Why do we care about Vitamin D?

May 28, 2020

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

Sheldon the dog is getting a little older now. He is nine and a little set in his ways. Emily calls him a grumpy little old man. I think that is a little unfair. Maybe because Emily calls me a big grumpy old man. When Sheldon is in what we call "Puppy Play Mode", he certainly doesn't act like an old man. In Puppy Play Mode, Sheldon wants a cookie and to chase a laser pointer dot and to jump on your lap and sample your snack and bark at a leaf he saw blowing by the window and all like NOW! But when not in Puppy Play Mode, Sheldon is very mellow. And like other older guys, he often needs to pee at 3:30 am. But when he always turns clockwise while answering nature's call, that is also starting to get old.

A friend sent me an article on Vitamin D and COVID-19 from WebMD. It was well written and balanced. On a scale of Donald Trump Clorox crazy to a 100% safe and effective vaccine, where does Vitamin D fall? Let's start with what is Vitamin D? There are different forms of Vitamin D, but the most potent form is called calcitriol. The type of Vitamin D your body makes is called Vitamin D3 (or cholecalciferol). The formation is complicated, but it goes something like this. A Pre- Vitamin D3 is converted to Vitamin D3 in the skin with the help of sunlight (UV Radiation). Vitamin D3 is converted to a second form in the liver called calcidiol. The calcidiol is converted to calcitriol by the kidney. Again calcitriol is the most active form. So you can get Vitamin D3 from taking pills, having your skin make it from sunshine or eating things like fish. Then you hope your kidneys are healthy enough to convert the Vitamin D3 to calcitriol. There is another form of Vitamin D called Vitamin D2 . It is formed by plants and it can be converted to calcitriol in your body as well. There are those that argue that Vitamin D2 doesn't form calcitriol as well at Vitamin D3.

Why do we care about Vitamin D? The most important thing about Vitamin D is still that it helps your gut absorb calcium. We know this because young children who don't get enough Vitamin D develop rickets. Rickets is a condition characterized by bone deformities and "soft bones" which don't have enough calcium. If we treat these children with Vitamin D and/or sunlight, their bones get better. This is why we give breast fed babies a Vitamin D supplement. We assume that the newborns aren't put in the sun (mostly because we told the mothers not too) and the mothers aren't in the sun either. Once the babies go onto formula or milk, they don't need the Vitamin D supplement anymore.

We need Vitamin D to absorb calcium. That isn't a new recommendation. But there are other things about Vitamin D you probably haven't thought of. First, we are all probably getting less Vitamin D than we did before. We are using more sunscreen which is good for preventing skin cancer, but it reduces the Vitamin D our skin can produce. We spend less and less time outdoors, and as people age their bodies are less good at absorbing Vitamin D from their diet. The second thing is the recommendations for how much Vitamin D we need keeps going up. It used to be 400 IU of Vitamin D was fine. Now we don't think 400 IU of Vitamin D will prevent fractures in adults. The recommendations are for at least 400 IU if you are healthy and less than 50. If you are over 50, you should consider 800 to 1000 IU. Vitamin D is generally considered safe up to 4000 IU per day in healthy adults.

Another reason that Vitamin D seems to be in the news more is that it is inexpensive, relatively safe and every time we turn around it seems to do another good thing for us. Let's look at some of the health claims for Vitamin D.

Vitamin D has been shown to prevent falls. In the February 2008 issue of the Journal of the American Geriatric Society there was a study that said nursing home patients on 800 IU of Vitamin D fell less than ones on less Vitamin D or on placebo. There are still researchers who aren't sure if Vitamin D reducing falls is a real effect or not. But since many elderly are not in the sun anyway, Vitamin D supplements still seem like a good idea.

The Canadian Cancer Society now recommends 1000 IU of Vitamin D during the fall and winter. There is some evidence that Vitamin D prevents some cancers, especially colorectal cancer and breast cancer. Of course, there are conflicting studies saying Vitamin D doesn't decrease cancer risk. And there are other studies that say if you have cancer, Vitamin D may help you stop dying from it. But even with the mights and maybes, I'll take the bet that Vitamin D might help with cancer.

Multiple Sclerosis and Vitamin D may have a relationship, but that relationship is unclear. The further you live from the equator, the more likely you are to get MS. Is that because you get more sun and thus more Vitamin D near the equator? Maybe. Studies have shown people with high levels of Vitamin D in them have a lower risk of getting MS, but giving people with MS Vitamin D hasn't shown much success. Recently researchers in Canada and the UK found that if you have a defective gene that normally converts Vitamin D to the active form you are more likely to get MS. So, the complicated dance continues.

What about Vitamin D and COVID-19? Now we get into speculation and guessing. We don't know anything for sure. Some researchers think that if your Vitamin D level is low, you are more likely to be sicker if you get COVID-19. The hypothesis is Vitamin D helps modulate the immune system so the body's own immune system doesn't damage the body as much during a COVID-19 infection. They've been calling this immune system damage a cytokine storm. The problem is that Vitamin D for COVID-19 is still just an untested idea. In her WebMD article, Kathleen Doheny counted at least 8 Vitamin D and COVID-19 trials on clinicaltrials.gov. And the Centre for Evidence-Based Medicine in the UK did a Rapid Review of the evidence and concluded, "There was no evidence related to vitamin D deficiency predisposing to COVID-19, nor were there studies of supplementation for preventing or treating COVID-19." So, I think that makes Vitamin D way, way, way safer than drinking bleach (which you should never, ever do), but as to effectiveness versus COVID-19? We still have no idea.

When Sheldon wakes me up in the middle of the night to pee, I walk with him to the kitchen. Then I hook him onto a dog line outside the kitchen door. He trots down the stairs, snorfles around a little, barks a couple times to let the world know he is going to go pee now and finds a good spot. The problem is he wants to circle clockwise before and after his business. Now that spring is here, Doris has set out our inverted umbrella close drying stand. When Sheldon circles the pole of the drying stand, he only goes clockwise. He winds his line around and around the pole. Then he barks at me to release him. I go down the stairs onto the wet lawn in my robe and bare feet. The I try to convince him to run counter-clockwise to freedom. Then we both go back to bed. I guess at least us two grumpy old men have our routine together.

As always if you have any questions or concerns about these products, ask your pharmacist.

The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.

More Vitamin D, Lower Risk of Severe COVID-19? WebMD - https://www.webmd.com/lung/news/20200518/more-vitamin-d-lower-risk-of-severe-covid-19

Vitamin D: A rapid review of the evidence for treatment or prevention in COVID-19 - https://www.cebm.net/covid-19/vitamin-d-a-rapid-review-of-the-evidence-for-treatment-or-prevention-in-covid-19

 


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