Vitamin D is one of the most important substances in our body. Yet, according to a paper from the Charak Foundation (Ref 1), 70% of Indians are deficient in this essential compound. Although excessive time in the sun and sunburns increase the risk of skin cancer, healthy, moderated exposure to sunlight actually decreases it–and has a whole host of other benefits!
Ref 1: Vitamin D Deficiency in India: Prevalence, Causalities and Interventions
A short biochemistry lesson
Vitamin D is an essential compound, meaning that our bodies cannot manufacture it. Additionally, it one of very few substances that is generated when sunlight hits our skin.
Here's a diagram from a paper in the journal Nutrients (Ref 2) that shows vitamin D synthesis and metabolism.
A guide through the main steps:
In the skin, there's 7-dehydrocholesterol.
When UVB rays hit the skin, 7-dehydrocholesterol becomes previtamin D3.
The previtamin D3, upon being heated in the body, turns into what we know as vitamin D3. This is the same vitamin D3 as what you get in a supplement.
The vitamin D3 then goes to the liver where the enzyme CYP2R1 turns it into 25D.
Then, the kidneys turn 25D into 1,25D. This 1,25D is the final active version, which acts on hundreds of different places in the body.
After some time, the enzyme CYP24A1 inactivates 1,25D and it gets excreted from the body.
Ref 2: Vitamin D and the Liver—Correlation or Cause?
Importance & Benefits of vitamin D & sunlight
Now that you have a strong understanding of how vitamin D works in the body, we'll tall about why it's so important. Because it is very difficult to distinguish between the effects of vitamin D and the effects of sunlight, and because they are so intertwined, I will be covering the effects of both together!
Scientists from the University of Copenhagen have shown that "Vitamin D is crucial to activating our immune defenses and that without sufficient intake of the vitamin, the killer cells of the immune system -- T cells -- will not be able to react to and fight off serious infections in the body." (Ref 3)
Research published in the Journal of Clinical Endocrinology & Metabolism shows that "Over 80 percent of COVID-19 patients have vitamin D deficiency." (Ref 4)
A study shows that the "Vitamin D levels during pregnancy are linked with child IQ." (Ref 5)
Research shows that those with "active sun exposure habits were at a lower risk of cardiovascular disease (CVD) and noncancer/non-CVD death as compared to those who avoided sun exposure." (Ref 6)
Ref 3: Vitamin D crucial to activating immune defenses
Ref 4: Over 80 percent of COVID-19 patients have vitamin D deficiency, study finds
Ref 5: Vitamin D levels during pregnancy linked with child IQ
Ref 6: Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort
How to increase this valuable substance
Now that we know just how important vitamin D is for us, and that you are likely to be deficient in it (statistically speaking), let's see how we can increase this compound in our bodies. One important thing to keep in mind is that we shouldn't give ourselves a sunburn. Other than it's painful effects, sunburns actually increase the risk of skin cancer–while healthy, moderated exposure to sunlight actually decreases it.
Spend time in the sun:
such as 5-20 minutes outside at midday
One important thing to keep in mind when doing this is to take off your sunglasses. This is because, when you wear sunglasses, you are filtering and dimming the light that your eyes receive. Your brain will think that it's the evening, while it's actually midday. Your body then won't be prepared to handle the higher intensity of sunlight.
vitamin D supplement
No matter how much time you spend outside, it is very unlikely that you will have strong vitamin D levels. That is why it is a good idea to take a supplement. A good dose is 5,000 IU every day.
It's a good idea to take some vitamin K2 with vitamin D3. Supplementation of vitamin D3 without K2 may lead to problems with excess calcium, which can be deposited in the arteries and lead to atherosclerosis (plaque buildup).
Now, you are equipped with the knowledge to help optimize your vitamin D levels–and in turn, many parts of your body.
All that's left is for you to put on some shorts and a t-shirt, forget the sunglasses, and go for a walk outside!