Vitamins

Introduction

Classification of vitamins, functions, food sources, nutritional requirements, interesting facts

Introduction

  Vitamins are organic compounds, which human's organism cannot produce (or produces them in little amount in digestive system thanks specific bacterial flora), they must be provided together with food in finished form or form of provitamins, which during metabolism acquire full biologic activity. Vitamins - complementary factors, this term was introduced by Polish biochemist Casimir Funk, who in 1911 had separated a compound of such character and called it vitamin B₁.

  Vitamins are compounds which are neither a source of energy nor structural tissue ingredients but they are essential to organism growth and correct run of metabolism processes. Their biological action is visible just at very small concentration.
  Mechanism of vitamin action is different but all of them affect directly or indirectly cell metabolism processes, most frequently as so called co-enzymes or biologically active ingredients of hormone character.
  As it is well-known, deficiency of any vitamin in organism causes hypovitaminosis and their deficiency avitaminosis. Even little deficiency of vitamins may lead to different kinds of disorder and increase hazard of occurrence of so-called civilization diseases. Excessive consumption or overdose of some of them is also very harmful and may be a reason of disease caused by their excess - hypervitaminosis, with symptoms of poisoning.

Classification of vitamins, functions, food sources, nutritional requirements, interesting facts

Fat soluble vitamins. They can be stored so organism in higher grade may tolerate their periodical deficiency.

• Vitamin A

• Vitamin D

• Vitamin E

• Vitamin K

Water soluble vitamins. These vitamins are stored in organism in little grade so a nutritious dose should contain their optimum amount.

• Vitamin B₁

• Vitamin B₂

• Vitamin B₅ (Pantothenic acid)

• Vitamin B₆

• Vitamin B₁₂

• Vitamin PP (Niacin)

• Vitamin C

• Vitamin H (Biotin)

• Folic acid (Folate)

 

 

Vitamin A

Function of vitamin: 
Activity of vitamin A is revealed by many compounds structurally related. In animal organism it is retinol and its derivates (e.g. retinal, 3-dehydroretinol). In plants and fungus vitamin A occurs only as provitamin and its main compound is ß-carotene, additionally compounds defined as carotenoids occur. Vitamin A prevents nyctalopia, sight weakening, helps in treatment of many eye diseases because it belongs to retinal pigment, photosensitive dye located in stamens of retina. Vitamin A also ensures correct appearance of skin and affects synthesis of proteins, lipids and thyroid gland hormones, keeps in health mucous membranes of oral cavity, nose, throat, lungs, digestive system and increases immunity against infections.


Food sources: 
As Retinol and its derivatives: liver, fish-liver oil, egg yolk, milk, butter, margarine. As ß-carotene and its derivatives (provitamin A): red and yellow fruit and vegetables (carrot, pumpkin, apricot, peach), dark-green vegetable parts (spinach, broccoli, kale, lettuce).


Nutritional requirements:  
The content of vitamin A in food products is expressed as "Retinol Equivalent" in micrograms [?g]. Retinol presents 100% of biological activity.

The content of vitamin A in food products can be also expressed in International Units [I.U.]. In order to convert International Units into "Retinol Equivalent" we have to use the conversion factor.

1 [?g] Retinol Equivalent = 3,3 International Units [I.U.].

Dietary Reference Intakes for various life stage groups - vitamin A

^*1 Recommended Dietary Allowances (RDAs) - the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97,5%)) healthy individuals in a particular life stage and gender group..

^*2 Tolerable Upper Intake Levels (ULs) - the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

^*3 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• as vitamin A called Retinol it is located only in food of animal origin. As provitamin A called carotene it is placed in food of plant origin,

• in connection with high eye strain, people, whose work is associated with long sitting in the front of a computer monitor, need more vitamin A,

• ß-carotene occurs especially in red and yellow fruit and vegetables. It is responsible for saturated yellow, orange and red dye of these plants,

• only ß-carotene is effective antioxidant. Moreover its overdose does not show so high toxicity as vitamin A overdose,

• high vitamin A doses given during pregnancy may cause premature labor and also abnormalities and difficulties during labor,

• vitamin A (as retinol and carotene) belongs to quite durable vitamins, which during cooking and properly conducted heat treatment processes does not undergo a change. At very high temperatures used during frying it inquires into high losses of vitamin A. Retinol also inquires into decomposition during rancid becoming of fat. Vitamin A is sensitive to light,

• products with high ß-carotene content may provide necessary dose of vitamin A without hazard of carcinogenic changes causing.

