Everything you need to know about vitamin D: Importance, Dosage and Sources
Vitamin D: benefits
Vitamin D is more than just a nutrient: it is a fundamental ally for the general well-being of our body. One of the best-known benefits of this nutrient concerns the health of our skeletal system: vitamin D promotes the absorption of calcium, an essential mineral for the development and maintenance of strong, firm bones and teeth. But not only that, this vitamin also plays a key role in preventing diseases such as osteoporosis, a pathology characterized by the progressive weakening of bone tissue. The action of vitamin D does not stop at the skeletal system, but also extends to our immune system. A correct intake of this substance helps to increase the activity of the cells responsible for the body's immune response, helping us to defend ourselves more effectively from viruses and bacteria. Furthermore, vitamin D has been shown to have anti-inflammatory properties, modulating the inflammatory response and helping to prevent the onset of numerous chronic diseases. Another aspect that deserves to be highlighted concerns the relationship between vitamin D and sleep. Some studies suggest that this vitamin can help regulate the sleep-wake rhythm, improving the quality of our rest. This means that a correct intake of vitamin D could help reduce insomnia and improve our mood and our ability to concentrate. Finally, vitamin D helps maintain balanced calcium and phosphorus levels in the blood. These two minerals are fundamental for many functions of our body: calcium, for example, is essential for the contraction of muscles and for the transmission of nerve impulses, while phosphorus is involved in the process of energy production within cells. In conclusion, the benefits of vitamin D are multiple and fundamental for our health. To ensure a correct intake of this precious nutrient, it is important to follow a balanced and varied diet, which includes food sources of vitamin D such as fatty fish, milk and derivatives, eggs and liver, and, where necessary, use food supplements. We also remember that vitamin D is the "sun vitamin", since our skin is able to synthesize it when exposed to sunlight: another good reason to spend time outdoors, respecting the safety measures. protection against UV rays.
How much vitamin D to take every day
The daily requirement of vitamin D varies depending on age and is measured in micrograms (µg) or in International Units (IU). These daily doses are established by health authority bodies, such as the Nutrient Reference Intake Levels (LARN), the Italian Society of Human Nutrition (SINU) and the European Food Safety Authority (EFSA). For infants up to 1 year of age, LARN recommends an intake of at least 10 micrograms or 400 IU per day. From 1 to 10 years, the recommended daily requirement is 15 micrograms or 600 IU. Adolescents and adults up to age 70 should get 20 micrograms or 800 IU of vitamin D per day. For those who are older, the recommendation is 25 micrograms or 1000 IU per day, to compensate for the body's reduced ability to produce vitamin D due to aging. LARN points out that sun exposure can produce up to 10,000 IU of vitamin D in the body in a single day, but this can vary depending on the weather, latitude and skin. Therefore, some people may need to supplement their intake with supplements. SINU, by contrast, argues that actual vitamin D needs may vary based on individual conditions, such as diet, sun exposure and genetics. It recommends a daily intake of 10-20 micrograms for infants and children, and 15-30 micrograms for adults. Finally, EFSA has established that a daily intake of 15 micrograms is adequate for all individuals over 12 months of age, while newborns should have a daily intake of 10 micrograms. It is important to remember that vitamin D is fat-soluble, meaning the body can store it for future use. Excessive amounts of vitamin D can build up in the body and cause toxicity. This makes it important not only to get enough vitamin D, but also not to go beyond the tolerable upper limit, which is set at 100 micrograms per day for adults according to LARN and EFSA. Therefore, before you start taking vitamin D supplements, it is always advisable to consult a healthcare professional.
