by Diane Masiello


Teenagers are beset by stressors that affect their mental health and well-being. They have to deal with hormonal fluctuations, growth spurts, relationship dynamics, uncertainty about their future, navigating friendships, breaking away from parental control and facing the consequences of their independent decisions. During these years, the level of uncertainty and change they experience— physically, emotionally, and mentally—is unprecedented and often out of their control. However, one thing they can control is what they eat, and this raises the question: how does nutrition affect teens’ mental health?

In “Examining the Role of Anxiety and Depression in Dietary Choices Among College Students,” Michelle M. Keck and her colleagues say that while the connection between nutrition and anxiety has not been proven, “the association between depression and diet … have been well-established.” Choosing foods high in healthy oils, fish, soy, fruits, vegetable, and folate are related to decreased symptoms of depression. In contrast, food with added sugar, high fat, refined grain, and all processed foods are associated with increased symptoms of depression. Keck et. al add that “individuals who are depressed are more likely to consume more calories, have a higher Body Mass Index (BMI) and poorer diet quality.”

So there is a cyclical relationship between diet and mental health—the more refined sugar, high fat, and processed foods in a teen’s diet, the more depressed they become, and the more depressed they become, the more they eat. Why might this be? In their study “Link Between Diet and Mental Health Among Female Adolescents: A Brief Note” Dr. Jaya Bharti and Dr. Priyanka Sigh describe the gastrointestinal tract as the body’s “second brain.” People have a variety of bacteria in their gut; this bacteria is designed to digest different types of foods. The bacteria that help the body process refined sugar is different than the bacteria that help process protein. These bacteria, however, are not just helping their human host digest. They are also being fed on the type of food they process, which allows them to grow and reproduce.

The more refined sugar a person eats, the more sugar-processing bacteria will grow. The more protein a person eats, the more protein-processing bacteria will grow. Some scientists believe that
these bacteria send signals to the brain, which drives the person to eat more of the kind of food they process. If a person eats a lot of refined sugar, the bacteria will send signals to get the person to eat more and more refined sugar. A person who eats fish and nuts will feed the bacteria that thrive on protein and good fats, which will, in turn, send the brain a signal to eat more protein and good fats.

The problem comes in that the bacteria which digest refined sugar, unhealthy fats, and processed foods cause inflammation which hinders the production and growth of neurotransmitters essential for mental health. In contrast, the bacteria that thrive on healthy oils and protein are instrumental in creating neurotransmitters that positively affect the brain and mood.

The article, “Promoting Mental Health and Wellness in Youth Through Physical Activity, Nutrition, and Sleep” by Daniel Hosker, MD and R. Meredith Elkins, PhD., asserts that teens whose diet
contains mostly whole grains, seafood, fruits and vegetables, and nuts have improved mental health. These teens also eat a moderate amount of low-fat dairy products, but they also avoid red meat, added sugars, sodium, processed foods, and saturated and trans-fats.

Does this sound familiar? It should because it’s the dietary recommendations adults should also follow. But how likely is it a teen is going to bake salmon when it’s so much easier to grab a burger from a drive-through? How do we encourage teens to make healthier food choices when unhealthy ones are tailored to their fast-paced lifestyle?

The first step is to encourage teens not to miss meals or turn to sweet or fatty foods. It’s fine to stop at a fast-food restaurant so long as they order a salad instead of burger and fries. They can
grab something from the convenience store as long as it’s dried fruit and nuts rather than chips or sugary treats. Some gas stations even now have fresh-cut fruit and veggie trays. These are all better options for on-the-go meals than doughnuts or fries.

Simply encouraging kids to make choices that have a minimum amount of preservatives, food coloring, and are not as processed (a nutrition bar with whole nuts rather than a candy bar) can go a long way toward feeding the “good” gut bacteria, which will eventually improve their neurotransmitter production. If they do want to eat candy, dark chocolate—especially over nuts—is the best choice.

Berries and leafy greens, which are high in anti-oxidants, help fight inflammation hinders neurotransmitter production. Vitamin D, which people usually get from sunlight but which teens (who
are more naturally drawn to be active in the late-night hours) often lack helps the production of serotonin which fights depression. This is not always easy to make up for in their diet, so multivitamins are an excellent solution to help teens obtain vitamin D. Most multivitamins also contain magnesium which improves muscle and nerve function and also promotes a steady heartbeat. Taking a vitamin shouldn’t give teens permission to eat anything but sugar the rest of the day, but it does go some way toward offsetting the traditional teen junk-food diet.

The key to remember is that what people eat as teens will often determine what they eat as adults. Food habits are hard to break. The sooner people develop healthy eating habits by turning to
fruits, vegetables, whole grains, and healthy fats, the more their brains and bodies will benefit. With the increase in obesity and the decline in the mental health of so many teens and adults, it seems
more imperative than ever to bring eating habits in line with these physician and dietitian recommendations.