Vitamin D

Function of vitamin:
Vitamin D (as vitamin D₂ that is Ergocalciferol and vitamin D₃ that is Cholecalciferol) fulfills relevant function in regulation of calcium and phosphorus transformation and bones forming. This vitamin increases absorption of calcium and phosphorus from intestines and also reduces the amount of calcium expelled from organism. It is also essential to optimum forming of osseous system, indirectly influences correct nervous conduction and correct heart beat.


Food sources: 
Synthesized by organism under influence of sun light; fish-liver oil, sardine, mackerel, herring, salmon, tuna, egg yolk, liver, milk and dairy products.


Nutritional requirements:  
The content of vitamin D in food products is expressed in micrograms [?g] or in International Units [I.U.].

 

Dietary Reference Intakes for various life stage groups - vitamin D

^*1 Recommended Dietary Allowances (RDAs) - the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97,5%)) healthy individuals in a particular life stage and gender group..

^*2  Tolerable Upper Intake Levels (ULs) - the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

Interesting facts:

• vitamin D is created in human's skin in result of ultraviolet sun rays action. With nourishment mainly its initial form (provitamin) is taken; provitamin in following stages is processed in liver, kidneys and skin to right vitamin D,

• older people are especially exposed to occurrence of vitamin D deficiency. In association with the age skin ability to production of this vitamin under influence of light drops down. Also much lower physical activity of the older is responsible for that,

• vitamin D is soluble in fats. It makes its storage in organism easier, that is why too high its doses may cause hypervitaminosis,

• 20 g of a salmon covers daily demand for vitamin D.

Vitamin E

Function of vitamin:
Tocopherol that is vitamin E is a main antioxidant which protects cells against oxidants. It takes part in providing of nutrients to cells. It strengthens blood vessel walls and protects erythrocytes against premature decomposition. It is used to treatment of male sterility, muscle disorder, arteriosclerosis and heart diseases.


Food sources: 
Plant oil (soybean, corn, sunflower), almond, margarine, eggs, walnut, peanut, wheat germ, wholewheat flour, milk, Brussels sprouts and other green-leaf vegetables.


Nutritional requirements:  
The content of vitamin E in food products is expressed as "a-Tocopherol Equivalent" in miligrams [mg] taking into consideration the content and the activites of various other forms. a-Tocopherol presents 100% of biological activity.

In food tables we can encounter with International Units [I.U.]

1 [mg] a-Tocopherol Equivalent = 1,5 International Unit [I.U.]. 

Dietary Reference Intakes for various life stage groups - vitamin E

^*1 Recommended Dietary Allowances (RDAs) - the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97,5%)) healthy individuals in a particular life stage and gender group..

^*2 Tolerable Upper Intake Levels (ULs) - the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

^*3 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• antioxiding properties of this vitamin are often used in process of processing and production of plant oil, margarine, roast foodstuffs, where it occurs as preservative counteracting rancid becoming of fat,

• natural vitamin E is formed only in plants. Animals cannot produce it,

• during blanching and drying of vegetables and fruit losses of this vitamin are high. Vitamin E deficiency in food may accelerate processes of natural ageing of organism and also increase hazard of arteriosclerosis and tumors,

• as vitamin soluble in fats and stored in adipose tissue, taken for a longer time in a synthetic form, in doses higher than 1000 mg of a-tocopherol acetate a day, in older people, may cause fatigue, headaches, muscle weakening and sight disturbance,

• vitamin E interacts with vitamins A, C, carotenoids, bioflavonoids and also with selenium decreasing hazard of carcinogenic diseases growth and formation of free radicals.

Vitamin K

Function of vitamin:
Vitamin K (as vitamin K₁ - Phylloquinone, K₂ - Menaquinone and K₃ - Menadione) also called antihemorrhagical vitamin, fulfills a key role in forming of prothrombin, an important factor of blood coagulation process. Its best known function is antihemorrhagical action. It also participates in formation of osseous tissue. It possesses antibacterial and fungicidal properties.


Food sources: 
Kale, spinach, Brussels sprouts, lettuce, cauliflower, cress, broccoli, milk, yogurt, soybean oil, fish liver oil, meat, eggs, produced by bacteria existing in human's colon (large intestine).


