Why women are paler and vitamin D deficiency
Survival of the palest and vitamin D deficiency in men, women and children
Infertility, brain growth and other development issues
Some 50,000 years ago small bands of people, almost certainly dark skinned, moved into Europe probably by way of Turkey. The virgin territory of Europe provided plentiful food in summer. However in winter not only was food in short supply, but also low levels of vitamin D must have increased the susceptibility of these pioneering bands of people to disease and reduced their fertility. Vitamin D deficiency causes infertility, and during pregnancy and lactation stunts the growth of the brain and other organs in the fetus and newborn. How this occurs, causing common diseases such as schizophrenia, is only now beginning to be understood.
Pale skin and vitamin D uptake
A pale skin exposed to the sun makes vitamin D six times faster than a dark skin and so pale skin has an important advantage in northern countries. Natural selection, powered by infertility and disease, took its toll on the migrants heading north. Human skin colour changed by genetic mutation over a period of thousands of years to a lighter shade. These changes in skin colour occurred several times in different human races in various parts of the globe. Not only do native peoples everywhere have paler skins the further they live from the equator, women and children always have paler skins than mature men of the same tribe, a neat adaptation to provide the maximum vitamin D that is needed for fertility of women and growth of children.
The risk to babies and children
Breastfeeding is of course natural, but our knowledge of vitamin D brings an alarming challenge to doctors and midwives who dogmatically believe that breast is best – always. Most women living modern urban lives get little exposure to the sun and so secrete little vitamin D in their breastmilk (20,21). So breastfed babies, particularly those born in spring or early summer – April and May in the northern hemisphere – may get too little vitamin D, whereas bottle-fed babies get vitamin D from their formula which is fortified.
Babies born in May at high latitudes have been found to have a greater risk of certain diseases occurring later in life, particularly multiple sclerosis, but also anorexia nervosa, autism, schizophrenia and diabetes type 1 (22-26). Deficiency of vitamin D in pregnancy may seriously damage growth and development of the baby in other ways and in the extreme may lead to heart failure (27). These risks are easily overcome by giving babies a vitamin D supplement, but some passionate proponents of breastfeeding are unwilling to recommend vitamin D to nursing mothers because it means acknowledging that breastmilk is less than perfect.