This nutrient is more important for growing taller than calcium, but many children don't get enough of it

445th original article

When it comes to height, Chinese parents are among the most anxious parents in the world. In the pediatric nutrition clinic, on the TOP3 list of the most concerned issues by parents, height is listed all year round.

Even for babies with a length/height curve in the 90th percentile, parents will worry about "not being tall enough". Not to mention the median and below-average children.

For the height problem, the nutrients that parents are most concerned about are calcium in the first place, and protein in the second. But here's the truth: most children's dietary intake of these two nutrients is often adequate. Protein intake is even excessive.

However, another nutrient that is closely related to height growth is often overlooked by parents, especially children over 2 years old. This nutrient is:

vitamin d

Let's start with a recent study published in the Chinese Journal of Pediatrics.

From September 2018 to September 2019, a total of 2,924 children aged 2~<7 years old in 20 cities in China were investigated and analyzed by 17 children's professional institutions, including the Child Nutrition Research Center of the Children's Hospital of Chongqing Medical University, the National Clinical Research Center for Child Health and Diseases, and the Key Laboratory of Child Developmental Diseases of the Ministry of Education. The following results were obtained:

Findings:

The overall deficiency rates of vitamin A and D were 2.19% and 3.52%, respectively.

The overall deficiency rates of vitamin A and D were 29.27% and 22.0%, respectively.

10.50% of children had vitamin A and D deficiencies.

The insufficiency rates of vitamin A and D in children aged 3~<5 years and 5~<7 years were higher than those in children aged 2~<3 years.

The prevalence of vitamin A and D insufficiency in children with an annual family income of < 60,000 yuan was significantly higher than that of children with an annual family income of ≥60,000 yuan.

The northwest and southwest regions have the highest rates of vitamin A and vitamin D deficiency in 2~<7 years old, respectively.

Supplementation of vitamins A and D for 3 months can help improve vitamin A and D deficiencies.

From the above data, it is not difficult to extract a core conclusion: the deficiency and deficiency rate of vitamin A and D in preschool children in mainland cities are more common. This is especially true in the northwest, northeast and southwest of the country.

Vitamin A is easier to get from the diet than vitamin D. Animal liver is a very rich source of vitamin A. The β-carotene in various red, yellow and green vegetables and fruits, under the premise of the presence of fat, can be partially converted into vitamin A in our body. Therefore, it is relatively not so difficult to correct vitamin A deficiency through diet.

Vitamin D is not so easy. Foods that provide vitamin D are very few and in low amounts, and there are only a handful of common sources: egg yolks, shiitake mushrooms (vitamin D2 from plant sources, not the active form of D3), animal liver, various oily fish (such as sardines, salmon, etc.).

But even if you eat these foods regularly, you can only provide about 10% of the vitamin D your body needs, and the remaining 90% needs to be synthesized by getting a good sun on your skin. However:

Getting some sun is not an easy task!

In order for your skin to "get enough sunlight", you first need to live in an area with abundant ultraviolet rays, that is, high levels of solar radiation. The positive side is typical of the Qinghai-Tibet Plateau, where the scorching sun shines in the sky every day. The negative example is the Sichuan-Chongqing region, where there is more rain and fog and less sunny days. In the north of the "January zero isotherm" on the mainland, that is, in the higher latitude area north of the "Qinling-Huai River", there are at least 4 months of 12 months of the year (November ~ March of the following year) with insufficient sunlight radiation (so the temperature in autumn and winter is particularly low).

In addition, it can be difficult to get in the sun when you are active indoors during the day, when you go out, when you wear tight clothes and sunscreen, and when you are not in the rainy season in summer, when the time of the sun is not suitable (the height angle of the sun is not enough to cause insufficient radiation when the sun is oblique).

Love Reminder: Basking in the sun through the glass cannot achieve the purpose of allowing the skin to synthesize vitamin D. Because the ultraviolet rays that can help the human body achieve this goal can only be UVB with a wavelength of 280 ~ 320 nm. Most glass ruthlessly blocks out this medium-wavelength UV light, which is why all pediatric textbooks give breastfed babies vitamin D supplements.

