What is the connection between SUNLIGHT, melanin, and vitamin D?

Melanin acts like a natural shield when you expose your skin to sunlight. It protects your skin by absorbing some of the sun’s rays, rays that are vital for the production of vitamin D.

TABLE OF CONTENTS

What is Melanin?
Types of Melanin
How to Get Vitamin D from Sunlight
The Melanin Effect on Vitamin D Production
Sunlight, Skin Color, and Science
Vitamin D, Melanin, and Your Health
Melanin and Vitamin D Deficiency
Blacks, Vitamin D, and COVID-19
How Much Vitamin D Do You Need?
Learn More About It
Sources

Because melanin blocks UV (ultraviolet) rays, people with dark skin may not get enough sun to produce an adequate supply of vitamin D.

Lighter skin tones can absorb more sunlight, resulting in higher levels of vitamin D production. However, increased sun exposure also raises the risk of harmful UV radiation.

This article explores the relationship between sunlight, melanin, and vitamin D and why they are essential to your health.

What is Melanin?

Melanin is a natural pigment. It’s found in your skin, hair, and eyes, giving them color.

The amount and type of melanin in your body determine your skin, hair, and eye color—and their different shades from light to dark.

The skin has three main layers, each with a unique job.

The top layer, the epidermis, has two main cell types: keratinocytes and melanocytes.

Keratinocytes make up the surface of your skin. They’re like the skin’s protective shield. Deeper in the epidermis are melanocytes. These cells make a color pigment called melanin.

Inside melanocytes, there are tiny structures called melanosomes. This is where melanin is made.

The type and amount of melanin and the number of melanosomes decide a person’s skin color.

Melanosomes make melanin, but they need to move it to the keratinocytes. Once there, some melanosomes act like umbrellas, shielding the center of the cell.

Melanin is your skin’s natural sunscreen.

It catches harmful sun rays, called ultraviolet (UV) rays, to protect your skin’s DNA. Too much UV can injure your DNA and cause skin damage.

When you’re in the sun more, your skin makes more melanin to protect itself. This is why you might get a tan. But everyone’s skin is different. Some people tan easily, while others don’t. A lot of this is because of the genes handed down to you from your parents.

HOW WE GET OUR SKIN COLOR — VIDEO

TYPES OF MELANIN

Humans have three types of melanin: eumelanin, pheomelanin, and neuromelanin.

Eumelanin
- Produces dark colors in skin, hair, and eyes.
- Imparts rich hues that range from deep brown to black.
- The more eumelanin in the skin, the darker its tone.
- Higher concentrations in hair and eyes produce dark black or brown shades.
- Small quantities of eumelanin contribute to lighter colors like light brown or blonde.

Pheomelanin
- Pheomelanin produces red and yellow colors in hair and freckles.
- When combined with eumelanin, pheomelanin creates diverse shades, such as strawberry blond hair or auburn hair with a red tint.
- Individuals with fair skin often have more pheomelanin than eumelanin, which gives them a lighter overall skin tone.

Mixed Eumelanin and Pheomelanin

Many people have eumelanin and pheomelanin working together to create a mix of colors.
For example, hazel eyes occur when eumelanin and pheomelanin blend in your irises.
The combination of eumelanin and pheomelanin can contribute to diverse tones and subtle highlights.

Neuromelanin

Neuromelanin is a unique form of melanin found in specific regions of the brain.
It is not primarily involved with external appearances.
Neuromelanin functions within the brain to protect and regulate nerve cells.
As scientists study neuromelanin, what they learn could help prevent neurological disorders such as Parkinson’s.

Table of Contents

How to get vitamin D from sunlight

Vitamin d Production

Sunlight contains a type of ultraviolet (UV) radiation called UVB rays.

When these UVB rays reach the skin, they interact with 7-dehydrocholesterol, which is present in the skin cells.

When UVB rays interact with 7-dehydrocholesterol, it undergoes a chemical reaction, converting it into a compound known as pre-vitamin D3.

To become active, pre-vitamin D3 needs further processing.

This occurs naturally in the body through the heat of the skin, converting pre-vitamin D3 into vitamin D3 (also known as cholecalciferol).

