Can Vitamin D Protect You During this Coronavirus Pandemic?
Can vitamin D help against COVID-19? Several publications and studies have suggested that maintaining adequate levels of vitamin D would seem potentially beneficial in fighting the COVID-19 infection. This article explains what you need to know about vitamin D and COVID-19.
What Is Vitamin D?
Vitamin D is a fat-soluble vitamin, meaning that it dissolves in fats and oils and can be stored in your body for a long time.
Two main dietary forms exist (Trusted Source):
- Vitamin D3 (cholecalciferol). Found in some animal foods, like fatty fish and egg yolks.
- Vitamin D2 (ergocalciferol). Found in some plants, mushrooms, and yeasts.
Of the two, D3 (cholecalciferol) seems to be almost twice as effective at increasing blood levels of vitamin D as D2 (ergocalciferol) (Trusted Source, Trusted Source).
What Does It Do in Your Body?
Vitamin D needs to undergo two conversion steps to become active (Trusted Source, Trusted Source).
First, it is converted to calcidiol, or 25(OH)D, in your liver. This is the storage form of the vitamin.
Second, it is converted to calcitriol, or 1,25(OH)2D, mostly in your kidneys. This is the active, steroid-hormone form of vitamin D.
Calcitriol interacts with the vitamin D receptor (VDR), which is found in almost every single cell in your body (Trusted Source, Trusted Source).
When the active form of vitamin D binds to this receptor, it turns genes on or off, leading to changes in your cells. This is similar to how most other steroid hormones work (Trusted Source, Trusted Source).
Vitamin D affects various cells related to bone health. For example, it promotes the absorption of calcium and phosphorus from your gut (Trusted Source).
But scientists have recently discovered that it also plays roles in other areas of health, such as immune function and protection against cancer (Source).
Best Time to Get Vitamin D from Sun in Malaysia
Most studies show that approximately 10 – 25 minutes of sun exposure between 11.00 am and 2.00 pm at least twice a week to the face, arms, legs, or back without sunscreen will usually provide sufficient daily vitamin D requirements (Harinarayan, 2013, Alshahrani, 2013, Holick, 2007).
The amount of sun exposure needed to synthesize adequate vitamin D depends upon the type of skin, time of the day, the month of the year, and the latitude.[Reichrath, 2014] The duration needed in an individual with dark skin is about 10 times that in fair-skinned individuals.
It has been suggested that exposure to sunlight for 5 min to 5 h per day (depending upon the above-mentioned factors) may be sufficient to synthesize our daily requirement of vitamin D.
However, a recent study from India found that despite an intense sun exposure, 90% of infants continued to have vitamin D insufficiency and needed supplementation.[Karthikeyan, 2017] This fact is often not emphasized. A similar study from New Delhi, India that was carried out in school-age children found no increase in vitamin D levels, 4 weeks following sun exposure.[Marwaha, 2016]
Farrar et al. (2013) published a study from the United Kingdom (UK) that included volunteers from South Asian countries (India, Pakistan, and Bangladesh) staying in the UK and exposed 35% of their body surface area to variable doses of UV rays in a controlled environment for 6 weeks.[Farrar, 2013] It was found that vitamin D levels rose significantly after UV exposure. However, a significant proportion of subjects still remained vitamin D insufficient. A similar study carried out in the UK by Farrar et al. (2011) found that UV exposure may correct vitamin D deficiency in white skin individuals but not in South Asian individuals.[Farrar, 2011]
Therefore, sun exposure alone may not be an adequate source of vitamin D for dark skin children and adults. Dietary supplementation of vitamin D is necessary. The commonly recommended daily dose of vitamin D is 600 IU (15 mcg) (nih.gov).
Further, the American Academy of Pediatrics (AAP) has stated that “Use of deliberate sun exposure to maintain vitamin D sufficiency is not recommended” and “Infants younger than 6 months should be kept out of direct sunlight as much as possible.”
Also, UV (Ultraviolet) rays are immunosuppressive. UV rays damage the the skin and stimulate the regulatory T cells to produce the immunosuppressive cytokine. UV radiations can also lead to DNA strand breaks.