After a thorough analysis, you will find that just wanting to bask in the sun and replenish vitamin D - this simple and small wish is far more difficult to realize than we imagined. Either the sun is too far away, or the clouds and rain are in trouble, or the time is not right, or you are afraid of sunburn...... In short, if you want to get enough radiation of UVB radiation at noon in the summer and autumn when the weather is sunny and the amount of radiation is strong enough without getting sunburn - such a "chance and harmony" number of days seems to be a few days a year.

It is no wonder that both adults and children are not enough to brush vitamin D.

As mentioned at the beginning, vitamin D is very important for children to grow taller. Because it is the "refueling agent" for calcium absorption and storage, it can not only enhance the body's reabsorption of calcium and phosphorus and promote bone calcification, but also directly act on bone cells to promote the differentiation of osteoblasts, the strength of bone density and the growth of human bone mass. Without the help of vitamin D, the amount of calcium and phosphorus that children consume from food, which are essential for bone growth, will be absorbed and transported to the bones will be reduced.

However, there are not many parents who can always pay attention to their children's vitamin D nutritional status. Before the age of 1 year, vitamin AD or vitamin D supplements may be taken as appropriate under the advice of a paediatrician (depending on whether or not they are breastfed and if complementary foods are added). After the age of 1, some parents begin to ignore this matter, and it is good to be able to make up for their children every once in a while. After 2~3 years of age, vitamin D is further neglected. Parents' focus on their children has shifted from nutrition to early education......

The vitamin D supplementation we observed in the outpatient clinic was consistent with the conclusions of this study in the Journal of Pediatrics.

What to do?

For most children, supplementing with vitamin D3 supplements on days when sun exposure is not guaranteed is the surest way to avoid deficiencies. According to the Dietary Guidelines for Chinese Residents 2022, the daily requirement is 400 IU (or 10 micrograms/μg).

For children over 1 year old, if milk powder is used as the main milk source, parents need to calculate how much vitamin D is contained in the milk powder that their children drink every day (refer to the table below for the calculation method), if it is less than 400IU (or 10 micrograms/μg) per day, then supplement it intermittently on days when they can't bask in the sun to ensure that the average daily intake reaches the standard.

Calculation method of vitamin D intake in milk powder

Calculate how much milk your baby drinks a day (the amount of milk after preparation)

Find out how many micrograms (ug) of vitamin D is in the nutrition facts list of the milk powder package per 100ml of milk

Divide the milliliters of the day's milk volume by 100 and multiply by the number of micrograms of vitamin D to get the total amount of vitamin D

1 ug of vitamin D = 40 IU (40 IU)

[Easter eggs]: If you don't eat enough food and eat too much meat, eggs, fish and shrimp, it may also affect your growing height~ 

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(The picture in the article is from the Internet)

Otherwise, you may not be able to find me at any time

Sui Qian shattered his thoughts

Drying a car, drying a house, and showing affection?

I suggest you bask in the sun!

About the Author

Liu Suiqian: Australian DAA Certified Registered Practicing Dietitian (APD), Certified Registered Dietitian of the Chinese Nutrition Society, Member of the Australian DAA and Chinese Nutrition Society, Master of Clinical Nutrition (MND) of the University of Sydney, and holds a Graduate Course Certificate in Pediatric Nutrition from Boston University School of Medicine。 He is a member of the translation committee of "Krause Nutrition Diagnosis and Treatment" and other translations, and is the author of many magazines and media nutrition columnists, and has edited five sets of maternal and infant books, and is the author of the book "7 Lessons on Baby Feeding, Say Goodbye to Anxiety and Start with Food Education". In the face of clinical elderly and young maternal patients for 18 years, it has been determined that prevention and psychological support are the direction of doctors' help and healing - the road of popular science, and we work together.

Bibliography:

SUN Jingjing, LU Wenya, NIU Caiyun. A retrospective study on the relationship between vitamin D levels and gender, age, season, sunshine hours and average temperature in a population of 22161 people in Lanzhou. Chinese Journal of Osteoporosis. 2023,29(06):840-846.

Chinese Nutrition Society. Dietary guidelines for Chinese residents 2022 [M]. Beijing: People's Medical Publishing House, 2022.