Human health is the result of constant interaction between genes and environmental factors. The most significant environmental factors are our diets and daily lifestyles.
Of the over 3 billion base pairs of the human genome, 97 to 99% are identical among any two given individuals. Therefore, the fundamental processes of food metabolism in every human body are largely the same. This is why some general practices, such as eating healthy and staying active, are beneficial to everyone. However, the 1 to 3% genome difference among us makes us respond differently to different types of food. For example, descendants of hunting tribes are better-suited for high-protein diets while descendants of farming tribes are better-suited for high-carbohydrate diets. This is why personalized diets are necessary.
A mismatch between genes and diet would inevitably lead to detrimental effects on our health. Accumulation of such detrimental effects eventually manifest as chronic diseases such as cardiovascular disease, diabetes, cancer, obesity, autoimmune diseases, rheumatoid arthritis, asthma and depression.
The genetic variations responsible for food metabolism are the result of millions of years of evolution during which there have been several major dietary transitions. During each transition, human genes were subject to natural selection to better suit the foods available for survival.
About 2.5 million years ago, our human ancestors began to use stone tools, which led to increased hunting and meat consumption. During these hunter-gatherer years, food resources were limited and the human genome developed so-called “thrifty genes.” These genes promoted more efficient food utilization, fat deposition, and rapid weight gain during times of food surplus in order to give carriers a higher chance of survival during food shortage.
Around 100 to 200 thousand years ago, modern humans began to domesticate plants and animals. This transition made food more available but nutrient sources less diverse since diets were comprised of only a few domesticated plants and animals. Crops and livestock varied by region and, in response, genetic variations that suited regional diets were preferentially selected.
The most dramatic transition of the human diet occurred within the last century. Industrialized food production made all kinds of food available in excess at extremely low prices. Since then, overeating has become an epidemic, especially in affluent Western countries. The advances of modern technology have also led to an increase in sedentary lifestyles and overall lower energy expenditure. This combination has resulted in rapid weight gain among human populations.
Regardless of these dietary changes, the human genome has remained almost the same over the last 100 years. The 200 or so “thrifty genes” that were once advantageous are incompatible with modern diets and cause the “diseases of civilization” — chronic conditions including obesity, diabetes, cardiovascular disease, metabolic syndrome, cancer, autoimmune diseases, rheumatoid arthritis, asthma and depression.
Equipped with the latest advances in nutrigenetics and nutrigenomics, scientists at GB HealthWatch are working diligently to better understand gene-nutrition-disease interactions. Our goal is to develop personalized, gene-based diets and fitness programs to combat overweight, obesity and said “diseases of civilization” for people of any genetic makeup.