How to Rely on Sunlight for Vitamin D

Living in Florida has its perks. When you think of Florida, what cliché images come to your mind? Beaches. Palm Trees. Warm weather. Citrus. Sunshine. Because we’re close to the equator, we get a lot of warmth from the sun that allows us to enjoy all those images I just mentioned. But regardless of where you live, you can enjoy the benefits of being exposed to sunshine. Vitamin D, also known as the sunshine vitamin, is created when we’re exposed to the sun. Below we’ll discuss the benefits of Vitamin D, how much you need, and how to rely on sunlight for Vitamin D.

Health Disclaimer: The information provided on this site is for informational purposes only. It is not intended as a substitute for advice from your physician or other health care professional. It is not for the diagnosis, treatment, prescription, or cure of any disease or health condition. Always consult with a healthcare professional before starting any diet, exercise, or supplementation program, before taking any medication, or if you have or suspect you might have a health problem.

Vitamin D Benefits

According to the U.S. Department of Agriculture, vitamin D helps the body absorb calcium and phosphorus, both vital minerals for building strong and healthy bones. It also contributes to muscle health.

Vitamin D helps to reduce the risk of certain cancers, reduce blood pressure, and reduce migraines. It can also help the immune system and reduces the risk of upper respiratory infections and tuberculosis. It helps with nerves and brain function and may reduce the risk of Parkinson’s disease, Alzheimer’s disease, depression, and schizophrenia. And it can also help reduce the risk of autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, Crohn’s disease, and type 1 diabetes.

Vitamin D deficiency is incredibly common, roughly 40% of the US population is deficient as of 2011, with anyone having a darker skin tone having a higher chance of being deficient. It’s also more common if you are older, overweight, do not consume fish, live far from the equator, always use sunscreen, or stay indoors.

Sunlight for Vitamin D

Vitamin D Sources

As of May 2020, the FDA recommends 20mcg of Vitamin D (800 IU). The recommendation used to be 400 IU, but has since been updated. I have seen recommendations upward of 5,000 IU for those who are deficient in vitamin D, but if you’re considering supplements, you should check with your primary care physician first to see if you are deficient.

Vitamin D can be acquired in two ways – through diet or sunshine. Vitamin D is a fat-soluble vitamin that is naturally present in a few foods or available as a dietary supplement. It is also produced when ultraviolet (UVB) rays from the sun strike the skin and trigger vitamin D synthesis.

When it comes to diet, fatty fish and egg yokes are good sources of vitamin D. Below are average IU amounts per source.

  • Salmon: wild-caught salmon provides 988 IU per serving (3.5-ounces)
  • Halibut: 384 IU per half a fillet.
  • Mackerel: 360 IU per half a fillet.
  • Herring: Fresh Atlantic herring provides 216 IU per serving (3.5 ounces)
  • Sardines: One can (3.8 ounces) provides 177 IU
  • Egg Yolks: 1 pasture-raised egg yolk contains about 130 IU.
  • Cod Liver Oil: 1 teaspoon of this particular cod liver oil can provide you roughly 400 IU. Be aware that most cod liver oil is purified using the process that removes most of the natural vitamin D (and vitamin A). Some manufacturers add it back in, but it is usually synthetic, and not in an ideal ratio compared to vitamin A. If you want to consume natural vitamin D, it’s important to find a brand that preserves the natural vitamin D by employing old fashioned processing methods (cold-pressed) and does not add any synthetic vitamins.

Vitamin D food sources

Vitamin D Supplements

While supplements are another form to consume vitamin D, that is something you would want your blood levels to be tested for first. Taking too much of anything can cause an imbalance. For example, when synthetic vitamin A and D are added to some forms of cod liver oil, the ratio might not be optimal (or natural). A lot of times too much vitamin A is added. The ratios of vitamin A and D you consume is important. Without vitamin D, vitamin A can be ineffective or even toxic. But if you’re deficient in vitamin A, vitamin D cannot function properly. An increase in vitamin D also requires magnesium as well as K2.

Consuming natural foods makes it much more unlikely for you to overdo your consumption of vitamins or minerals.

Relying on Sunlight for Vitamin D

Vitamin D is also referred to as the sunshine vitamin, and for good reason. But there’s a little more to it than what you might think. Most people (myself included until I did some research) believe that as long as the sun is up and you’re outside you’re getting enough sunlight for vitamin D. But that’s actually not true.

