Fat-soluble vitamins in nutrition.

Although our body's daily vitamin requirements consist of doses of just a few milligrams, their role in health is not limited to avoiding the diseases that their deficiencies cause, but they are essential elements for the body's functioning.

Vitamins: these are organic micronutrients that do not provide energy and must be obtained from food, because although some can be formed in varying amounts in the body, they are generally not sufficient to cover the needs, so they must all be provided to a greater or lesser extent by the diet.

Vitamins can be easily destroyed due to their high sensitivity to different physical and chemical agents such as heat, light, oxidants, reducing agents, humidity, acids and bases. For this reason they can suffer losses during culinary processes, especially if foods are subjected to prolonged cooking, with vitamin C, folic acid and vitamin B1 being the most sensitive.

Chemical classification of vitamins: they are classified according to the substances in which they are soluble in two groups:

• Lipid-soluble vitamins (a, d, e, k): they arelipid-soluble vitamins, generally transported in the fat of food. Each vitamin fulfills complementary functions that intervene in the correct functioning of the organism. A diet deficient in fats would provide low levels of lipid-soluble vitamins, causing health disorders. On the contrary, an excess in the consumption of fats, would cause very high levels of these vitamins, which could be harmful for the organism.

• Water-soluble vitamins (vitamins of group B and vitamin C): they are contained in the aqueous compartments of food. These vitamins, when dissolved in water, are easily eliminated through urine, so they do not accumulate in the organism, being necessary the periodic intake to maintain health. Vitamin A (Retinol, Carotenes (Provitamin A))

Functions:

• Participates in protein synthesis and cell differentiation.

• In vision, it prevents xerophthalmia, a disease that causes dryness of the conjunctiva and corneal opacity.

• It intervenes in the growth process of the organism.

• Contributes to the functioning of the immune system.

• It affects the health of the skin and mucous membranes.

Consequences of vitamin A deficiencies in the organism:

• Eye ulcers develop and the cornea becomes opaque, leading to blindness.

• The immune system is depressed, increasing the risk of infections.

• Digestive, nervous, muscular and skin disorders occur.

Consequences of vitamin A excesses in the organism:

• Retinol consumed in large quantities, can cause toxic reactions.

• Carotenes when consumed excessively can accumulate under the skin and color the mucous membranes, but without danger.

Foods containing vitamin a:

• Foods of animal origin such as dairy products, egg yolk, blue fish and pates.

• Foods of vegetable origin such as tomatoes, watermelon, cherries, chard, spinach, green celery, carrots and in some fruits.

Vitamin D (Cholecalciferol (D3), Ergocalciferol (D2))

Functions:

• It is antirrachitic.

• It favors the intestinal absorption of calcium and phosphorus as well as its renal reabsorption, which gives it a prominent role in bone mineralization.

• It participates in the prevention of several chronic diseases.

• It performs many functions related to the nervous system, brain and pancreas.

Consequences of vitamin d deficiencies in the organism:

• It causes rickets in childhood and osteomalacia in adults.

• In the elderly it can contribute to the appearance of osteoporosis, manifesting itself by the loss of bone mass.

Consequences of the excesses of vitamin d in the organism: they can cause toxicity if its intake exceeds the recommended intake in ten times.

Foods that contain vitamin d: vitamin d is obtained fundamentally by cutaneous synthesis, mediated by the ultraviolet radiation of the sun. The remaining vitamin d can be obtained from animal foods such as fatty fish, egg yolk, liver, dairy products and butter. Vitamin E (Tocopherols)

Functions:

• Involved in proton and neutron transfer and membrane stabilization.

• It is a potent antioxidant that protects lipids and other cell components from oxidative damage.

• It is involved in the maintenance of cell membrane structure.

• Protects against cardiovascular disease.

Consequences of vitamin e deficiencies in the organism: they cause neurological disorders due to a bad conduction of the nervous impulses. Consequences of vitamin E excesses in the organism: it is one of the least toxic vitamins, the consequences could be very slight or imperceptible.Foods that contain vitamin e:

• They are obtained fundamentally in foods of vegetable origin, like the dry fruits, the virgin olive oil, the oils of sunflower seeds and corn, and in the olives.

• They are also obtained in eggs.

Vitamin E can be easily destroyed by the action of heat and oxygen in the air. Vitamin K (Phylloquinone (K1), Menaquinone (K2))

Functions:

• It is antihemorrhagic.

• Participates in the transfer of protons and electrons.

• Synthesizes specific bone proteins and participates in the metabolism of certain calcium-binding proteins, thus contributing to proper bone development.

Consequences of vitamin K deficiencies in the organism: they cause abnormal blood coagulation, with risk of hemorrhages. Consequences of vitamin k excesses in the body: cause toxicity only if amounts between 50 and 100 times the recommended intakes are ingested.Foods containing vitamin K:

• Foods of animal origin such as milk, eggs, fish, meat and in the liver.

• Foods of vegetable origin such as apples, oranges, strawberries, bananas, cabbage, parsley, spinach, broccoli, lettuce, carrots, potatoes, green beans, cucumber, tomato, peas, asparagus and mushrooms.