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Vitamins :
Drivers of Cell Processes
Vitamins : Essential nutrients needed in tiny amounts to regulate body processes.
There are 13 known vitamins.
As a nutrient group, vitamins assist with the following functions :
1. Nutrient Metabolism
2. Energy production and release
3. Tissue maintenance
4. Normal digestion
5. Infection resistance
Provitamins : Several vitamins have provitamin forms. Provitamins are
compounds that are not vitamins, but the body can convert them into the active
form of a vitamin. Example : Beta-carotene is a provitamin for vitamin A. It is a
deep yellow, dark green compound found in vegetables.
How much of the vitamins are needed?
You need only about one ounce of vitamins for every 150 lbs of food that you eat.
Vitamin Deficiency
There are two main causes for vitamin deficiencies :
1. An insufficient amount of a vitamin in the diet. In cases of poverty,
people may lack the variety of foods that would provide all the vitamins
they need.
2. The failure of the body to absorb vitamins. For instance, changes in the
body that occur with age can affect a persons ability to absorb vitamin
B12.
Vitamin Classification
All vitamins are grouped into two categories :
1. Fat soluble (These vitamins are dissolved through the intestinal walls
with fats from foods)
2. Water soluble ( Lean tissues may store surpluses of these vitamins for
short periods)
Some vitamins dissolve in fats, the four fat soluble vitamins are : vitamins A, D,
E, K.
Other vitamins dissolve in water, the nine water soluble vitamins are : B complex
vitamins ( Thiamin, ribolflavin, niacin, pantothenic acid, biotin B6, folate, and
B12) and vitamin C.
Toxicity: A poisonous condition. Vitamins A, and D are especially toxic if
consumed in large amounts over long periods. Toxicity does not occur from eatng
vitamin- rich foods. It occurs when people take large amounts of vitamin
supplements.
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Vitamin A
Vitamin A deficiency is the leading cause of blindness in children living in Africa,
Asia, and South America. Up to 500 000 children go blind each year b/c their diets
lack vitamin A.
Functions of Vitamin A
Vitamin A is necessary for the formation of healthy epithelial tissues. The
epithelial cells are the surface cells that line the outside of the body. They
cover the eyes, passages to the lungs, reproductive organs. Because of this
function, vitamin A plays a role in keeping skin and hair healthy. Adequate
amounts of vitamin A help keep the eyes free from dryness and infections.
Vitamin A also helps the linings of the lungs and intestines stay moist and resistant
to disease.
Without sufficient Vitamin A the cells in the eyes cannot make the compound
needed by the eyes to see well in dim light. That means the eyes adapt slowly to
darkness and night vision becomes poor. This condition is called night blindness.
Meeting Vitamin A Needs
Vitamin A in foods exists in two basic forms :
1. Animal Sources
2. Plant Sources
Animal foods usually provide vitamin A as a preformed vitamin (this is an active
form of a vitamin that the body can use).
Plant foods provide vitamin A is a provitamin carotenes. Including alpha and beta
carotene. The body can convert these compounds into the more usable form of
vitamn A.
Effects of Vitamin A Deficiencies and Excesses
Symptoms of the deficiency may include night blindness, dry, scaly skin, and
fatigue.
Getting too much Vitamin A can cause health problems.
Symptoms of Vitamin A toxicity are :
1. Severe Headaches
2. Bone pain
3. Dry skin
4. Hair loss
5. Vomiting
6. Liver damage
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Vitamin D
Vitamin D is a unique fat soluble vitamin. With direct exposure to sunlight, your
body can make all the vitamin D it needs.
Functions of Vitamin D
Vitamin D helps to regulate the levels of calcium in the bloodstream. Normal
amounts of calcium in the blood are needed for healthy nerve function, bone
growth and maintenance.
Vitamin D also controls the absorption of calcium from the intestines.
Meeting Vitamin D Needs
As was previously mentioned, with exposure to sunlight the body can make
vitamin D. When sunlight shines on skin, a cholesterol like compound in the skin
forms a provitamin. The liver and kidneys change the provitamin into vitamin D.
Effects of Vitamin D Deficiency and Excess
A lack of vitamin D can cause rickets. This disease causes bones to become
misshapen, by a lack of vitamin D reaching bones.
The leg bones may bow in or out. The chest bones may bulge outward.
A similar vitamin D deficiency in adults is called osteomalacia. It can cause the
leg and spine bones boned to soften and bend.
Too much vitamin D can be poisonous and toxicity occurs most quickly in
children.
Toxic intakes of vitamin D occur as a result of consuming supplements in the
amount greater than the normal limit.
Overdoes of vitamin D can not be caused by prolonged sun exposure or by eating
foods that contain vitamin D.
Excessive amounts of vitamin D cause too much calcium to be absorbed into the
bloodstream. This surplus calcium is then deposited in the kidneys and other soft
organs.
