Is the Loomis Hypothesis wrong?

I remember an old vitamin D book – I believe it was Feldman’s Vitamin D – that argues that if we are going down the Transsahara Route (Algier-Lagos) human skin color gets always darker towards Tamanrasset due to increased solar power- also known known as the  Loomis hypothesis (Science 1967).

So , let’s have a look at three maps. Solar power first.

1. Solar power. Source:

Second, skin tones – the Tamanrasset observation is correct but the overall picture does not match the Loomis hypothesis.

2. Skin tone. Source For full details see the original paper

Neither does the new vitamin D map published last week in the Lancet.

3. Vitamin D map. Source: For full details see the original paper

Maps are still patchy but let me already believe that the Loomis hypothesis is wrong.