Best Food Sources of Vitamin D
Here is the vitamin D3 content of a few of the best food sources (nih.gov):
Food | Amount | % RDI |
Cod liver oil, 1 tablespoon (15 ml) | 1,360 IU / 34 mcg | 227% |
Salmon, cooked, 3 ounces (85 grams) | 447 IU / 11 mcg | 75% |
Tuna, canned in water, 3 ounces (85 grams) | 154 IU / 4 mcg | 26% |
Beef liver, cooked, 3 ounces (85 grams) | 42 IU / 1 mcg | 7% |
1 large whole egg (D is found in yolk) | 41 IU / 1 mcg | 7% |
1 sardine, canned in oil, drained | 23 IU / 0.6 mcg | 4% |
Although fatty fish like salmon, mackerel, swordfish, trout, tuna, and sardines are decent sources, you would have to eat them almost every day to get enough.
The only excellent dietary source of vitamin D is fish liver oil — such as cod liver oil — which contains upwards of two times the Reference Daily Intake (RDI) in a single tablespoon (15 ml).
Keep in mind that dairy products and cereals are often fortified with vitamin D (Trusted Source).
Some rare mushrooms also harbor vitamin D, and egg yolks contain small amounts.
Symptoms of Deficiency
Vitamin D deficiency is one of the most common nutrient deficiencies.
Some people are at a greater risk than others. In the United States, 41.6% of the total population is deficient, although minorities fare worse — 82.1% and 69.2% of blacks and Hispanics are deficient, respectively Trusted Source).
Additionally, older adults are at a much greater risk of being deficient (Trusted Source).
Those who have certain diseases are also very likely to be deficient. One study showed that 96% of people who had experienced heart attacks were low in vitamin D (Trusted Source).
Overall, vitamin D deficiency is a silent epidemic. The symptoms are usually subtle and may take years or decades to surface.
The most well-known symptom of vitamin D deficiency is rickets, a bone disease common in children in developing countries.
Rickets has been mostly eliminated from Western countries because of the fortification of some foods with vitamin D (Trusted Source).
Deficiency is also linked to osteoporosis, reduced mineral density, and increased risk of falls and fractures in older adults (Source).
What’s more, studies indicate that people with low vitamin D levels have a much greater risk of heart disease, diabetes (types 1 and 2), cancer, dementia, and autoimmune diseases like multiple sclerosis (Trusted Source).
Finally, vitamin D deficiency is linked to a reduced life expectancy (Trusted Source, Trusted Source, Trusted Source).
That said, it’s unclear whether deficiency contributes to these diseases or whether people with low levels are just more likely to get them.
Vitamin D and COVID-19: The Evidence
A preprinted study published in June 2020 from Singapore (CW Tan, MedRxiv 2020), among 43 patients age 50 or older who were hospitalised with COVID-19, found that those who were started on a daily oral dose of vitamin D3 (1,000 IU), magnesium (150 mg) and vitamin B12 (500 mcg) within the first day of hospitalisation and continued up to 14 days were significantly less likely to require oxygen therapy and further intensive care.
According to an editorial review (Aliment Pharmacol Ther. 2020) published in June 2020 by Irish researchers, people with vitamin D deficiency appear to be far more prone to severe COVID-19 infections.
The epidemiology of COVID-19 provides evidence that vitamin D might be helpful in reducing risk associated with COVID-19 deaths. A May 6, 2020, report published in Aging Clinical and Experimental Research (its prepublication featured in the Daily Mail) found that countries with lower vitamin D levels also have higher mortality rates from COVID-19.
Another May 6, 2020 report (Nutrients. 2020) in the journal Nutrients pointed out that vitamin D concentrations are lower in patients with positive PCR (polymerase chain reaction) tests for SARS-CoV-2. As noted in this report, which retrospectively investigated the vitamin D levels obtained from a cohort of patients in Switzerland.
The Irish Longitudinal Study on Ageing (TILDA) published in April 2020, suggested that vitamin D deficiency could have serious implications for COVID-19. Results from the Irish Longitudinal Study on Ageing (TILDA), showed that vitamin D plays a critical role in preventing respiratory infections, reducing antibiotic use, and boosting the immune system response to infections.
Another study, published in the journal Nutrients (April 2, 2020), carries the telling title, "Evidence That Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Death."
Mark Alipio with GrassrootsHealth conducted a retrospective multicenter study involving 212 patients in Southeast Asia who had COVID-19. He too found a strong correlation between vitamin D levels and disease severity. Those with the mildest disease had the highest vitamin D levels, and vice versa.
A preprinted study published in May 2020, looked at Vitamin D levels and inflammatory markers in hospitalized COVID-19 patients in Germany, South Korea (S. Korea), China (Hubei), Switzerland, Iran, UK, US, France, Spain, Italy (Daneshkhah, MedRxiv 2020). Patients with the lowest Vitamin D levels were about 15% more likely to get severe COVID-19 and cytokine storm. Vitamin D3 plays a role in inhibiting the cytokine storm that causes viral infections to become lethal.
