[Health Lecture] How to save you, my vitamin D

In order to ensure the effectiveness of the popularization of health knowledge in the 3rd China Elderly Health Knowledge Competition, the organizers have collected various health science articles suitable for elderly people to learn from various hospitals. We will share them through the "Health Lecture Hall" column. Today, Wang Sihui, a clinical pharmacist at Mudanjiang Second People's Hospital, brought us "How to Save You, My Vitamin D". Elderly friends are welcome to learn.

When it comes to calcium supplementation, everyone may be familiar with it, but when it comes to calcium's "golden partner" - vitamin D supplementation, everyone may be unfamiliar. "How can I tell if I am deficient in vitamin D? How much should I supplement every day? Faced with the dazzling array of vitamin D supplements on the market, how should I choose?" Today, let's take a look at it.

1. What is vitamin D?

Vitamin D is a class of compounds with a cyclopentahydrophenanthrene ring structure, derived from steroids, soluble in fat solvents, and relatively stable to heat and alkali. Generally, natural forms of vitamin D2 and D3 are collectively referred to as vitamin D. Among them, vitamin D2 (ergocalciferol) is produced from plants or mushrooms and is irradiated with ultraviolet rays, while vitamin D3 (cholecalciferol) is produced by human skin under ultraviolet rays in sunlight. Vitamin D needs to undergo two steps of activation processing in the body to become its active form - 1,25-dihydroxyvitamin D (active vitamin D, calcitriol). The first step of the activation process is the activation of vitamin D into 25-hydroxyvitamin D (calcidiol) in the liver, which is the main form of vitamin D in the blood and can reflect the nutritional status of vitamin D in the body. The second step is the activation of 25-hydroxyvitamin D into 1,25-dihydroxyvitamin D mainly in the kidneys to exert its final biological effect. Since the half-life of 25-hydroxyvitamin D2 is shorter than that of vitamin D3, the final activity of vitamin D3 is better, and it is generally recommended to use D3 as a dietary supplement for vitamin D.

2. How to determine whether you are deficient in vitamin D?

In fact, the phenomenon of vitamin D deficiency and deficiency among Chinese residents is widespread. The "2015-2017 China Residents Nutrition and Health Status Monitoring Report" pointed out that the serum vitamin D deficiency rate of children and adolescents aged 6 to 17 in China was 18.6% in 2016-2017; the serum vitamin D deficiency rate of people aged ≥18 in China was 21.4% in 2015; the serum vitamin D deficiency rate of men was 16.1%, and that of women was 26.8%; the serum vitamin D deficiency rate of urban residents was 24.7, and that of rural residents was 17.8%. According to the "Expert Consensus on Evaluation and Improvement of Vitamin D Nutritional Status" issued by the Health Management Branch of the Chinese Nutrition Society in April 2023, 25 (OH) D is the main circulating form of vitamin D in the blood, with good stability, and is recognized as the main indicator for evaluating the nutritional status of vitamin D in the human body. Usually, the determination of vitamin D nutritional status is divided into four categories: normal, insufficient, deficient, and poisoning.

3. Why does vitamin D deficiency occur?

Many people may think that living conditions are getting better and better, and the types of food are gradually diversified. How can the intake of vitamin D be insufficient? In fact, it is not. Vitamins are divided into water-soluble vitamins and fat-soluble vitamins. Vitamin D is a fat-soluble vitamin, which is mainly found in animal foods such as high-fat marine fish (such as salmon, tuna, sardines, etc.), animal liver, mushrooms, egg yolks and other foods. Among them, eggs are relatively easy to obtain ingredients, while the intake of high-fat marine fish and animal liver may be affected by factors such as region and food culture. In addition, 90% of the vitamin D needed by the human body is synthesized through the skin, so it is very necessary to ensure sufficient light. Nowadays, it is difficult for most people to get enough sunlight from 8 am to 5 pm, not to mention the 996 and 007 working people. In addition, our awareness of sun protection has gradually increased. Sun protection clothing and parasols have become a must-have for travel, which is also the main reason for our own insufficient synthesis.

4. How should vitamin D be supplemented?

1. The first thing we have to consider is to maintain adequate sunlight. 30 minutes of sunlight a day can meet the body's vitamin D needs. For ordinary office workers, taking a short break after lunch and taking a walk outdoors can meet the day's sunlight index, but everyone should also be careful not to avoid excessive exposure to the sun to avoid sunburn. 2. Dietary vitamin D is also a good way. Dietary sources are mainly divided into non-fortified foods and fortified foods. Just like the high-fat marine fish, animal liver, mushrooms, eggs and other foods mentioned above are non-fortified foods. Let's take dairy products as an example. Vitamin D is added to some formula milk powder or milk, so this type of food is a fortified food. 3. For some specific groups of people, such as infants, pregnant women, lactating women and the elderly, you can choose vitamin D preparations according to the table below for appropriate supplementation.

5. Faced with a wide variety of medicines on the market, how do you choose the right product?

1. Choice of dosage form Common dosage forms on the market are mainly divided into two categories, oral preparations and injections. Generally speaking, we mainly choose oral preparations. If there is a situation that affects the gastrointestinal absorption of vitamin D, vitamin D can be injected intramuscularly. Oral preparations include tablets, capsules, pills, etc. If it is for children, vitamin D drops, soft capsules and cod liver oil are more suitable choices. The drops and soft capsules can be softened with hot water and squeezed into the baby's mouth. However, when taking cod liver oil, it should be noted that cod liver oil contains animal-derived vitamin A. Infants and young children are more sensitive to vitamin A. If taken in excess, there may be a risk of poisoning, so the dosage problem must be mastered. For adults, general oral preparations are optional. If there are patients with dysphagia or the elderly, the above-mentioned children's drops and soft capsules can be selected and administered using the method of children's medication.

2. Choice of ingredients. In addition to the common D supplements mentioned above, there is also active vitamin D and its analogs. Active vitamin D mainly refers to calcitriol [1,25-(OH)2-D3], which is the most active vitamin D. Representative drugs of active vitamin D analogs are alfacalcidol [1α-hydroxyvitamin D3] and paricalcitol [19-nor-1,25-(OH)2-D]. How should we choose this type of drug? ① Alfacalcidol: It does not need to be converted by the kidneys, but it is biologically active only after conversion by the liver. It is suitable for people with renal insufficiency but normal liver function, especially patients with renal osteopathy and the elderly. ② Calcitriol: It has complete biological activity and can take effect without conversion by the liver and kidneys. Therefore, it is suitable for the treatment of various types of osteoporosis, especially osteoporosis patients with combined liver and kidney insufficiency.

3. Price selection. Vitamin D generally requires long-term supplementation, so price is also an important consideration. You can choose regular products with high cost performance. There is no need to choose famous ones with beautiful packaging. Warm reminder from clinical pharmacists: It should be noted that in actual application, under the guidance of a physician or pharmacist, you can choose a vitamin D supplement according to the condition, avoid repeated administration, and do not need to supplement other drugs or health products containing vitamin D. Do not increase the dosage on your own to avoid poisoning.

About the Author:

Wang Sihui is currently a clinical pharmacist at the Second People's Hospital of Mudanjiang City. She is a pharmacist stationed in the Department of Respiratory Medicine and is mainly involved in the department's clinical antimicrobial drug consultation, antimicrobial drug prescription review, Class I incision review, drug consultation, medication guidance, adverse drug reactions, pharmacy popularization, pharmacy clinic, data reporting, clinical pharmacy publicity and other work.