| You don’t need
research to tell you that stress can make you sick. However, a
new study may have discovered the link between stress and health – interleukin-6
(IL-6).1
IL-6 is a proinflammatory cytokine (small protein released by cells)
that directly affects the behavior of other cells in the body. It
is associated with many diseases, including arthritis, cancer, diabetes,
osteoporosis, Alzheimer’s dementia, periodontal disease and
cardiovascular disease. IL-6 has also been linked to frailty and
functional decline in old age. Perhaps one of the most important concerns about IL-6 is that
it is directly linked to cardiovascular disease. This is due,
at least in part, to the fact that it plays a central role
in promoting the production of C-reactive protein (CRP), a
marker of inflammation that, when elevated, is a significant
risk factor for heart attack and other cardiovascular diseases.2 Both IL-6 and CRP are also involved in the pathogenesis of diabetes.
In one study, women with elevated levels of these proteins were
much more likely to develop type 2 diabetes during a four-year
study period than women with low levels of IL-6 and CRP.3 Other studies have shown that negative emotions such as depression
and stressful experiences can promote the production of IL-6 and
other proinflammatory cytokines. Furthermore, negative emotions
can lead to greater risk of infection, prolonged infection,
and slowed wound healing. All of these processes, in turn,
can promote sustained release of proinflammatory cytokines,
such as IL-6. In an effort to elicit the connection between stress and poor health,
researchers at Ohio State University measured IL-6 levels of 119
people caring for spouses with dementia and compared their findings
to IL-6 levels in 106 healthy control participants who were not caring
for a sick relative. The average caregiver spent more than nine hours
each day in caregiving-related activities over an average of nearly
five years. The average age of the participants was just over 70.
Prior to starting the study, 28 of the caregivers’ spouses
had already died and an additional 50 died during the study period.
For their research, the investigators drew blood levels of IL-6
and gave the participants surveys at least once a year for
six years. The surveys included questions on perceived stress,
depression, loneliness, general health, alcohol intake, smoking
habits, sleep, and exercise. They compared the survey results
to the IL-6 levels and published their findings in the July
22, 2003 issue of the Proceedings
of the National Academy of Sciences of the United States of America. The researchers found that during the six-year study period,
caregivers reported significantly more stress and loneliness
than the control subjects. During that same time frame, blood
levels of IL-6 increased an average of four times faster among
the caregivers than the control participants.
Even after a spouse died, the caregivers continued to exhibit
an increase in IL-6 levels. The investigators hypothesize that
this may be due to a combination of biological and psychological
mechanisms, as previous research has already shown that stress
and depression can permanently alter the immune system. In a previous study, caregivers who described themselves as “strained” were
63% more likely to die during the study period than non-caregiving
control subjects.4 The authors of the current study suggest that
their “IL-6 findings provide one viable mechanism that could
explain caregivers’ substantial differences in mortality across
a range of illnesses.” The researchers concluded the study article by stating: “The
finding that caregivers’ average rate of increase in IL-6 was
about four times as large as that of non-caregivers suggests that
a chronic stressor is capable of substantially augmenting normal
age-related increases, effectively prematurely aging the immune response.
These data provide important evidence of a key mechanism through
which chronic stressors may have potent health consequences for older
adults, accelerating risk of a host of age-related diseases.” It is important to note that previous research has shown that
poor health habits can also raise levels of IL-6. This includes
smoking, lack of exercise, poor sleep habits, and being overweight.
These findings suggest that although reducing stress is important
in our pursuit for better health, maintaining a healthy lifestyle
is imperative as well. “The bad news is that if you are experiencing chronic stress,
such as caregiving or another difficult situation, you need to be
aware that the stress can significantly impact your health,” study
author Dr. Ronald Glaser, Director of the Institute for Behavioral
Medicine Research at the Ohio State University College of Medicine,
told Life Extension magazine. “The good news is you can minimize the impact stress has on
your health by exercising, stopping smoking, getting good sleep,
and social networking with friends and family to help cope with your
stressors,” said Glaser. “All of these can lower IL-6
levels. They are not easy to do, but well worth it.” —Marc Ellman, M.D. Editor’s note: Supplements that have been shown to lower elevated
IL-6 are DHEA and the DHA fraction of fish oil. If IL-6 levels remain
persistently high even when taking these supplements, consider asking
your doctor to prescribe a bisphosphonate drug (such as Zometa®)
that protects against bone destruction that releases excess IL-6
into the body. The Life Extension Foundation may soon have an IL-6-lowering
herbal extract available. |