It is a simple fact of science that over evolutionary time, such as thousands or even millions of years, an organism’s diet can influence and alter its genetics to make it more adapted toward the food it eats.
The Effects of Agriculture
There is a natural assumption that the same is true for humans, as can be seen even in modern differences between different groups. Examples being those who can digest lactose in milk products and those who can digest seaweed and certain plants easier.
But one of the biggest changes to the human diet for all people occurred just over 10,000 years ago. That was the development of agriculture. It fundamentally changed the diet of people and also allowed permanent living places to form and civilization to truly begin.
Agriculture, however, did more than just change our society and how we live, it also changed our genes themselves, sometimes in very dramatic ways.
Fatty Acid Desaturation
The focus of a new study on evolutionary biology has looked at the changes that occurred for the groups of humans that left Africa and had to contend with different environment and temperatures. This also necessitated a change in agriculture and what was grown.
Two of the most important genes related to our consumption of food are FADS1 and 2, which stands for fatty acid desaturase. These genes code for the same named enzyme that breaks down essential fatty acids and are found in some form in all organisms, as necessary to maintain cell wall function.
For this study, they were looking into the function of FADS genes that converts short chain version of omega-3 and omega-6 poly-unsaturated fatty acids into their long chain forms.
Different Strokes For Different Folks
Different cultures developed changes to these genes that altered the types of fatty acids that are broken down to match the foods consumed. For example, those in the far north that fared more on animal protein sources rather than plants formed enzymes more capable of breaking down animal fatty acids. The opposite has been the case for cultures that focused on eating only plants, such as in India and Asian cultures.
The study was conducted by researchers from the University of California, University of Copenhagen, Harvard University, and several other organizations and involved comparing the FADS genes from DNA samples of Bronze Age peoples that lived three to five thousands years ago to those living now from different regions.
The modern subjects were taken from Europe, South Asia, and Greenland for comparison. One of the effects discovered was an increase in production of arachidonic and eicosapentaenoic acids and a decrease of linoleic acid in Europeans for some time, while Inuit Greenlanders saw an opposing result. But then that changed as time went on.
This is due to the fact that the former acids are examples of long chain omega fatty acids, Animal fat contains more long chain fatty acids, so Europeans developed this early on in Bronze Age examples, but lately have been seeing the opposite occur as Europeans move more to a plant based diet. Similarly, the Inuit moved from a plant diet to one more based on marine animals, changing the types of FADS enzymes they required.
Another final difference found was more critical toward current health, with mutations that affected low-density lipoprotein (LDL) levels. Europeans, during their alteration, developed regional mutations centered on these LDL levels, likely due to the plant diet promotion. These, in turn, affect cholesterol levels.
The Evolution Of Diet
These genetic variants and mutations of the FADS genes could lead to a better and more individualized understanding of the relationship between the genes and fatty acid usage in the body, allowing personalized diets to be constructed.
The changes in FADS genes appear to have been also occurring back before the split between Homo sapiens sapiens and the other subspecies of humans, though it doesn’t appear that such gene changes were obtained from inbreeding with the other human-like groups.
Overall, this research allows scientists to use the evolution of the human genome to determine and predict the effects of changes to important dietary genes.
With further testing on the differences mutations to the genes make, future dietary needs could be catered to specifically and be determined by the needs of each person.
Photo CCs: 1982 Farm near Hódmezővásárhely – Near to Elderberry Farm, Ploughing in autumn from Wikimedia Commons