Nutritional requirements:  
The content of vitamin K in food products is expressed in micrograms [?g]. For this vitamin Tolerable Upper Intake Levels (ULs) has been not determined due to lack of data of adverse effects. Source of intake should be from food only to prevent high levels of intake.

Dietary Reference Intakes for various life stage groups - vitamin K

^*1 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• children and bedridden people are doomed to supply their organism in vitamin K only by nourishment. In healthy adults this vitamin is produced by intestine bacterial flora,

• vitamin K₁ (Phylloquinone) is retrieved from food, K₂ (Menaquinone) is produced by intestine bacteria, and vitamin K₃ (Menadione) is synthesized what means artificially manufactured,

• antibiotic treatment may cause vitamin K deficiency because antibiotics destroy intestine flora. That is why, adequately to therapy, one should consider increased consumption of this vitamin,

• yogurt and kefir are ideal dishes between meals, stimulating production of vitamin K,

• rancid become fats, medicine overuse (salicylates or antibiotics) and preservatives in cans and ready-to-eat foodstuffs destroy vitamin K, make its absorption harder or lead to its premature expelling from organism,

• as vitamin soluble in fats and stored in adipose tissue in case of excessive consumption it may negatively influence liver work,

• in some cases newborns receive vitamin K from their birth, what minimizes bleeding occurrence.

Vitamin B₁

Function of vitamin: 
Thiamine that is vitamin B₁ constitutes relevant factor in reactions of carbohydrates combustion in cells. Also close relation between demand for this vitamin and the amount of provided energy exists. Specially important role is fulfilled by vitamin B₁ in actions and regeneration of nervous system. It is an ingredient of enzymatic systems and supports growth process.


Food sources: 
Cereal seeds, whole-wheat products, bran, groats, enriched corn flakes, beer yeast, lean pork, in majority of vegetables, milk, nuts.


Nutritional requirements:  
The content of vitamin B₁ in food products is expressed in miligrams [mg]. For this vitamin Tolerable Upper Intake Levels (ULs) has been not determined due to lack of data of adverse effects. Source of intake should be from food only to prevent high levels of intake.

Dietary Reference Intakes for various life stage groups - vitamin B1

^*1 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• flour is usually enriched with vitamin B₁ in purpose of compensation of losses during grain grinding process,

• weak source of vitamin B₁ in human is bacterial flora of digestive system,

• in ruminants thiamine synthesis is conducted by microbes located in prestomachs because of what these animals do not suffer from its deficiency,

• total lack of vitamin B₁ in organism is defined as Beri - beri disease. This extraordinary disease has been discovered in prisons of Java Island in people fed only with white rice,

• vitamin B₁ overdose rarely occurs and characterizes itself with vertigo, oversensitiveness, muscle shivering, disorder of heart beat and allergic reactions,

• physically hard working people, athletes, pregnant and feeding women and also people who smoke cigarettes, overuse alcohol and consume much sugar have higher demand for vitamin B₁,

• vitamin B₁ belongs to vitamins most sensitive to action of high temperature and ionizoning rays, it is easily destroyed in basic environment. During culinary processes its losses reach 20-50%,

• people with thiamine deficiency are often victims of mosquitoes and other insects. The cause is lower level of substances deterring insects in skin. Additionally thiamine speeds up wound heeling and reveals pain killing action.

Vitamin B₂

Function of vitamin:
Riboflavin that is vitamin B₂ participates in processes of oxidation and reduction, interacts in correct nervous system functioning, interparticipates with vitamin A in appropriate functioning of mucous membranes, respiratory ducts, digestive system mucosa, epithelium of blood vessels and skin, takes part in transformation of amino acids and lipids, fulfills an important role in functioning of sight organ.


Food sources: 
Liver, skim cheese, almond, fungus, venison, eggs, green parts of vegetables, salmon, trout, mackerel, whole-wheat bakery products, clam, bean, pea, soybean, milk, yogurt, walnut.


Nutritional requirements:  
The content of vitamin B₂ in food products is expressed in miligrams [mg]. For this vitamin Tolerable Upper Intake Levels (ULs) has been not determined due to lack of data of adverse effects. Source of intake should be from food only to prevent high levels of intake.

