The human biology saturated with experiences

epigenetic mechanism

http://tidsskriftet.no/article/48374/en_GB

This article from the Norwegian Medical Journal Nr. 7 – 8. April 2011 points  to a new paradigm in medical science. That experience  are the most important factor that influences our biology, health and life in general.

Human experiences  is not only absent from contemporary evidence-based medicine, it is in fact explicitly eliminated by the mathematical analyses performed during assembly of evidence.

Summary

Background. Human beings are reflective, meaning-seeking, relational and purposeful organisms. Although experiences associated with such traits are of paramount importance for the development of health and disease, medical science has so far failed to integrate these phenomena into a coherent theoretical framework.

Material and method. We present a theory-driven synthesis of new scientific knowledge from a number of disciplines, including epigenetics, psycho-neuro-endocrino-immunology, stress research and systems biology, based on articles in recognised scientific journals and other academic works. The scientific sources have been deliberately chosen to provide insight into the interaction between existential conditions in the widest sense (biography) and biomolecular processes in the body (biology).

Results. The human organism literally incorporates biographical information which includes experienced meaning and relations. Knowledge from epigenetics illustrates the fundamental biological potential for contextual adaptation. Intriguingly, different types of existential stresses can enhance disease susceptibility through disturbances to human physiological adaptation systems, mediated in part through structural influences on the brain. Experiences of support, recognition and belonging, on the other hand, can help to strengthen or restore a state of health.

Interpretation. New knowledge from integrative research projects reveals a need for theoretical and practical reorientation in medicine with respect to understanding health, on both the individual and the community level.

 

Human beings have unique characteristics that distinguish them from all other known organisms – a capacity for self-reflection, for designing sophisticated symbolic structures, for attaching metaphorical concepts to experiences and for building models and categories with the aid of the imagination. Nevertheless, the traditional scientific methodology of biomedicine fails to take account of the self-aware, meaning-seeking, purposeful and relational nature of humans . Doctors therefore lack theoretical understanding of how experiences associated with self-image, relations and values become «inscribed» in the body.

During the past decade, empirical documentation has demonstrated that experience – the information that an individual acquires during a lifetime of sensing and acting – is of fundamental biological relevance. Unfortunately, such experience does not lend itself easily to standardised interpretation; it is always an experience of something for someone, in a unique context (2). In this article, we attempt to exemplify the importance of subjective experiences for health.

New integrated stress research – the concept of allostatic overload

Long-term overtaxation of the physiological adaptability of human beings may lead to health impairment. This phenomenon, called «allostatic overload»  is a consequence of physiological «wear and tear» due to strong and/or persistent threats to an individual’s existence or integrity (the word encompasses both mental and physical aspects). The human body’s reaction to stressors, which in our culture can be classified as physical (e.g. undernourishment, overfeeding, malnutrition, pollution, lack of sleep, lack of exercise, infections, noise) prove to converge at the same biological «level» as stressors we would classify as psychosocial (e.g. a life characterised by threats, neglect, abuse, poverty or overwhelming caregiving burdens): Both categories of stress can contribute over time to the development of autonomic dysfunction, changes in the immune system, chronic low-grade inflammation, endocrine disruptions and accelerated cell aging, measured as telomere shortening (Box 1).

Chronic metabolic disturbances related to  experienced overload of the human organism appear to contribute, at least partly through epigenetic mechanisms, to the development of the major, complex diseases of our time – cardiovascular disease, overweight, diabetes, chronic obstructive pulmonary disease,unclear fatigue symptoms,  other immunological and inflammation-driven diseases, osteoporosis, depression, anxiety, so-called behavioural disorders, substance dependence and other complaints classified as psychiatric, cognitive complaints, adverse pregnancy outcomes in the form of premature births and low birth weight, pain syndromes and chronic fatigue etc.

Recent trauma research provides insight into how detrimental childhood experiences may lead to toxic stress  which is reflected in disturbed maturation of brain structure in the developing individual. Neuroimaging studies have linked such structural changes (gray and/or white matter alterations) to experiences of verbal abuse, harsh corporal punishment and sexual abuse . The plasticity and vulnerability of the brain appear to vary with the individual’s age; the detrimental potential of adverse experiences will depend on when they occur and how long they last .

The brain appears to remain receptive to relational effects throughout life. Fortunately, favorable brain changes can also occur, in response to experiences which promote healing and health (salutogenesis). A number of studies have documented structural changes in the brain associated with successful psychotherapy . On a more general level, a recent meta-analysis demonstrated that strong social relations provide as good protection against premature death as smoking cessation, and this statistical protection is numerically greater than the risk associated with, for example, obesity and physical inactivity . This protective effect is independent of age, gender and a number of other factors, and is therefore unlikely to be limited to sub-groups.

Future medical science must be experience orientated. We strongly emphasize the need to revise the theoretical foundation of medicine, organisation, methods and the necessity of integrating this new knowledge into clinical practice, research, teaching and health policy.

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