(Continuation…)
In their writings on “Elongated Africans" Hiernaux and Baker didn’t even attempt to explain why desert environments would produce large foreheads in, say, Somalis. But I know of a condition induced by milk consumption which can swell the size of the forehead: the Bahima disease.
In 1962 British doctors in Uganda made note of a number of young patients who had arrived in recent months with swollen foreheads and iron deficiency. The children were all part of the same minority group: the Bahima, close relatives of the Tutsi.
The large foreheads were produced through overproduction of red blood cells in the marrow of the skull. Ruling out malaria or sickle cell disease, the researchers concluded that this iron deficiency came about through excessive drinking of cow’s milk early in life.
Cow's milk can produce anemia not only because it is low in iron, but because its calcium actively interferes with iron metabolism. The addition of milk or cheese to common meals is enough to reduce iron absorption by 50-60%.
Milk anemia was so common among the Bahima that their healers had a standard practice to treat it: they branded circular scars on the head. It may have been common elsewhere: I have seen images of Fulani and Rendille that have the same tower shaped skulls described in the paper.
The authors of the Bahima paper speculated that perhaps this early anemia is related to the ethnic qualities of Tutsi skulls, as though they all suffer from a mild form of the disease. I think though that, being common, natural selection has come to expect it, to fix it in place.
Moreover, the persistence of anemia throughout the lifespan would help to explain the gaunt, “Somali” physique as a body type designed, not to survive desert heat, but to function on a bare minimum of iron.
Some researchers write about milk anemia as though it were a disease only suffered by children, because they reason that only at a young age can cow’s milk be so important in the diet. But among the Tutsi milk could represent >50% of dietary calories even in adulthood.
But even that is not much compared to what you see in Somalia. There were once nomads in that country who would subsist_entirely_ upon camel’s milk, 5 liters worth a day, something I didn’t think was possible.
There are Somali minorities in Ethiopia and Kenya and in both places they are distinguished by their high anemia rates. The Somali region of Kenya was once unique in that blood disorders like anemia were the leading cause of death
If iron deficiency is such a problem, you might ask why the Somali didn’t just evolve higher iron stores. The issue is that higher iron is closely associated with malaria infections, so much so that some doctors feel that giving iron tablets to the anemic hurts more than it helps
5,000 kms to the west, the milk drinking Fulani show the same distinct mortality pattern as the Somali. Compared to their immediate farmer neighbors like the Dogon they have much higher rates of anemia, but lower susceptibility to malaria.
When heavy milk consumption co-exists with malaria the result of selection is a thin body type. Because iron levels remain low, we could call this “acquiescence”. When the same diet is consumed in non-malarial areas the result is “adaptation”: iron overload, hemochromatosis.
(To be Continued)