This causes the organs to become hard and unable to perform their vital functions.
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Vitamin E
Function of Vitamin E
1. Helps maintain healthy immune and nervous systems.
2. Main function is to act as an antioxidant.
3. Antioxidants are substances that react with oxygen to protect other
substances from harmful effects of oxygen exposure. Vitamin A/C are
also antioxidants.
4. Protects the cells of the lungs.
Meeting Vitamin E Needs
1. Research provides no strong support for consuming large amounts of vitamin
E. Therefore you do not need to take supplements, you can receive daily
amounts from foods.
Effects of Vitamin E Deficiencies and Excesses
1. Deficiencies are not common, however, deficiencies have been seen in
premature babies.
2. These deficiencies cause red blood cells to break, a condition called
erythrocyte hemolysis, this makes babies weak and listless.
Vitamin K
Functions of Vitamin K
1. Main function is to make proteins needed in the coagulation of blood.
(Coagulation means clotting).
2. Also needed to make a protein that helps bones collect minerals they need for
strength.
Meeting Vitamin K Needs
1. The need for vitamin K increases throughout childhood, the teen years, and
young adulthood.
2. Bacteria in the intestinal tract help meet a significant part of your vitamin K
needs.
3. Food sources of vitamin K include :
- green leafy vegetables and liver
- fruits, milk, meat, eggs, and grain.
Effects of Vitamin K Deficiency
1. Deficiencies usually occur to people who take antibiotics to kill intestinal
bacteria.
2. Newborns may also have a vitamin K deficiency as they do not yet have
bacteria in their intestines to synthesize the vitamin.
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Water Soluble Vitamins
1. Includes all B vitamins, and vitamin C.
2. Excesses of these vitamins can be excreted in urine.
B Vitamins
The B Vitamins are as follows :
1. Thiamin
2. Riboflavin
3. Niacin
4. Pantothenic Acid
5. Biotin
6. B6
7. Folate
8. B12
Coenzyme : a nonprotein compound that combines with an inactive enzyme
to form an active enzyme system.
Thiamin
Functions
1. Plays a vital role in energy metabolism
2. Required for normal functioning of the nerves and the muscles they control.
Meeting Thamin Needs
1. Whole grain breads and cereals are sources of thiamin as well as several other
B vitamins.
2. Refined grain products are commonly enriched with these vitamins and iron.
3. Enriched foods have had vitamins and minerals added back that were lost
in the refining process.
Effects of Thiamin Deficiencies and Excesses
1. Without thiamin the body cannot perform the tasks required for everydy living.
Symptoms include weakness, loss of appetite, and irritability.
2. Beriberi is a thiamin deficiency disease.
3. Alcoholism increase the risk of thiamin deficiency b/c alcohol diminishes the
bodys ability to absorb and use thiamin.
Riboflavin
Functions
1. Helps the body release energy from carbohydrates.
2. Needed for healthy skin, and normal eyesight.
Meeting Riboflavin Needs
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1. Milk and milk products, enriched and whole grain cereal, meats, poultry and
fish are excellent sources for meeting these needs.
2. People who do not drink milk or eat milk products may be at risk for
developing a deficiency.
Effects of Riboflavin Deficiency and Excesses
1. Symptoms include :
- inflamed tongue
- cracked skin around the mouth
- various eye disorders
- mental confusion
2. Toxicity symptoms have not been reporter, extra riboflavin is excreted in the
urine.
Niacin
Functions
1. Involved in energy metabolism
2. Helps keep the skin and nervous system healthy, and promotes normal
digestion.
Meeting Niacin Needs
1. Whole grain and enriched breads and cerals, meat, poultry, and nuts are
popular sources of niacin
Effects of Niacin Deficiencies and Excesses
1. Pellagra is the niacin deficiency disease. The four systems of pellagra are
known as the 4 Ds :
1. Diarrhea
2. Dermatitis
3. Dementia
4. Death
2. Early disease symptoms include poor appetite, weight loss, and weakness.
Pantothenic Acid
Functions
1. Promotes growth
2. It is part of a coenzyme that is critical to the metabolism of the energy
nutrients.
Effects of Pantothenic Acid Deficiencies and Excesses
1. Is found in many foods therefore deficiency symptoms are rarely a problem.
Toxicity is also rare.
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Biotin
Gets its name from the Greek word for sustinence, which means something that
supports life.
Functions of Biotin
1. Helps activate several enzymes involved in the release of energy from
carbohydrates, fats, and proteins.
2. Biotin also helps the body make fats and glycogen.
Meeting Biotin Needs
1. There is no RDA for biotin.
2. Is widespread in foods :Egg yolks, yeast, beans, nuts, cheese, and liver.
Effects of Biotin Deficiencies and excesses
1. Deficiencies are uncommon as biotin is widely available in foods.
2. However if a deficiency was to occur the symptoms would be : abnormal heart
rhythms, pain, weakness, fatigue, and depression. Nausea; loss of appetite; dry
scaly skin; and hair loss are other symptoms.
