1. Vitamins in general. Antivitamins. Vitamin antagonists Flashcards
Vitamins in general:
- Vitamins are organic nutrients
- We only need a trace amount
- we get it from diet, either as a precursor or the active form
- deficiency symptoms if we lack it
- important for growth, maintainance of normal body function and reproduction
- Species need different amount (Ascorbic acid - important for man,monkey,guinea pig, but others can make it)
Which vitamins does human require?
The thirteen vitamins required by human metabolism are:
vitamin A
vitamin B1 (thiamine)
vitamin B2 (riboflavin)
vitamin B3 (niacin)
vitamin B5 (pantothenic acid)
vitamin B6 (pyridoxine)
vitamin B7 (biotin)
vitamin B9 (folic acid or folate)
vitamin B12 (cobalamins)
vitamin C (ascorbic acid)
vitamin D (calciferols)
vitamin E (tocopherols and tocotrienols)
vitamin K (quinones).
How is the structure of a vitamin?
Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols.
Which types of antaginists are there?
- structurally very similar - Antivitamin
- antagonist with different structure
Explain antivitamin:
An antivitamin is simply “a substance that makes a vitamin ineffective.” A vitamin antagonist is essentially the same thing as an antivitamin. It is a substance that lessens or negates the chemical action of a vitamin in the body.
Example: Pyrithiamine inhibits thiamine, deficiency symptoms apear, so animal need more thiamine. Dicumarol in sweet clover hay.
(none for A and D)
What is an antagonist with different structure?
Avidin - Avidin is a tetrameric biotin-binding protein produced in the oviducts of birds, reptiles and amphibians and deposited in the whites of their eggs.
Since it binds to biotin it makes a unabsorbable complex and we can not take it up.
What is thiaminase and what does it do?
Thiaminase is an enzyme that breaks molecules of thiamine in half, makes it useless and unable to perform the functions it is required for in the body. Even if the diet initially contained enough thiamine, the body can suffer from thiamine deficiency due to thiaminase activity.
Thiaminase is found in many species of fish and shellfish, cooking can destroy it.
Fat-soluble vitamins
Fat-soluble vitamins are stored in the fatty tissues of the body and the liver. Vitamins A, D, E, and K are fat-soluble. These are easier to store than water-soluble vitamins, and they can stay in the body as reserves for days, and sometimes months.
Fat-soluble vitamins are absorbed through the intestinal tract with the help of fats, or lipids.
Water-soluble vitamins
Water-soluble vitamins do not stay in the body for long. The body cannot store them, and they are soon excreted in urine. Because of this, water-soluble vitamins need to be replaced more often than fat-soluble ones.
Vitamin C and all the B vitamins are water soluble.
Explain vitamin A:
Name:
Deficiency:
Good source:
Chemical names: Retinol, retinal, and four carotenoids, including beta carotene.
It is fat soluble.
Deficiency may cause night-blindness and keratomalacia, an eye disorder that results in a dry cornea.
Good sources include: Liver, cod liver oil, carrots, broccoli, sweet potato, butter, kale, spinach, pumpkin, collard greens, some cheeses, egg, apricot, cantaloupe melon, and milk.
Vit B1
Name:
Deficiency:
Good source:
Chemical name: thiamine.
It is water soluble.
Deficiency may cause beriberi and Wernicke-Korsakoff syndrome.
Good sources include: yeast, pork, cereal grains, sunflower seeds, brown rice, whole-grain rye, asparagus, kale, cauliflower, potatoes, oranges, liver, and eggs.
Vit B2
Name:
Deficiency:
Good source:
Vitamin B2
Chemical name: Riboflavin
It is water soluble
Deficiency may cause ariboflavinosis
Good sources include: asparagus, bananas, persimmons, okra, chard, cottage cheese, milk, yogurt, meat, eggs, fish, and green beans
Vit B3
Name:
Deficiency:
Good source:
Vitamin B3
Chemical names: Niacin, niacinamide
It is water soluble.
