Ever wondered why do we the Irish burn in the sun, yet the Scandinavians tan? Summer thoughts from South Africa on skin colour, factor 50 and yer man, the Salmon of Knowledge

Today, my column comes from Johannesburg, written in the café of the Apartheid Museum close to Soweto. Here is an example of what the great German philosopher Hannah Arendt, reporting on the Adolf Eichmann trial, described as “the banality of evil”. The sheer effort the Apartheid regime put into keeping people segregated is phenomenal in its tedious attention to the smallest detail, snooping, spying, humiliating, terrorising and, ultimately, losing.

When the change came, it came swiftly and largely peacefully.

Twenty years on, South Africa no doubt has its economic problems. The upper echelons of the ANC have turned large parts of the productive economy into, if not quite a kleptocracy, something of a cronies’ free-for-all. But the big picture shouldn’t be forgotten. The country survived. There was no civil war and large swathes of the population benefited.

What is it about race that so divides humans?

When you are sitting in this museum here in Africa, or looking at the black/white tensions in the US, or even reading about the caste system in India, one strange human weakness reappears over and over again, and it is racism. Why do/did many whites feel superior to blacks? Why are darker people in India considered to be from a lower caste and discriminated against? Why do African and Indian women spend millions of euro each year on “whitening” products?

Why do we have different skin colours in the first place and why does it matter to so many people?

Let’s leave Africa and go far north from here to just south of the Arctic circle and a small Swedish town of Matfors. Mat in old Swedish means food and fors means stream. Matfors is full of salmon. The river is bursting with these fish and that is what the people have been eating for years. However, by the late 19^th century the people had reached ‘peak salmon’. By then, the town was operating a successful paper mill and wanted to attract more workers. As well as good wages, one of the perks of the job — written explicitly in the job advertisement — was a commitment from the management not to feed the workers salmon more than three days a week. The Swedes were simply sick of salmon.

How could that be, particularly today when all doctors tell us to eat more, not less fish?

And critically, what relevance has this ‘peak salmon’ story (which I came across for some other research) got to do with race and skin colour and Apartheid?

Permit me a bit of a digression here.

As you head to the sun for a week or two, have you ever asked yourself why Scandinavians tan in the sun and Irish people don’t? There are far fewer hours of sunlight in northern Scandinavia than Ireland and yet when the Swedes go abroad on holiday to the sun, these very blonde, fair people go a deep bronze colour in a matter of hours. The Irish, who in the winter look like Scandinavians and share a preponderance for red hair, fair skin and blue eyes, are burnt to a crisp on the beach. Why is this?

The reason is Vitamin D.

The reason we have black, white and yellow people is because of Vitamin D. We all need a minimum of Vitamin D, which we get by either absorbing it through our skin from sunlight or we ingest it in certain foods. We need Vitamin D for our bones to strengthen. This is why people with a Vitamin D deficiency can get rickets. (The science is a little more complicated and involves Folic Acid as well as Vitamin D; for a more detailed, yet accessible, explanation see ‘Skin’, a biography by Dr Sharad Paul.)

Black skin is a protector against the sun. It repels sunlight and this obviously helped the first humans not to ‘overdose’ on the abundant Vitamin D that they were getting from the sun’s rays.

We were all black when we walked out of Africa about 120,000 years ago and headed on a slow march North and East. But as we moved north from sunny Africa to less sunny Europe, our black skin began to lighten to allow it to absorb more Vitamin D from less sunlight. The more sparse the sunlight, the whiter the people became until you went to northern Europe, to Ireland and Scandinavia, where the people’s hair and skin lightened in order to eke out the maximum Vitamin D from the very few hours of sunlight we were exposed to.

But what explains the Swedes tanning and the Irish burning? This is where the salmon comes in.

Sweden and Ireland, although very far north, are distinguished by one major climatic difference. We get the Gulf Stream and they don’t. This makes our climate a lot warmer and wetter. This warmer climate allows cereals and grass to grow. This means that the cultivation of cereals, cattle and sheep is much more suited to us. This is how the ancient Irish derived protein. Because large parts of Sweden are too cold for grass, they had to find their protein in fish. Fish, and salmon in particular, are very rich in Vitamin D.

So over thousands of years, Swedes supplemented their meagre Vitamin D intake from the sun by gorging on salmon. As they did, their skin went darker because they didn’t need to be so pinkish white and open to sunrays to absorb the precious Vitamin D.

This is why they tan and we don’t.

Our cereal-based economy, due entirely to the warm influence of the Gulf Stream, may also explain why fishing in Ireland was never as developed as fishing in Scandinavia, despite our better Atlantic position.

So you see that skin colour is just the result of the great human battle for Vitamin D. The more constant your supply of Vitamin D, the less white you had to be to absorb it. In contrast, the more deprived of sun you were, the whiter you had to be — unless like the Scandinavians, you ate so much fish that you got sick of it!

As I walk around this museum, the horrific and very human results of the great battle for Vitamin D are all too evident and, in terms of the great march of humanity, all too pathetic to behold.