotic treatment, in conjunction with low vitamin K intake, can
induce bleeding.
 Less than a few days' intake of vitamin K is stored, most of it in liver and
bone
 symptoms appear rapidly.
Deficiency of Vitamin K
 Suboptimal vitamin K status (Vs.
deficiency) may contribute to the
progression of osteoporosis and
atherosclerosis
 4-hydroxy coumarins are vitamin K
antagonists that interfere with
reactivation of the vitamin and
suppress production of mature Glaproteins needed for coagulation.
 Some 4-hydroxy coumarins are
medically important anticoagulants
 What age group may be deficient in
Vitamin K, thus requiring an
injection?
http://bob.usuhs.mil/biochem/nutrition/images/wein-6-5.jpg
Toxicity of Vitamin K
 Large amounts of phylloquinone or menaquinones can be
consumed over extended periods with no toxic effects
 Menadione is currently used in animal feeds, but not in
foods for human consumption, because it causes
hemolytic anemia, hyperbilirubinemia, and kernicterus in
infants.
References
Nutrient Information (2010). American Society
for Nutrition. Retrieved on May 18, 2010 from
http://jn.nutrition.org/nutinfo/