Vitamin D is a fat-soluble vitamin naturally in the body through exposure of the skin to sunlight, and can also be obtained in greater quantities through the consumption of some foods of animal origin, such as fish, egg yolk and milk, for example.
This vitamin has important functions in the body, mainly in reducing the concentration of calcium and phosphorus in the body, favoring the absorption of these minerals in the intestine and regulating the cells that degrade and form bones, maintaining their levels in the blood.
Vitamin D deficiency could cause bone changes, such as osteomalacia or osteoporosis in adults, and rickets in children. In addition, some scientific studies have linked the deficiency of this vitamin to an increased risk of developing some types of cancer, diabetes mellitus and hypertension.
Vitamin D is necessary for several processes in the body and, therefore, it is important that its concentration in the blood is at adequate levels.
The main functions of vitamin D are:
Strengthening of bones and teeth, as it increases the absorption of calcium and phosphorus in the intestine and facilitates the entry of these minerals into the bones, which are essential for their formation.
Prevention of diabetes, because it acts in maintaining the health of the pancreas, which is the organ responsible for the production of insulin, the hormone that regulates blood glucose levels.
Improves the immune system, preventing bacterial and viral infections.
Reduction of inflammation in the body, because it decreases the production of inflammatory substances and helps to fight autoimmune diseases, such as psoriasis, rheumatoid arthritis and lupus, in which case the use of supplementation according to medical advice is necessary.
Prevention of diseases such as multiple sclerosis and some types of cancer, such as breast, prostate, colorectal and kidney, since it participates in the control of cell death and decreases the formation and proliferation of malignant cells.
Improves cardiovascular health, as it works by lowering blood pressure and the risk of hypertension and other cardiovascular diseases.
Muscle strengthening, since vitamin D participates in the process of muscle formation and is linked to greater muscle strength and agility. In addition, due to its antioxidant power, it is also able to prevent premature aging, as it prevents damage to cells caused by free radicals.
Sources of vitamin D
The main source of vitamin D is its production in the skin from exposure to sunlight. Therefore, to produce adequate amounts of vitamin D, light-skinned people must remain in the sun for at least 15 minutes a day, while darker-skinned people must remain exposed to sunlight for at least 1 hour. The ideal is for the exhibition to take place between 10am and 12pm or between 3pm and 4pm 30, as at that time it is not so intense.
In addition to sun exposure, vitamin D can be obtained from dietary sources such as fish liver oil, seafood, milk and dairy products.
Daily amount of vitamin D
The required amount of vitamin D per day varies according to age and stage of life, as indicated in the following table:
|Phase of life||Daily recommendation|
|0-12 months||400 UI|
|Between 1 year and 70 years||600 UI|
|More than 70 years||800 UI|
The consumption of foods rich in vitamin D is not enough to meet the daily needs of this vitamin and, therefore, it is important that the person is exposed to sunlight daily to maintain an adequate production of this vitamin in the body and, in the case of not being enough, as in the case of people who live in colder countries or in the case of people who have changes in the fat absorption process, the doctor for indicating the intake of vitamin D supplements. See more about vitamin D supplements.
Good levels of vitamin D in the body and how to measure it.
The vitamin D levels considered good by the Brazilian Society of Clinical Pathology / Laboratory Medicine and the Brazilian Society of Endocrinology and Metabology are above 20 ng / mL for healthy people up to 60 years old and between 30 and 60 ng / mL for people over 60 years old, pregnant or breastfeeding women, people with kidney failure or malabsorption syndromes, for example.
These levels can be measured through a blood test, called a hydroxyvitamin D or 25 (OH) D test. Thus, from the results, it is possible to know if the person has a deficiency or excess of vitamin D in the body.
Vitamin D deficiency
Symptoms and signs of vitamin D deficiency in the body are decreased amount of calcium and phosphorus in the blood, muscle pain and weakness, weakened bones, osteoporosis in the elderly, rickets in children and osteomalacia in adults.
The absorption and production of vitamin D can be impaired due to some diseases such as kidney failure, lupus, Crohn’s disease and celiac disease. Vitamin D deficiency in the body can be identified through a blood test called 25 (OH) D and occurs when levels below 20 ng / mL are identified.
Excess of vitamin D
The consequences of excess vitamin D in the body are weakening of the bones and elevation of calcium levels in the bloodstream, which can lead to the development of kidney stones and cardiac arrhythmia.
The main symptoms of excess vitamin D are lack of appetite, nausea, vomiting, increased urination, weakness, high blood pressure, thirst, itchy skin and nervousness. However, excess vitamin D only occurs due to overuse of vitamin D supplements.