The story of our skin – migration, lifestyle, and vitamin D

The story of our skin and its colour is the result of a brilliant survival strategy – for thousands of years, pigmentation has adapted to the amount of light in the environment.

Today, however, our lives look very different from the past – we spend most of our time indoors, with little contact with natural sunlight, and the rate of vitamin D synthesis now depends on many factors…

Melanin – the guardian of DNA

Let’s recall that melanin plays a significant protective role. In regions with high sunlight exposure (close to the equator), darker skin colour protected cells from excessive UV radiation and DNA damage. It acted as a natural “biological umbrella”, reducing the risk of burns and skin cancers.

On the other hand, in areas where UV radiation was much lower (Northern Europe, Northern Asia), evolution favoured lighter skin. Why? Because it allowed for more efficient vitamin D production under conditions of limited sun exposure.

Vitamin D Levels in the US Population by Ethnicity

Migration and modern deficiencies

The problem arises today when many people live far from the climatic zones their skin was originally adapted to. For example, individuals with darker skin living in Northern Europe or Canada may face a much higher risk of vitamin D deficiency than local populations.

Such patterns are confirmed by population studies. Analyses from the USA (GrassRootsHealth, 2025) clearly show that people with darker skin (e.g., African Americans, Latinos) have significantly lower vitamin D levels compared to lighter-skinned groups — despite living in the same climate.

It is worth mentioning here that, as an alternative, tanning beds have been the subject of scientific research on vitamin D synthesis. Prof. Susan Kimball and her colleagues demonstrated that properly controlled doses of UVB radiation in tanning beds can effectively increase vitamin D levels in the body. We discuss these studies in more detail here: “Can a tanning bed boost your Vitamin D? A scientific look at UVB light”.

The scale of deficiency and challenges in Poland

The problem of vitamin D deficiency in Poland is particularly severe. As emphasised by Dr. Paweł Płudowski, professor at the Children’s Memorial Health Institute and one of the leading experts in this field:

“To recall, in Poland, vitamin D deficiency affects about 90% of the population considered healthy.” (Płudowski, 2025)

Tak dramatyczne dane wynikają zarówno z szerokości geograficznej i klimatu, jak i ze stylu życia – większość populacji spędza znaczną część dnia w pomieszczeniach, przemieszczając się samochodami i mając niewielki kontakt z naturalnym światłem słonecznym. To sprawia, że zarówno dzieci, jak i dorośli rzadko mają okazję do codziennej, efektywnej ekspozycji na promieniowanie UVB.

It is also important to remember that not everyone can fully benefit from sunlight. People with very fair skin (phototype I – e.g., blond or red hair, blue eyes, skin that burns easily) should not regularly expose their skin to the sun due to an increased risk of melanoma. Check your skin phototype here.

Why isn’t diet enough?

The second potential source of vitamin D is diet – but in Poland, foods are not fortified with this nutrient, and we consume marine fish only occasionally. As Dr. Płudowski explains: “To meet the daily requirement solely from food, we would have to eat dozens of eggs, several hundred grams of fatty fish, or drink several litres of milk every day. In practice, this is impossible – which is why vitamin D deficiency is so widespread in our climate.”

Individual differences in vitamin D metabolism and supplementation

There is growing evidence that our need for vitamin D is not the same for everyone (Dr. Płudowski, 2025). Blood levels of 25(OH)D are influenced by both genetic factors and lifestyle, as discussed above. Mutations in genes responsible for vitamin D metabolism mean that two people taking the same dose may respond very differently – with one experiencing a clear increase, while another remains up to 20% below the average.

Other factors also affect vitamin D status: the rate of skin synthesis in summer (which varies depending on skin type and pigmentation), body weight and BMI, medications, diet and possible dietary restrictions, as well as hormonal balance. This is why it is essential not to rely on “one-size-fits-all” doses, but rather to monitor 25(OH)D levels and tailor supplementation in a personalised way – taking into account both genetic predispositions and individual lifestyle.

Summary – why your skin tone and color still matter

Although today we rarely think about skin colour in the context of health, it still plays an important role in our physiology. The way our skin responds to sunlight directly affects our ability to produce vitamin D, the rate of its synthesis, and even the risk of developing various chronic diseases.

Evolutionary history, migration, geographic latitude, and lifestyle – all these factors shape the fact that there is no single universal approach to sunlight for everyone. What we truly need is an individualised perspective – one that takes into account the many variables influencing how our bodies interact with the sun.

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