Vitamin D3 travels to the liver through the bloodstream. In the liver, it undergoes another transformation, becoming a substance called calcidiol or 25-hydroxyvitamin D.

Finally, in the kidneys, calcidiol is converted into its active form, known as calcitriol 0r 1,25-dihydroxy vitamin D.

This active form is what the body can use for its various functions.

The Melanin Effect on Vitamin D Production

Melanin levels can have an impact on the amount of vitamin D that is produced and makes its way into your bloodstream.

Melanin, being dark in color, absorbs and scatters UVB rays, offering protection.

With light-colored skin, a smaller amount of melanin protects against UVB rays, leaving other rays to reach the lower layers of the epidermis, where vitamin D is synthesized.

The more melanin you have, the darker your skin tone, as depicted in the following graphic. And a more significant amount of melanin means more rays are absorbed and scattered. It also means fewer rays reach the part of the epidermis where vitamin D is produced.

Vitamin D is a crucial nutrient and is essential for maintaining optimal health.

And if you have a higher amount of melanin (darker skin), you might have less vitamin D available for your body’s use.

Table of Contents

Sunlight, skin color, And Science

HOW you GoT yOUr SKIN COLOR

When ultraviolet sunlight comes into contact with the skin, it affects each person differently. The time it takes for skin to react varies depending on its color. Some people with light skin tan very quickly, while others need more time for any change to show.

Why does skin have so many different shades? And how did this color variation come to be?

The story of skin is fascinating. It’s about human adaptability and resilience.

Melanin is at the center of the tale. It determines the color of your skin and hair, from the various shades of brown skin and hair that come from eumelanin to the red hair and freckles from pheomelanin.

However, human ancestors didn’t always have the range of skin tones we see today.

A critical change happened around 50,000 years ago when early humans migrated from Africa to Europe and Asia. These individuals lived in regions heavily exposed to the Sun’s UV rays, between the Equator and the Tropic of Capricorn. The prolonged UV exposure posed risks, including DNA damage and sunburns.

The story of skin reflects our biological differences.

The Science of Skin Color

Human ancestors adapted by relying on their skin's built-in defense mechanism: melanin.

When exposed to UVB radiation, the skin triggers melanin production, protecting cells from damage. Light-skinned people developed more melanin and tanned, while darker skin tones evolved. Humans adapted to the sun-saturated latitudes of Africa, while melanin levels provided better protection from skin damage.

However, as humans migrated northward, they encountered less direct sunlight.

This presented a challenge because UV light is essential for producing vitamin D, which is crucial for bone health. Dark skin blocks some sunlight, leading to vitamin D deficiency in regions with less sun.

Yet, some individuals produced less melanin and absorbed more UV light, benefiting from increased vitamin D production. Over generations, this contributed to the gradual lightening of skin tones in those areas.

The primary factor influencing skin color is the production and distribution of melanin.

As a result of these adaptations, the world today showcases a remarkable spectrum of skin colors. People closer to the Equator typically have darker skin that is rich in eumelanin, providing protection against UV radiation.

Meanwhile, those in regions with less sunlight have lighter skin with higher pheomelanin content. This complex relationship between biology, adaptation, and environment led to the diverse skin tones we see across the globe today.

As humans migrated and settled in different parts of the world, their skin adjusted to the local climate in order to optimize health and survival.

Sunshine and Skin Color

SOURCE: George Chaplin, *Geographic Distribution of Environmental Factors Influencing Human Skin Coloration,* American Journal of Pysical Anthropology 125:29-302, 2004; map updated in 2007. https://www.science.org/doi/10.1126/science.346.6212.934

In regions with intense sunlight and higher levels of UV radiation, people developed higher levels of melanin to protect their skin from the harmful effects of the sun.

Darker skin provides a better defense against UV rays, thus reducing the risk of sunburn, skin damage, and skin cancer.

This adaptation was especially beneficial for people living near the equator, where the sun is more direct and intense throughout the year.

Conversely, in regions with lower levels of UV radiation, such as higher latitudes or areas with more cloud cover, people developed lighter skin with lower melanin levels.

This adaptation allowed their skin to absorb more sunlight and produce adequate vitamin D even with less sunlight.

