What vitamins are and what they do

Vitamins are organic substances that the body needs in small amounts, which are indispensable for the functioning of the organism, since they are essential for the maintenance of a healthy immune system, proper functioning of the metabolism and for growth.

Due to its importance in the regulation of metabolic processes, when they are ingested in insufficient quantity or when the body has some vitamin deficiency, this can bring serious health risks, such as vision, muscle or neurological problems.

As the body is unable to synthesize vitamins, they must be ingested through food, and it is very important to eat a balanced diet, rich in vegetables and varied sources of protein.

Classification of vitamins

Vitamins can be classified into fat-soluble and water-soluble, depending on their solubility, fat or water, respectively.

Fat-soluble vitamins

Fat-soluble vitamins are more stable and resistant to the effects of oxidation, heat, light, acidity and alkalinity, when compared to water-soluble vitamins. Their functions, dietary sources and consequences of their deficiency are listed in the following table:

Vitamin

FunctionsSourcesConsequences of disabilityA (retinol)

Maintaining a healthy vision

Differentiation of epithelial cells

Liver, egg yolk, milk, carrots, sweet potatoes, pumpkin, apricots, melons, spinach and broccoli

Blindness or night blindness, throat irritation, sinusitis, abscesses in the ears and mouth, dry eyelidsD (ergocalciferol and cholecalciferol)

Increases intestinal calcium absorption

Stimulates bone cell production

Decreases the excretion of calcium in the urine

Milk, cod liver oil, herring, sardines and salmon

Sunlight (responsible for the activation of vitamin D)

Varus knee, valgus knee, cranial deformities, tetany in infants, bone fragility

E (tocopherol)

Antioxidant

Vegetable oils, whole grains, green leafy vegetables and nutsNeurological problems and anemia in premature babiesK

Contributes to the formation of coagulation factors

Helps vitamin D to synthesize a regulatory protein in bones

Broccoli, Brussels sprouts, cabbage and spinachClotting time extension

See more vitamin-rich foods.

Water-soluble vitamins

Water-soluble vitamins have the ability to dissolve in water and are less stable than fat-soluble vitamins. The following table lists the water-soluble vitamins, their dietary sources and the consequences of deficiency in these vitamins:

VitaminFunctionsSourcesConsequences of disabilityC (ascorbic acid)

Collagen formation

Antioxidant

Iron absorption

Fruit and fruit juices, broccoli, Brussels sprouts, green and red peppers, melon, strawberry, kiwi and papayaBleeding from mucous membranes, inadequate wound healing, softening of the ends of bones and weakening and falling of teethB1 (thiamine)Carbohydrate and amino acid metabolismPork, beans, wheat germ and fortified cerealsAnorexia, weight loss, muscle weakness, peripheral neuropathy, heart failure and wernicke encephalopathyB2 (riboflavin)Protein metabolismMilk and dairy products, eggs, meat (especially liver) and fortified cerealsLesions on the lips and mouth, seborrheic dermatitis and normochromic normocytic anemiaB3 (niacin)

Production of energy

Synthesis of fatty acids and steroid hormones

Chicken breast, liver, tuna, other meats, fish and poultry, whole grains, coffee and teaSymmetrical bilateral dermatitis on the face, neck, hands and feet, diarrhea and dementiaB6 (pyridoxine)Amino acid metabolismBeef, salmon, chicken breast, whole grains, fortified cereals, bananas and nutsMouth injuries, drowsiness, fatigue, microcytic hypochromic anemia and seizures in newbornsB9 (folic acid)

DNA formation

Formation of blood, intestine and fetal tissue cells

Liver, beans, lentils, wheat germ, peanuts, asparagus, lettuce, Brussels sprouts, broccoli and spinachFatigue, weakness, shortness of breath, palpitations and megaloblastic anemiaB12 (cyanocobalamin)

DNA and RNA synthesis

Metabolism of amino acids and fatty acids

Myelin synthesis and maintenance

Meat, fish, poultry, milk, cheese, eggs, nutritional yeast, soy milk and fortified tofuFatigue, pallor, shortness of breath, palpitations, megaloblastic anemia, loss of sensation and tingling in the extremities, abnormalities in locomotion, loss of memory and dementia

In addition to eating foods rich in vitamins, you can also take food supplements that usually contain the recommended daily doses of vitamins and minerals essential to the proper functioning of the body. Know the various types of dietary supplements.

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Bibliography

• LUTZ, Carroll; PRZYTULSKI, Karen. Nutrition and diet therapy. 5. Philadelphia: Mc Graw Hill, 2011. 90 - 103.
• COZZOLINO Silvia. Nutrient bioavailability. 4th. Brazil: Manole Ltda, 2012. 453-477.