“When we feel stressed, we seek foods that are going to comfort us immediately, but oftentimes those foods are the very ones that lead to surges and crashes in hormones and blood sugar that increase our susceptibility to new stresses,” explained David Ludwig, professor of pediatrics at Harvard Medical School, on National Public Radio’s Morning Edition last July.
But the evidence that foods can make us more vulnerable to stress is quite spotty. The NPR report cited a 15-year-old study that gave 12 obese teenage boys one of three breakfasts.
“One included protein-rich eggs, and another meal included high-fiber, steel-cut oats, which provide for a slow release of energy,” said the NPR reporter. “A third meal was a bowl of instant oatmeal, which is digested much more rapidly.”
But the oatmeal breakfasts weren’t typical. The steel-cut oats were sweetened with four teaspoons of pure fructose, which doesn’t raise blood sugar much. (Fructose is often marketed to people with diabetes, and it isn’t likely to show up in most cupboards.)
In contrast, the instant oatmeal was sweetened with four teaspoons of pure glucose, which raises blood sugar more than most other sweeteners—like table sugar and high-fructose corn syrup— which are roughly half fructose and half glucose. (Karo Corn Syrup is one of the only pure glucose sweeteners in the grocery store.)
To pump up blood sugar levels even more, the milk served with the instant oatmeal was treated with an enzyme so it had more glucose than ordinary milk. (The boys got ordinary milk with the steel-cut oats.)
All that extra glucose might help explain what happened next.
“After the highly refined instant oat¬meal, blood sugar surged but then crashed a few hours later,” said Ludwig. “And when that happened, the hormone adrenaline, or epinephrine, surged to very high levels.”
Does that mean, as the NPR report suggested, that “eating lots of sugar and refined carbs can exacerbate our responses to stress”? Not necessarily. Few studies have looked…or found much.
For example, a few years ago, Dutch researchers gave 38 adults either a high-stress or low-stress computer task followed by either a high-carb lunch (salad, cheese biscuits, bacon biscuits, and a high-carb strawberry shake) or a high-protein lunch (salad, cheese, salami, and a high-protein strawberry shake). The result: the participants felt no more—or less—stressed after the high-carb than after the high-protein lunch.
“We know more about the effect of stress on food choices than we know about the effect of foods on stress,” says researcher Tanja Adam, of Maastricht University in the Netherlands.
Do some foods make us more resilient to stress?
“You can either be good at weathering a lot of stresses or you can be brittle,” researcher Joe Hibbeln, of the National Institute of Mental Health, told the NPR reporter. “Omega-3 fatty acids make your stress system more flexible.”
But few good studies have tested whether people who are given omega-3 fats are less stressed than those who get a placebo. In one of the few, medical students who got EPA (2,100 mg) and DHA (350 mg) every day for three months reported 20 percent less anxiety than those who got a placebo. However, neither group experienced much stress, so it’s not clear that omega-3s would have made them more resilient.
“I would not recommend omega-3 supplements for stress or anxiety relief on the basis of the limited data to date,” says Janice Kiecolt-Glaser, lead author of the study and director of the Institute for Behavioral Medicine Research at Ohio State University.
A large trial called VITAL is now testing whether EPA and DHA (the omega-3 fats in fish oil) have any effect on mood in roughly 25,000 healthy people aged 50 and older. Results are due in 2017.
Last but not least, the NPR report cited Drew Ramsey, a psychiatrist at Columbia University and author of The Happiness Diet.
Nutrient-rich foods like kale, eggs, and pumpkin seeds “can affect how the stress gets to us,” explained the reporter.
Is there solid evidence that those foods can help us handle stress? Nope.
Bottom Line: There are plenty of reasons to eat leafy greens, seeds, and fish—and to avoid sugars and refined grains. But if those or other foods soften the impact of stress, no one has published the evidence to prove it.
Sources: Pediatr. 1999. doi:10.1542/peds.103.3.e26; PLoS ONE 2011. doi:10.1371/journal.pone.0016826; Brain Behav. Immun. 25: 1725, 2011.
Other relevant links:
• Do people eat worse when they are under stress? See: Is Stress Making You Fat?
• Is there a link between boredom and weight gain? See: How to Diet: Are You Hungry or Just Bored?
• Follow these tips to make healthy decisions while grocery shopping. See: How to Diet: Healthy Shopping Tips