Table of Contents

vitamin d, melanin, and your health

The relationship between melanin and vitamin D is crucial. Both are essential for maintaining good health and overall well-being.

Here’s why they’re essential.

BONE HEALTH

Vitamin D plays a vital role in calcium absorption, which is essential for maintaining strong, healthy bones.

Vitamin D helps regulate calcium and phosphorus levels in the body, promoting proper bone growth and development.

IMMUNE SYSTEM and DISEASE PREVENTION

Both melanin and vitamin D protect the body from infection and disease, helping to boost your immune system.

An adequate vitamin D level can lower the risk of chronic diseases like cancer, heart disease, diabetes, and autoimmune disorders.

Vitamin D also helps your muscles work well and regulates your hormones.

Like vitamin D, melanin also aids with disease prevention. Its antimicrobial properties help to protect against harmful bacteria and viruses.

Melanin is also involved in the body’s response to injury and inflammation. It helps to limit the damage caused by harmful substances and free radicals, reducing the risk of cellular damage and chronic diseases.

MENTAL HEALTH

Optimal vitamin D levels are associated with improved mood, reduced risk of depression, and enhanced brain health and cognitive performance.

SKIN AND EYE HEALTH

Melanin acts as a natural sunscreen, absorbing and dissipating harmful ultraviolet radiation from the sun.

This protection helps prevent sunburn and premature aging and reduces the risk of skin cancer.

Melanin’s natural defense against UV radiation also reduces the risk of eye problems such as cataracts.

The benefits of melanin and vitamin D are many. But what happens when melanin and vitamin D are deficient?

Table of Contents

Melanin and Vitamin D Deficiency

WHAT Conditions Are Linked to Melanin Deficiency?

Melanin deficiency can contribute to various conditions. The severity of these disorders and how they present can vary.

Albinism: A genetic disorder characterized by the absence or low production of melanin. It can lead to very light skin, hair, and eyes, increased sensitivity to sunlight, and an elevated risk of skin damage and skin cancer.

Vitiligo: An autoimmune disorder that causes depigmentation or loss of melanin in patches of skin, resulting in white or light-colored areas. It can affect any part of the body.

Hypopigmentation: Various conditions can arise from injuries, infections, or certain medical conditions and can result in lighter patches of skin due to reduced melanin production.

Ocular Albinism: Primarily affects the eyes, resulting in reduced visual acuity, light sensitivity, and eye coordination issues.

Increased Skin Cancer Risk: Individuals with lower melanin levels are at a higher risk of developing skin cancer due to reduced natural protection against UV radiation.

WHAT Conditions Are Linked to Vitamin D Deficiency?

Schizophrenia & Depression
Asthma & Respiratory Infections
Heart Disease
Diabetes
Muscle Weakness
Osteoporosis
Rickets

Other conditions or diseases are linked to low vitamin D levels, though the exact reasons are still being researched:

Dementia
Erectile Dysfunction
Prostate Cancer
Mood Disorders
Skin and Hair Changes

Vitamin D testing and African-Americans

The type of vitamin D, known as 25-hydroxyvitamin D, is tightly bound to a protein. This means that it can't be used by essential cells like those in your bones and immune system.

To become useful, your kidneys must change 25-hydroxyvitamin D into a different form known as 1,25-dihydroxyvitamin D.

For White people, the levels of 25-hydroxyvitamin D in the blood usually give a good idea of how much usable vitamin D they have.

But this isn't true for Black Americans.

Dr. Thadhani says that African Americans have only about 25% to 33% of the protein that binds to this form of vitamin D compared to White people.

Because of this, the usual blood test for 25-hydroxyvitamin D doesn't give an accurate picture of African American vitamin D levels.

His studies show that even with these lower protein levels, African Americans still have enough vitamin D that their bodies can actually use.

This is why Black Americans generally have strong bones, even though the standard blood tests would suggest they shouldn't.

**FROM THE NATIONAL CENTER FOR HEALTH STATISTICS**

Dr. Thadhani recommends that doctors do extra tests, like checking the calcium levels in the blood and testing bone strength, when treating African American patients.

Currently, there's no approved test for measuring the usable form of vitamin D, known as 1,25-dihydroxyvitamin D. However, Thadhani and his team are developing such a test and have submitted a patent application for it.

