Vitamins are essential components of our body and play a major role in the development and growth. Hence, they must be consumed on a regular basis through variety of foods or as supplementation to the diet (if prescribed by the doctor).

There are 13 essential vitamins the human body needs, in very small amounts, to function properly. It includes 2 groups: fat-soluble (A,D,E, and K) and water-soluble (B Complex – Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Pyridoxine (B6), Biotin (B7), Folate (B9), Cobalamin (B12).

It is well known that natural vitamins are better “recognised”, absorbed and used by our body than artificial ones. Natural vitamins are derived from plants and animals or synthesized by certain bacteria of upper gastrointestinal tract (vitamin B 12, biotin, folic acid, etc.) in humans.

Vitamins deficiency in everyday nutrition can trigger series of physiological and pathological changes in the body from fatigue, depression, obesity, skin problems to rickets and scurvy, liver disease and many more.

The most important vitamins are:

Vitamin B Complex

Vitamin B1 (Thiamine)

Vitamin B2 (Riboflavin)

Vitamin B3 (Niacin)

Vitamin B5 (Pantothenic Acid)

Vitamin B6 (Pyridoxine),

Vitamin B7 (Biotin)

Vitamin B9 (Folic Acid)

Vitamin B12 (Cobalamin)

Vitamin C (Ascorbic acid)

Vitamin A

Vitamin D

Vitamin E

Vitamin K

Vitamin B complex

All 8 B complex vitamins are essential for optimal functioning: they facilitate energy pathways (converting carbs into glucose), maintain normal heart work and cell division, support nervous system, regulate metabolism of proteins and fats. The body does not create a reserve of this vitamin group and it must be taken regularly. The vitamin deficiency commonly occurs in the elderly, vegetarians and people with chronic digestive problems.

Vitamin B7(Biotin)

Food rich in Biotin: Yeast, egg (yolk), beef (liver, kidneys), mushrooms, cauliflower, apples, chocolate, etc.

Physiological functions: As a coenzyme, it participates in the oxidation of fatty acids, carbohydrates, etc.

Biotin deficiency: A condition known as a ‘disease of raw egg whites’ may develop after eating only raw egg whites over prolonged period of time. Symptoms include dermatological (alopecia dermatitis, depigmentation of hair, eyebrow and eyelashes loss), as well as various neurological disorders.

Biotin drug interactions:The use of anticonvulsants can cause biotin deficiency.

Vitamin B1 (Thiamine)

Food rich in vitamin B1: Milk, eggs, pork meat (liver), brewer’s yeast, wheat cereals, bran, cereal grains (whole grain), cabbage, spinach, various fruits and nuts (especially walnuts), orange, eggplant. Daily needs for adults are around 1 mg, which is quite sufficient if we consume mixed food, especially fresh plants.

Physiological functions of B1: It helps convert carbohydrate into energy and proper functioning of central nervous system.

Thermal treatment: Very unstable at temperatures above 100 ° C.

Vitamin B1 deficiency: It may develop due to insufficient intake and/or decreased absorption of the vitamin, with certain conditions such as chronic alcoholism and pregnancy (vomiting). Early symptoms of vitamin B1 deficiency are depression, fatigue, and various mental disorders.

Vitamin B1 drug interactions:

  • Diuretics for lowering blood pressure and improving heart rate may cause a deficit of vitamin B1
  • Oral contraceptives can also lead to vitamin B1 deficiency
  • Antidepressants increase the need for B1

Vitamin B2 (Riboflavin)

Food rich in vitamin B2: Foods of plant and animal origin like garlic, soy, germinating seeds, especially wheat germ, nuts, algae, etc. It can also be found in green vegetables: lettuce, cabbage, green beans, potatoes, and dried apricots. In animal food has it most in liver, kidneys, muscles, milk and eggs.

Physiological functions of B2: It has an important role in the metabolism of carbohydrates, and is essential for good eye vision, etc.

Thermal treatment: Stable when heated and resistant in the acid and/to oxidation.  Riboflavin is extremely sensitive to visible rays of the sun spectrum.

Vitamin B2 deficiency: Early symptoms are related to inflammation of the oral cavity (tongue) and eyes, including cheliosis (cracking of the corners of the mouth with the appearance of yellow scab and painful inflammation of the lips) and glossitis (inflammatory changes of the tongue).

Vitamin B2 drug interactions:

  • Chemotherapeutic Doxorubicin can cause B2 deficiency
  • Oral contraceptives may cause vitamin B2 deficiency
  • Prolonged use of tetracycline may cause deficiency of B2
  • Probenecid, which is used in the treatment of gout, decreases absorption of vitamin B2 and increases the excretion of B2 by urine
  • Tricyclic antidepressants and vitamin B2 have a synergistic effect

Vitamin B3 (Niacin)

Food rich in vitamin B3: Yeast, tuna fish, chicken, turkey, pork, lamb (liver) rice, grains, green peas, peanuts, avocado.

