Functional medicine asks how and why illness occurs and restores health by addressing the root causes of disease for each individual. It is an approach to patient care that views health and illness as part of a continuum in which all components of the human biological system
interact dynamically with the environment, producing patterns and effects that change over time. Functional medicine may be described as the clinical application of systems biology.
Chronic disease is usually preceded by a period of declining function in one or more of the body’s systems. Restoration of health requires improving the specific dysfunctions that have contributed to the disease state. Functional medicine provides tools and a reproducible method to enable clinicians to identify dysfunction and promote balance in physiology as the primary means of improving patient health.
Human biology is far more complex than the human genome. In fact, most diseases are not genetically determined. It is gene expression rather than genetic inheritance that is essential in the emergence of disease. Gene expression is altered by myriad influences, including environment, lifestyle, diet, activity patterns, psycho-social-spiritual factors, and stress. Diet and lifestyle choices and environmental exposures can render disease more or less likely by turning on—or off—certain genes. Functional medicine directly addresses modulators of gene expression, an individual’s environment, and other underlying causes of disease
through a systems-oriented approach. The functional medicine clinical model provides practitioners with the method and the means to thoroughly evaluate the myriad interactions among genetic, environmental, diet, and lifestyle factors that influence health and may manifest as complex chronic disease.
Functional medicine recognizes that a patient’s “environment” is not limited to physical and biochemical exposures, but also to societal conditions and the “human interactome.” As the field of health care becomes more aware of the impacts of social determinants of health, as well as discrimination writ large, functional medicine practitioners must be willing to explore their own unconscious/implicit biases and be willing to explore a patient’s history of trauma from injustices and prejudice of any kind, and to authentically ask patients what they want them to know about their personal stories. Such an approach is capable of improving the therapeutic partnership between patient and clinician, allowing the patient’s experiences to favourably influence the therapeutic plan and improving health outcomes.
The functional medicine clinical model enables practitioners to obtain and incorporate clinical information that leads to individualized, patient-centred interventions. Functional medicine concepts, practices, and tools have necessarily evolved over the past 30 years and will continue to do so. This reflects the dramatic growth in the evidence base identifying potential root causes of disease: the primacy of lifestyle factors such as diet, stress, sleep, and physical activity as well as the role of the environmental exposome, including infections, allergens, and toxins. Personalization of the therapeutic approach is informed by the ‘OMICS’ revolution, considering the gene-environment phenotype through the expression of proteomics, metabolomics, and metagenomics.