Table of Contents

BLACKS, Vitamin D, AND COVID-19

Besides bone health, vitamin D also improves your immune system to help fight off disease.

Although Black Americans generally seem to have good bone health despite low vitamin D levels, higher amounts appear to be needed to boost the immune system, especially for such diseases as COVID-19.

According to David Meltzer, chief of hospital medicine at the University of Chicago Medicine and lead author of the study, there are indications that vitamin D can enhance the immune response and reduce inflammation. However, the results so far aren’t totally clear.

There’s a lot of disagreement over what the ideal Vitamin D level is.

The normal range of 25-hydroxy vitamin D is measured as nanograms per milliliter (ng/mL). Many experts recommend a level between 20 and 40 ng/mL. Others recommend a level between 30 and 50 ng/mL. (*)

Past research may have used too low doses of vitamin D to see a significant immune boost, even though those doses were good for bone health.

Meltzer's findings showed that Black individuals with lower vitamin D levels had a much higher risk of getting COVID-19, with those at the lowest levels being 164% more likely to test positive. However, this wasn't the case for White individuals.

The study suggests that having vitamin D levels above 40 ng/mL might reduce the risk of COVID-19, especially for Black people.

Table of Contents

HOW MUCH Vitamin D DO YOU NEED?

You make a lot of vitamin D you need from sunlight. Exposure to your arms and legs for 10-15 minutes just a few times a week may be enough for you.

Getting the right amount of sun for you individually isn’t always easy. The season, time of day, where you live, clouds, pollution, and other factors can affect how much sun you get.

Older people don’t make as much as younger folks. Also, those with darker skin usually have less vitamin D than people with lighter skin.

***Darker skin protects from sunburn, but produces Vitamin D more slowly.***

What if you don't get enough sun? Can't you eat foods that are loaded with vitamin D?

There aren't many foods that naturally have a lot of vitamin D3.

The best sources are fatty fish like salmon and fish liver oils. You can also find smaller amounts of vitamin D3 in foods like egg yolks, cheese, and beef liver.

Some mushrooms have a bit of vitamin D2, and certain mushrooms you can buy in stores have more D2 because they're purposely exposed to intense ultraviolet light.

Additionally, dairy products, cereals, and orange juice have extra vitamin D added. This increases their nutritional value.

Not many foods are rich in vitamin D.

And if you have certain health conditions like Crohn's or celiac disease and liver or kidney problems, your body might have trouble using the vitamin D you get from food.

VITAMIN D DAILY RECOMMENDATIONS

The National Institutes of Health (NIH) has some suggestions for how much vitamin D we should get each day, depending on our age.

Vitamin D, although a hormone, is called the sunshine vitamin. An adequate supply of it is crucial for maintaining strong bones and healthy bodies.

If you are not getting enough vitamin D from sunlight and your food, your physician may want you to consider taking supplements.

For babies (0-12 months old), the NIH recommends 400-1,000 IU of vitamin D daily, about 10-25 micrograms. From one year old through teen years, aim for 600-1,000 IU, or 15-25 micrograms daily.

The recommendation for adults (19-70 years old) is 600-800 IU (15-20 micrograms) daily.

But if you're a senior (71 years and older), 800-1,000 IU (20-25 micrograms) is advised.

Pregnant or breastfeeding moms should also follow these guidelines, with a daily goal of 600-800 IU or 15-20 micrograms.

These recommendations help ensure you stay healthy, inside and out!

Mayo Clinic Minute: How much vitamin D do you need?

Table of Contents

Discovering the right amount of sunlight and finding other ways to get vitamin D can lead to better health and boost your immune system.

Melanin gives skin its diverse and vibrant colors, which can sometimes block your skin from getting enough vitamin D from the sun.

If you are uncertain of your vitamin needs, the best thing you can do is talk to your doctor or healthcare provider.

Your health is essential, so don’t hesitate to have that conversation!

They will consider your health, lifestyle, and special needs and advise you on your supplement requirements. Working together, you can make intelligent choices that keep you healthy and feeling your best!

And remember, melanin isn’t only about how you look. It’s about culture. It reflects your rich history and background.

So, embrace and celebrate your unique skin colors and features because they show how wonderfully diverse we are.