What are vitamins? And what are they for?

May 29 2023 – Melissa Alvarez

¿Qué son las vitaminas? ¿Y para qué sirven? 
¿Qué son las vitaminas? ¿Y para qué sirven? 

Vitamins are a group of substances necessary to carry out different functions in the body, known as micronutrients. Each of the vitamins has a unique function in the metabolic processes of the human body.

They are classified into two categories:

  • Fat-soluble vitamins.- They are fat-soluble and are stored in the liver, fatty tissue and muscles. Within these, we find vitamin A, D, E and K. These vitamins, consumed in excess, can be toxic to the body.
  • Water -soluble vitamins.- They are soluble in water, they can quickly lose their nutritional value in the processes of cooking, storage or exposure to sunlight. Within these, we find the B complex vitamins and vitamin C. 

  • Its duties?

  • Vitamin A (retinol).- Prevents blindness and strengthens night vision, helps maintain hydrated and healthy skin, participates in the synthesis of sex hormones, promotes the growth of bones and teeth, strengthens the immune system and prevents diseases because it is a powerful antioxidant.

    It is found in foods of animal origin in the form of retinol (egg, milk, cheese and liver) and in foods of plant origin in the form of beta-carotene (carrot, spinach, pumpkin, melon and mango).

    Caution should be taken when supplementing as it may have interactions with some drugs and in excess may cause toxicity.

    • Vitamin D.- Its function is related to the mineralization of bones, it plays a fundamental role in the absorption of calcium and phosphorus; necessary to maintain healthy bones and teeth. This is obtained from exposure to the sun through the skin and in food through egg yolk, milk, fish and liver.
    • Vitamin E.- It is a powerful antioxidant and anticoagulant. It delays cellular aging, protects blood vessels and reduces the risk of cardiovascular diseases. It is found in polyunsaturated vegetable oils (safflower, corn and soybean oil), wheat germ, whole grains, egg yolk, nuts and seeds.
    • Vitamin K.- Necessary for good blood clotting. It is found in green leafy vegetables, such as cabbage, spinach, and asparagus.
    • Vitamin B1 (Thiamin).- Participates in the correct functions of the muscles and the nervous system, as well as intervenes in the energy metabolism of carbohydrates, fat and proteins. It is found in whole grains, seeds, green leafy vegetables, fish, meat and milk.
    • Vitamin B2 (Riboflavin).- Maintains good eye health, helps maintain healthy nails, skin and hair, important for the production of red blood cells. It is found in milk, liver, fish and eggs.
    • Vitamin B3 (Niacin).-It has functions related to the nervous system, digestive system and skin. It is found in tuna, salmon, sea bass, liver, cheeses and rice.
    • Vitamin B5 (Pantothenic acid).- It is essential for food metabolism, it plays a role in the function of hormones and cholesterol. It is found in meat, eggs, seafood, milk, broccoli, mushrooms and avocado.
    • Vitamin B6 (Pyridoxine).- It is very important as a coenzyme in many metabolic processes and is related to cognitive function. It is found in liver, almonds, walnuts and turkey.
    • Vitamin B7 (Biotin).- Important for the health of hair, nails and skin. It is found in meat, fish, eggs, seeds, spinach and broccoli.
    • Vitamin B9 (Folic acid).- It is important in the formation of red blood cells, it helps tissue growth and cellular work. Essential during early pregnancy to reduce the risk of birth defects in the brain and spine. It is mainly found in liver, green leafy vegetables, beans and citrus fruits.
    • Vitamin B12 (cobalamin).- Fundamental role in the formation of red blood cells, cellular metabolism, nervous function and DNA synthesis. It is found in fish, meat, eggs, milk and other dairy products.
    • Vitamin C (ascorbic acid).- Powerful antioxidant that helps protect cells from damage caused by free radicals. It also plays a fundamental role in the immune system, participates in the production of collagen and improves the absorption of iron. It is found in fruits and vegetables, orange, kiwi, strawberries, broccoli, melon and tomato.


    1. Latham, Michael. (2002). Human nutrition in the developing world. Rome. Chapter 11: Vitamins, available at:
    2. Mónica, PR (2004b, September 1). Elsevier. Vitamins and health . Offarm.