The sun produces UVA and UVB rays. When your skin is exposed to UVB rays it hits cholesterol in the skin cells, providing the energy for vitamin D synthesis to occur. The form of vitamin D that you get from the sun is called D3 (also known as cholecalciferol).

But there are many factors when it comes to UVB rays reaching your skin, and how your individual body handles that. Where you live plays a big factor. As do your personal demographics.

Sunlight for Vitamin D

Location

Location matters. Unlike UVA rays, which are always penetrating the atmosphere, UVB needs a more ideal scenario to reach us. Your body only generates vitamin D when the angle of the sun is 35° or more above the horizon (although I’ve also seen 50° reported as the angle minimum).

When the angle of the sun is lower, the ozone layer ends up absorbing all of the UVB rays and the rays don’t reach us. The time of day, time of year, and your location all impact the angle of the sun.

In the early morning and late afternoon, UVB rays don’t reach us. Once the sun reaches 35° your body will start producing vitamin D, and the higher the angle, the more vitamin D you’ll be able to produce until the sun reaches the top position of “solar noon.”

During winter months the angle of the sun is lower, so you produce less vitamin D during the same window of time if it was the summer. This affects locations that are further from the equator. If you live far enough away from the equator, it’s possible to not make any vitamin D from sun exposure for half the year.

If you live less than 35 degrees from the equator, it’s possible to produce enough vitamin D from the sun throughout the whole year. You may need to spend more time outside during the fall and winter months, but it’s still possible. Otherwise, you’ll need to get your vitamin D through diet during some months. Below is a chart that shows what’s possible.

Sunshine calendar

Altitude also matters. If you live at a higher elevation, you’ll be able to produce more vitamin D than being at sea level. Clouds and smog can also affect UVB rays reaching you.

Demographics

Once UVB rays start reaching you, there are still a few more factors as to how much vitamin D you can produce. The lighter your skin, the more vitamin D your body will be able to produce. Darker skin takes more time in the sun to produce the same amount. Age and weight also matter. If you are older or are overweight, your body may not produce as much. The amount of skin you have exposed, and how long you are exposed for also matter.

According to the National Institutes of Health, in ideal conditions, exposing arms and legs for 5–30 minutes between 10 AM and 3 PM, 2-3 times a week usually leads to sufficient vitamin D synthesis for most light-skinned people. People with darker skin may need a little more time.

Skin types

The more skin you expose, the shorter amount of time needed, and the less likely you are to burn. To protect yourself from the negative effects of the sun, without blocking the production of vitamin D, it’s recommended to eat foods with natural antioxidants (colorful fruits and veggies – oh hello, organic garden 😉).

Sunscreen can block vitamin D production. Usually, a person can be in the sun 10-30 minutes before needing to apply sunscreen. Once sunscreen is applied, it reduces your body’s ability to make Vitamin D by about 95%. Take advantage of a sensible amount of sun exposure, but then either apply a physical sunscreen or layer up. 

It’s best to apply sunscreen after 10–30 minutes of unprotected sun exposure to avoid the harmful consequences of excess sunlight. Your exposure time should depend on how sensitive your skin is. It’s so important not to overdo your sun exposure! Too much sun exposure can lead to skin cancer.

Vitamin D App – dminder

I recently discovered an app that keeps track of how much vitamin D your body makes based on your location, demographics, and sun exposure. If you want to know how much sunlight for vitamin D you need, this is a great resource.

Dminder is a free app. When you first download it, it will ask for your demographics and will then calculate the window of time you can make vitamin D based on your location and time of year. It takes into account your latitude, your altitude, and the time of day.

dminder vitamin D app You can also record sessions by sharing the time, the percentage of skin exposed, and how much sun visibility there is (which it can also calculate for you).

On my phone, I have noticed one minor glitch. If I’m in the middle of recording a sun session and I go to do something else on my phone and then click the app button instead of going back to the page already running, it will close my session without saving it. You can also save historic sun sessions, which is an easy workaround. I just make a mental note of what time I start.

I’ve found this to be a great resource to become more aware of my body’s ability to produce vitamin D. I can conveniently get vitamin D while I’m outside working in my backyard garden. Use this app as a guide, but always follow common sense. Never stay outside longer than you know will cause burning.

Do you live somewhere to get enough sunlight for vitamin D all year round? Comment below!

Be safe. Happy Sunbathing!

How to Rely on Sunlight for Vitamin D

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