Transcript Vitamins - FTK

Vitamins
Iva Řehová
• The discovery of the first vitamin was published
in 1911 by a Polish biochemist, Casimir Funk.
• The term vitamine is derived from the words vita
(meaning lifegiving) and amine (were originally thought
to be amines).
• Although not all vitamins are amines, they are organic
compounds required by humans in small amounts from
the diet.
• Usually only a few milligrams (mg) or micrograms (μg)
are needed per day, but these amounts are essential for
health.
• Most vitamins cannot be made by the body,
so have to be provided by the diet.
• An exception is vitamin D which can be
obtained by the action of sunlight on the skin.
• Small amounts of a B vitamin (niacin) can be
made from the essential amino acid, tryptophan.
• Vitamin K is formed by bacterial action in the
large intestine.
• Vitamins do not contain energy per se, but they
help regulate energy process in the body.
• Vitamins have a variety of functions in the body:
some are co-factors in enzyme activity, some are
antioxidants (prevent oxygen from doing damage in
the body) and one (vitamin D) is a pro-hormone.
• If insufficient amounts of vitamins are available to the
body because of a poor diet or some medical
condition (e.g. malabsorption of nutrients), specific
symptoms will appear and can develop into a
deficiency disease.
• Vitamin deficiency diseases are rare in the
westernized society, but still occur in some parts of
the world.
• Vitamins and minerals are measured in milligrams
(mg), micrograms (µg) and international units (IU).
How much of the vitamins do we
need?
• The body requires different amounts of
each vitamin because each of them has a
different function.
• People have different requirements too,
according to their age, gender, level of
activity and state of health.
Vitamin supplements
• Although most people are able to meet their requirements
for vitamins by eating a varied diet, there are certain groups
of the population who have higher than normal
requirements, e.g. the sick, those taking certain drugs and
pregnant women.
• Infants and young children are recommended to have
supplements of vitamins A and D for at least 2 years.
• Some women many require additional iron if menstrual
losses are high.
• The evidence for benefits from antioxidant
supplementation for athletes is mixed.
• Vitamins have been traditionally grouped into
two categories:
– the fat soluble vitamin (A, D, E, K),
– and the water soluble vitamins (C, B complex).
Originally, vitamins were given letters (A, B, C, etc.)
but now are usually referred to by their chemical
names, e.g. folate.
• The fat soluble vitamins are stored in the
body and their deficiencies are relatively
rare.
• On the other hand, excessive intakes may
be toxic.
• The water soluble vitamins are not
stored to any significant extent in the body.
• Excess supplements of these vitamins are
usually excreted in the urine.
Vitamin A (Retinol)
• Retinol and beta–carotene preformed vitamin A.
• Beta carotene can be converted to retinol in the body; 6mg of beta
carotene is equivalent to 1mg of retinol.
sources:
• Retinol is found in liver, whole milk, cheese and butter.
• Carotenes are found in milk, carrots, dark green leafy vegetables and
orange coloured fruits, e.g. mango and apricots.
• The law states that margarine must be fortified with vitamin A (and
vitamin D).
RDA (retinol): 1000 mcg of retinol, or 5000 IU, for adult males and 800 mcg
of retinol, or 4,000 IU, for adult females
one glass of milk provides 10% of the RDA
one medium carrot provides 200% of the RDA
a serving of liver provides 900% of RDA
Major function in the body
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vital to good vision
prevents night blindness
antioxidant
necessary for healthy skin, hair growth
keeps mucous membranes healthy
promotes bone development
• Vitamin A is stored in the body in relatively large
amounts, and thus deficiencies are rare.
• deficiency: night blindness, intestinal infections,
impaired growth
• hypervitaminosis: nausea, headache, fatigue,
liver and spleen damage, skin peeling, risk of
birth defect
• It is for this reason that women who are
pregnant, or who might become pregnant, are
advised not to take vitamin A supplements
unless they are advised to do so by a health
professional. Liver and liver products may
contain a large amount of vitamin A, so these
should also be avoided.
