Update on Vitamin D: New research examines if supplements improve Covid-19 outcomes

Apr 20, 2020 | 7 comments

It’s been one month since I published this column on the importance of obtaining sufficient vitamin D from food and from sunshine because vitamin D is essential for a healthy immune system.

Since that time researchers have been working hard on identifying links between coronavirus survival rates and factors such as pre-existing conditions, diet, ethnicity, and income disparities.

This is what we do know from the CDC:
Based on what we know now, those at high-risk for severe illness from COVID-19 are:

People of all ages with underlying medical conditions, particularly if not well controlled, including:

  • People with severe obesity (body mass index [BMI] of 40 or higher)
  • People with chronic lung disease or moderate to severe asthma
  • People who have serious heart conditions
  • People who are immunocompromised
    • Many conditions can cause a person to be immunocompromised, including cancer treatment, smoking, bone marrow or organ transplantation, immune deficiencies, poorly controlled HIV or AIDS, and prolonged use of corticosteroids and other immune weakening medications
  • People with diabetes
  • People with chronic kidney disease undergoing dialysis
  • People with liver disease

Even though African Americans make up 13 percent of the US population, they account for 30 percent of the country’s Covid-19 patients. Scott Heins/Getty Images

As reported in Vox and The New York Times, the coronavirus is killing black and Latino people in New York City at twice the rate that it is killing white people, according to preliminary data released on Wednesday by the city.

A number of factors contribute to poor health among people of color — they’re out on the front lines, sometimes without proper PPEs (personal protective equipment), many working service jobs that put them in close contact with possibly infectious people. Other reasons include racism in medical settings to the physical health effects of discrimination, and poverty, of course, means a poor diet and a lack of health insurance and prompt treatment.

In the United States,  redlining and other forms of housing discrimination have made people of color more likely to live in neighborhoods affected by environmental contamination, which federal and state officials have been slow to respond to, in turn raising rates of chronic illness.

Melanin, which causes skin pigmentation, lowers the skin’s ability to make vitamin D in response to sunlight exposure. Some studies show that older adults with darker skin are at high risk of vitamin D deficiency.

As reported in the UK’s Daily Mail, scientists are investigating a potential link between survival rates for coronavirus and levels of Vitamin D.

A ten-week trial involving 200 Covid-19 patients at the University of Granada in Spain will seek to establish if the ‘sunshine vitamin’ can help fight the illness. The researchers cite studies that linked reduced levels of vitamin D in calves as the main cause of bovine coronavirus infection in the past, and the study will investigate if the use of vitamin D as an “immune modulator agent” that the researchers hope improve people’s ability to fight the virus. This is a randomized, double-blinded study. To learn more about the study (start date, April 10, 2020) click here.

Note that this is a preliminary study of just 200 participants. There’s a need for large randomized-controlled that will examine patients with low serum concentrations of vitamin D.

How to get more vitamin D? How much is enough? As we continue to spend most of our time indoors, we can mindfully stand at our window or on our balcony and get some Vitamin D (about 10 minutes daily). Supplementation is an option too. Read more below:

Could vitamin D play a role in coronavirus resistance?

Vitamin D: why do we need it?
The major role of vitamin D is to maintain normal blood levels of calcium and phosphorus and keep them in balance to support and maintain healthy bones.  Researchers from The Irish Longitudinal Study on Ageing (TILDA) have found that vitamin D also plays a role in preventing respiratory infections, reducing antibiotic use, and improving the immune system’s response to infections, noting that in Ireland, 47 percent of all adults over 85 are deficient in winter, and one in eight adults over 50 are deficient all year round.

Vitamin D also plays an important role in insulin sensitivity and artery stiffness.

An extreme and prolonged deficiency of vitamin D causes rickets, resulting in soft bones and bowed legs in children. Low levels of vitamin D are associated with increased loss of muscle strength and mass as we age, increased risk for cancers, lower immunity, high blood pressure, development of neurological disorders, and development of diabetes.

Vitamin D comes in two forms:

Vitamin D2ergocalciferol, and Vitamin D3cholecalciferol.

