7 factors hindering you from making Vitamin D from the Sun

Discover the best time to make vitamin D through your skin and the 7 factors hindering you from synthesizing this vital vitamin!

The Sun is the best source of vitamin D, but can you enjoy the Sun to synthesize vitamin D without exposing yourself to UV radiation?

Sun's rays are the source of life since they give energy to all creations. These rays are light, ultraviolet, or infrared. 

While infrared rays/waves are responsible for maintaining optimal temperatures on Earth, ultraviolet rays help us synthesize vitamin D through the skin, which is crucial for better health.

The synthesis of vitamin D is greatly influenced by 

• the season, 
• weather, 
• latitude, 
• altitude, 
• air pollution, 
• time of the day, 
• skin pigmentation, 
• use of sunscreens, 
• whether the sunrays are passing through a window

Vitamin D actually is a hormone since our body can synthesize it, and it plays many roles in our health. 

• It helps the absorption and retention of calcium and phosphorus.
• It's vital for the formation and growth of strong bones.
• Vitamin D can reduce cancer cell growth.
• It acts as an anti-inflammatory.
• It helps control inflections.
• This vitamin regulates our immune system.
• It supports good moods.
• Vitamin D is required for good prostate, breast, and colon health.
• During pregnancy, vitamin D can reduce the risk of developing gestational diabetes.
• Lower vitamin D levels are associated with a risk of multiple sclerosis.

There are two types of vitamin D. D2 and D3.

Vitamin D3 is the one our body makes upon exposure to sunlight, while D2 comes from plants and mushrooms.

Vitamin D3 is more efficient in our body than D2. Though you can obtain vitamin D from food, the best and most efficient way would be to make it yourself. The caveats here are the ultraviolet rays that can be harmful in the long term.

How do you make vitamin D from the Sun?

UVB rays penetrate the skin during exposure to sunlight, where they are absorbed by DNA, RNA, and a protein known as 7-dehydrocholesterol to form previtamin D. 

Previtamin D is then converted into D3, the active form of vitamin D.

You can't make more vitamin D3 than the amount you need by exposing yourself longer to the sunlight because any extra vitamin D3 produced by the skin is down-degraded to other photoproducts that do not affect calcium.

Sun is the best source of vitamin D because it offers you other benefits you'll not get from supplements, e.g., regulating circadian rhythm and some hormones. I talk about this with my clients on my 1:1 coaching.

Vitamin D deficiency 

Most of our body cells have receptors for vitamin D; thus, a deficiency in this vitamin can increase the risk of many health issues like cancers, autoimmune diseases, cardiovascular, bone weakness, osteoporosis, infectious diseases, type 2 diabetes, and schizophrenia.

Difference between UVA and UVB

Ultraviolet radiation is invisible light to your eyes, but your skin can feel it; Ultraviolet A (UVA) has a longer wavelength than ultraviolet B (UVB).

UVA penetrates deeper into the skin derm, is responsible for skin aging, wrinkles, and dark pigmentation (on light-skinned people), and can cause cancer.

UVB does not penetrate deep into the skin dern. However, prolonged exposure to UVB would destroy the skin's natural barrier, thus inducing inflammation, and sunburn, causing skin aging, and exposing the skin to infections, cell death, and cancer development.

Both UVA and UVB can cause cataracts and eyelid cancer.

If you stand behind a window, you are still exposed to UVA but not UVB, even though the effects are not the same as being directly exposed to the Sun.

It's essential to remember that it can take up to 20 years to develop skin cancer after having several sunburns. 

Healthy levels of vitamin D

If you did a blood test for vitamin D, here are the numbers to check 

If your Vitamin D level is below 30, you are deficient, and it's better to talk to your doctor about supplementing yourself. 

Level 30-50 is generally inadequate for optimal bone health.

Level 50-120 is adequate.

A level beyond 125 is too high. Too much vitamin D can lead to toxicity resulting in a buildup of calcium in the blood (hypercalcemia).

7 Factors affecting vitamin D synthesis through the skin

Here are 7 factors that will hinder your skin from making vitamin D. 

1) Time of the day- Early morning and late afternoon, the UVB rays aren't strong enough to make vitamin D.

2) Latitudes and altitudes,  the far you are from the Equator, the less sunshine you get. At higher altitudes, the UVB has less distance to travel to reach your skin. For example, someone in a mountain will synthesize more vitamin D than someone in a valley.