Dietary Reference Intakes for various life stage groups - vitamin B2

^*1 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• 50% of vitamin B₂ is annihilated after exposing it to direct action of sun light. It is the most important reason of not selling milk in transparent glass bottles,

• in high overdose nausea and vomiting may occur,

• flour is often enriched with vitamin B₂ and other vitamins from group B in purpose of compensation of losses emerged during production process.

Vitamin B₅ (Pantothenic acid)

Function of vitamin:
Pantothenic acid participates in heme synthesis to hemoglobin and cytochromes. As ingredient of coenzyme A it participates in synthesis and decomposition of fatty acids, synthesis of cholesterol and steroid hormones. It takes part in regeneration of skin cells and mucous membranes, participates in antibody production. It supports hair pigmenting process.


Food sources: 
Liver, whole-wheat cereal seeds, sunflower seeds, wheat germs, meat, trout, herring, mackerel, beer yeast, egg yolk, green vegetables, walnut, milk, crab, Camembert cheese.


Nutritional requirements:  
The content of vitamin B₅ (Pantothenic acid) in food products is expressed in miligrams [mg]. For this vitamin Tolerable Upper Intake Levels (ULs) has been not determined due to lack of data of adverse effects. Source of intake should be from food only to prevent high levels of intake.

Dietary Reference Intakes for various life stage groups - vitamin B5 (pantothenic acid)

^*1 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• pantothenic acid belongs to the least lasting vitamins from group B. in process of grain grinding pantothenic acid losses reach up to 50%, meat roasting results in from 25 to 50% and during boiling from 15 to 30%. Synthetic preparations of pantothenic acid exist in form of calcium pantothenate. Calcium pantothenate is resistant to action of light and air,

• in people whose main ingredients of a diet are cooked dishes, canned food, French fries, white bakery products, pizza, pasta, and moreover they eat much sugar and sweets, deficiency of pantothenic acid may occur,

• in case of synthetic pantothenic acid taking in quantity of over 10g a day accidents of digestive system disorder and diarrhea happen to occur,

• the bacteria that normally colonize large intestine (the colon) are capable of making their own pantothenic acid. It is not yet known whether humans can absorb the pantothenic acid synthesized by their own intestinal bacteria in meaningful amounts.

Vitamin B₆

Function of vitamin:
Vitamin B₆ includes six related compounds (pyridoxine, pyridoxal, pyridoxamine and their phosphates), which are easily and mutually transformed and characterize with the same metabolism activity. Vitamin B₆ takes part in amino acid transformation, protein synthesis and fatty acid metabolism. It increases immunity resistance and participates in antibody forming. It helps in change of amino acid - tryptophan into vitamin PP, what lifts up the level of this vitamin in organism. Essential in porhyrine synthesis (hem synthesis to hemoglobin - essential in production of erythrocytes) and hormone synthesis (e.g. serotonin, histamine).


Food sources: 
Fish, pork, wheat germs, walnut, eggs, liver, brown (natural) rice, soybean, wheat, banana, avocado, spinach, poultry, whole-wheat bakery products.


Nutritional requirements:  
The content of vitamin B₆ in food products is expressed in miligrams [mg]. 

Dietary Reference Intakes for various life stage groups - vitamin B6

^*1 Recommended Dietary Allowances (RDAs) - the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97,5%)) healthy individuals in a particular life stage and gender group..

^*2 Tolerable Upper Intake Levels (ULs) - the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

^*3 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• vitamin B₆ surplus, similarly as in case of other vitamins soluble in water, is expelled from organism. But comparing it with other vitamins from this group, excess of Vitamin B₆ taken in form of pills may be toxic,

• synthetic Vitamin B₆ is produced in form of hydrochloride,

• this vitamin is resistant to oxidation and high temperature, sensitive to action of ultraviolet radiation,

• together with increase of protein consumption demand for vitamin B₆ grows, during frying, boiling and curing of meat its losses reach 30-50%.

Vitamin B₁₂

Function of vitamin:
Cobalamin that is Vitamin B₁₂ takes part in erythrocytes formation, genetic material formation (DNA and RNA synthesis), participates in metabolism transformation of fats and carbohydrates, nervous system appropriate functioning, takes part in purine and vitamin B6 transformation. It prevents malignant anemia.  


Food sources: 
Liver, beef, pork, poultry, oyster, spinach, salmon, herring, mackerel, trout, egg yolk, cheese, milk, Lucerne germs, enriched corn flakes.