Physiological functions of Niacin: An important role in the metabolism of fats, carbohydrates and proteins; it participates in the processes of cellular respiration of the skin, mucous membranes, the formation of red blood cells, synthesis of hormones and normal functioning of the nervous system. Vitamin B3 could help prevent skin cancer.

Thermal treatment: Stable when heated.

Vitamin B3 deficiency: Due to diarrhoea, dermatitis, and dementia.

Vitamin B3 drug interactions:

  • Niacin may raise level of sugar in blood
  • Parkinson’s disease medication acts synergistically with vitamin B3
  • Isoniazid for tuberculosis treatment may cause deficiency of vitamin B3
  • Nicotine patches in conjunction with vitamin B3 can cause increased redness and pain
  • Oral contraceptives can lead to a slight deficit of vitamin B3
  • Vitamin B3 together with tetracycline may improve efficacy of the treatment
  • Tricyclic antidepressants act synergistically with vitamin B3

Vitamin B5 (Pantothenic Acid)

Food rich in vitamin B5: Fresh vegetables, corn, tomato, broccoli, cauliflower, avocado, peas, peanuts, yeast, beef (liver, kidneys), turkey, chicken, milk, cereals, legumes, etc.

Physiological functions of vitamin B5: Essential for metabolism of fats, carbohydrates and proteins, participates in the synthesis of fatty acids, cholesterol, in the formation and activation of antibodies.

B5 deficiency: Unknown in those eating variety of well-balanced food groups.  Symptoms of B5 malabsorption include nausea, intestinal problems, reduced immune function, dermatitis, convulsions and other non-specific symptoms.

Vitamin B5 drug interactions:

The vitamin may interfere with the absorption and effectiveness of tetracycline.

Toxicity: In some cases, daily intake of 10 to 20 mg may cause diarrhoea.

Vitamin B6 (Pyridoxine)

Food rich in vitamin B6: Brewer’s yeast is the best source of B6 and meat including beef (liver), tuna, salmon, chicken, egg, etc. Vegetables rich in B6 are potatoes, corn, spinach, rice (white), banana, watermelon, etc.

The amount of the vitamin in the body is very small. The need for B6 increases with protein intake. For example, if we consume 100 grams of protein daily, amount of vitamin B6 should be 2 mg.

Physiological functions of vitamin B6: It participates in the production of antibodies (deficiency can cause skin problems), in the synthesis of elastin and degradation of glycogen, etc.

Toxicity: High dose (2000 mg) can cause nerve damage!

Vitamin B6 deficiency: No risk of B6 deficiency if consumed through variety of fresh food. Inadequate absorption of this vitamin may develop due to hyperthyroidism and alcoholism. Symptoms of B6 deficiency: changes to the skin around the eyes, nose, mouth, glossitis (inflammation of tongue) and number of other infections.

Vitamin B6 drug interactions:

  • Anticonvulsants may cause a deficiency of vitamin B6 since this vitamin increases the metabolism of anticonvulsant drugs
  • Erythromycin, antibiotic, during the long-term therapeutic uses, can interfere with the absorption of vitamin B6
  • Oral contraceptives may cause vitamin B6 deficiency
  • Gentamicin may lead to a mild deficit of vitamin B6
  • Hydralazine may lead to a mild B6 deficiency
  • Isoniazid and vitamin B6 are competitive antagonists
  • Tricyclic antidepressants with vitamin B6 show synergistic effects

Folic Acid

Food rich in Folic Acid: Green vegetables (spinach, broccoli, chickpeas) and meat (liver), cereals, etc.

Physiological functions of vitamin B Complex: They participate in the formation of red blood cells and support other important biochemical processes.

Folic Acid deficiency may develop due to insufficient intake of vitamin B complex or malabsorption. One of the causes of megaloblastic anaemia can be deficiency of the vitamin over a period of 3-5 months.

Folic acid drug interactions:

  • Antacids can interfere with the absorption of folic acid
  • Aspirin leads to increased excretion of folic acid
  • Diuretics can cause increased excretion of folic acid
  • Erythromycin can interfere with the absorption of folic acid
  • Oral contraceptives can reduce the level of folic acid

Vitamin B12

Food rich in vitamin B12: Diary products like cheese, milk and milk products, shellfish, salmon, oysters, poultry, beef, soy and other food.

Physiological functions of vitamin B12: Participates in cell metabolism and tissue growth and is important for maintenance of the cognitive functions and central nervous system. As a coenzyme, B12 is responsible for the DNA synthesis and has an important role in the formation of red blood cells.