Carrot
1 big carrot - 78 g
vit. A - 270%
vit. C - 10%
Calcium - 2%
Iron - 0%
Spinach
1 1/2 cup - 85g
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vit. C - 25%
vit. A - 70%
Calcium - 6%
Iron - 20%
It is full of vitamin A, iron, folate and
magnesium
Apricots
3 apricots - 114g
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vit. C - 20%
vit. A - 45%
Calcium - 2%
Iron - 2%
It is full of vit. A and potassium.
Apricots dried
6 pieces - 42g
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vit. C - 0%
vit. A - 50%
Calcium - 2%
Iron - 10%
Lettuce
1 1/2 cup - 85 g
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vit. C - 6%
vit. A - 40%
Calcium - 4%
Iron - 0%
Vitamin D (Cholecalciferol)
• Vitamin D is found in foods in two main forms, mostly as
cholecalciferol and in small amounts as ergocalciferol.
• The physiologically active form is calcitriol, which is
the hormone of this vitamin.
• The ultraviolet rays from sunshine convert a compound
found in the skin into cholecalciferol which is released
into the blood and is eventually converted by the liver
and kidneys into active hormone calcitriol. In this form it
works as a hormone in controlling the amount of calcium
absorbed by the intestine.
• It is also essential for the absorption of phosphorus and
for normal bone mineralization and structure.
• sources: fish liver oils, eggs, tuna, salmon,
fortified foods like dairy products and margarine,
and some breakfast cereals, action of sunlight on
the skin = deficiencies are unusual
• RDA (cholecalciferol): 10 micrograms or 400 IU
• one glass of milk provides 25% of RDA
• one tin of sardines provides 100% of RDA
Major function in the body
• acts as a hormone to increase intestinal
absorption of calcium
• promote bone and tooth formation
• prevents rickets in children and
osteomalacia in adults
• deficiency: rickets in children and osteomalatia in
adults,
• Deficiencies are rare. Some groups of people (e.g. older
adults, and children) are at risk of vitamin D deficiency
because of low vitamin D intake from food and/or
inadequate exposure of skin to sunshine.
• hypervitaminosis: loss of appetite, nausea, joint pains,
loss of muscle tone, damage to soft tissues such as the
kidney, heart, and blood vessels due to deposits of
calcium.
• In general, vitamin D supplement are not recommended.
Vitamin E (alpha-tocopherol)
• Vitamin E is a group of compounds called tocopherols
and tocotrienols, of which alpha tocopherol is the most
active.
• sources: vegetable oils, margarine, green leafy
vegetables, wheat germ, whole grain products, egg yolks
• RDA (tocopherol): 10 mg for men, and 8 mg for women
• one tablespoon of margarine provides 74% of RDA
Major function in the body
• helps breakdown polyunsaturated fats
• antioxidant, protect cells against oxidative
damage by free radicals, for example
oxidation of the lipids in the cell
membranes
• plays a role in aging, sexual performance,
or prevention of cancer and/or heart
disease
• deficiency: disruption of red blood cell
membranes, anemia
Deficiencies are extremely rare.
• hypervitaminosis: headache, fatigue, diarrhea,
general lack of toxicity with doses up to 400 mg
Vitamin E is one of the most popular nutrient
supplements. There are many health claims for
supplementation – slowing of the aging process
or an improvement in sexual potency.
Vitamin K (phylloquinone)
• Vitamin K is found in foods from both plant
and animal sources and is also made by
bacteria in the gut.
• sources: pork and beef liver, eggs,
spinach, cauliflower, broccoli, tomatoes
• RDA: 80 µg for men, 65 µg for women
Major function in the body
• essential for clotting of blood (vitamin K is
named antihemorrhagic vitamin)
• normal bone structure
• deficiency: increased bleeding and
hemorrhage
Deficiency states are rare, they may occur in
some individuals when antibiotic
medications kill the intestinal bacteria that
produce the vitamin.