3) Season- cold, rainy days, clouds, and winter are factors that block the UVB to us. Even sunny days from November to March in the north and south hemispheres don't offer enough UVB to make any vitamin D.

4) Air pollution absorbs UVB rays, thus reducing the effectiveness of synthesizing vitamin D by the skin! People living in large cities with high pollution volumes will have difficulty producing vitamin D through their skin!

5) Sunscreens are designed to absorb UVB rays. A sunscreen with SPF 30 (sun protection factor) blocks up to 97% UVB. Therefore, reducing at 97% the capacity of the skin to produce vitamin D. Applying sunscreen hinders you from making vitamin D. 

People with dark skin applying sunscreen will definitely not make any vitamin D.

6) Melanin or skin pigment is another factor that can affect the absorption of UVB by the skin because melanin is a natural UVB blocker. Even though dark-skinned people synthesize vitamin D through the skin, it demands them to expose themselves much longer to the Sun to get an adequate amount of UVB.

7) Aging reduces the capacity of the skin to make more vitamin D.

Who is really concerned with sunburn and skin cancer?

We are not all equal regarding sun exposure and the eventual damage to the skin. Skin plays the role of a barrier between the environment and the body.

It also synthesizes vitamin D from the UVB while offering protection against UV damage.

Your skin type depends on the concentration of melanin, which determines how much vitamin D you can synthesize as well as the risk of developing skin cancer. 

Melanin exists in 2 chemical forms; 

1. Eumelanin, a dark pigment responsible for dark skin complexion, and is more efficient in blocking UV radiation.
2. Pheomelanin, a light-colored sulfate pigment that gives a red/blond complexion.

Pheomelanin levels are equal in both dark and light-skinned people, and the only difference is the amount of eumelanin that determines the skin complexion. People with less eumelanin are sensitive to UV and are at high risk of developing skin cancer.

People with dark skin rarely burn and are at low risk (if any) of skin cancer due to UV radiation. The only issue is that they must expose themselves to the Sun much longer to synthesize enough vitamin D.

How to get the right amount of vitamin D without the risk of sunburn?

To synthesize optimal vitamin D, you need to consider the abovementioned factors—season, time of the day, skin melanin, pollution, sunscreens, etc.

For those in both North and South hemispheres, the best season to make enough, if not more, vitamin D is during the summer season. But, you must have heard or read that you should avoid Sun exposure after 10 am when the Sun becomes scorching, haven't you?

Surprisingly, only about 1% of UVB reaches the Earth's surface, even at noon during summer for those living in the North and South Hemispheres! Because most UVB is absorbed by ozone in the stratosphere, which protects the Earth from Sun's radiation.

Unfortunately, the far we are from the Equator, the few UVB rays are insufficient to make vitamin D3 through the skin. In the same case, in the morning and late afternoon, the Sun rays are not strong enough to synthesize any vitamin D.

Therefore, the optimal time to make vitamin D through the skin (even during summer) is between 10 am and 3 pm for those far from the Equatorial zone. The best time is when the Sun is on Zenith (right above your head)!

Tips to know when to make enough vitamin D in a shorter time

• The Sun should be above your head.
• Your shadow should be shorter than you.
• The UV index should be above 3.
• Expose a large part of your skin, but cover your face with a hat.

Warnings

Remember that UVA rays can create reactive oxygen species (ROS) that can damage your DNA, while UVB rays are directly absorbed by DNA and therefore can, to some extent, rearrange the DNA leading to mutation and cancer.

If you are light-skinned, expose yourself reasonably during the pick hours (10 am -3 pm). It's better to expose yourself several times a day than a long exposure that will burn your skin. Sunburns are the major cause of melanoma and skin cancer!

Your face counts for about 9% of your body surface, and each arm is 9%, while each leg is 18%. Therefore, wearing a hat covering the face is advisable since it doesn't synthesize as much vitamin D and is more prone to UV damage and aging.

Seek shades when you are outdoors and wear protective clothing. Keep in mind that the sunlight bounces off reflective surfaces, and it can reach you even under an umbrella or a glass.

Once you've gotten your dose for the day, protect your skin using sunscreens that offer optimal protection against both UVA and UVB.

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Resource; National Library of Medicine.

Photos from Unsplash