Deficiency of vitamin B12: Can lead to megaloblastic anaemia, abnormal gastric mucosa, and particular changes in the CNS.

Vitamin B12 drug interactions:

  • Anticonvulsants can cause anaemia due to deficit of Folic Acid and B12
  • Colchicine (gout therapy) interferes with B12
  • Drugs for lowering blood pressure can also lower B12 levels
  • Oral contraceptives can cause B12 deficiency
  • Sulphonamide antibiotics can cause B12 deficiency

Vitamin A & Provitamin A (Beta-Carotene)

Food rich in vitamin A: Plants do not contain vitamin A but can synthesize various carotenes. After absorption in the animal/human organism some carotene is converted to vitamin A (Beta-Carotene).

Carotenoids are responsible for orange, red and yellow coloured herbs such as red papers, pomegranate, pumpkin, carrots, cranberries, wild pumpkin, etc.

Good sources of vitamin A are oily fish and fish oil – highly recommended for better calcium transport, growth and development of bones, and as a first line of

defence against various diseases in children. Good sources of vitamin A are also cabbage, pine needles, haw, cranberries, peaches, apricots, plums and other fruits.

Milk and butter obtained from grazing animals has more vitamin A and D than butter and milk from cows fed with dry hay.

Thermal treatment: Vitamin A is resistant to elevated temperatures but is very sensitive to oxidizing agents and light. It is, therefore, important to consume fresh fruits and vegetables since it is very difficult to prevent the destructive effects of light and oxygen from the air.

Low temperature has no influence on depletion of this vitamin, but significant amount of vitamin A is lost by leaching into cooking water.

Physiological function of vitamin A: It has an important role in a variety of biochemical and physiological processes including normal functioning of the immune system and vision. Retinol (form of vitamin A) has synergistic, antioxidative effect with vitamin E.

Vitamin A deficiency can cause variety of symptoms from night blindness to serious eye damage, skin changes, stunted growth, and susceptibility to infections.

Vitamin A toxicity:

Vitamin A overdose (above the recommended daily allowances) might be dangerous for pregnant women because of the potential embryo toxicity. The pregnant women should instead use low dose of carotene supplements.

The symptoms of vitamin acute and chronic toxicity include: liver damage, dermatitis, scabs, sweating, fatigue, and even death in amounts exceeding 300 mg.

Vitamin A drug interactions:

  • Vitamin A in ointments and creams helps repair the wound
  • Oral contraceptives interfere with the absorption of vitamin A
  • Vitamin E is necessary for absorption and storage of vitamin A and prevents its toxic effect in the organism
  • Zinc increases the absorption of vitamin A

Vitamin D

Food rich in vitamin D: Cod liver oil, salmon, tuna, sardines, butter, cheese, milk, meat (liver), and mushrooms.

Since breast milk has a low content of vitamin D it is recommended to take additional amount of vitamin D (drops) when breastfeeding.

Physiological functions of vitamin D: It has essential role in construction and regeneration of bones, absorption and metabolism of calcium and phosphorus, phospholipids, muscle activity, and many more still being the subject of research.

Vitamin D deficiency: In children, various deformities may develop such as scoliosis (spine curvature) bowed legs or delay of teeth growth.

In adults, deficiency may cause osteomalacia, brittle and fragile bones, neurological disorders and other conditions. This is particularly the case in the northern hemisphere where many people don’t get enough sunlight over the winter, which is necessary for our body to synthesize enough vitamin D, and supplementation should be taken regularly.

Vitamin D overdose

  • During pregnancy and breastfeeding it is necessary to seek medical advice on safe dosage of vitamin D
  • Excessive intake of vitamin D (supplements) can cause oxidation of membrane and deposition of calcium in soft tissues
  • Overdose symptoms include nausea, vomiting, increased blood pressure and kidney damage, growth retardation in children and other serious conditions.

Vitamin D drug interactions:

  • Antiepileptic drugs can accelerate the metabolism of vitamin D
  • Mineral oils reduce the absorption of vitamin D
  • Verapamil can raise levels of calcium in blood
  • Digitalis can increase the levels of calcium in the blood
  • Barbiturates reduce the activity of vitamin D

Vitamin E

Food rich in vitamin E: Plants are good reservoirs of this vitamin, primarily the germ of wheat and other cereals. Rich source of vitamin E are also walnut, peanuts, almond, chestnut, soybeans, the young green leaves, lettuce, clover, young peas and cottonseed, banana, apples. This vitamin is most resistant to heat, oxygen and oxidation and ultraviolet rays.

