Does food affect your mood? The fact is that we aren’t disconnected at the neck, and what’s good for our bodies is good for our minds—and vice versa. Research shows that what you eat—and whether you’re eating regularly—can affect your mood. Scientists have known for years about the gut-brain axis, which links the emotional and cognitive centers of the brain with intestinal functions. This connection is clear when stress or anger causes your stomach to “be tied up in knots” or when you have “a gut feeling.”
The “hangry” phenomenon. When you’re hungry, that can affect your mind—and your moods—as well as your body. When your brain senses low fuel levels, it triggers shifts in your nervous system, hormones, and emotions. This can contribute to anger or other emotions, which, combined with hunger, leaves people feeling “hangry.”
“Hunger for most healthy people who eat regularly can generate unpleasant feelings. When blood glucose falls, a host of hormones often involved in stress like cortisol and adrenaline are released. These hormones make us feel wired, tense, and generally unpleasant,” says Jennifer MacCormack, MA, a PhD student in the Department of Psychology and Neuroscience at the University of North Carolina, Chapel Hill and co-author of a 2018 article on hanger in the journal Emotion. “However, our studies show that just feeling the physiological effects of hunger doesn’t seem to be enough to transform hunger into hanger. The situations we are in and our awareness of our feelings and our body also seem to matter.”
For example, they found that people are most likely to get hangry only in negative situations—like when working on a frustrating task, when insulted by a customer or co-worker, or when stuck in rush hour traffic. “Hungry people are not as likely to get hangry in situations that are neutral, like walking down a quiet street, or positive, like relaxing at home with your favorite film,” she says.
Why does situation matter? MacCormack says it’s likely because the shared negativity between hunger and unpleasant situations makes it easier for us to mistakenly think our hunger-induced feelings are being caused by our rude co-worker. But being aware of our feelings in the moment can help nip hanger in the bud.
“Hungry people who focused on feelings immediately before the frustrating tasks in the experiment reported feeling roughly the same as people who were full,” she says. “Only hungry people who hadn’t focused on feelings beforehand were the ones who got ‘hangry’—saying that they felt more stressed, irritable, and hateful.”
The role of the gut microbiota. An emerging twist in our knowledge of the gut-brain axis is the concept of a microbiome-gut-brain axis. Evidence suggests that the gut microbiota interacts with both the gut and the brain to the point where it’s been called the “peacekeeper” between the two. Your gut microbiota is made up of 100 trillion bacteria and other microbes that live in your intestine, mostly your large intestine, and your gut microbiome is the collective genes of all those microbes.
Studies have found that the gut microbiota influences brain chemistry, which can contribute to anxiety and depression. Emeran Mayer, MD, director of the Center for Neurobiology of Stress and Resilience at UCLA, says that the microbiota can also use byproducts of the fiber it ferments to trigger production of the natural mood stabilizer serotonin, which is stored in intestinal cells. “More than 95% of all of our serotonin is stored in these cells that are interspersed in the gut lining,” he said, speaking at the 2017 Nutrition & Health Conference.
Foods to choose. Research suggests that a diet rich in whole plant foods, along with probiotic-rich fermented foods, may support body and mood by supporting a diverse gut microbiota. A 2015 study in the American Journal of Clinical Nutrition found that a diet high in refined carbohydrates like sugar and white flour increased the risk of depression in postmenopausal women, but that a diet high in fiber from whole grains, vegetables and whole fruit was associated with a lower risk of depression.
A 2013 study co-authored by Mayer randomized 36 healthy women to one of three groups: probiotic yogurt, non-fermented milk product with no probiotics, or no yogurt or milk products. After four weeks, brain scans indicated that the women who ate the probiotic-rich yogurt twice a day had less of a negative emotional response when shown photos of people who were angry, sad or fearful.
Research has found that people with depression and anxiety tend to have lower levels of omega-3 fatty acids in their blood. Although more research is needed, it appears that increasing intake of these healthy fats, found in fatty fish like wild Alaska salmon, Atlantic mackerel and sardines, may help reduce symptoms. So can the essential amino acid tryptophan, found in many protein-rich foods, including eggs, dairy, soy foods, turkey, salmon, nuts and seeds. “Tryptophan-containing foods are a major stimulus for microbes to stimulate serotonin synthesis.”
—Carrie Dennett, MPH, RDN