For a long time it was thought that mapping the human genome would lead to breakthroughs in medicine.
What we are seeing in recent years as the research matures, is environment weighs in heavier than genetics. In fact, environmental factors account for over 90% of what ends up expressing genetically. My teacher uses this phrase to illustrate the connection: “Genes load the gun but environment pulls the trigger.”
This theory explains how evolutionary medicine can influence environmental factors and turn around the epidemic of modern disease. The mismatch between how we evolved to live and how most people are living today is problematic. For example, humans have not evolved to digest grains and the genetic leap that would allow us to is unlikely. However human infants digest lactose and this explains why in some places up to 90% of people have learned to be lactose tolerant as adults. Dairy can be an excellent source of nutrients and some people have adapted to use this as a food source. Genetically this is not such a big leap.
Mismatch theory isn’t only applied to diet but also lifestyle. Consider light, dark cycles and sleep. Insomnia is a real problem and has serious health consequences. Apply an evolutionary approach by dimming lights at night, using amber-coloured glasses if you must use a screen and ensuring adequate exposure to bright daylight for at least an hour during the day. Many people work indoors and forget that daylight anchors our circadian rhythm. Moving regularly during the day is also important and this allows our body to rest at night. Of course it is easy to overdo this as well so finding a balance is key. These lifestyle factors are linked to environment but harness our genetic memory to optimize health. This is how genetics can be applied in a practical day-to-day way.
Genetics: A gene can be present but may not express
Let’s look at the growing list of diseases linked through autoimmunity. Genetically we have been able to associate a group of genes called HLA (human leukocyte antigen) with several autoimmune conditions including juvenile onset of arthritis (1) and other heightened immune responses. Leukocyte refers to white blood cell which is part of any immune response.
Environment: includes all of the non-genetic influences beginning with conception
Autoimmunity is linked with gut health. A huge proportion of our immune system is housed in the gastrointestinal tract through the GALT (gastro associated lymphatic tissue). New research shows that probiotics stimulate immunity but do not substantially increase populations of good bacteria. Feeding theses bacteria with prebiotics promotes the long term health of the human microbiome by increasing beneficial gut microbes. Not surprising breastmilk is full of prebiotics.(3) A diet high in cellulose from plant foods is also known to feed the good bugs. Acellular or processed carbohydrates leads to an overgrowth of dysbiotic or pathogenic flora. Complete proteins and a nutrient dense diet supports the repair and growth of the gut lining. Good fats help absorption and blood sugar.
Chemical and biotoxin exposure need mentioning as well. Exposure can lead to chronic inflammatory response syndrome in roughly 25% of people. Mold illness has been linked with the HLA gene as well. One person may be unable to clear this biotoxin from their system whereas another might end up in chronic pain.due to the HLA gene. This same person may be able to integrate diet and lifestyle choices that mitigate damage, reduce inflammation and prevent further health complications long term.
I’m working with a 21 year old male who was given high doses of NSAIDS throughout childhood and who now suffers poor gut health as a result. He is committed to lowering stress, changing his diet and repairing his gut. Functional Medicine offers an approach that he never found in conventional medicine where diet was never discussed. He was continually given more medication that never addressed the root cause. NSAIDS damage the gut as do most medications.
The benefit of an evolutionary approach is the simple lens it offers to complex situations. It harnesses the power of our genetics in a very practical way. Choosing the right diet can seem overwhelming but if we think of how we evolved to eat it is much more manageable. The same can be applied to sleep, movement other important lifestyle factors. The momentum of our genetics is thousands of years in the making so even small changes have enormous benefit.