New research has uncovered startling connections between the consumption of high-fat foods and the body’s ability to cope with everyday stress. The findings highlight a significant impairment in the body’s recovery mechanisms when fatty foods are consumed during stressful periods.
The study involved healthy young adults consuming high-fat foods before undergoing a stress-inducing math test.
“We took a group of young healthy adults and gave them two butter croissants as breakfast. We then asked them to do mental maths, increasing in speed for eight minutes, alerting them when they got an answer wrong. They could also see themselves on a screen whilst they did the exercise. The experiment was designed to simulate everyday stress that we might have to deal with at work or at home,” explained study lead author Rosalind Baynham, a PhD researcher at the University of Birmingham.
“When we get stressed, different things happen in the body, our heart rate and blood pressure go up, our blood vessels dilate and blood flow to the brain increases. We also know that the elasticity of our blood vessels – which is a measure of vascular function – declines following mental stress.”
“We found that consuming fatty foods when mentally stressed reduced vascular function by 1.74% (as measured by Brachial Flow-mediated dilatation, FMD). Previous studies have shown that a 1% reduction in vascular function leads to a 13% increase in cardiovascular disease risk,” said Baynham.
“Importantly we show that this impairment in vascular function persisted for even longer when our participants had eaten the croissants.”
The researchers were able to detect reduced arterial elasticity in participants who ate the croissants for up to 90 minutes after the stressful event was over.
The study also revealed that eating high-fat foods reduced cerebral oxygenation in the prefrontal cortex, with 39 percent lower oxygen delivery during stress compared to when participants consumed a low-fat meal. Furthermore, fat consumption negatively impacted the participants’ mood, even after the stressful test.
“We looked at healthy 18–30-year-olds for this study, and to see such a significant difference in how their bodies recover from stress when they eat fatty foods is staggering. For people who already have an increased risk of cardiovascular disease, the impacts could be even more serious,” noted Professor Jet Veldhuijzen van Zanten.
“We all deal with stress all the time, but especially for those of us in high-stress jobs and at risk of cardiovascular disease, these findings should be taken seriously. This research can help us make decisions that reduce risks rather than make them worse.”
Dr. Catarina Rendeiro, assistant professor in Nutritional Sciences, emphasized the importance of food choices during stressful periods. Consuming low-fat meals showed a lesser impact on vascular function, which returned to normal 90 minutes after the stress event.
Remarkably, the researchers found that consuming foods rich in polyphenols, like cocoa, berries, and certain fruits and vegetables, could entirely prevent impairment in vascular function.
“The impact of these foods during stressful periods cannot be understated. For example, reduced oxygenation to the brain could potentially impact mood and mental health, making people even more stressed,” noted Professor Rendeiro.
“On the other hand, it could affect cognitive function and people’s ability to perform the very task they are stressing about, such as an interview, an exam or work meeting. This is something we would like to do more research into in the future.”
“Our studies show that food choices around stressful episodes can exacerbate or protect from the effects of stress on our cardiovascular system. The good news is that this means we can do something about this,” said Professor Rendeiro.
“We know that when people are stressed, they tend to gravitate towards higher-fat foods, either because it is the more convenient option if time is in short supply, or as a treat to deal with the stress. But by doing this, they are making their physical and psychological response to stress worse. By picking low-fat foods, they could be positioning themselves to cope with the stress more effectively.”
“The world is an incredibly stressful place right now, and even without outside factors such as war or a cost-of-living crisis, stress is something we all need to deal with. So, next time you are in a big meeting, or taking part in a job interview maybe try and resist the free biscuits and go for some berries instead. You might find you feel more relaxed and can cope with the stress just a little bit better,” concluded Baynham.
The study is published in the journal Frontiers in Nutrition.
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