Optimal vitamin D values
There are different points of view and recommendations on what the optimal amount of vitamin D is for an individual. An important factor to consider when determining your optimal vitamin D intake is how much 25(OH)D, the precursor to vitamin D, is present in your blood. Before we get into more detail, it's important to understand that vitamin D is an essential nutrient, necessary for a number of bodily functions, including calcium absorption and immune function. Our body synthesizes vitamin D when the skin is exposed to sunlight, however, often the amount of vitamin D produced in this way is not sufficient, requiring an additional supply through diet or supplements. As for optimal values, the National Academy of Medicine, in the United States, suggests that a sufficient level of vitamin D is between 20 and 50 nanograms per milliliter of blood. However, the Endocrine Society says a level above 30 nanograms per milliliter would be more beneficial, especially for people at risk of vitamin D deficiency such as the elderly, patients with obesity or those with related diseases such as osteoporosis. Similarly, the Vitamin D Council recommends a vitamin D level of between 40 and 80 nanograms per milliliter, arguing that this range may offer greater health benefits and reduce the risk of several diseases. This association highlights how a high level of vitamin D can play a protective role against various conditions, including cancer, cardiovascular disease and multiple sclerosis. However, it is important to note that there is also such a thing as too high a level of vitamin D. Too much vitamin D, known as hypervitaminosis D, can cause a number of health problems, including tissue calcification and kidney damage. In conclusion, despite the different opinions, a general consensus emerges on the fact that maintaining an adequate level of vitamin D in the blood is important for our health. It is essential that each individual, together with their doctor, evaluate their specific situation to determine the optimal level of vitamin D based on their needs and health conditions.
Where is vitamin D found?
Vitamin D is a fundamental nutrient for our body and is mainly produced by our skin in response to exposure to ultraviolet rays from the sun. This synthesis process occurs when the sun hits the skin and triggers a series of chemical reactions that lead to the production of vitamin D. For this reason, it is easy to understand how its availability in our body largely depends on the environmental conditions in which we live. : Sufficient sun exposure of at least 15-30 minutes a day, preferably in the central hours of the day when the sun is highest, can provide much of the vitamin D we need. However, vitamin D doesn't come exclusively from sunlight. In fact, it can also be introduced through food, although this source represents a smaller portion of the total. Numerous foods in nature contain this precious vitamin, often in non-negligible concentrations. Among these, fish is one of the richest sources, especially fatty species such as salmon and sardines. Mushrooms are also an excellent source of vitamin D, especially those exposed to sunlight. This is because fungi, like our skin, are able to produce vitamin D in response to exposure to ultraviolet light. Other foods from which you can get vitamin D are eggs, fatty cheeses, liver, butter and milk. In particular, milk is a fundamental food for the supply of vitamin D, especially in children, but also in adults it can make a valid contribution to covering the daily requirement of this vitamin. However, it is important to point out that, even if a correct diet can help to guarantee a good supply of vitamin D, food alone will hardly be sufficient to cover the entire daily requirement, especially in subjects at risk of deficiency such as the elderly or those who live in areas with little sun exposure. In these cases, it may be useful to resort to specific supplements, always under strict medical supervision to avoid excessive intake which could be harmful to the body. In fact, as with all nutrients, "too much" can be as harmful as "too little" for vitamin D. In conclusion, to ensure an adequate intake of vitamin D it is advisable to combine a healthy and varied diet, rich in foods that contain it, with regular exposure to the sun, always respecting precautionary measures to avoid ailments linked to excessive exposure to the sun's rays.
When it is insufficient
In assessing whether the amount of vitamin D in the blood is adequate or not, one of the most effective methods is the analysis of the metabolite 25-OH vitamin D. In fact, this substance is the result of the metabolism of vitamin D in the liver and represents the most precise indicator of vitamin D levels in the body. If, following the analysis, values lower than 20 ng/ml are revealed, we are faced with a situation of vitamin D insufficiency. This deficiency can represent a serious risk for skeletal health, compromising bone density and favoring the development of conditions such as osteoporosis and fractures. This problem is particularly common in older people, who tend to have less exposure to the sun, the main natural source of vitamin D. In fact, the body's ability to produce vitamin D decreases as we age, resulting in less sun exposure. Furthermore, the body's ability to absorb vitamin D from food also tends to reduce over the years, contributing to exacerbating the problem of deficiency. In addition to the elderly, even subjects who live in higher latitudes or who have darker skin (a characteristic that reduces the body's ability to produce vitamin D from the sun's UV rays) are significantly at risk of showing insufficient values of this vitamin in the blood. An unbalanced diet or one lacking in foods rich in vitamin D, such as oily fish, beef liver, dairy products, eggs, can contribute to this insufficiency. In these cases, experts recommend taking food supplements such as cod liver fish, rich in vitamin D. Consequently, it is essential to pay attention to the levels of vitamin D in your body, especially if you belong to one of the categories at risk. In this case, it may be useful to organize a regular check through the analysis of the 25-OH vitamin D metabolite, so as to be able to intervene with the necessary precautions in case a deficiency occurs. Let us always remember the importance of a healthy, balanced and active lifestyle, which includes exposure to the sun and a varied and complete diet.
