Summary of “The Cholesterol Also Rises” from Survival of the Sickest by Sharon Moalem and Sharon M

Survival traits passed down to us from our ancestors may be a blessing and a curse due to humans transplanting all over the world. Such traits include traits regarding skin color, the ability (or lack of ability) to process milk or alcohol, and defenses against diseases that can lead to chronic genetic conditions. Skin color seems to be directly linked to the amount of UVB rays available in an area. Close to the equator where sunlight is more intense, skin color tends to be darker and gets lighter as you move toward the poles. UVB rays break down folic acid which the body needs for cell growth; however, UVB also converts cholesterol into Vitamin D which essential for healthy skeletal, nervous, immune, and circulatory systems. The body’s solution for limited UVB radiation penetrating the skin whether by melanin or climate is to increase the amount of cholesterol available for processing. Relocation of person’s with this characteristic to areas of the world with dramatically different UVB radiation has led to an increase in individuals with high cholesterol levels and rickets (Vitamin D deficiency). Though most of the world cannot digest lactose beyond weaning, persons whose ancestors herded cattle have been selected for to continue the production of lactase later in life. This group included those of northern European decent and those from certain areas of Africa. When clean water became an issue when humans started developing close communities, Europeans and Asians found different solutions to the problem. Europeans discovered that fermentation had antimicrobial effects; Asians used boiling to kill bacteria and organisms. Because of this, the ability to efficiently process alcohol was selected for in Europe but not in Asia. This resulted in a percentage of Asians unable to process alcohol efficiently and getting very ill when they consume it. Infectious disease also played a role in trait selection. Malaria led to an increase in body hair in some Middle Eastern areas while populations in Africa developed a defense that centers around their blood. Unfortunately, a person who carries a double dose of this mutation ends up with a chronic condition called Sickle Cell Anemia.

Though these variations are intriguing, the questions that they raise are more intriguing. What defines race? Is there even such a thing? Persons can be descendent from the same ancestral group and look nothing alike. Jews who have little to no resemblance have been found to be related on a genetic level. Genetics can tell far more accurately about a person’s heritage than phenotypical data.