Vitamin B6
Functions of Vitamin B6
1. Plays a key role in synthesizing non-essential amino acids
2. It is needed to convert the amino acid tryptophan into niacin.
3. Helps make protein that allows red blood cells to carry oxygen.
4. Affects the health of the immune and nervous systems.
Meeting Vitamin B6 Needs
1. B6 is found in many foods such as : meats, fish, and poultry, dairy products,
fruits, vegetables, and spinach.
Effects of Vitamin B6 Deficiencies and Excesses
1. Deficiencies are rare and are related to poor amino acid and protein
metabolism.
2. Symptoms include skin disorders, fatigue, irritability, and convulsions.
3. People who have taken large amounts of b6 have reported symptoms of
toxicity. These include walking difficulties and numbness in the hands and
feet.
4. Irreversible nerve damage can also result from excessive intakes of this
vitamin.
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Folate
Is derived from the latin folate meaning leaf, and is a logical name because leafy
green vegetables are good sources of folate.
Functions of Folate
1. Main function is to help synthesize DNA.
2. Without folate, cells cannot divide to form new cells.
3. Is especially important to any woman of childbearing age.
4. Women with inadequate folate intakes are more likely to give birth to babies
with neural tube damage.
Meeting Folate Needs
1. Dark green leafy vegetables are excellent sources of folate.
2. Doctors recommend that all women of childbearing age consume 400
micrograms of folic aicd daily from supplements or fortified foods.
Excesses of Folate Deficiencies and Excesses
1. Risk of nerual tube damage to unborn children.
2. Folate deficiencies are not uncommon. Usually as a result from low intakes of
folate.
3. Several medications, such as aspirin and oral contraceptives, can interfere with
the bodys ability to use folate.
4. The first sign of a folate deficiency appears in the red blood cells. The blood
cells become fragile and canot mature and cannot carry oxygen.
5. This leads to the individuals becoming tired or weak.
6. Other symptoms include :
- diarrhea
- increased risk of infection
Vitamin B12
Is a chemical compound that contains cobalt.
Functions of B12.
1. Helps folate function
2. Is needed for growth, maintenance of healthy nerve tissue, and formation of
normal red blood cells.
3. Needed for the release of energy from fat.
Meeting B12 Needs
1. People who eat foods from animal sources easily meet their b12 needs.
2. B12 does not occur naturally in plant sources.
Effects of B12 Deficiencies and Excesses
1. Causes Pernicious Anemia which is a disease associated with vitamin B12. It
is caused by an inability to absorb the vitamin.
- Perniciour anemia page 141.
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Vitamin C
Is commonly referred to as ascorbic acid.
Nutritionists know that it was vitamin C in the citrus fruit that helped cure scurvy.
(Scurvy is a disease caused by vitamin C deficiency).
Functions of Vitamin C
1. Assists in the formation of collagen.
- Collagen is a protein substance that holds cells together.
- It is needed for healthy bones, cartilidge, muscles, and blood vessels.
- Helps wounds heal quicker
- Maintains capillaries and gums
2. Vitamin C increases iron and calcium absorption.
3. Helps to synthesizethyroxine, the hormone that controls basal metabolic rate.
4. Vital for a persons immune system.
5. Is an antioxidant
Meeting Vitamin C Needs
1. The body does not store vitamin C, so a daily intake is necessary.
2. People exposed to cigarette smoke need extra vitamin C. This is because
smoke hinders the bodys use of vitamin C.
3. Vitamin C is found in many fruits and vegetables .
- Fruits include : citrus fruits, cantaloupe, strawberries.
- Vegetables include : sweet peppers, broccoli, cabbage, potatoes.
Effects of Vitamin C Deficiencies and Excesses
1. Most vitamin C needs are met through diet.
2. What happens if there is inadequate vitamin C in the diet?
- Scurvy is the most severe form of vitamin C deficiency. It rarely occurs
in developed countries b/c the causes and cure are known. However, in
underdeveloped countries where there may be a lack of resources scurvy
is not uncommon.
- Symptoms of scurvy are many things : tiredness, weakness, shortness of
breath, aching bones and muscles, swollen wounds heal slowly,.
3. Some extra vitamin C may not be harmful. However, large doses of one to
three grams can produce side effects. People taking large doses have
complained of nausea, diarrhea and stomach cramps.
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Nonvitamins and Other Nonnutrients
A number of substances have been discovered to have vitaminlike quantities.
Such as : choline and inositol
Research has shown that these compounds are active in the body, yet they are not
vital to life. Therefore they cannot be termed vitamins