Johnny eats the stuff he likes out of the cereal bowl for breakfast, then walks away. Mom walks by the kitchen and spies his abandoned bowl of cereal milk. Then comes the familiar refrain, “How are you supposed to have strong bones if you don’t drink your milk?”
What Mom’s referring to here is the vitamin D in fortified milk and its ability to produce strong bones.
Most of us associate Vitamin D primarily with its bone-and-teeth strengthening role, but lately, this all-important nutrient has been making headlines for something else—its potential to reduce one’s risk for novel coronavirus.
Is this valid? Or is it just wishful thinking on the part of a population desperate to break free of COVID-19.
We’ll explore that question in this article, but first, let’s cover a few basics.
What is vitamin D?
Vitamin D is not technically a vitamin because vitamins are things that you can’t produce on your own. The body can produce vitamin D, however, and it does so in reaction to the skin’s exposure to sunlight. Vitamin D is actually a prohormone or precursor of a hormone. (But “prohormone D” just doesn’t quite have that same ring to it as vitamin D.)
That’s not to say that vitamin D can’t be gleaned from external sources. You can eat foods that contain vitamin D and also take it in supplement form. This can augment the body’s internally produced vitamin D levels.
What does vitamin D do for us?
Vitamin D helps increase the internal absorption of calcium and phosphate in the body. That’s why it’s helpful for strong bones and teeth. It has also been credit with:
Supporting muscle growth
Supporting immune function
Supporting the health of the brain and nervous system
Regulating insulin levels in diabetic patients
What about Vitamin D and COVID-19?
The well-known “Radiolab” podcast broadcast on NPR featured an episode called “Invisible Allies” in July. It discussed an informal study conducted in homeless shelters in cities with high volumes of COVID-19. Roughly 30 to 40% of the occupants tested positive for the virus, but almost none showed symptoms. The episode highlighted the fact that homeless people are outside a lot more than others, which allows for greater exposure to the sun and, hence, higher vitamin D levels.
This was just a correlation, and more studies are needed to confirm the link between the asymptomatic COVID-carriers and their vitamin D levels, but other studies present a compelling case in favor of vitamin D. Consider the following:
A study published on September 3, 2020, in JAMA Network Open examined the vitamin D levels of 489 UChicago Medicine patients. Those with untreated vitamin D deficiency were nearly twice as likely to test positive for COVID-19 as those who had adequate levels of the vitamin.
A retrospective cohort study of 1,382 hospitalized patients published in June in the NFS Journal concluded the following: “There is ample evidence that various non-communicable diseases (hypertension, diabetes, CVD, metabolic syndrome) are associated with low vitamin D plasma levels. These comorbidities, together with the often concomitant vitamin D deficiency, increase the risk of severe COVID-19 events.”
An August article in The Lancet recapped that the meta-analysis of randomized controlled trials conducted over the last 13 years reveals “protective effects” of vitamin D against acute respiratory infections.
More studies are underway to explore the link between COVID-19 and vitamin D, but until those results are out, consider this perspective from The Lancet article referenced above: “Pending results of such trials, it would seem uncontroversial to enthusiastically promote efforts to achieve reference nutrient intakes of vitamin D… These are predicated on benefits of vitamin D for bone and muscle health, but there is a chance that their implementation might also reduce the impact of COVID-19 in populations where vitamin D deficiency is prevalent; there is nothing to lose from their implementation, and potentially much to gain.”
How do I know if I’m deficient in vitamin D?
Symptoms of vitamin D deficiency include:
Muscle weakness or cramping
Bone and joint pain
High blood pressure
If you suspect that you’re low in vitamin D, talk to your doctor about ordering a blood test through your lab.
What if you don’t have enough vitamin D?
Here in Australia, it’s estimated that roughly 30 percent of the population is vitamin D deficient, and that figure increases for people of color. You can increase your vitamin D levels in the following ways:
Spend 10-15 minutes per day outside in the sun (remember to wear sunscreen; it won’t keep you from getting the needed sunlight, but it will keep you from increasing your risks for skin cancer)
Take a high quality vitamin D supplement
Eat foods that are rich in vitamin D
What foods contain vitamin D?
There aren’t a lot of foods that provide vitamin D, but there are some:
Fatty fish such as tuna, mackerel and salmon
There are also foods that are fortified with vitamin D, to include certain types of:
Who is most at risk for vitamin D deficiency?
People with darker skin. Fair skinned people are better at converting sunshine into vitamin D; darker-skinned people are at greater risk for vitamin D deficiency. This can be confusing because we’re used to hearing about skin cancer risks, which are the exact opposite.
Older people. Younger people are more effective at producing vitamin D. Those over age 50 tend to experience vitamin D deficiency at higher rates.
Homebound people. Older people who aren’t able to get out of their homes much, and other people with limited mobility, may not be able to soak up enough of the sun’s rays to make sufficient vitamin D.
People who live in places with limited sunlight. If you live in an area that is overcast, it will be harder for you to get vitamin D. For example, in Europe (which is known for its overcast, wintery days), 70 percent of the population was reported to be vitamin D deficient in 2012.
Now for the tricky part—finding a good vitamin D supplement. Not all supplements are created equal. Some are packed with fillers, others don’t absorb well into the body. Whether you’re taking vitamin D as a bone supplement or as a preventative measure against COVID, check out our capsules, tablets, and liquid (for kids). We vet each of our products carefully and ensure that we are selling the top-of-the-line supplements that deliver the greatest bang for your buck.
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