Vitamin Categories
Vitamins cannot be synthesized by the body so must be supplied by diet. Vitamins have no common structure or function but are essential in small amounts for the body to be able to utilize other dietary components efficiently.
Vitamins fall into two categories, fat soluble vitamins such as vitamin A, D, E and K which are ingested with fatty foods and water soluble vitamins such as the B group vitamins and vitamin C. Vitamins are known as micronutrients because only small quantities are required for a healthy diet, in fact fat soluble vitamins can be toxic in high concentrations, for example the body stores vitamin A, or retinol, in the liver as it is toxic if kept in high concentrations in the blood stream, a dose of more than 3300mg of vitamin A can be considered toxic. Water soluble vitamins such as vitamin C and B groups vitamins can be excreted in the urine if in excess in the diet.
Vitamins A
Vitamin A is essential to the proper functioning of the retina in the eye and the epithelial tissues. A lack of vitamin A results in dry, rough skin, inflammation of the eyes, a drying or scarring of the cornea - xerophthalmia, which occurs when the secretion of lubricating tears is stopped, the eyelids become swollen and sticky with pus. Mucous surfaces of the eye may become eroded allowing infection to set in, leading to ulceration and destruction of the cornea. Night blindness - an inability to see in dim light can also occur. Rod cells in the retina of the eye detect light of low intensity, they convert vitamin A into a pigment, rhodopsin, which is bleached when light enters the eye. Rod cells resynthesis rhodopsin, but if there is a deficiency of the vitamin, rod cells can no longer function and the result is night blindness. Epithelial cells use retinol to make retinoic acid, an intracellular messenger used in cell differentiation and growth. Without retinoic acid epithelial cells are not maintained properly and the body becomes susceptible to infections, particularly measles and infections of the respiratory system and gut.
Xenophthalmia is common among children who's diets consist of mainly cereals with little meat or fresh vegetables, this is common in Indonesia, Bangladesh, India and the Philippines.
Vitamins D
Vitamin D, or calciferol, is another fat soluble steroid vitamin which functions to stimulate calcium uptake from the gut and its deposition in bone. vitamin D acts as a hormone when converted by enzymes in the gut and liver into an active form of "active vitamin D", which stimulates epithelial cells in the intestine to absorb calcium. vitamin D is therefore essential in growing children's diets to enable the growth of strong bones. Without adequate amounts of vitamin D children can develop rickets, which is the deformation of the legs caused when they lack calcium to strengthen the bones. In adults a lack of vitamin D in the diet can lead to osteomalacia, a progressive softening of the bones which can make them highly susceptible to fracture.
Vitamin D is made by the body when exposed to sunlight and is stored in the muscles, however, if the skin is rarely exposed to the sunlight or is dark little vitamin D is produced. Foods such as eggs and oily fish are all rich in vitamin D.
Vitamins K
Vitamin K, phylloquinone, is found in dark green leafy vegetables such as spinach and kale. It is a fat soluble vitamin which is involved in the clotting process of blood. In the intestines bacteria synthesize a number of important clotting factors which need vitamin K. Without vitamin K cuts can fail to heal and internal bleeding can occur.
Vitamins C
Vitamin C is a water soluble vitamin, known chemically as ascorbic acid. It is found in citrus fruits such as oranges and lemons, and also in potatoes and tomatoes. The main function of vitamin C is the formation of connective tissues such as collagen. It is also known to be an antioxidant which helps to remove toxins and aids the immune system. A lack of vitamin C leads to Scurvy, a condition experienced by sailors on long journeys when they did not have fruit in their diets. Scurvy causes painful, bleeding gums. As vitamin C is water soluble, it is not toxic in high doses as it can be excreted in the urine, very high doses can however cause diarrhea.
Vitamins B
B group vitamins have a wide range of roles acting as co-enzymes in metabolic pathways. They are found in most plant and animal tissues involved in metabolism, therefore foods such as liver, yeast and dairy products are all rich in B group vitamins. Deficiency of B group vitamins include dermatitis, fatigue and malformation of red blood cells.
1. An adult needs about 12,000kJ of energy a day from ________.
A. the cell
B. the respiring process of carbohydrates
C. fats in the cell
D. a balanced diet
2. Carbohydrates are ultimately absorbed into cells in the process of _______.
A. digestion
B. respiration
C. oxidization
D. mobilization
3. The Essential Amino Acids which build part of proteins can be obtained from______.
A. stomach
B. body tissues
C. the body
D. the diet
4. The ultimate cause of kwashiorkor is lack of ________.
A. protein
B. carbohydrates
C. vitamins
D. diet
5. Vitamins are called “micronutrients” in that _________.
A. excessive fat soluble vitamins can be excreted in the urine
B. the body only requires small amount of vitamins
C. a dose of 3300mg of vitamins can be considered toxic
D. the high concentrations of water soluble vitamins are toxic
6. Night blindness is a disease normally caused by lack of __________.
A. fat soluble vitamins
B. water soluble vitamins
C. vitamin A
D. innate disability
7. The main function of vitamin D is to prevent adults from ________.
A. the growth of strong bones
B. fracture
C. a progressive softening of the bones
D. calcium uptake from the gut
8. Although the human body produces vitamin D normally, it fails to do so if there is not enough ______________.
9. The reason why vitamin C is seen as an antioxidant is that it drives __________ out of the body.
10. If you are in lack of B group vitamins, you should turn to _______________.
Vitamins cannot be synthesized by the body so must be supplied by diet. Vitamins have no common structure or function but are essential in small amounts for the body to be able to utilize other dietary components efficiently.
