Vitamin S is probably the most under utilized vitamins out there…

aka: Vitamin SUNSHINE

Yes, that’s right. Something that is so accessible to us every day is completely under utilized. Getting sunlight exposure can have incredible benefits to our health, and better yet, it’s completely free, universally accessible, and takes as little as 20 minutes a day to reap the benefits from.

The Sun and Vitamin D

Okay okay, so the sun in and of itself may not be a vitamin…but it does work to make vitamin D in the body.

When your skin is exposed to sunlight it begins the process of making the active form of vitamin D. The sun’s ultraviolet rays (UVB to be exact) turn cholesterol in the skin (7-drhydrocholesterol) into vitamin D3, where it is then carried to your liver and then your kidneys to become the active form of vitamin D (1,25(OH)2D).

This is crucial as it is estimated that up 40% of the population is deficient in vitamin D. And why is that a big deal? Well, vitamin D is needed for bone strength and health, meaning all the calcium in the world won’t be able to override a deficiency in vitamin D.

Low vitamin D has also been linked to an increase in cancer risk, poor immune system, and negative impacts on our hormones. At the hormone health level, vitamin D supports ovulation, altering AMH and increasing progesterone. We also know that vitamin D is crucial during pregnancy, working to support fetal growth, regulate the placenta, and influence prenatal hormone levels. In fact, optimal vitamin D levels have been linked to a reduced risk of preeclampsia and gestational diabetes, highlighting its importance throughout stages of life.

The issue is that food is generally very low in vitamin D – but not to fear, because the sun is what we really need. The American Journal of Clinical Nutrition estimated that sun exposure accounts for around 90% of vitamin D among most individuals (those not taking vitamin D supplements). This shows what a huge contribution the sun has to our vitamin D production. And while a high quality supplement can definitely play a role, we should first be utilizing what nature has to offer.

The Sun and the Circadian Rhythm

The circadian rhythm is like our body’s little internal clock, influencing everything from our metabolism to our sleep-wake cycle behind the scenes. However, blue light, jet lag, caffeine, marijuana, and alcohol are just a few of the many culprits that interfere with our body’s natural rhythm. And what happens when our inner clock is out of whack? We have worsened ovarian function and other hormonal issues, higher stress hormones and inflammation, decreased alertness, issues with memory and decision making, and so much more.

And one of the things you can do EVERY DAY to restore your circadian rhythm is so simple – replace that morning Tiktok scroll with a dose of sunshine. Exposure to sunshine helps to regulate our levels of cortisol and melatonin, influencing our feelings of “awake” and feeling “sleepy.” While darkness tells our brain to start revving up the melatonin production, light exposure tells it to bring it to a halt so that we don’t feel tried during the day.

In fact, our circadian rhythm is most sensitive to light 2 hours before bedtime and 1 hour after waking. While we would need a whole new post to discuss optimal sleep routines (or you can check out my freebie here), catching those rays upon rising can go a long way in helping you feel more energized in the morning and even help you to fall asleep faster come night.

The Sun and Mental Health

Sunshine exposure has been examined for its benefits on mental health. Researchers have shown that seasonal affective disorder (SAD) or moods that seem to be influenced by seasonal and weather changes can be greatly influenced by sun exposure.

Other research has gone on to show that light can help mitigate symptoms of depression and other factors of mental health. While we know that vitamin D is implicated in some of these – such as depression – the impacts of sun seem to go much deeper than this. One large study of over 400,000 people found that for every additional hour spent outdoors during the day, there were significantly lower odds of developing major depressive disorder, less frequent anhedonia (inability to experience pleasure), low mood, neuroticism, and increased happiness. We know that the sun influences neurochemistry, with exposure stimulating the brain to produce serotonin – meaning we literally feel happier.

But we don’t even have to look at research to understand this. Ask yourself – do you feel happier when you’re inside all day or out in the sun? When it’s a gloomy sky? Or clear blues? The answer is clear.

So What About Sunscreen?

There has to be a balancing act here. We know that sun damage is a very real cause of skin cancer. However, we also know that vitamin D production and sunlight exposure are key to health.

And when it comes to sunscreen, research has shown that an SPF 30 can reduce vitamin D production by 95%. So how do we balance it all?

My advice is to avoid direct sun (meaning without sunscreen) between 10:00 am and 2:00 pm, when the sun is strongest, and instead opt for that early morning walk sunscreen free or using a light layer of a mineral based sunscreen. However, during that midday time slot is when those UVB rays have the greatest impact on producing vitamin D.

This is why I recommend checking in with your own context. Skin tone greatly impacts vitamin D production, with those with darker skin requiring up to 6x more time in the sun to produce the same amount of vitamin D as a pale skinned person. Similarly, people with lighter skin are at a greater risk for skin cancer due to less melanin which has protective properties against UV light. So as with everything, consider your personal context.

The Takeways

The sun influences everything from our vitamin levels to our hormones. Aiming for exposure daily is key, with most people finding that about 10-30 minutes will do the trick. So shine brightly sunshine!

Written By: Amanda Wahlstedt, RDN