How do UVB rays help stimulate vitamin D production?

The article is expertly consulted by Assoc. Dr. Dr. Huynh Thoai Loan - Head of Pediatrics - Neonatology Department, Vinmec Central Park International General Hospital. Uncle is one of the leading experts in Pediatrics - Neonatology in Ho Chi Minh City with nearly 30 years of experience in examining and treating diseases of pediatric endocrinology, pediatric nephrology and other pediatric - neonatal problems.

UVB rays are the only rays in the sun that stimulate the production of vitamin D. Thanks to that, the body easily absorbs calcium, creating the best conditions for strong bones.

UV rays (ultraviolet rays) in sunlight are divided into three types: UVA rays, UVB rays and UVC rays.
UVC rays are the most harmful ultraviolet rays, potentially harmful to human health. But UVC rays do not reach the Earth's surface because they are reabsorbed by the ozone layer. Therefore, among the rays reaching the ground there are no UVC rays.
UVA rays are the rays that exist most in sunlight reaching the Earth's surface (accounting for 95%). Even when the sunlight has weakened, the clouds cover it, or it rains, UVA rays still exist. UVA rays have the ability to penetrate the ozone layer, clouds, water, glass, thin clothing. UVA rays are completely incapable of synthesizing vitamin A, even penetrating the dermis, damaging the basal cells of the skin, which is the cause of tanning, skin aging, and skin cancer.
UVB rays are the only rays capable of stimulating vitamin D production. UVB rays have a shorter wavelength than UVA rays and are partially absorbed by the ozone layer. The time when UVB rays penetrate the ozone layer the most during the day is from 9am to 4pm. However, at this time, intense sunlight can damage the skin. Although UVB rays have the ability to synthesize vitamin D, exposure to strong UVB rays also has certain harmful effects. Therefore, experts recommend that the most suitable time to sunbathe is before 9 am and after 4 pm.

Vitamin D is made in the skin through photosynthesis, photolysis, and photolysis. Human skin contains the compound 7-dehydrocholesterol which is a precursor to vitamin D. When sunlight hits the skin, UVB rays present in sunlight will break the molecular bonds of 7-dehydrocholesterol, thereby converting 7-dehydrocholesterol into vitamin D3, helping the body to absorb the necessary amount of calcium.
According to the recommendations of nutrition institutes in the world, on average, children from 1 to 18 years old need 600 - 1000 IU of vitamin D / day and in adults it is from 800 - 1000 IU of vitamin D / day. Exposure to the sun for about 10-15 minutes is enough to synthesize 50 times the amount of vitamin D needed for a day. Therefore, there is no need to expose to the sun for too long.
In case there is no sun exposure, vitamin D can be supplemented through daily foods and vitamin D3 products in drops and spray form with a dose appropriate for each age.
As a key area of ​​Vinmec Health system, Pediatrics Department always brings satisfaction to customers and is highly appreciated by industry experts with:
Gathering a team of top doctors and nurses in Pediatrics : consists of leading experts with high professional qualifications (professors, associate professors, doctorates, masters), experienced, worked at major hospitals such as Bach Mai, 108.. Doctors All doctors are well-trained, professional, conscientious, knowledgeable about young psychology. In addition to domestic pediatric specialists, the Department of Pediatrics also has the participation of foreign experts (Japan, Singapore, Australia, USA) who are always pioneers in applying the latest and most effective treatment regimens. . Comprehensive services: In the field of Pediatrics, Vinmec provides a series of continuous medical examination and treatment services from Newborn to Pediatric and Vaccine,... according to international standards to help parents take care of their baby's health from birth to childhood. from birth to adulthood Specialized techniques: Vinmec has successfully deployed many specialized techniques to make the treatment of difficult diseases in Pediatrics more effective: neurosurgery - skull surgery, stem cell transplantation. blood in cancer treatment. Professional care: In addition to understanding children's psychology, Vinmec also pays special attention to the children's play space, helping them to have fun and get used to the hospital's environment, cooperate in treatment, improve the efficiency of medical treatment.