(16-05-14) Chronic Stress, Poor Diet May Up Metabolic Risk

Larry Hand
May 05, 2014



For the first time in humans, a small study has shown that chronically
stressed women whose diet contains high-fat and high-sugar foods are more
vulnerable than low-stressed women who eat the same foods to metabolic
health risks, including abdominal fat and insulin resistance.

If the association is confirmed in interventional studies, the finding
suggests that increasing stress-resilience skills might improve on
interventions to treat metabolic syndrome and obesity, which have reached
epidemic proportions.

"In order for scientists and doctors to give the public better and more
reliable answers about what they can do about their stress, we need support
for this kind of research - how stress and resilience training affects
biology," first author Kirstin Aschbacher, PhD, assistant professor of
psychiatry at the University of California, San Francisco (UCSF) told
Medscape Medical News.

The study was published online April 12 in the journal
Psychoneuroendocrinology.

Inspired by a 2007 research article that associated stress with development
of fat gain and metabolic syndrome in mice, primarily through activation of
neuropeptide Y (NPY), Dr. Aschbacher and colleagues conducted a case-control
study comparing 33 postmenopausal caregivers as the high-stress group with
28 age-matched, low-stress women.

The high-stress group consisted of women caring for a spouse or parent with
dementia for an average of 4.7 years.

Participant characteristics included a mean age of 62 years and a median
income of $70,000 to $79,000; 66% had a bachelor's or advanced degree, and
80% were white.

The participants self-reported their dietary consumption on food frequency
questionnaires, and both groups reported eating high-fat/high-sugar foods.

Researchers took fasting blood samples from participants at UCSF and
measured abdominal fat through dual-energy X-ray absorptiometry.

They also measured NPY levels in plasma.

Participants underwent a 3-hour oral glucose test immediately after their
fasting blood draws.

All measures were taken at baseline and 1 year later and largely remained at
the same levels because of the high stability of outcomes over time.

The high-stress group reported a mean time of caregiving of 13.6 hours a
day, compared with no hours of caregiving for the low-stress group.

The chronically stressed group did not report a significantly higher
consumption of high-fat, high-sugar foods than the low-stress group, but
providing more hours of care per day in the high- stress group was
associated with more high-fat, high-sugar food consumption (P = .03) and had
significantly higher levels of NPY (P = .001). Controlling for age, physical
activity, and medication use, the researchers found that higher consumption
of high-fat, high-sugar foods was associated with greater activation of NPY
and waistline circumference (P = .02), truncal fat (P = .01), and insulin
sensitivity (P = .04), but not levels of 8-hydroxyguanosine, a marker of RNA
oxidation (P = .40).

"Our data are the first to demonstrate in humans that the synergistic
combination of chronic stress along with consuming more high-fat/high-sugar
foods was associated with significantly worse metabolic outcomes and greater
waist circumference," the researchers write. "[T]his study represents a
critical step needed to justify considerably more resource-intensive studies
involving feeding paradigms, multiple daily dietary assessments, and
biomarkers for macronutrient consumption."

An independent expert agrees. "Now is exactly when we need this kind of
research. A lot of prior research has really focused on one thing at a time.
I really think this kind of study is so valuable because we are not just in
a bubble where you're stressed. Now I'm in a different bubble where I'm
hungry. This kind of tie-in that looks at the interaction of all of these
factors is so important," A. Janet Tomiyama, PhD, assistant professor of
psychology at the University of California, Los Angeles, told Medscape
Medical News.

"They took this really interesting finding in rodents and are actually
bringing it the human arena, which I think is already a huge step forward in
terms of making it relevant to everyday people. It makes us more confident
that it is a mixture of stress and food that is contributing to this
[reduced] metabolic health," she continued.

She added that an intervention into the types of foods eaten while stressed
could be done quickly. "We don't reach for celery when we're stressed. We
reach for brownies and potatoes. We're really far from [a treatment] still.
But one place that combines the 2 factors [stress and diet], is where we
could - I think tomorrow - create an intervention."

"When you have diabetes, doctors know what to measure in your blood to see
whether your treatments are working," Dr. Aschbacher said. "But right now
there's no consensus about what biological measures we should use to judge
whether or not a stress management program is really working to improve your
health.

"When you look at guidelines published by some of the leading organizations,
the focus for metabolic health is really on diet and exercise. I hope that
in the future, stress management will become integrated as an important part
of good preventative care," she added.

This research was supported by the National Institutes of Health, the
Marchionne Foundation, and the Institute for Integrative Health. The authors
and Dr. Tomiyama have reported no relevant financial relationships.


SOURCE: Psychoneuroendocrinol. Published online April 12, 2014. Abstract

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