Vitamin D2 is produced by plants and mushrooms exposed to sunlight.

Vitamin D3 is synthesized in the skin of humans and animals — earning the moniker “The Sunshine Vitamin.”

Global Deficiency of Vitamin D?

The VitaminCouncil.org reports that before the 20th-century humans obtained approximately 95% of vitamin D3 through sun/skin synthesis. Since the middle-late part of the 20th century, research shows that it could be as low as only 15-25%.

Health experts report that vitamin D deficiency is a “global health problem.” As reported in the International Journal of Health Sciences (January 2010), “Over a billion people worldwide are vitamin D deficient or insufficient”. A study published in the journal Food and Nutrition Bulletin (March 2013) examined the data and found that throughout Latin and Central America vitamin D deficiency may be a public health problem, despite the abundance of sunshine.

  • Certain medical conditions including Crohn’s disease, cystic fibrosis, and celiac disease increase the risk of vitamin D deficiency: these can affect the intestine’s ability to absorb vitamin D from foods.
  • Obese and overweight people may have a more difficult time maintaining optimal limits of D; since vitamin D is a fat-soluble vitamin, subcutaneous fat may sequester the vitamin. A May 22, 2018 study concludes that higher levels of abdominal fat may predict vitamin D deficiency.
  • Vegans may be at increased risk since they avoid the most bioavailable dietary sources of vitamin D3, including fish and fish oils, egg yolks, fortified milk, and liver. They need to be sure to eat fortified foods and/or take dietary supplements.
  • Some medications can decrease the activity of vitamin D in the body including anticonvulsants, bile acid sequestrants, gastroesophageal reflux disease (GERD) medications, corticosteroids, and heparin.
  • Seniors may be at high risk for a deficiency, due both to the decrease in time in the sun/sun exposure, but also because a person over 70 produces about 30% less vitamin D than a younger person with the same sun exposure. As people age, they’re less able to convert vitamin D to its active form.
  • Because of the awareness of potential dangers of skin cancer, many people use UVB-blocking sunscreen, blocking the skin’s ability to manufacture D3. And of course, dark-skinned people absorb less vitamin D from the sun.

 Vitamin D For Optimal Health

All vitamin D supplements are not equal in terms of how your body can use the vitamin. Research shows that vitamin D3 supplements are twice as effective as vitamin D2. But how much is enough? When does too much become dangerous? And is supplementation necessary or effective for everyone?

Vitamin D is a fat-soluble vitamin, which means it can dissolve in fats and oils and are absorbed with fats in the diet, and stored in the body’s fatty tissue (other fat-soluble vitamins are A, E, and K).

According to WebMD.com, “Guidelines from the Institute of Medicine increased the recommended dietary allowance (RDA) of vitamin D to 600 international units (IU) for everyone ages 1-70, and raised it to 800 IU for adults older than age 70 to optimize bone health.”

The safe upper limit was also raised to 4,000 IU.

 How Much Is Too Much?

Studies show that people with the highest levels of vitamin D have more bone fractures, fall more frequently, get less sleep, and have a higher mortality rate compared to those with lower, but sufficient, levels. Signs of vitamin D toxicity include chronic constipation, nausea, confusion, kidney stones, and abnormal heart rhythm.

There’s a very important message here. If a little is good, more is not necessarily better. And self-medicating with potentially toxic doses of any vitamin or mineral can have potentially dangerous results. Don’t do it. Doctors may prescribe more than 4,000 IU to correct a vitamin D deficiency.

 How To Increase Your Vitamin D3 Naturally

  • Food sources of vitamin D3 include oily fish and fish oil, egg yolk, butter, and supplements. Plant sources of vitamin D2 include mushrooms exposed to sunlight or UV light, fortified foods, and dietary supplements. Formerly it was advised that since vitamin D is a fat-soluble vitamin you should take your D3 with your largest meal of the day. However, the VitaminDCouncil.org cites studies that show that absorption is not significantly different whether you take vitamin D with food, in pill form, or a powder. The takeaway about diet and vitamin D is that it’s unlikely that you’re consuming adequate vitamin D from diet alone, which is why you need some …
  • Sunlight! For lighter skin, 15-30 minutes of mid-day sun daily. For darker skin, 30 minutes. Your body will not make more D3 than it needs; however, overexposure to the sun holds its own hazards. Since in Cuenca we live much closer to the sun, you may need less exposure than what’s recommended for the general public. You just never want your skin to burn so ten cuidado. And of course, the American Cancer Society advises steering clear from any type of tanning bed.