In a May 18, 2020, letter to the Federal Chancellor of Germany, Angela Merkel; Bernd Glauner and Lorenz Borsche highlight these and other studies and ask whether a nationwide supply of vitamin D has been considered in Germany.
While large controlled studies demonstrating vitamin D's effectiveness in COVID-19 are still lacking, there are many such studies underway. You can review the status of these trials on clinicaltrials.gov. As of July 2020, 20 studies have been launched to investigate the benefits of vitamin D against COVID-19.
Buy Online: You can purchase Vitamin D as a dietary supplement online and from local health stores in Malaysia i.e. Guardian and Watson.
Do take note that you can also get good amounts of vitamins C and D, zinc, and other essential vitamins and minerals from a basic multivitamin.
How Much Should You Take?
The only way to know if you are deficient — and thus need to supplement — is by having your blood levels measured.
Your healthcare provider will measure the storage form of vitamin D, which is known as calcifediol. Anything under 12 ng/ml is considered deficient, and anything above 20 ng/ml is considered adequate.
The RDI for vitamin D is as follows (nih.gov):
- 400 IU (10 mcg): infants, 0–12 months
- 600 IU (15 mcg): children and adults, 1–70 years old
- 800 IU (20 mcg): older adults and pregnant or breastfeeding women
Although adequacy is measured at 20 ng/ml, many health experts believe that people should aim for blood levels higher than 30 ng/ml for optimal health and disease prevention (Trusted Source).
Additionally, many believe that the recommended intake is far too low and that people need much more to reach optimal blood levels (Trusted Source).
According to the U.S. National Academy of Medicine, the safe upper limit is 4,000 IU (100 mcg) per day (Trusted Source).
Vitamin D3 supplements appear to be more effective at raising vitamin D levels than D2 supplements. D3 capsules are available in most supermarkets and health food stores, as well as online.
Optimize Your Other Nutrients
It's important to keep in mind that nutrients usually don't work in isolation.
Many of them depend on one another, and increased intake of one nutrient may increase your need for another.
Some researchers claim that fat-soluble vitamins work together and that it’s crucial to optimize your vitamin A and K intake while supplementing with vitamin D3 (Trusted Source, Trusted Source).
This is especially important for vitamin K2, another fat-soluble vitamin that most people don't get enough of (Trusted Source).
Magnesium — another important mineral often lacking in the modern diet — may also be important for vitamin D function (Trusted Source).
What Happens if You Take Too Much?
Vitamin D toxicity is extremely rare, but does occur with extreme doses. It is almost impossible to get too much vitamin D from sunlight or food.
Vitamin D toxicity usually develops over time, since extra vitamin D can build up in the body.
Nearly all vitamin D overdoses result from taking high amounts of vitamin D supplements.
The main symptoms of toxicity include confusion, lack of concentration, drowsiness, depression, vomiting, abdominal pain, constipation, and high blood pressure (Trusted Source).
A recent case report (BMC Geriatrics. 2020): a Brazilian retired 64-year-old female, presented to the emergency service with vomiting, abdominal pain, frontal headache, fatigue, weight loss of 18 kg, severe itchiness, musculoskeletal pain in the limbs and high blood pressure. Due to the rarity of vitamin D toxicity, the definitive diagnosis was prolonged. The diagnosis was confirmed with a Vitamin D blood test. Lab results also showed high level of blood calcium (hypercalcemia) and acute kidney injury.
Wrap-up
Do we have large randomised controlled trials to prove that vitamin D can combat COVID-19. Not at the moment.
Of course, the most important thing you can do to avoid infection with coronavirus is to prevent exposure by following the latest recommendations of the CDC and World Health Organization such as wearing face mask, social distancing and hand sanitisation. Also take steps to stay healthy, including getting adequate sleep and exercise and eating a healthful diet that includes adequate (but not excessive) intakes of essential nutrients, such as vitamins C and D.
For those with hypertension, please take steps to control your blood pressure as high blood pressure is associated with more severe outcome if infected.
Your own immune system, works best when fed right. As long as you are taking supplements under medical supervision and within a safe range, the risk is low but the potential benefit is high? What have you got to lose?
References:
Buy Vitamin D supplement in Malaysia: You can purchase Vitamin D as a dietary supplement online and from local health stores i.e. Guardian and Watson.
Comments
Post a Comment