Vitamin D (calciferol) Vitamin D was once called the «vitamin produced by light». Another, more prosaic name for it is calciferol, i.e. carrying calcium. Vitamin D is a fat-soluble vitamin; The functions that it performs in our body are diverse. Why is it needed? Once in the body, vitamin D undergoes a variety of complex transformations with the formation of the so-called «active metabolites» or «active forms». The most important of them is formed in the kidneys and plays a key role in calcium metabolism and the body. Active metabolites of vitamin D, together with a number of hormones, form a system for regulating and maintaining calcium balance in the body. Thus, vitamin D ensures normal growth and development of bones, prevention of rickets and osteoporosis. It regulates mineral metabolism and promotes the deposition of calcium in bone tissue and dentin (the main substance of the teeth), preventing the softening of bones. Vitamin D affects the body’s susceptibility to skin diseases, heart disease, and cancer. This vitamin prevents muscle weakness, improves immunity (the level of vitamin D in the blood is one of the criteria for assessing the life expectancy of AIDS patients), is necessary for the functioning of the thyroid gland and normal blood clotting, and prevents the growth of cancer cells. Sources Vitamin D is formed in the skin under the action of sunlight from the precursors of vitamin D — provitamins, partly supplied to the body in finished form with food, and partly formed in the tissues from cholesterol. Additional food sources of vitamin D are dairy products, fish oil, cod liver, Atlantic herring, egg yolk. Daily norm The requirement of women of childbearing age for vitamin D is 5 micrograms, and during pregnancy and lactation increases to 10-15 micrograms. Vitamin D deficiency In vitamin D deficiency, there is a risk of developing rickets. This is a disease of childhood, the first signs of which may appear already in the second month of a child’s life in the form of excessive sweating, excessive excitability, sleep disturbances, stools, characteristic sharp shudders when touched, loud sounds, bright light. Due to disturbances in calcium metabolism, the process of mineralization and ossification of the growing skeleton slows down. In the second half of life, when a child suffering from rickets begins to sit down and stand up, the bones of the spine are unable to withstand the increased load and are subject to curvature. The main symptom of vitamin D deficiency is rickets and softening of the bones. Excess Vitamin D Excessive intake of vitamin D can lead to high levels of calcium in the blood. In this case, calcium can penetrate into the walls of blood vessels and provoke the formation of atherosclerotic plaques. With an overdose of vitamin D, there is: weakness, loss of appetite, nausea, vomiting, constipation, diarrhea, sharp pains in the joints, headaches and muscle pains, fever, increased blood pressure, convulsions, slow heart rate, shortness of breath.