Vitamins: what they are, what they are for and types

Vitamins are organic compounds not synthesized by the body, being incorporated through food.

They are essential for the functioning of important biochemical processes in the body, especially as catalysts for chemical reactions.

The main sources of vitamins are fruits, vegetables, vegetables, meat, milk, eggs and cereals.

Partial vitamin deficiency is called hypovitaminosis, while the excess intake of vitamins is called hypervitaminosis. Avitaminosis is the extreme or total lack of vitamins.

There are also provitamins, substances from which the body is able to synthesize vitamins. For example: carotenes (pro-vitamin A) and sterols (pro-vitamin D).

Types

Vitamins are divided into two groups, depending on the substance in which they dissolve:

Fat-soluble vitamins: are the vitamins fat soluble and so they can be stored. This group includes vitamins A, D, E and K.
Water-soluble vitamins: These are the B complex vitamins and vitamin C, water soluble. They cannot be stored in the body, making hypervitaminosis cases rare. They are also quickly absorbed and excreted.
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fat soluble vitamins

Vitamin A (Retinol/Beta-Carotene)

Functions: Tissue growth and development; antioxidant action; reproductive functions; integrity of epithelia; important for vision.
Sources: Liver, kidney, cream, butter, whole milk, egg yolk, cheese and oily fish. Sources of carotenes present in carrots, zucchini, sweet potatoes, mangoes, melon, papaya, red peppers, broccoli, watercress, spinach.
Hypovitaminosis: Keratinization of the mucous membranes that line the respiratory tract, digestive tract and urinary tract. Keratinization of the skin and eye epithelium. Changes in the skin, insomnia, acne, dry skin with scaling, decreased taste and appetite, night blindness, ulcers in the cornea, loss of appetite, growth inhibition, fatigue, bone abnormalities, weight loss, increased incidence of infections.
Hypervitaminosis: Joint pain, thinning of long bones, hair loss and jaundice.

Vitamin D

Functions: Absorption of calcium and phosphorus. Helps the growth and strength of bones, teeth, muscles and nerves;
Sources: Milk and dairy products, enriched margarines and cereals, oily fish, eggs, brewer's yeast.
Hypovitaminosis: Bone abnormalities, rickets, osteomalacia;
Hypervitaminosis: Hyperkalemia, bone pain, weakness, failure to thrive, calcium deposition in kidneys;

Vitamin E (Tocopherol)

Functions: Antioxidant action, protects cells from damage caused by free radicals, helping to prevent cardiovascular disease and some types of cancer.
Sources: Vegetable oils, walnuts, almonds, hazelnuts, wheat germ, avocado, oats, sweet potatoes, dark green vegetables.
Hypovitaminosis: Hemolytic anemia, neurological disorders, peripheral neuropathy and skeletal myopathy.
Hypervitaminosis: There is no known toxicity.

Functions: Catalyze the synthesis of blood clotting factors in the liver. Vitamin K acts in the production of prothrombin, which combines with calcium to help produce the clotting effect, and is needed to maintain bone health.
Sources: Green leafy vegetables, liver, beans, peas and carrots.
Hypovitaminosis: Tendency to bleeding.
Hypervitaminosis: Dyspnea and Hyperbilirubinemia.

Water Soluble Vitamins

Functions: Antioxidant, healing, acts on the growth and maintenance of body tissues, including bone matrix, cartilage, collagen and connective tissue.
Food sources:fruit citrus, berries, apple, tomato, potato, sweet potato, cabbage, broccoli.
Hypovitaminosis: Bleeding spots on skin and bones, weak capillaries, fragile joints, difficulty in healing wounds, bleeding gums.

At exotic fruits they are also excellent sources of vitamin C.

Complex B vitamins

The B complex vitamins comprise eight vitamins, they are:

Thiamine (B1)

Functions: Energy release from carbohydrates, fats and alcohol.
Sources: Wheat germ, peas, yeast, fortified breakfast cereals, peanuts, liver, potatoes, pork and beef, liver, grains, pulses.
Hypovitaminosis: Beriberi (pain and paralysis of the extremities, cardiovascular changes and edema), anorexia, indigestion, constipation, gastric atony, secretion insufficient hydrochloric acid, fatigue, general apathy, cardiac muscle weakness, edema, heart failure and chronic pain in the system skeletal muscle.
Hypervitaminosis: May interfere with the absorption of other B-complex vitamins.

Riboflavin (B2)

Functions: It provides energy from food, growth in children, tissue restoration and maintenance.
Sources: Yogurt, milk, cheese, liver, kidney, heart, wheat germ, vitamin breakfast cereals, grains, oily fish, yeast, eggs, crab, almond, pumpkin seed, vegetables.
Hypovitaminosis: Cheilosis (cracks in the corners of the mouth), glossitis (edema and redness of the tongue), blurred vision, photophobia, peeling skin, seborrheic dermatitis.

Niacin (B3)

Functions: Required for energy production in cells. It plays a role in the actions of enzymes in fatty acid metabolism, tissue respiration, and toxin elimination.
Sources: Lean meats, liver, oily fish, peanuts, vitamin cereals, milk, mushroom cheese, peas, green leafy vegetables, eggs, artichokes, potatoes, asparagus.
Hypovitaminosis: Weakness, pellagra, anorexia, indigestion, skin rash, mental confusion, apathy, disorientation, neuritis.

Pantothenic Acid (B5)

Functions: Transformation of energy from fats, proteins and carbohydrates into essential substances such as hormones and fatty acids.
Sources: Liver, kidney, egg yolk, milk, wheat germ, peanuts, walnuts, whole grains, avocado.
Hypovitaminosis: Neurological disorders, headache, cramps and nausea.

Pyridoxine (B6)

Functions: It plays a role in the central nervous system, participates in the metabolism of lipids, in the structure of phosphorylase and in the transport of amino acids across the cell membrane.
Sources: Wheat germ, potato, banana, cruciferous vegetables, nuts, nuts, fish, avocado, sesame seed.
Hypovitaminosis: Central nervous system anomalies, skin disorders, anemia, irritability and seizures.
Hypervitaminosis: Ataxia and sensory neuropathy.

Biotin (B8)

Functions: Energy production through food, fat synthesis, excretion of protein residues.
Sources: Egg yolk, liver, kidney, heart, tomato, yeast, oats, beans, soy, nuts, artichoke, pea and mushroom.
Hypovitaminosis: Skin changes.

Folate (B9) - Folic Acid

Functions: It acts as a coenzyme in carbohydrate metabolism, maintains immune system function, along with vitamin B12, is present in the synthesis of DNA and RNA, in addition to participating in the formation and maturation of cells of the blood.
Sources: Green leafy vegetables, liver, beets, wheat germ, vitamin cereals, nuts, peanuts, grains, pulses.
Hypovitaminosis: Megaloblastic anemia, mucosal lesions, neural tube malformation, growth problems, gastrointestinal disorders, changes in nuclear cell morphology.

Cobalamin (B12)

Functions: It acts as a coenzyme in the metabolism of amino acids and in the formation of the heme portion of hemoglobin; essential for DNA and RNA synthesis; participates in the formation of red blood cells.
Sources: Animal foods, liver, kidney, lean meat, milk, eggs, cheese, yeast.
Hypovitaminosis: Pernicious anemia, megaloblastic anemia, gastrointestinal disturbances.

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