Bone health is an important part of physical health, and whether calcium is enough and whether it is absorbed well is the focus of modern people. Whether calcium can be absorbed by the body is closely related to vitamin D, because vitamin D has the functions of promoting calcium absorption, regulating blood calcium and phosphorus, and participating in bone metabolism. Zhao Yanhua from the Maternal and Child Health Center of the National Health Commission reminded that in daily life, many people still have misunderstandings about the use of vitamin D.
Myth 1: You can get enough in the sun.
There are three main benefits of vitamin D for human health. One is to help calcium absorption, if the lack of vitamin D will cause calcium malabsorption, children lack of vitamin D is easy to cause rickets or osteomalacia. The second is to regulate blood calcium and blood phosphorus, which is conducive to bone growth and the stability of calcium and phosphorus, as well as the secretion of parathyroid hormone, thereby regulating the balance of blood calcium and blood phosphorus in the body. The third is to participate in bone metabolism, make calcium deposition in the bone matrix, promote bone mineralization, increase muscle strength and balance, improve muscle function, and at the same time, promote the proliferation of osteoblasts and osteoclasts, and help bone formation.
Because vitamin D is a fat-soluble vitamin, it cannot be hydroxylated in the human liver, so it must be supplied by food. Although vitamin D is known as the "sunshine vitamin", it is unlikely that the human body** will convert a limited range of solar UVB rays into enough vitamin D3, and there are many factors that can affect this process, such as geographical location, season, UV index, climate, pollution, skin color and even age, not to mention that many people are not guaranteed to have enough time outdoors in the sun.
Therefore, while properly ensuring outdoor time, you should also increase the amount of vitamin D-rich foods in your diet, such as milk, mushrooms, cheese, salmon, etc. Under the guidance of a dietitian or doctor, you can also choose to take vitamin D drops or supplements.
Myth 2: A blood VD level of 30 ng ml is sufficient.
Anyone who has done a 25(OH)D blood level test (the most accurate way to measure vitamin D levels in the body) should have seen this numerical standard: less than 20ng ml is considered vitamin D deficiency;20 ng ml to 30 ng ml is vitamin D insufficiency;More than 30 ng ml, vitamin D is sufficient.
In fact, 30 ng ml is only the cut-off for vitamin D deficiency and does not represent an "excellent level". Today, some nutritionists believe that 50 ng ml is the new standard that needs to be met or exceeded in order to provide the vitamin D needed for optimal physiological function.
However, 50 ng ml of vitamin D is difficult to achieve, the average person is generally 30 ng ml, and outdoor workers or athletes can reach 40 ng ml. If you want to achieve this level, you can do it by exercising outdoors and getting more sunlight and eating foods rich in vitamin D, such as cod liver oil and dairy products.
Myth 3: Ingestion of vitamin D can cause poisoning.
While vitamin D toxicity (also known as hypervitaminosis D) is possible, it is actually very difficult to achieve vitamin D toxicity levels.
In an article published in 2018 in the top international journal "Frontiers in Endocrinology", both the Chinese Medical Research Society and the Endocrine Society came to the same conclusion that the concentration of 25(OH)D in human blood exceeds 150ng ml, so you need to worry about the toxicity of vitamin D. And even if you consume a lot of foods rich in vitamin D, it is difficult to reach the level of 50 ng ml.
Unless the patient takes drugs containing vitamin D for a long time, such as vitamin D drops, vitamin AD drops, etc., it may lead to excessive vitamin D in the body, which can cause poisoning. Therefore, patients with this condition should follow the doctor's instructions to recheck regularly and make timely medication adjustments according to the vitamin D level in the body.
Myth 4: All supplements are the same.
I don't know if you have noticed, vitamin D is also classified. There are two main forms of vitamin D: vitamin D2 and vitamin D3.
Vitamin D2, also known as ergocalciferol, is a plant-based vitamin D, mainly found in mushrooms, yeast and other foods, and can also be obtained through artificial synthesis, its main function is to promote the absorption and utilization of calcium and phosphorus, maintain bone health, and also have the role of regulating the immune system, promoting muscle function, and preventing cardiovascular diseases.
Vitamin D3, also known as cholecalciferol, is an animal vitamin D, mainly found in foods such as cod liver oil, egg yolks, dairy products, etc., and can also be synthesized by exposure to ultraviolet light. Its main role is the same as vitamin D2, which can promote the absorption and utilization of calcium and phosphorus, maintain bone health, etc.
Vitamin D3 is more bioavailable than vitamin D2. In pharmacology, bioavailability is a subcategory of absorption, which refers to the fraction (%) of the administered drug that reaches the systemic circulation, and the vitamin D naturally produced in the human body belongs to the form of vitamin D3, that is, vitamin D3 is closer to the natural form of the body, while vitamin D2 needs to undergo a series of transformations to become the vitamin D3 available to the body. Therefore, vitamin D3 plays a better role in the human body, and it is recommended that you choose vitamin D3 (cholecalciferol) instead of vitamin D2 (ergocalciferol) when supplementing vitamin D according to the doctor's instructions, and the efficacy and stability of vitamin D3 are incomparable to vitamin D2.
Beijing ** client).