• hypervitaminosis: thrombosis, vomiting
Vitamin C (Ascorbic acid )
• Vitamin C is the most famous vitamin.
• sources: almost exclusively in foods from plant
sources (citrus fruits, broccoli, peppers, kiwi,
strawberries, potatoes, tomatoes), although
fresh milk and liver contain small amounts.
• RDA: 80 mg
• one kiwi, small orange or 4 strawberries
provides 100% of RDA
Major function in the body
• helps form collagen
• helps in growth and repair of body tissue and
blood vessels
• prevents scurvy
• a strong antioxidant
• aids in absorption of iron
• helps regulate the metabolism of cholesterol and
amino acids
• deficiency: weakness, slows wound
healing, bleeding gums, scurvy
• The vitamin can be decreased by cigarette
smoking, stressful injuries, stress and oral
contraceptives.
• hypervitaminosis: excessive doses can
cause kidney stones and break down red
blood cells
Red pepper
1 red pepper - 148 g
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vit. C - 190%
vit. A - 8%
Calcium - 2%
Iron - 2%
Strawberry
8 pieces - 147g
vit. C - 160%
vit. A -0%
Calcium - 2%
Iron - 4%
Very good source of vit.C, fiber and
folate.
Grapefruit
1/2 of grapefruit - 154g
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vit. C - 110%
vit. A - 15%
Calcium - 2%
Iron - 0%
VITAMIN B COMPLEX
Eight vitamins that make up the B Complex of vitamins:
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B1 - Thiamine
B2 - Riboflavin
B3 - Niacin
B5 - Panthotenic acid
B6 - Pyridoxine
B7 – Biotin
B9 - Folate (folic acid)
B12 – (Cobalamin, cyanocobalamin)
Thiamin (Vitamin B1)
• sources: whole grains, nuts and meat, especially pork.
White and brown flour and many breakfast cereals are usually fortified with
thiamin.
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RDA: 1,5 mg for men, 1,1 mg for women
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function: Thiamin is needed to release energy from carbohydrate. It is
involved in the normal function of the nervous system and the heart.
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deficiency: causes beri-beri (symptoms: weight loss, emotional
disturbances, weakness and pain in the limbs, irregular heart rate...), a
disorder of the nervous system, which occurs in communities where white
rice is the main food eaten.
A different type of thiamin deficiency affecting brain function is sometimes seen
in alcoholics, where daily thiamin intake is low and absorption and utilisation
of the vitamin is impaired.
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hypervitaminosis: general lack of toxicity
Riboflavin (Vitamin B2)
• sources: milk, eggs, fortified breakfast cereals, liver and green
vegetables.
• RDA: 1,7 mg for men, 1,3 mg for women
• function: Riboflavin is required to release energy from protein,
carbohydrate and fat. It is also involved in the transport and
metabolism of iron in the body and is needed for the normal
structure and function of mucous membranes and skin.
• deficiency: Although there is no specific deficiency disease, low
intakes lead to dryness and cracking of the skin around the mouth
and nose.
• hypervitaminosis: general lack of toxicity, excess riboflavin is
excreted in the urine.
Niacin (nicotinic acid, B 3)
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sources: Niacin is found in most foods, although meat is the major source.
It can also be made by the body from the amino acid tryptophan.
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RDA: 19 mg for men, 15 mg for women
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function: It is required for the release of energy from food, for the normal
structure of the skin and mucous membranes and for normal functioning of
the nervous system.
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deficiency: a disease called pellagra (symptoms: high sensitivity to
sunlight, aggression, dermatitis, red skin lesions, insomnia...)
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Nicotinic acid is sometimes prescribed by doctors (as a drug) to treat high
blood lipid levels, i.e. hyperlipidaemia (excess fat in the blood).
