vitamina

Vitamina is a class of organic micronutrients essential for normal metabolism, growth, and health. In nutritional science, vitamins are required in small amounts because they enable enzymes and biochemical reactions throughout the body. Most vitamins cannot be produced in sufficient quantities by humans, so they must be obtained from the diet, though some can be synthesized in limited amounts endogenously (for example, vitamin D in the skin with sunlight).

Vitamins are commonly divided into two groups: water-soluble and fat-soluble. Water-soluble vitamins, including vitamin C and the B-complex vitamins, are not stored in large amounts and are excreted in urine; they need regular replenishment. Fat-soluble vitamins (A, D, E, K) are stored in body fat and the liver, which means excessive intake can lead to toxicity if supplementation is high over time.

Dietary sources vary by vitamin but typically include fruits, vegetables, grains, dairy products, meat, eggs, and fortified foods. Each vitamin has specific roles, such as vitamin A for vision and epithelial health; B vitamins for energy metabolism and red blood cell formation; vitamin C for collagen synthesis and antioxidant protection; vitamin D for calcium balance and bone health; vitamin E as an antioxidant; and vitamin K for blood clotting.

Deficiencies and excesses can cause a range of problems, from night blindness and anemia to bone disorders and impaired immunity. Adequate intake should be achieved through a balanced diet, with supplements considered only under medical guidance, especially in pregnancy, older age, or certain health conditions.