Saturday, May 15, 2010
Contributions of genetic alleles to disease are useful for understanding, but not in predicting disease. Diet and lifestyle are the major determinants of disease and not genes for most common diseases.
OTC Genetic Screening Kits
A recent headline touted the availability of a kit at Walgreens to screen for “predisposition” to a hundred common diseases. A few months earlier, scientists admitted that after lengthy examination of a dozen major diseases, the genetic contribution was negligible. It may now be possible to cheaply (less than $25,000) determine the sequence of the entire genome of an individual or even more cheaply test for the presence of particular genetic alleles, but that information is useless compared to diet for predicting if the person will actually get the disease. The screening kits were pulled before they reached the shelves.
Gut Flora Dominates Gut Genotype
I think that the reason why an individual’s genes don’t dominate health issues, is because the composition of meals dominates the development of the gut flora community and it is the interaction between the gut and its bacteria that dominates health. The genes of the individual are just not that important in determining disease.
You Are What You Ate
For each individual, the meals eaten over the last years have cultivated the existing gut flora, composed of hundreds of different species of bacteria with unique metabolic capabilities to digest unusual meal molecules and modulate the immune system. Molecular communication between gut and the bacteria in intimate contact determine food intolerance, allergies, autoimmunity and many other disease processes. Healthy eating produces a healthy gut flora and bad meal decisions can lead to unhealthy gut flora and the modern litany of inflammatory ailments. Some genes may mitigate or magnify the development of unhealthy gut flora, but it is difficult to be healthy with compromised gut flora.
Antibiotic Disruption of Gut Flora Trumps Good Genes
It doesn’t matter if there are great genes to help avoid disease, if the function of those genes is compromised by gut dysbiosis, a lack of functional gut flora. Many antibiotic treatments, e.g. for acne, act by attacking the gut flora that support a specific portion of the immune system. Deletion of this function causes cosmetic improvement, e.g. relief of skin inflammation, but at the expense of producing a dysfunctional immune system that may lead to other diseases. Presence or absence of healthy genes can be made irrelevant, if the gut flora is dysfunctional.