One of the most exciting and previously unsuspected (until the last 25 years) elements of the "omics" revolution is the awareness that environmental signals are often greater determinants of health and disease than genes themselves. Signals from dietary intakes, physical exercise, stress, toxin exposure, and many other sources can turn off or on different genes--pushing our life's trajectory toward either health or disease. This primarily happens when these signals influence the proteins expressed by our genes and, downstream, how those proteins affect our metabolism--our basic biologic functioning.
Today, clinicians require an understanding of the chief actors in this stream of "omics" to educate patients as to why their lifestyle choices and environmental exposures have such a powerful influence on their health." Institute for Functional Medicine.