Nutritional requirements:  
The content of vitamin B₁₂ in food products is expressed in micrograms [?g]. For this vitamin Tolerable Upper Intake Levels (ULs) has been not determined due to lack of data of adverse effects. Source of intake should be from food only to prevent high levels of intake.

Dietary Reference Intakes for various life stage groups - vitamin B12

^*1 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• vegetarians excluding from their diet eggs and dairy products are exposed to vitamin B₁₂ deficiency in perspective of several years after switching to vegetarianism,

• in relation with the fact vitamin B₁₂ acts together with folate, increase of taking of folate partially levels its deficiency,

• correct working thyroid gland makes vitamin B₁₂ absorption easier,

• vitamin B₁₂ activates iron substances in organism and allows vitamin A absorption because it stimulates carotenes to participation in metabolism to allow them to transform later in active form of this vitamin,

• iron and vitamin B₆ deficiency decrease vitamin B₁₂ absorption,

• micro flora of human's digestive system possesses the ability to vitamin B₁₂ synthesis.

Vitamin B3 (Niacin)

Function of vitamin: 
Niacinamide that is vitamin B3, also called niacin, includes nicotinic acid amide, nicotinic acid and derivatives emerging nicotinamide biological activity. This vitamin participates in regulation of sugar level in blood (production of energetic compounds), regulation of cholesterol level, takes part in reduction and oxidation processes (as coenzyme ingredient), participates in keep-up of appropriate state of skin, is involved in regulation of blood flow in vessels, interacts in sex hormones synthesis.


Food sources: 
Fish, pork, wheat germs, walnut, eggs, liver, brown (natural) rice, soybean, wheat, banana, avocado, spinach, poultry, whole-wheat bakery products.


Nutritional requirements:  
The content of vitamin B3 (Niacin) in food products is expressed in miligrams [mg].

Dietary Reference Intakes for various life stage groups - vitamin B3 (niacin)

^*1 Recommended Dietary Allowances (RDAs) - the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97,5%)) healthy individuals in a particular life stage and gender group..

^*2 Tolerable Upper Intake Levels (ULs) - the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

^*3 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• it is one of the few vitamins which does not change in spite of processing and storage of food,

• daily demand for vitamin B3 is usually satisfied by its forming from an amino acid - tryptophan, it is assumed 1mg of niacinamide equals 60 mg of tryptophan,

• excessive consumption of food containing sugar leads to loss of vitamin B3,

• nicotinic acid and amide of this acid should not be mixed up with harmful nicotine, which is contained in tobacco,

• vitamin B3 deficiency may cause disadvantageous changes in permeability because this vitamin is necessary to correct functioning of brain and peripherel nervous system,

• synthetic vitamin B3 excess may cause: headaches, formication, skin reddening, head itchiness, noise in ears, dyspepsia, jaundice, heart arrhythmia, psychosis, likelihood of liver damage, loss of hunger, uric acid concentration, increased glucose content in plasma.

Vitamin C

Function of vitamin:
Ascorbic acid or dehydroascorbic acid, that is vitamin C, participates in production of collagen and basic proteins in the whole organism (bones, cartilages, tendons, ligaments), takes part in metabolism processes as substance conveying electrons, as one of the most important antioxidants it also fulfills a relevant function in reaction of depoisoning and immunity of organism protecting it against oxidation processes, participates in metabolism of fats, cholesterol and gall acid, takes part in vitamin E regeneration, is a factor balancing immunity system, reduces formation of carcinogenic nitrosoamines in stomach, has bacteriostatic and bactericidal properties in relation to some pathogenic microbes, participates in biosynthesis of hormones of adrenal gland cortex, lifts up organism immunity.


Food sources: 
Wild rose (brier) fruit, black and red currant, red and green pepper, Brussels sprouts, elder, cauliflower, strawberry, spinach, kiwi, orange, lemon, raspberry, grapefruit, tomato, potato, cabbage, onion, broccoli, kohlrabi, asparagus, wild strawberry, liver, blackberry.


Nutritional requirements:  
The content of vitamin C in food products is expressed in miligrams [mg].

Dietary Reference Intakes for various life stage groups - vitamin C

^*1 Recommended Dietary Allowances (RDAs) - the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97,5%)) healthy individuals in a particular life stage and gender group..

