We Are What Our Ancestors Ate: Part 2

SCIENCE GEEK ALERT:  As previously mentioned, I am alarming you before I get into the nitty gritty of nutrition!
Food can be considered an environmental factor to which our bodies adapt for optimal function.  In fact, the relatively new fields of nutrigenomics and epigenetics aim to explore how foods and the environment (respectively) influence genetic expression and what are known as genetic polymorphisms.  Genetic polymorphisms are differences in the genetic code among a given species giving rise to different characteristics.  In our case, examples include blood type and skin complexion caused by differences in melanin production.

Similar to the genetic polymorphism resulting in melanin to protect against damage from the sun, the foods we eat create an environment within our digestive systems to which our bodies must adapt.  Discordant with enthusiasts of the Paleo diet, I would argue that the diets of more recent ancestors have influenced the evolution of digestion and metabolism among different ethnic groups.  (Just as an example: The human body has the amazing capability to increase the number of enzymes used to burn fat in the muscle of trained individuals in a matter of weeks.  Considering this, just imagine the body’s adaptability within just a 1,000 year period, let alone a 10,000+ period!).

With variations in the flora and fauna of regions across the world, it’s certainly plausible that these differences exist.  In fact, current research is expanding our knowledge of these differences—from that noting differences in how women of varying ethnic backgrounds metabolize caffeine (read more), to the research that went into the development of BiDil, an African-American-specific drug used to treat those with heart failure.  In fact, my undergraduate research showed varying anti-cancerous effects of one natural compound on prostate cancer cells derived from Caucasians and African Americans.

Despite limited research directly comparing metabolism across various ethnic groups, epidemiological research revealing higher rates of disease within certain populations cannot be solely attributed to dietary choice alone and validates the potential of variation in metabolism and biochemical processes among people of different races.  Ultimately, the body naturally responds to overabundance or underexposure within ancestral environments through adaptations.  Fast forward to the modern day food system and vulnerable populations are submerged in dietary environments, which they are genetically ill-equipped to tolerate.

Below are two such examples:

Pima Indians and Diabetes:
Recognized as having the highest prevalence of type 2 diabetes in the world, the Pima Indians of Arizona serve as an archetypical example of ancestral diets influencing biochemical and metabolic processing of foods.  The Pima Indians in Arizona have adopted the typical Western diet to which they are not genetically equipped to handle.  Historically, the traditional Pima diet consisted of approximately 70-80% carbohydrate, 8-12% fat, and 12-18% protein and considerably higher amounts of sugar-regulating dietary fibers.  Arguably so, the proportionately larger ingestion of carbohydrates coupled with lower fat and fiber intakes has lead to the development of genetic polymorphisms altering the expression of enzymes involved in the use of sugar and fats in the body.  Ultimately, it’s these genetic adaptations that contribute to the increased progression of insulin resistance (aka type 2 diabetes) among Pima Indians (read more).

African Americans and Hypertension:
In another example, although diet and lifestyle play roles in the increased prevalence of hypertension within African American populations, scientific research suggests enhanced sensitivity to salt and altered regulation of the widening of blood vessels (a process known as vasodilation) within this demographic.  This sensitivity can be considered an evolutionary adaptation to the thermoregulatory process of sweating and water balance in the hot climates of their West African ancestors.  In response to increased sodium and water losses in sweat, a genetic polymorphism has evolved to conserve these essential dietary components.  More research exploring the complex interactions between genetics, ancestral environments, and the current food environment would certainly be beneficial.   I believe that the popular expression “we are what we eat” may one day be rephrased to “we are what we eat because of what our ancestors ate.”

With all this said, we know our ancestors didn’t eat potato chips and gulp down soda. While some of us may be aware of our ancestry and others of us may not, we certainly have an understanding that our ancestors ate real, whole foods!

 

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