Vitamins

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Vitamins

• Chapter 8

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What are Vitamins?

• 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 
• Nutrient Metabolism
• Energy production and release
• Tissue maintenance
• Normal digestion
• Infection resistance

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What are Provitamins?

• 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.

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How much of the vitamins are needed?

• You need only about one ounce of vitamins for
  every 150 lbs of food that you eat.

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Vitamin Deficiency

• There are two main causes for vitamin
  deficiencies 
• 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.
• 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.

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Vitamin Classification

• All vitamins are grouped into two categories 
• Fat soluble (These vitamins are dissolved through
  the intestinal walls with fats from foods)
• 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.

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Toxicity

• Toxicity A poisonous condition. Vitamins A, and
  D are especially toxic if consumed in large
  amounts over long periods. Toxicity does not
  occur from eating vitamin- rich foods. It occurs
  when people take large amounts of vitamin
  supplements.

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Deficiency

• 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.

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• 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.

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Vitamin A
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.

• 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.

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Meeting Vitamin A Needs

• Vitamin A in foods exists in two basic forms 
• Animal Sources
• 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.

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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 
• Severe Headaches
• Bone pain
• Dry skin
• Hair loss
• Vomiting
• 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.

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Effects of Vitamin D Deficiency

• 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.

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Vitamin D Continued

• 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.

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• 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
• Helps maintain healthy immune and nervous
  systems.
• Main function is to act as an antioxidant.
• Antioxidants are substances that react with
  oxygen to protect other substances from harmful
  effects of oxygen exposure. Vitamin A/C are also
  antioxidants.
• Protects the cells of the lungs

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• Meeting Vitamin E Needs
• 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.

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• Effects of Vitamin E Deficiencies and Excesses
• Deficiencies are not common, however,
  deficiencies have been seen in premature babies.
• These deficiencies cause red blood cells to
  break, a condition called erythrocyte haemolysis,
  this makes babies weak and listless.

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Vitamin K

• Vitamin K
• Functions of Vitamin K
• Main function is to make proteins needed in the
  coagulation of blood. (Coagulation means
  clotting).
• Also needed to make a protein that helps bones
  collect minerals they need for strength.

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Vitamin K

• Meeting Vitamin K Needs
• The need for vitamin K increases throughout
  childhood, the teen years, and young adulthood.
• Bacteria in the intestinal tract help meet a
  significant part of your vitamin K needs.
• Food sources of vitamin K include 
• green leafy vegetables and liver
• fruits, milk, meat, eggs, and grain.

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• Effects of Vitamin K Deficiency
• Deficiencies usually occur to people who take
  antibiotics to kill intestinal bacteria.
• 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

• Water Soluble Vitamins
• Includes all B vitamins, and vitamin C.
• Excesses of these vitamins can be excreted in
  urine.

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B Vitamins

• The B Vitamins are as follows 
• Thiamin
• Riboflavin
• Niacin
• Pantothenic Acid
• Biotin
• B6
• Folate
• B12
• Coenzyme  a nonprotein compound that combines
  with an inactive enzyme to form an active enzyme
  system.

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Thiamin

• Thiamin
• Functions
• Plays a vital role in energy metabolism
• Required for normal functioning of the nerves and
  the muscles they control.
• Meeting Thiamin Needs
• Whole grain breads and cereals are sources of
  thiamin as well as several other B vitamins.
• Refined grain products are commonly enriched with
  these vitamins and iron.
• Enriched foods have had vitamins and minerals
  added back that were lost in the refining
  process.

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Effects of Thiamine Deficiencies and Excesses

• Without thiamine the body cannot perform the
  tasks required for everyday living. Symptoms
  include weakness, loss of appetite, and
  irritability.
• Beriberi is a thiamine deficiency disease.
• Alcoholism increase the risk of thiamine
  deficiency b/c alcohol diminishes the body's
  ability to absorb and use thiamine.

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Riboflavin

• Functions
• Helps the body release energy from carbohydrates.
  
• Needed for healthy skin, and normal eyesight.
• Meeting Riboflavin Needs
• Milk and milk products, enriched and whole grain
  cereal, meats, poultry and fish are excellent
  sources for meeting these needs.
• People who do not drink milk or eat milk products
  may be at risk for developing a deficiency.

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Effects of Riboflavin Deficiency and Excesses

• Symptoms include 
• inflamed tongue
• cracked skin around the mouth
• various eye disorders
• mental confusion
• Toxicity symptoms have not been reporter, extra
  riboflavin is excreted in the urine.

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Niacin

• Functions
• Involved in energy metabolism
• Helps keep the skin and nervous system healthy,
  and promotes normal digestion.
•  
• Meeting Niacin Needs
• Whole grain and enriched breads and cereals,
  meat, poultry, and nuts are popular sources of
  niacin
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• Effects of Niacin Deficiencies and Excesses
• Pellagra is the niacin deficiency disease. The
  four systems of pellagra are known as the 4 Ds 
• Diarrhoea
• Dermatitis
• Dementia
• Death
• Early disease symptoms include poor appetite,
  weight loss, and weakness.

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Pantothenic Acid

• Functions
• Promotes growth
• It is part of a coenzyme that is critical to the
  metabolism of the energy nutrients.
• Effects of Pantothenic Acid Deficiencies and
  Excesses
• 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
• Helps activate several enzymes involved in the
  release of energy from carbohydrates, fats, and
  proteins.
• Biotin also helps the body make fats and
  glycogen.
• Meeting Biotin Needs
• There is no RDA for biotin.
• Is widespread in foods Egg yolks, yeast, beans,
  nuts, cheese, and liver.

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• Effects of Biotin Deficiencies and excesses
• Deficiencies are uncommon as biotin is widely
  available in foods.
• 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.

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Vitamin B6

• Functions of Vitamin B6
• Plays a key role in synthesizing non-essential
  amino acids
• It is needed to convert the amino acid tryptophan
  into niacin.
• Helps make protein that allows red blood cells to
  carry oxygen.
• Affects the health of the immune and nervous
  systems.
•  
• Meeting Vitamin B6 Needs
• B6 is found in many foods such as  meats, fish,
  and poultry, dairy products, fruits, vegetables,
  and spinach.

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Effects of Vitamin B6 Deficiencies and Excesses

• Deficiencies are rare and are related to poor
  amino acid and protein metabolism.
• Symptoms include skin disorders, fatigue,
  irritability, and convulsions.
• People who have taken large amounts of b6 have
  reported symptoms of toxicity. These include
  walking difficulties and numbness in the hands
  and feet.
• Irreversible nerve damage can also result from
  excessive intakes of this vitamin.

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