Vitamins fall into two categories, fat soluble vitamins such as vitamin A, D, E and K which are ingested with fatty foods and water soluble vitamins such as the B group vitamins and vitamin C. Vitamins are known as micronutrients because only small quantities are required for a healthy diet, in fact fat soluble vitamins can be toxic in high concentrations, for example the body stores vitamin A, or retinol, in the liver as it is toxic if kept in high concentrations in the blood stream, a dose of more than 3300mg of vitamin A can be considered toxic. Water soluble vitamins such as vitamin C and B groups vitamins can be excreted in the urine if in excess in the diet.
Vitamins A
Vitamin A is essential to the proper functioning of the retina in the eye and the epithelial tissues. A lack of vitamin A results in dry, rough skin, inflammation of the eyes, a drying or scarring of the cornea - xerophthalmia, which occurs when the secretion of lubricating tears is stopped, the eyelids become swollen and sticky with pus. Mucous surfaces of the eye may become eroded allowing infection to set in, leading to ulceration and destruction of the cornea. Night blindness - an inability to see in dim light can also occur. Rod cells in the retina of the eye detect light of low intensity, they convert vitamin A into a pigment, rhodopsin, which is bleached when light enters the eye. Rod cells resynthesis rhodopsin, but if there is a deficiency of the vitamin, rod cells can no longer function and the result is night blindness. Epithelial cells use retinol to make retinoic acid, an intracellular messenger used in cell differentiation and growth. Without retinoic acid epithelial cells are not maintained properly and the body becomes susceptible to infections, particularly measles and infections of the respiratory system and gut.
Xenophthalmia is common among children who's diets consist of mainly cereals with little meat or fresh vegetables, this is common in Indonesia, Bangladesh, India and the Philippines.
Vitamins D
Vitamin D, or calciferol, is another fat soluble steroid vitamin which functions to stimulate calcium uptake from the gut and its deposition in bone. vitamin D acts as a hormone when converted by enzymes in the gut and liver into an active form of "active vitamin D", which stimulates epithelial cells in the intestine to absorb calcium. vitamin D is therefore essential in growing children's diets to enable the growth of strong bones. Without adequate amounts of vitamin D children can develop rickets, which is the deformation of the legs caused when they lack calcium to strengthen the bones. In adults a lack of vitamin D in the diet can lead to osteomalacia, a progressive softening of the bones which can make them highly susceptible to fracture.
Vitamin D is made by the body when exposed to sunlight and is stored in the muscles, however, if the skin is rarely exposed to the sunlight or is dark little vitamin D is produced. Foods such as eggs and oily fish are all rich in vitamin D.
Vitamins K
Vitamin K, phylloquinone, is found in dark green leafy vegetables such as spinach and kale. It is a fat soluble vitamin which is involved in the clotting process of blood. In the intestines bacteria synthesize a number of important clotting factors which need vitamin K. Without vitamin K cuts can fail to heal and internal bleeding can occur.
Vitamins C
Vitamin C is a water soluble vitamin, known chemically as ascorbic acid. It is found in citrus fruits such as oranges and lemons, and also in potatoes and tomatoes. The main function of vitamin C is the formation of connective tissues such as collagen. It is also known to be an antioxidant which helps to remove toxins and aids the immune system. A lack of vitamin C leads to Scurvy, a condition experienced by sailors on long journeys when they did not have fruit in their diets. Scurvy causes painful, bleeding gums. As vitamin C is water soluble, it is not toxic in high doses as it can be excreted in the urine, very high doses can however cause diarrhea.
Vitamins B
B group vitamins have a wide range of roles acting as co-enzymes in metabolic pathways. They are found in most plant and animal tissues involved in metabolism, therefore foods such as liver, yeast and dairy products are all rich in B group vitamins. Deficiency of B group vitamins include dermatitis, fatigue and malformation of red blood cells.
1. An adult needs about 12,000kJ of energy a day from ________.
A. the cell
B. the respiring process of carbohydrates
C. fats in the cell
D. a balanced diet
2. Carbohydrates are ultimately absorbed into cells in the process of _______.
A. digestion
B. respiration
C. oxidization
D. mobilization
3. The Essential Amino Acids which build part of proteins can be obtained from______.
A. stomach
B. body tissues
C. the body
D. the diet
4. The ultimate cause of kwashiorkor is lack of ________.
A. protein
B. carbohydrates
C. vitamins
D. diet
5. Vitamins are called “micronutrients” in that _________.
A. excessive fat soluble vitamins can be excreted in the urine
B. the body only requires small amount of vitamins
C. a dose of 3300mg of vitamins can be considered toxic
D. the high concentrations of water soluble vitamins are toxic
6. Night blindness is a disease normally caused by lack of __________.
A. fat soluble vitamins
B. water soluble vitamins
C. vitamin A
D. innate disability
7. The main function of vitamin D is to prevent adults from ________.
A. the growth of strong bones
B. fracture
C. a progressive softening of the bones
D. calcium uptake from the gut
8. Although the human body produces vitamin D normally, it fails to do so if there is not enough ______________.
9. The reason why vitamin C is seen as an antioxidant is that it drives __________ out of the body.
10. If you are in lack of B group vitamins, you should turn to _______________.