With schoolchildren switching to online lessons during the pandemic and having fewer opportunities to go out and play, their vitamin D absorption may be affected. A paediatric specialist noted that more parents are seeking medical advice due to concerns about their children’s physical growth; clinically, it has been found that only 10% of children attending consultations have vitamin D levels within the recommended range,whilst 3 to 4 in 10 adults have levels below the recommended threshold. This could affect bone growth; once the growth plates have closed, it may be difficult to gain further height in the future.Doctors recommend that children wear short-sleeved tops and trousers when going out to soak up the sun; just 5 to 15 minutes of sun exposure every other day is sufficient to naturally replenish vitamin D levels. They also advise eating more foods rich in vitamin D, such as salmon, tuna and egg yolks.
Vitamin D is very important for bone development. Paediatrician Dr. Tsui Chi-Kwan points out that vitamin D aids in the absorption of calcium from the intestines, maintains normal levels of phosphorus and calcium in the blood, keeps bones healthy, and can regulate the nervous system and the development of bones and muscles. "If children are deficient in vitamin D, their bones will grow poorly, affecting their height, and it may even cause bone deformities, leading to rickets and other soft bone conditions. Adults with insufficient vitamin D also have an increased risk of osteoporosis."
Expose to the sun for 5 to 15 minutes every other day.
Xu stated that there are two main ways to naturally obtain vitamin D, with sun exposure being the most important. "The skin produces vitamin D after coming into contact with UV-B rays from sunlight. It is recommended that children sunbathe for 5 to 15 minutes every other day to absorb enough sunlight." She reminded readers that the summer sun is intense, and sunbathing directly at noon could cause sunburn. It is therefore best to sunbathe between 10 am and 12 pm, or between 3 pm and 5 pm, "Remember to wear short sleeves and shorts to allow your skin to fully absorb sunlight."
In addition, some foods naturally contain vitamin D, such as oily fish like salmon and tuna, eggs, and animal liver; processed foods like milk and cornflakes also contain vitamin D, but she pointed out, "The effect of dietary intake is always less effective than sun exposure."
Furthermore, the fact that children have often been confined indoors during the pandemic has also affected their vitamin D absorption.Dr Xu noted that more parents are seeking medical advice out of concern for their children’s development. Clinical diagnoses revealed that only 10% of the children seen had adequate vitamin D levels, meaning 90% were not getting enough; of these, 30% to 40% were even deficient.“We cannot rule out that this is linked to children attending school less and playing outside less during the pandemic.”
Delayed treatment may not be fully rectifiable
Dr. Xu pointed out that because Hong Kong is a prosperous society with adequate nutrition for children, a lack of sun exposure usually will not worsen to the extent of causing rickets. However, if there are concerns, medical attention should be sought as soon as possible. She gave an example that infants who are primarily breastfed, without formula milk or supplements, may easily become irritable, sweat a lot, and be easily startled due to electrolyte deficiency if they do not get enough sun exposure. Older children who lack Vitamin D might be shorter than their peers, or fail to keep up with standard growth trajectories. They may also experience "late teething" or even a "fontanelle that doesn't close" – "if the fontanelle still feels very wide after the age of 1, one should pay attention." Children might also develop "rachitic rosary" due to Vitamin D deficiency, where their ribs protrude in a "bead-like" fashion.
She added that if sufficient vitamin D is ingested, children's conditions can generally improve, but warned that if treatment begins after the "growth plates have closed," it will be difficult to regain height even with vitamin D supplementation.
Reporter: Chut Chi-ching
Art: Chiu Yau Hung
Doctors recommend that children wear shorts and a t-shirt for sun exposure for 5 to 15 minutes every other day, allowing their skin to absorb sufficient sunlight.
Paediatric Specialist Doctor Tsui Chi-kwan
Column Name: Healthy Life
