Understanding why and how the human brain evolved to reach its present size is perhaps the most important part of human evolution studies. According to the generally accepted view in the scientific world, the growth in our brain dimensions is closely related to our diet, which has changed in the last 3 million years; the increase in our meat consumption and the effects of our cooking skills on the growth rate of our brains draw the attention of scientists.
But dr. Karen Hardy and her team published a new study in the journal Quaterly Reviev of Biology, archeology, anthropology, genetics, physiology and anatomy gathered data collected in the analysis of carbohydrates, especially in the form of starch-accelerated growth in the human brain over the last 1 million years critical in the increase of The results show that carbohydrate consumption evolves simultaneously with the number of copies (CNV) in the saliva-amylase genes (an enzyme found in saliva that converts starch to denstrin and maltose) and the use of fever for cooking.
With the global increase in obesity and nutrition-related metabolic diseases, interest in stone age feeding patterns has intensified. The reason for this is that human physiology has developed in accordance with the nutritional profile of our evolutionary process. To date, the effects of eating animal proteins and food on the human brain during the last 2 million years have been focused on, and the importance of carbohydrates in starch-rich plant foods has often been overlooked.
Hardy and his team underline that the carbohydrate-based diet has a critical role in the evolution of the modern-minded modern man, highlighting the following observations:
1) 25 percent of the total energy budget in the human body and 60 percent of the glucose in the blood is used for the needs of the brain. Although it is possible to synthesize glucose from other sources – without consuming directly the foods that contain glucose directly – this method is extremely inefficient and it is not possible to meet this high glucose demand with low carbohydrate feeding method,
2) The human body needs more glucose than normal during pregnancy and breastfeeding, and low levels of maternal blood in blood are a risk to the health of both the mother and her offspring,
3) Our ancestors have the opportunity to obtain starch from seeds, some fruits and walnuts as well as tubers,
4) Raw starch can only be poorly digested by the human body, but when cooked it loses its crystalline structure and greatly facilitates digestion,
5) Saliva-amylase genes are seen in many copies (average 6) in human, while in other primates only 2 copies. This increases the amount of saliva-amylase produced and thus its ability to digest starch. It remains unclear as to when the salivary-amylase genes proliferate, but genetic data indicate that this period has been in the past 1 million years.
According to Hardy, the common evolution of the number of copies in the cooking and salivary-amylase genes, after cooking became widespread, made the primitive forms of glucose-based nutrition appropriate to the needs of the brain and fetus, allowing our brain size to accelerate and increase for 800 millennia.
As a result, meat consumption may be a touchstone in the evolution of today’s large human brain, but cooked starch-based nutrients continue to make us smarter creatures with increasing saliva-amylase genes.