Since March, the COVID-19 pandemic has greatly affected the lives of Shanghai residents. In such a warm and wonderful spring, however, we had to be isolated at home. Streets and communities were divided into lockdown, control and precautionary areas to strictly contain the pandemic.

During the lockdown period, many people might experience 7, 14, 14+7, 14+14 days of isolation. For those who couldn’t go out and get enough exposure to sunlight, do you have a normal level of vitamin D? The “polyclonal” antibody cocktail therapy, which was approved by FDA (Food and Drug Administration), has been widely used to treat COVID-19 in the United States. It contains 8 drugs and supplements, including vitamin D.

Is vitamin D deficiency related to the infection and treatment of COVID-19?

Since the outbreak of COVID-19, many studies have suggested that low vitamin D level is a risk factor for COVID-19 infection, and is associated with adverse outcomes such as severe condition, admission to ICU and death.

Study findings:

• Boston University：A study by Boston University medical school in September 2020 showed that COVID-19 patients with adequate vitamin D were much less likely to die or become seriously ill.

• Anglia Ruskin University：Having conducted research on the population from 20 European countries, scientists from Anglia Ruskin University and other institutions found that lower average level of vitamin D is directly linked to higher numbers of COVID-19 cases and mortality.

• Northwestern University：Severe vitamin D deficiency may double the possibility of major complications and deaths resulting from COVID-19 infection.

• Israel：A study of medical records in the first two years of confirmed COVID cases shows that: those lacking vitamin D for a long time are up to 14 times more likely to develop severe post-COVID illness.

The use of vitamin D for prevention and treatment of COVID-19 cannot be confirmed by epidemiological correlations, the results of animal experiment and in vitro studies. Well-designed clinical trials are needed, so scientific research is still continuing.

But all these studies have told us that vitamin D deficiency needs to be improved! After the lockdown, the first thing you need to do is check you “serum 25-OH vitamin D” level!

Why is vitamin D so important?

Vitamin D is beneficial to our health in many respects.

1. Anti-infection

Vitamin D can mobilize cells to secrete an immune active substance called “antimicrobial peptides” , which can destroy the viral envelope, and treat lung RNA virus infection. Besides, vitamin D can promote the transformation of monocytes into phagocytes, enhance the strength of immune cells, activate T and B lymphocytes and promote proliferation to enhance the body’s immunity.

2. Make the bone stronger

Vitamin D can promote the absorption of calcium and phosphorus, prevent osteoporosis and rickets, and make the bone stronger.

3. Prevent cancer

Vitamin D supplementation can prevent and reduce the risk of certain cancers.

4. Protect the heart and brain

Vitamin D3 can regulate the calcium concentration in the plasma to reduce blood pressure, thus preventing cardiovascular and cerebrovascular diseases.

5. Lower the risk of diabetes

For patients with vitamin D deficiency, vitamin supplementation can improve insulin resistance and promote insulin secretion, thereby lowering the risk of diabetes.

6. Improve your mood

Patients with moderate to severe depression may feel better after taking vitamin D supplements.

Who are at high risk for vitamin D deficiency?

• People who spend most of their time indoors (all Shanghai residents undergoing isolation during the lockdown)

• Pregnant and breastfeeding women

• Breast-fed babies

• People aged 65 and above

• People with darker skin (their skin is less able to produce vitamin D from the sunlight)

• Obese people (their fat may combine with vitamin D and prevent it from entering the blood circulation)

What are the symptoms caused by vitamin D deficiency?

At the early stage, the deficiency of most people is generally hard to be found until they take physical examination. Annual testing is recommended (this indicator is abbreviated as serum 25-OH vitamin D on the lab test report).

Serum 25-OH vitamin D level is highly recommended to be tested if you often experience repeated inflammatory infection and inability to recover, feel depressed, especially in winter, feel tired, have pain in your joints and muscles, or have weak limbs.

At present, most domestic and international institutions and experts think that the standards of vitamin D nutritional status are as follows:

• Severe deficiency: Serum 25OHD < 10ng/ml(< 25nmol/L)

• Deficiency: Serum 25OHD < 20ng/ml(50nmol/L)

• Inadequate: Serum 25OHD 20-30ng/ml(50-75nmol/L)

• Adequate: Serum 25OHD >30ng/ml(＞75nmol/L)

What should we do if vitamin D deficiency is found?

1. Get exposure to sunlight

The easiest, most effective and safest way is to get exposure to sunlight. When in the sun, the body actively produces vitamin D. It is recommended to be exposed to sunlight at 11:00am-3pm in spring, autumn and winter and at 3pm-5pm in summer, with 15-20 minutes and 3-4 times a week. If possible, expose your limbs without sunscreen. It should be noted that being exposed to sunlight behind the window does not work; you d’ better open the window or go to the outdoors.

2. Food supplements

Salmon, sardines, tuna, lean pork, egg yolks and milk are all good sources of vitamin D. If possible, choose fortified foods, such as infant formula, which is fortified with vitamin D.

3. Supplement with vitamin D

It is recommended to supplement with vitamin D according to the process of “test- evaluate - supplement”.

Test—Check the level of vitamin D in the body;

Evaluate—Give comments based on vitamin gold standard and individual status;

Supplement—Give personalized suggestions on the amount of supplements to improve vitamin D levels.

Due to the complexity of vitamin D supplementation and individual differences, the therapeutic dose required by each person is not the same, and the dose is constantly adjusted in regular use, regular reexamination and doctor evaluation.

Reference:

[1] Petre Cristian Ilie, Simina Stefanescu,Lee Smith. et al. The role of vitamin D in the prevention of coronavirus disease 2019 infection and mortality, Aging Clinical and Experimental Research (2020).

[2] Nicholas Hutchingset.al,Patients hospitalized with COVID-19 have low levels of 25-hydroxyvitamin D.Endocrine. 2021 Feb;71(2).

[3] David O. Meltzer, MD, PhD; Thomas J. Best, PhD; Hui Zhang, PhD; et al Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results，JAMA Netw Open. 2020.3(9).

[4] 张磊，董砚虎, 维生素D抗感染机制研究进展. 中华内分泌代谢杂志, 2021. 37(02): 第168-171页.