What are vitamins?
A vitamin is an organic (carbon-containing) chemical compound
your body must have in very small amounts for normal growth, metabolism
(creating energy in your cells), and health. Vitamins are needed to make
enzymes and hormones, which are important substances human body uses to
make all the chemical reactions, needed to live. Your body has no way
to create vitamin molecules itself, so the vitamin molecules must come
in through food that you eat. Most of us get enough of vitamins from our
food, but it may be necessary for some people to take a vitamin
supplement, because an ongoing shortage of vitamins will lead to failed
health, weakness, susceptibility to disease.
The body needs at least 13 different vitamins to function properly:
Vitamin A – Retinol; Vitamin B complex (B1 – Thiamine; B2 – Riboflavin;
B3 – Niacin; B6 – Pyridoxine; B12 – Cyanocobalamin; B9 – Folic acid; B5 –
Pantothenic acid; H – Biotin); Vitamin C – Ascorbic acid; Vitamin D –
Calciferol (can be obtained through sunlight); Vitamin E – Tocopherol;
Vitamin K – Menaquinone.
There are two types of vitamins: fat soluble and water soluble.
Fat soluble vitamins
Vitamins A, E, D and K are fat-soluble, they dissolve in fat but not
water. Once these vitamins are absorbed by the body, they are stored
mostly in the fatty tissues and in the liver. Fat-soluble vitamins can
be stored in your body for up to six months. The liver provides the
primary storage tissue for vitamins A and D. Vitamin E is stored mainly
in body fat and to a lesser extent in reproductive organs. Relatively
little vitamin K is stored. When you need these vitamins, your body
takes them out of storage to be used.
Because you can store these vitamins, you don’t have to get a supply
of them every day. However, eating fats or oils that are not digested
can cause shortages of fat-soluble vitamins. On the other hand, getting
too much of these vitamins, particularly vitamins A and D, can lead to
toxic levels in the body and cause problems.
Vitamin A (Retinol)
Vitamin A, also called retinol, is a fat-soluble vitamin that has
many functions in the body. It helps the eyes adjust to light changes,
plays an important role in bone growth, tooth development, reproduction,
cell division and gene expression. Vitamin A helps regulate the immune
system, which helps prevent or fight off infections by making white
blood cells that destroy harmful bacteria and viruses. Also, the skin,
eyes and mucous membranes of the mouth, nose, throat and lungs depend on
vitamin A to remain moist.
Signs of vitamin A deficiency are night blindness, dry scaly skin,
low resistance to infection, poor tooth formation, slower bone growth,
formation of gall and kidney stones, sinus troubles, poor digestion, ear
abscesses.
Excess alcohol intake depletes vitamin A stores. Food sources of
Vitamin A: liver, butter, whole milk, cheese, egg yolk. Food sources for
Provitamin A: carrots, leafy green vegetables, sweet potatoes,
pumpkins, winter squash, apricots, cantaloupe.
Vitamin D (Calciferol)
Vitamin D is a fat soluble vitamin that is found in food and can also
be made in your body after exposure to ultraviolet (UV) rays from the
sun. Sunshine is a significant source of vitamin D because UV rays from
sunlight trigger vitamin D synthesis in the skin.
Vitamin D plays a critical role in the body’s use of calcium and
phosphorous. It increases the amount of calcium absorbed from the small
intestine and helps form and maintain bones. Vitamin D also works
together with other vitamins, minerals, and hormones to promote bone
mineralization. Without vitamin D, bones can become thin, brittle, or
misshapen. Children especially need adequate amounts of vitamin D to
develop strong bones and healthy teeth.
Lack of Vitamin D may cause rickets and fragile bones, bowed legs,
enlargement of the elbows and wrists joints, also muscle twitching and
muscle cramps.
Excessive amounts of Vitamin D may result in general depression,
abnormal calcium deposits in the blood vessel walls, liver, lungs,
kidneys, and stomach. It may also lead to diarrhea and have other severe
toxic effects.
Food sources of Vitamin D: Cod liver oil, salmon, mackerel, fortified milk and cereal tuna fish, sardines, eggs, liver (beef).
Vitamin E (Tocopherol)
Vitamin E is a fat-soluble vitamin. Vitamin E helps in the overall
health of the sexual organs, is good for the skin and helps promote its
healing. Is good for the heart and lungs. Vitamin E acts as an
antioxidant, protecting vitamins A and C, red blood cells and essential
fatty acids from destruction.
Lack of Vitamin E may cause sterility in both sexes, loss of hair, and miscarriage.
Food sources of Vitamin E: wheat germ oil, sunflower seed kernels,
sunflower oil, safflower oil, hazelnuts, peanuts, corn oil, spinach,
broccoli, kiwi, mango.
Vitamin K (Menaquinone)
Vitamin K plays an essential role in normal blood clotting and helps promote bone health.
Food sources of Vitamin K: dark green leafy vegetables, liver, olive
oil, cottonseed oil. Vitamin K is also made by bacteria in the
intestine.
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