Highly stressed people who eat a lot of high-fat, high-sugar food are more prone to health risks than low-stress people who eat the same amount of unhealthy food, according to new research.
For the study, published online in
the journal Psychoneuroendocrinology,
researchers from the University of California at San Francisco (UCSF) spent a
year studying a group of 61 healthy women; 33 were chronically stressed women
caring for a spouse or parent with dementia, and 28 were women with low stress.
The women also reported their
consumption of high sugar, high fat foods.
“Chronic stress can play an
important role in influencing biology, and it’s critical to understand the
exact pathways through which it works.” said Kirstin Aschbacher, PhD, an
assistant professor in the UCSF Department of Psychiatry and lead author.
When a calorie isn’t just a calorie
“Many people think a calorie is a
calorie, but this study suggests that two women who eat the same thing could
have different metabolic responses based on their level of stress. There
appears to be a stress pathway that works through diet – for example, it
could be similar to what we see in animals, where fat cells grow faster in
response to junk food when the body is chronically stressed.”
The researchers evaluated key
biological markers associated with elevated metabolic risk including waistline
measurements, assessments of abdominal fat deposits. They also tested participants’
insulin resistance – a key driver of metabolic syndrome – and used
blood tests to measure levels of hormones and a blood test to measure stress
hormones and oxidative (free radical) damage to lipids and cell RNA, a marker
that has predicted higher rates of death from diabetes.
Oxidative damage of the genome is
also an important outcome because it is one factor that can contribute to
faster cellular ageing.
The devastating impact of stress
What they found was that more
frequent high-fat, high-sugar consumption with a larger waistline, more
abdominal fat, higher oxidative damage, and more insulin resistance, but only
among the group of women exposed to chronic stress,”
But, adds Aschbacher. “The
chronically stressed women didn’t report eating more high sugar, high fat foods
than the low stressed women; however, they did have higher levels of a
stress-related biomarker, peripheral Neuropeptide Y (NPY).”
A new pathway
Based on what is known from animal
studies, stress triggers greater peripheral NPY which, in combination with junk
food, creates larger abdominal fat cells, and these cells may be more prone to
metabolic dysregulation.
While this stress-junk food pathway
has been well mapped out with rodents and primates, this study is the first to
suggest the same pathways may be at work in chronically stressed humans,
according to the researchers.
“Diet appears to be a critical
variable that can either amplify or protect against the metabolic effects of
stress,” said senior author Elissa Epel, ” but we still don’t know the details
of how much it takes.” Their next study, she says, will specifically feed high
stress people a consistently high sugar diet and monitor its effects.
More studies on the way
Metabolic syndrome is a cluster of
abnormalities – increased blood pressure, a high blood sugar level, excess
body fat around the waist and abnormal cholesterol levels – that occur
together, increasing a person’s risk of heart disease, stroke and diabetes.
“The medical community is starting
to appreciate how important chronic stress is in promoting and worsening early
disease processes,” said Aschbacher. “But there are no guidelines for
‘treating’ chronic stress. We need treatment studies to understand whether
increasing stress resilience could reduce the metabolic syndrome, obesity or
diabetes.”
