If you’ve ever felt hangry after going too long between meals, stress eaten a chocolate bar, or lost your appetite when anxious, you’ve experienced the food-mood connection firsthand.
A bidirectional highway exists between the brain and the gut that allows nutrients absorbed in the gut to impact mood. The route between your mouth and rectum is actually lined with hundreds of millions of neurons—yes, neurons as in brain cells!—that make up what’s now known as the enteric nervous system (ENS) or, more colloquially, “the second brain.”
The foods you consume come into direct contact with these neurons as they move through your digestive tract, triggering different reactions in the brain and body that impact mental health. As you might expect, healthy, whole foods like fruits and vegetables, whole grains, and fatty fish have the most positive effect. In contrast, excess intake of processed foods high in sugar and refined carbohydrates can create inflammation linked with mood disorders like anxiety and depression.
The following three nutrients are incredibly beneficial when it comes to mood support:
Carbohydrates have been vilified by diet culture, but the truth is they’re an essential component of a healthy diet. The brain actually runs exclusively on glucose, a type of sugar (a.k.a. a carbohydrate). Regular consumption of complex carbs like oats, quinoa, brown rice, whole-wheat bread and pasta, legumes, and beans also stabilizes blood sugar levels. Without sufficient complex carbs (or if simple carbs like those found in candy and white bread are eaten in large quantities), blood sugar levels fluctuate, which can lead to mood swings. Ideally, you want 45% to 65% of your diet to come from complex carbs. When consumed in these quantities as part of an overall healthy diet, carbs don’t cause weight gain.
You’ve likely heard the term “microbiome” before—it’s the massive ecosystem composed of trillions of bacteria residing in your gut that helps regulate several bodily processes, including digestion and immunity. These bacteria feast on the foods you eat, pulling out various nutrients and using them to create compounds that help your body hum with energy and health. One of their favorite things to eat? Fiber.
Fiber is a type of complex carbohydrate that the body cannot digest on its own. It needs help from the good-for-you bugs in your microbiome, most of which reside in the large intestine. When you eat beans, berries, whole grains, peas, nuts, seeds, and other high-fiber foods, the fiber passes through the small intestine without being digested. Once it hits the large intestine, those bacteria get to work, using special enzymes to break it down and ferment it. As this happens, compounds called short-chain fatty acids are produced. These fatty acids have a mood-based mission: They interact with neurons within the gut to create serotonin, a feel-good neurotransmitter intricately linked to mood. This serotonin doesn’t necessarily travel up to the brain to improve health; instead, it works locally, strengthening the gut-brain axis and improving the gut’s ability to communicate with the brain and other organs.
Ample amounts of fiber also help create a thick protective layer of mucus in the gut, which serves as a protective barrier, ensuring that compounds that are meant to stay in the gut, including partially digested food particles, do indeed stay there and don’t escape into the bloodstream by sneaking through the gut lining. When that happens, it can lead to all manner of inflammatory symptoms, including diarrhea, headaches, joint pain, fatigue, and mood troubles.
The Institute of Medicine recommends that women ages 51 and older eat 21 grams of fiber daily. Men ages 51 and older should consume 30 grams daily.
Heart- and brain-healthy omega-3 fatty acids—found in fatty fish such as salmon, trout, and sardines; seeds like flax and chia seeds; and walnuts—enable the brain to carry out its daily to-do list, including emotional and mood regulation. They’re called “essential fatty acids” because the body can’t produce them itself—it’s essential that you eat them.
Omega-3s are anti-inflammatory, which may protect against depression. Several studies have shown that combining an antidepressant medication such as fluoxetine (Prozac) with an omega-3 supplement boosts the efficacy of the medicine. These fatty acids help regulate levels of serotonin and dopamine (other mood-boosting neurotransmitters), which may explain their antidepressant effects.
While your diet can bump your mood up or down, that doesn’t mean you need to eat oatmeal and salmon for every meal for the rest of your life. Food brings us joy, and it brings people together, which has its own list of mental health benefits. Fill your plate with nutrient-dense foods as often as possible, but don’t deny yourself a slice of birthday cake. There’s a balance between eating for your mood and cultivating a healthy relationship with food.