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hypervitaminosis: rare, headache, nausea, burning and itching skin
Pantothenic acid (Vitamin B 5)
• sources: beef and pork liver, lean meats, milk, eggs, legumes,
whole grain products, most vegetables
• A recent study also suggests that gut bacteria in humans can
generate pantothenic acid
• RDA: 4–7 mg
• function: Pantothenic acid is needed to form coenzyme-A (CoA),
and is critical in the metabolism and synthesis of carbohydrates,
proteins, and fats.
• deficiency: rare, fatigue, nausea, loss of appetite, mental
depression
• hypervitaminosis: general lack of toxicity
Pyridoxine (Vitamin B6)
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Vitamin B6 comprising 3 forms – pyridoxine, pyridoxal and pyridoxamine.
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sources: is found in a variety of foods: beef, fish and poultry are rich sources. It
also occurs in eggs, whole-grains and some vegetables.
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RDA: 2 mg for men, 1,6 mg for women
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function: It is essential as a coenzym in protein metabolism, necesary for formation
of hemoglobin and red blood cells, needed for glycogenolysis and gluconeogenesis.
Together with folate and vitamin B12, vitamin B6 is required for maintenance of
normal blood homocysteine levels. Raised homocysteine is a risk factor for
cardiovascular disease.
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deficiency: a complication of cardiovascular disease, nerve damage, anemia
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hypervitaminosis: loss of nerve sensation,
Biotin (Vitamin B 7 or H)
• sources: meats, legumes, milk, egg yolk, whole grain
products, most vegetables
• RDA: 300 µg
• function: It is a coenzyme in the metabolism of
carbohydrates, fats, and protein.
• deficiency: rare, fatigue, nausea, skin rashes
• hypervitaminosis: general lack of toxicity
• Biotin supplements are often recommended
as a natural product to counteract the problem
of hair loss.
Folate (vitamin B 9)
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Folic acid is the synthetic form of the vitamin and the most stable. It is used in
supplements and for food fortification. Various folates are found in both plant and animal
foods.
sources: liver, yeast extract, orange juice and green leafy vegetables. Various
foods, e.g. breakfast cereals and bread may be fortified with folic acid.
RDA: 200 µg for men, 180 µg for women
function: Folate is essential for normal cell division and in the formation of blood
cells. It is also needed for the normal structure of the nervous system and specifically
in the development of the neural tube (which develops into the spine and skull) in the
developing embryo.
Together with vitamins B6 and B12, folate is involved with the maintenance of normal
blood homocysteine levels.
deficiency: megaloblastic anaemia, gastrointestinal disorders
Increasing intakes of folate through supplements of folic acid, before conception and
during the first twelve weeks of pregnancy, prevents the majority of neural tube defects
(e.g. spina bifida) in babies. It is recommended that all women of childbearing age, and
especially those planning a pregnancy and who are in the early stages of pregnancy,
take a daily supplement of 400μg folic acid as it is difficult to achieve this amount of
additional folate by diet alone. Women’s diets typically provide about 250 μg folate/day.
hypervitaminosis: may prevent of detection of pernicious anemia (caused by B 12
deficiency)
Cyanocobalamin (Vitamin B12)
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sources: Dietary intake is exclusively from animal sources, e.g. milk, meat
and eggs (and fortified foods). Although some bacteria can make vitamin
B12, it is probably not in a form that can be used by the body. Fortified
breakfast cereals can be a useful source of this vitamin.
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RDA: 2 µg
function: normal cell division and normal blood formation, for the normal
structure and function of nerves.
Together with folate and vitamin B6, it is required for the maintenance of
normal blood homocysteine levels; raised blood homocysteine is a risk
factor for cardiovascular disease.
deficiency: Dietary deficiency is rare, although it is sometimes seen in
vegans who obtain virtually no vitamin B12 in their diet. Deficiency is also
caused by a lack of intrinsic factor - the substance needed for the
absorption of vitamin B12. This leads to a type of pernicious anaemia in
which red cells are enlarged (megaloblastic), and to neurological damage
- paralysis.
hypervitaminossis: general lack of toxicity
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