Re-thinking the meaning of health: a Salk scientist suggests a paradigm shift. From the article:

The past 50 years of biological research have taken a disease-centric approach to understanding the mechanistic underpinnings of health. Indeed, it is easier to conceptualize a disease state than a healthy state of an individual. We know that disease is caused by the presence of an insult that can be genetic, environmental, or caused by a decline in normal physiological function, such as during aging. Health on the other hand, seems to be more metaphysical, a so-called state of “well-being.” This makes it problematic for describing health mechanistically. We know that an individual is healthy when there is an absence of disease, and this has led to a view of health as a passive state. In that view, disease occurs when there is a disruption in the system due to the presence of an insult, and therefore the mechanisms that drive disease are related to the ones that promote health: simply removing an insult or antagonizing a disease pathogenesis pathway is sufficient to promote health. We know that this is not necessarily true. One of the triumphs of biomedical research is that we can describe in exquisite detail the disease path taken by an individual when it is sick and the disease pathogenesis pathways that drive the disease course. We also have an excellent understanding of risk factors and mechanisms that allow avoidance or eradication of an insult. Thus, our primary methods for treating diseases are to block pathogenic responses or remove the insult, rather than inducing pathways that work to maintain health. However, the goal of modern medicine is to restore a patient to a healthy state, and a goal for biologists is to define methods to extend the healthspan of an individual. As we embark on a new decade of biomedical research, I propose that rather than continuing to ask “how should we treat disease?” we might instead ask, “how can we promote and maintain health?” These are not the same thing.

Health is not a passive state. Health is an active process that enables an organism to adapt to fluctuations in its intrinsic and extrinsic environments to maintain health or recover to a healthy state after disease occurs. This has important implications for our thinking about health mechanistically—that we have evolved adaptive mechanisms that promote the healthy state of an individual and that these health mechanisms are generally distinct from those that drive disease…. 

For 50 years, we have focused our efforts in controlling infection on developing vaccines and antibiotics and elucidating the mechanisms of the immune response. A challenge to this way of thinking arises when a pathogen infects and replicates inside a host without causing disease. With the discovery of the cooperative defense system that enables a host to adapt to the presence of a pathogen with disease tolerance and anti-virulence defensive health mechanisms, we are beginning to understand this phenomenon (Sanchez et al., 2018, Schneider and Ayres, 2008). We appreciate that we have specialized health mechanisms that enable an individual to withstand a hostile environment such as drought or heat, but the past decade of research with infectious disease has demonstrated that we have barely tapped into defining the full spectrum of these defensive health mechanisms for hostile conditions …. Although I focus on physiological health, the framework, concepts and approaches I describe here are applicable to mental health as well. Only when we understand health mechanistically will we truly be able to treat disease….

The traditional definition of health, “the absence of disease or injury,” gives the impression that removing the source of the disease or injury necessarily restores health, resulting in a focus on disease pathogenesis mechanisms that shift the health trajectory to disease and the mechanisms that eradicate the insult. However, we intuitively realize that health is an active process that can decline, for example with age, and that physiological processes independent of the mechanisms of disease pathogenesis can affect the maintenance or resilience capacity of an individual.

Defensive health mechanisms are specialized health mechanisms that evolved to promote maintenance or resilience of the health trajectory when challenged with extrinsic threats or hostile environments that drove the evolution of our physiologies, including food scarcity, predators, infections, heat/cold stress, hypoxia/hyperoxia, dehydration, and toxins. Defensive health mechanisms are inducible mechanisms that enable the organism to antagonize or withstand the insult. Antagonizing the insult is mediated by avoidance and resistance strategies that enable the organism to avoid or eliminate the insult. Withstanding the insult is mediated by disease tolerance and neutralization strategies that alleviate the fitness costs by promoting maintenance of health or resilience in the presence of the insult.

For other posts on health and wholeness, see here.