Deficiency may cause pellagra, with symptoms of diarrhea, dermatitis, and mental disturbance.
Good sources include: liver, heart, kidney, chicken, beef, fish (tuna, salmon), milk, eggs, avocados, dates, tomatoes, leafy vegetables, broccoli, carrots, sweet potatoes, asparagus, nuts, whole-grains, legumes, mushrooms, and brewer’s yeast.
Vit B5
Name:
Deficiency:
Good source:
Vitamin B5
Chemical name: Pantothenic acid
It is water soluble.
Deficiency may cause paresthesia, or “pins and needles.”
Good sources include: meats, whole-grains (milling may remove it), broccoli, avocados, royal jelly, and fish ovaries.
Vit B6
Name:
Deficiency:
Good source:
Vitamin B6
Chemical names: Pyridoxine, pyridoxamine, pyridoxal
It is water soluble.
Deficiency may cause anemia, peripheral neuropathy, or damage to parts of the nervous system other than the brain and spinal cord.
Good sources include: meats, bananas, whole-grains, vegetables, and nuts. When milk is dried, it loses about half of its B6. Freezing and canning can also reduce content.
Vit B7
Name:
Deficiency:
Good source:
Vitamin B7
Chemical name: Biotin
it is water soluble.
Deficiency may cause dermatitis or enteritis, or inflammation of the intestine.
Good sources include: egg yolk, liver, some vegetables.
Vit B9
Name:
Deficiency:
Good source:
Vitamin B9
Chemical names: Folic acid, folinic acid
It is water soluble.
Deficiency during pregnancy is linked to birth defects. Pregnant women are encouraged to supplement folic acid for the entire year before becoming pregnant.
Good sources include: leafy vegetables, legumes, liver, baker’s yeast, some fortified grain products, and sunflower seeds. Several fruits have moderate amounts, as does beer.
Vit B12
Name:
Deficiency:
Good source:
Vitamin B12
Chemical names: Cyanocobalamin, hydroxocobalamin, methylcobalamin
It is water soluble.
Deficiency may cause megaloblastic anemia, a condition where bone marrow produces unusually large, abnormal, immature red blood cells.
Good sources include: fish, shellfish, meat, poultry, eggs, milk and dairy products, some fortified cereals and soy products, as well as fortified nutritional yeast.
Vegans are advised to take B12 supplements.
Vit C
Name:
Deficiency:
Good source:
Vitamin C
Chemical name: Ascorbic acid
It is water soluble.
Deficiency may cause megaloblastic anemia.
Good sources include: fruit and vegetables. The Kakadu plum and the camu camu fruit have the highest vitamin C contents of all foods. Liver also has high levels. Cooking destroys vitamin C.
Vit D
Name:
Deficiency:
Good source:
Vitamin D
Chemical names: Ergocalciferol, cholecalciferol.
It is fat soluble.
Deficiency may cause rickets and osteomalacia, or softening of the bones.
Good sources: Exposure to ultraviolet B (UVB) through sunlight or other sources causes vitamin D to be produced in the skin. Also found in fatty fish, eggs, beef liver, and mushrooms.
Vit E
Name:
Deficiency:
Good source:
Vitamin E
Chemical names: Tocopherols, tocotrienols
It is fat soluble.
Deficiency is uncommon, but it may cause hemolytic anemia in newborns. This is a condition where blood cells are destroyed and removed from the blood too early.
Good sources include: Kiwi fruit, almonds, avocado, eggs, milk, nuts, leafy green vegetables, unheated vegetable oils, wheat germ, and whole-grains.
Vit K
Name:
Deficiency:
Good source:
Vitamin K
Chemical names: Phylloquinone, menaquinones
It is fat soluble.
Deficiency may cause bleeding diathesis, an unusual susceptibility to bleeding.
Good sources include: leafy green vegetables, avocado, kiwi fruit. Parsley contains a lot of vitamin K.