  • If you’re a vegan, know that vitamin D3 supplements are generally manufactured from lanolin in sheep’s wool or fish oil and are shown to be more effective at raising blood levels. However, vitamin D2, sourced from plants, can certainly help. PrecisionNutrition.com reports that daily vitamin D2 supplements are as good for preventing deficiency and protecting vitamin D status as animal-based vitamin D3.

 How to tell if you have enough D?

Vitamin D lab tests generally assess the total volume of 25-Hydroxyvitamin D (25(OH)D), which is the form of vitamin D circulating in the blood. They may also provide information levels vitamin D2 and D3.

Serum 25(OH)D greater or equal 20 ng/mL (nanograms per milliliter) or 50 nmol/L (nanomoles per liter) is generally considered the minimum adequate level for bone and overall health in healthy individuals.

A concentration below 20 ng/mL is generally considered inadequate, requiring supplemental treatment.

Consider getting tested to see if your vitamin D level is within normal limits. Speak to your doctor about taking a vitamin D supplement, particularly if you have risk factors for vitamin D deficiency, like age, medications, poor diet, and/or any of the diseases mentioned above that may prevent you from absorbing vitamin D. By the way, your body needs vitamin D to absorb calcium, which is why calcium supplements are often combined with vitamin D. However, they do not need to be taken at the same time.

Finally, reduce excess stored fat so that the vitamin D you do eat is more easily absorbed and metabolized. Getting to a healthy weight can also reduce your risk for type 2 diabetes, heart disease, arthritis, some cancers, and if you are infected with covid-19, you are more at risk for poor outcomes if you are obese.

ConsumerLab.com. Product Review: Vitamin D supplements review (including Calcium, Vitamin K, Magnesium.)
DailyMail.com. Can vitamin D help fight against the coronavirus? Scientists investigate after study found taking the supplement saw 50 percent fall in chest infections. European Congress of Endocrinology. Higher levels of abdominal fat may predict vitamin D deficiency.
Food & Nutrition Bulletin. Less than adequate vitamin D status and intake in Latin America and the Caribbean: a problem of unknown magnitude.
National Institute on Aging: Vitamins & Minerals.
MedicalNewsToday.com. Vitamin D guidelines may be changed following new study.
Medscape.com.  (Registration required) Vitamin D: A Rapid Review.
NutritionAction.com. The latest on vitamin D.
PrecisionNutrition.com. All About Vitamins & Minerals.
PrecisionNutrition.com. Vitamin D supplements: Are yours helping or hurting you?
Vitamin D Council.org. How much vitamin D comes from food, and how much vitamn D comes from sunlight?
The New York Times. Virus is twice as deadly for black and latino people than whites in NYC.
Trinity College Dublin. Vitamin D could help fight off Covid-19 – new TILDA research.
Vox.com. New CDC data shows Covid-19 is affecting African Americans at exceptionally high rates.
WebMD.com. Vitamin D Deficiency.

Food, Nutrition, and Your Health columnist Susan Burke March moved to Cuenca after 35 years as a Registered and Licensed Dietitian and Certified Diabetes Educator in the United States. She currently serves as the Country Representative from Ecuador for the Academy of Nutrition and Dietetics. 

Susan helps people attain better weight and health, and reduce the risk of heart disease, diabetes, and other conditions that can be improved with smart lifestyle modifications.

Susan is offering “Free” 20-minute consultations for just a $15 donation to one of the important foundations here in Cuenca. It’s a perfect time to address issues such as cooking at home, strategies for weight loss, or boosting your immunity by improving your diet.

Contact her at SusantheDietitian@gmail.com

Susan Burke March

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