Doctor's Health Tip
Dan Kenner, Ph.D., L.Ac., JAPAN
The effects of stress on the body have been studied scientifically since the 1930s. The effects on the endocrine system are well known, with a cascade of hormones that prepares us for emergency situations. The secretion of adrenaline and noradrenaline by the adrenal glands is the best-known response to stress, leading to the "flight or fight" reaction. Another adrenal hormone, cortisol, is sometimes called the 'stress hormone'. When stress is permanent, it becomes a threat to health. The link between body and mind, stress, psychological states and health used to be considered a vague pseudoscience, but today there is a wealth of scientific data confirming the damage that stress can cause to health. Some experts claim that stress is responsible for 90% of all illnesses, including cancer and heart disease.
Stress floods the body with cortisol, an anti-inflammatory hormone that also reduces white blood cells. One particular type of white blood cell is constantly affected by stress. This is the 'Natural Killer' cell, or NK cell, whose role is to destroy abnormal cells, whether they are normal aged cells, cells infected by a virus or cancerous cells. Reduced NK cell activity is one of the ways in which high levels of cortisol accelerate the development and growth of tumours, and increase the rate of infection and tissue damage. NK cells are large lymphocytes which, like cytotoxic T cells, are filled with granules. They selectively target tumour cells and other abnormal cells, as well as a wide variety of infectious microbes. Unlike cytotoxic T cells, they do not need to recognise a specific 'antigen' before attacking and destroying a target cell. Unlike macrophage cells, they do not engulf or ingest target cells, but attach themselves to them and inject chemicals that erode the target cell membranes until they burst. In many chronic and degenerative diseases, the level of NK cell function has been shown to be an important indicator of disease progression and patient prognosis. The effect of stress on NK cells is not necessarily to reduce their numbers, but to weaken their activity. Under stress, they become relatively inert and, as the abnormal cells are not destroyed or eliminated, they can accumulate in the system.
Several studies have shown that reduced NK cell activity is strongly correlated with the intensity and duration of the persistent mental and physical effects of PTSD. In some cases, this is the only immune system parameter that can be definitively correlated with the psychological damage associated with PTSD. More importantly, PTSD can have a long-term impact on health as it is known to suppress immunity for long periods of time. Subjects with a history of PTSD showed significantly lower immune competence, even years after the initial trauma. This implies that even buried trauma can potentially be a cause or co-factor of cancer or other catastrophic diseases.
Various 'stress factors' can suppress the function of NK cells: physical injuries caused by accidents, surgery and medical treatments, nutritional deficiencies, emotional trauma, bereavement, hormonal imbalances, and so on. Research on victims of disasters such as hurricanes and earthquakes shows reduced NK cell activity. NK cell activity is affected by negative psychological states such as depression, anxiety and fatigue, even though lymphocyte numbers and CD4/CD8 ratios do not change. Self-awareness and self-criticism have also been shown to decrease NK cell activity.
The sympathetic nervous system, driven by adrenaline and noradrenaline, is an important mechanism proposed to explain the relationship between stress and NK cell activity. A neuropeptide called substance Y activates the sympathetic nervous system and significantly suppresses NK cell activity. Noradrenaline has also been shown to inhibit NK cell activity, and b-adrenergic activation, where adrenaline activates the cardiovascular system and is often associated with stress-induced changes, also appears to have an immediate and significant negative impact on the ability of NK cells to function normally.
NK cell activity can also be positively influenced by various factors. Both music therapy and massage have been shown to increase NK cell activity. The benefits of daily massage have been seen even in AIDS patients with compromised immune systems. A study conducted in South Korea showed that the IQ emitted by a qigong practitioner and directed at tumour cells in culture significantly increased the activity of NK cells in the treated group alone. A QI projection of 3 to 5 minutes in series of 30 seconds was optimal for increasing NK cell activity.
Lifestyle habits also support and increase NK cell activity. Participants in the study who had a healthy lifestyle with a healthy diet including a daily breakfast, sufficient sleep, low stress levels, minimal or no smoking and alcohol consumption had significantly higher NK cell activity.
Dan Kenner, Ph.D., L.Ac.
College of Acupuncture and Integrative Medicine (AIMC Berkeley)
DAN KENNER, Ph.D., L.Ac graduated in 1979 from Meiji College of Oriental Medicine in Japan, passed the national examination for licensure in Japan, and then completed internships at the Osaka Medical University Pain Clinic and the Kinki University Medical Teaching Hospital. He is licensed to practise Oriental medicine in the United States and Japan. He also holds a doctorate in naturopathic medical sciences from the First National University of Naturopathic Medical Sciences. Dr Kenner is a member of the Board of Directors of the Acupuncture and Integrative Medicine College in Berkeley, California, and the National Heath Federation. He is the author of The Whole-Body Workbook for Cancer and other titles. Since 1983, he has worked to integrate the naturopathic medical traditions of North America and Europe with traditional East Asian medicine.