Sunday 19 February 2012

Vitamins and minerals

Vitamins and minerals are substances that are found in foods we eat. Your body needs them to work properly, so you grow and develop just like you should. When it comes to vitamins, each one has a special role to play. For example:
  • Vitamin D in milk helps your bones.
  • Vitamin A in carrots helps you see at night.
  • Vitamin C in oranges helps your body heal if you get a cut.
  • B vitamins in leafy green vegetables help your body make protein and energy.

Vitamins Hang Out in Water and Fat

There are two types of vitamins: fat soluble and water soluble.
When you eat foods that contain fat-soluble vitamins, the vitamins are stored in the fat tissues in your body and in your liver. They wait around in your body fat until your body needs them.
Fat-soluble vitamins are happy to stay stored in your body for awhile — some stay for a few days, some for up to 6 months! Then, when it's time for them to be used, special carriers in your body take them to where they're needed. Vitamins A, D, E, and K are all fat-soluble vitamins.
Water-soluble vitamins are different. When you eat foods that have water-soluble vitamins, the vitamins don't get stored as much in your body. Instead, they travel through your bloodstream. Whatever your body doesn't use comes out when you urinate (pee).
So these kinds of vitamins need to be replaced often because they don't stick around! This crowd of vitamins includes vitamin C and the big group of B vitamins — B1 (thiamin), B2 (riboflavin), niacin, B6 (pyridoxine), folic acid, B12 (cobalamine), biotin, and pantothenic acid.

Vitamins Feed Your Needs

Your body is one powerful machine, capable of doing all sorts of things by itself. But when it comes to vitamins, it can use some help. That's where food comes in. Your body is able to get the vitamins it needs from the foods you eat because different foods contain different vitamins. The key is to eat different foods to get an assortment of vitamins. Though some kids take a daily vitamin, most kids don't need one if they're eating a variety of healthy foods.
Now, let's look more closely at vitamins — from A to K:

Vitamin A

This vitamin plays a really big part in eyesight. It's great for night vision, like when you're trick-or-treating on Halloween. Vitamin A helps you see in color, too, from the brightest yellow to the darkest purple. In addition, it helps your body fight infections by boosting your immune system.
Which foods are rich in vitamin A?
  • milk fortified with vitamin A
  • liver
  • orange fruits and vegetables (like cantaloupe, carrots, sweet potatoes)
  • dark green leafy vegetables (like kale, collards, spinach)

The B Vitamins

There's more than one B vitamin. Here's the list: B1, B2, B6, B12, niacin, folic acid, biotin, and pantothenic acid. Whew — that's quite a group!
The B vitamins are important in metabolic (say: meh-tuh-bah-lik) activity — this means that they help make energy and set it free when your body needs it. So the next time you're running to third base, thank those B vitamins.
This group of vitamins is also involved in making red blood cells, which carry oxygen throughout your body. Every part of your body needs oxygen to work properly, so these B vitamins have a really important job.
Which foods are rich in vitamin B?
  • whole grains, such as wheat and oats
  • fish and seafood
  • poultry and meats
  • eggs
  • dairy products, like milk and yogurt
  • leafy green vegetables
  • beans and peas

Vitamin C

This vitamin is important for keeping body tissues, such as gums and muscles in good shape. C is also key if you get a cut or wound because it helps you heal.
This vitamin also helps your body resist infection. This means that even though you can't always avoid getting sick, vitamin C makes it a little harder for your body to become infected with an illness.
Which foods are rich in vitamin C?
  • citrus fruits, like oranges
  • cantaloupe
  • strawberries
  • tomatoes
  • broccoli
  • cabbage
  • kiwi fruit
  • sweet red peppers

Vitamin D

No bones about it . . . vitamin D is the vitamin you need for strong bones! It's also great for forming strong teeth. Vitamin D even lends a hand to an important mineral — it helps your body absorb the amount of calcium it needs. Vitamin D is made in the skin when exposed to sunlight, or you can get it from the foods you eat.
Which foods are rich in vitamin D?
  • milk fortified with vitamin D
  • fish
  • egg yolks
  • liver
  • fortified cereal

Vitamin E

Everybody needs E. This hard-working vitamin protects your cells and tissues from damage. It is also important for the health of red blood cells.
Which foods are rich in vitamin E?
  • whole grains, such as wheat and oats
  • wheat germ
  • leafy green vegetables
  • vegetable oils like sunflower, canola, and olive
  • egg yolks
  • nuts and seeds

Vitamin K

Vitamin K is the clotmaster! Remember the last time you got a cut? Your blood did something special called clotting. This is when certain cells in your blood act like glue and stick together at the surface of the cut to help stop the bleeding.
Which foods are rich in vitamin K?
  • leafy green vegetables
  • dairy products, like milk and yogurt
  • broccoli
  • soybean oil
When your body gets this vitamin and the other ones it needs, you'll be feeling A-OK!

Names in current and previous nomenclatures

Nomenclature of reclassified vitamins
Previous name Chemical name Reason for name change
Vitamin B4 Adenine DNA metabolite; synthesized in body
Vitamin B8 Adenylic acid DNA metabolite; synthesized in body
Vitamin F Essential fatty acids Needed in large quantities (does
not fit the definition of a vitamin).
Vitamin G Riboflavin Reclassified as Vitamin B2
Vitamin H Biotin Reclassified as Vitamin B7
Vitamin J Catechol, Flavin Catechol nonessential; flavin reclassified as B2
Vitamin L1 Anthranilic acid Non essential
Vitamin L2 Adenylthiomethylpentose RNA metabolite; synthesized in body
Vitamin M Folic acid Reclassified as Vitamin B9
Vitamin O Carnitine Synthesized in body
Vitamin P Flavonoids No longer classified as a vitamin
Vitamin PP Niacin Reclassified as Vitamin B3
Vitamin S Salicylic acid Proposed inclusion of salicylate as an essential micronutrient
Vitamin U S-Methylmethionine Protein metabolite; synthesized in body
               

 The reason that the set of vitamins skips directly from E to K is that the vitamins corresponding to letters F-J were either reclassified over time, discarded as false leads, or renamed because of their relationship to vitamin B, which became a complex of vitamins.
The German-speaking scientists who isolated and described vitamin K (in addition to naming it as such) did so because the vitamin is intimately involved in the Koagulation of blood following wounding. At the time, most (but not all) of the letters from F through to J were already designated, so the use of the letter K was considered quite reasonable The table on the right lists chemicals that had previously been classified as vitamins, as well as the earlier names of vitamins that later became part of the B-complex.

Anti-vitamins

Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins. For example, avidin is a protein in egg whites that inhibits the absorption of biotin Pyrithiamine is similar to thiamine, vitamin B1, and inhibits the enzymes that use thiamine.

 
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