In his book Survival Of The Sickest Sharon Moalem talks about how diabetes came to exist in the human population. According to his theory, some are predisposed to diabetes — higher sugar levels or insulin resistance like conditions — because it may have helped our ancestors survive suddenly new cold conditions.
However, now Stephanie Pappas, an editor with LiveScience, breaks this theory to bits by suggesting that not climate but diet could have in fact played a role in some populations being susceptible to Type 2 Diabetes. She cites a paper that studied the prevalence of diabetes in Native Americans.
Recent findings of fossilised faeces of Native Americans in northwestern Arizona show that the tribes that existed in that region around AD 1150 survived on food that was highly fibrous and very low on glycemic index. They ate prickly pear, yucca and flour ground from plant seeds.
What this means is that, as per current nutritionary guidlines, they were almost starving. Their bodies did not get the sugar that we deem ‘required’ now a days, tricking the body into producing sugar.
However, when the Caucasians arrived, bringing with them the farming of calorie-dense foodgrain the Natives had to hurriedly adapt to the sudden change in fibre and sugar intake, leading to insulin resistance and the onset of diabetes in their population.
The diet seen from the study of fossils of faeces to just 1,000 years ago is similar to what people ate world over up until about 15,000 years ago.
What this study essentially proves is that populations that had to adapt hurriedly to the new-age diet became prone to diabetes-like symptoms.
It gives impetus to the age-old debate of nature versus nurture. Whether we go by Moalem’s hypothesis or the recent findings documented by Pappas, it seems that a condition we credit to genetic causes, may well be a sudden adaptation by our ancestors to change in environmental conditions.