Physiological function of vitamin E: Protection of cell membranes and plasma lipoproteins from free radicals. This vitamin has important role in the development of sex cells.Vitamin C “backs up” (regenerates) vitamin E!

Toxicity: Unknown even in larger doses.

Vitamin E deficiencyMany serious conditions may develop due to malabsorbtion or insufficient intake such as muscle weakness, visual field limitations (even complete blindness), heart disease and brain changes.

Vitamin E drug interactions:

  • Mineral oils interfere with the absorption of vitamin E
  • Orlistat, cholestyramine, isoniazid reduces absorption of vitamin E
  • Iron can oxidize the non-esterified vitamin E
  • Vitamin E affects (potentiate) the antiplatelet activity of aspirin
  • Hypolipemics, orlistat, reduces absorption of vitamin E
  • Vitamin E interferes, at the level of absorption, with tricyclic antidepressants (desipramine), chlorpromazine, beta-blockers (propranolol, atenolol, metoprolol)

Vitamin K

Food rich in vitamin K: Green herbs (green foliage) are rich in chlorophyll, which is a form of vitamin K. The underground organs of plants have much less of the vitamin than aboveground green parts. Good sources of in vitamin K are Indian alfalfa, leafs of sweet and horse chestnut, spinach, nettle, cabbage, cauliflower, seaweed, tomatoes, peas, grains, soybeans, carrots, potatoes. Foods of animal origin are also rich in vitamin K pork liver, milk, eggs, spinach, cauliflower, and leafy vegetables. This vitamin can be synthesized in organism by the gut bacteria but the quantity is not the same for everyone as each person has a different intestinal flora.

Physiological functions in the body: Very important for all coagulation proteins (clotting factors) and skeletal system.

Vitamin K deficiency: Malabsorption of vitamin K may develop due to prolonged use of antibiotics, obstructive jaundice, etc. People with osteoporosis show low levels of vitamin K. With stented patients and those on anticoagulant therapy monitoring is necessary because of the deficiency/surplus of this vitamin.

Overdose of vitamin K: Can be severe including jaundice and liver damage, red blood cell destruction, and even death.  It is necessary to seek medical advice on vitamin K supplements.

Vitamin K drug interactions:

  • Oral anticoagulants interfere with the absorption of vitamin K
  • Antibiotics (cephalosporin) extended application inhibit the synthesis of vitamin K by intestinal micro flora
  • Mineral oils, orlistat, cholestyramine, colestipol, interfere with the absorption of vitamin K

Vitamin C

Food rich in vitamin C: Fresh and raw fruits, vegetables (99%) and food of animal origin (1%). Most of the vitamin C can be found in red, orange and yellow fruits, such as pomegranates, haw, oranges, mandarins, lemons, blackberries, red peppers, carrots, kale, tomato, cauliflower, radishes, irises and parsley leaves, pine needles, green walnuts with soft core, horseradish, cabbage, etc.

Thermal treatment: Vitamin C is the most sensitive of all the vitamins, it is completely destroyed at the temperature of 60 ° C (dry heat), and also unstable at lower temperatures.

It is best to consume fresh, unprocessed fruit and vegetables because vitamin C dissolves in cellular juice that is acidic, and dried herbs lose the acidity through the process.

Oxidation (oxygen from the air) also affects the vitamin C.

Sterilized, canned fruit and vegetables have 50% less of vitamin C than fresh one.

Physiological role of vitamin C: It necessary for collagen synthesis (a protein that participates in the composition of bones, skin, teeth, tendons, etc.). The vitamin is said to be at constant ‘war’ with free radicals. Vitamin C plays an important role in a body immune system. It also participates in production of thyroxin, a hormone that is essential for organism metabolic functions.

Vitamin C deficiency: Lack of ascorbic acid in foods leads to scurvy, joint pain, gums swelling, tooth loss, etc. Humans can’t synthesise vitamin C but are able to store it (between 2-4g); and the amount is sufficient to approximately 3 months without apparent deficiency symptoms.

Overdose and toxicity of vitamin C: If consumed in quantities exceeding 1000 mg a day may cause diarrhoea, nausea, formation of oxalate in kidneys in people with kidney problems, and increased oxidative stress in individuals who have increased levels of Fe (hemochromatosis).

Vitamin C drug interactions:

  • Ampicillin, antibiotics, lowers vitamin C in the body
  • Epinephrine, adrenaline, a natural hormone available as over-the-counter (OTC) product to relieve asthma symptoms, reduces the level of vitamin C in plasma
  • Oral contraceptives – can cause vitamin C deficiency
  • Aspirin – increases the elimination of vitamin C
  • Tetracycline – potential deficiency of vitamin C due to long-term use
  • Phenothiazine, used to treat various psychoses, has synergistic effects with vitamin C