^*2 Tolerable Upper Intake Levels (ULs) - the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

^*3 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• smokers have higher demand for vitamin C than non-smoking people,

• taking too high doses of synthetic vitamin C is conducive to formation of calculi in kidneys,

• vitamin C is very sensitive to action of high temperature, oxygen, light, moisture and also longer storage. Overdue foodstuff is recognized by decreased vitamin C content in it,

• a human has to take vitamin C from food, while animals can produce it themselves (except monkeys and guinea pigs),

• ascorbic acid that is vitamin C is a white odorless powder of little sour flavor. Synthetic preparations contain approximately 99% of this acid. It dissolves easily in water and dilute methyl and ethyl alcohol. It does not dissolve in fats and their solvents,

• long-lasting aspirin taking triples vitamin C expelling, that is why one should increase doses of this vitamin that time,

• thanks its antioxidating properties vitamin C significantly decreases hazard of chronic diseases occurrence such as cancer, heart diseases or cataract. In purpose of optimum reduction of hazard of such diseases occurrence the latest dietetic recommendations suggest consumption even up to 120 mg of this vitamin a day, best originated from vegetables or fruit.

Vitamin H (Biotin)

Function of vitamin: 
Biotin that is vitamin H, also called coenzyme R, takes part in synthesis of amino acids, sugars, proteins and fatty acids, supports thyroid gland functions, takes part in transformation of carbon dioxide, influences proper skin and hair functioning, participates with vitamin K in synthesis of prothrombine (responsible for blood coagulation).



Food sources: 
Liver, soybean flour, egg yolk, walnut, peanut, almond, sardine, fungus, brown (natural) rice, whole-wheat flour, spinach, crab, carrot, tomato.


Nutritional requirements:  
The content of vitamin H (Biotin) in food products is expressed in micrograms [?g]. For this vitamin Tolerable Upper Intake Levels (ULs) has been not determined due to lack of data of adverse effects. Source of intake should be from food only to prevent high levels of intake.

Dietary Reference Intakes for various life stage groups - vitamin H (biotin)

^*1 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• intestine bacteria possess ability to form vitamin H,

• in dry form biotin is quite durable, but in highly acid and alkaline solutions it loses its biological activity, especially at high temperatures,

• vitamin H deficiency hardly occurs, it may be caused only by a diet consisting of 30% and more of hen albumen, because it contains substance called avidin, which bonds vitamin H and because of that deactivates it. Avidin loses its features when albumen will be heated up.

Folic acid (Folate)

Function of vitamin: 
Folic acid that is Folate participates in DNA and RNA nucleic acids forming, synthesis of amino acids, purines, pyrimidines, takes part in cell division process, constitutes important function in process of erythrocytes formation (together with vitamin B₁₂), participates as coenzyme in monocarbic rests conveying.


Food sources: 
Wheat germs, roughage, baker's yeast, liver, parsley (leaves and root), pod vegetables, spinach, soybean, egg yolk, natural rice, endive, lettuce, asparagus, lentil, Brussels sprouts, cabbage, broccoli, cauliflower.



Nutritional requirements:  
The content of Folic acid (Folate) in food products is expressed in micrograms [?g].

Dietary Reference Intakes for various life stage groups - folic acid (folate)

^*1 Recommended Dietary Allowances (RDAs) - the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97,5%)) healthy individuals in a particular life stage and gender group..

^*2 Tolerable Upper Intake Levels (ULs) - the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

^*3 Adequate Intake (AIs) - the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate-used when an RDA cannot be determined.

Interesting facts:

• it has been concussively proved that occurrence of nervous system congenital anomalies in newborns is conditioned by too low consumption of folic acid by women before getting pregnant and in early stages of pregnancy,

• the team of experts of Health Ministry of Poland, according to other countries, advises to every young woman at reproductive age taking 400 ?g of folate in a daily diet,

• in correlation of the way of meal preparation, to boiling water even up to 90% of folic acid can infiltrate, and this happens because of its perfect solubility. Because of that reason meals should always be cooked with use of minimum of water, relatively it should not be poured out but used to preparation of sauce,

• with participation of folic acid so called happiness hormone - serotonin (which acts soothingly and quieteningly) and noradrenaline which is responsible for activity and dynamics during a day),

• there are proofs high level of substance called homocysteine in blood increases hazard of heart diseases occurrence. Increased consumption of folate may have significant influence for prevention of heart diseases.