Diet and Mental Health: How Nutrition Shapes Your Well-Being

Biology of Food-Mood Connection

Understanding the biological aspects of nutrition shows how food significantly influences the body’s ability to manage stressors and support mental well-being.

Serotonin

Serotonin is often called the “feel good” neurotransmitter or “feel good” hormone. Serotonin helps regulate your mood, sleep, appetite, and tolerance for pain.

It’s the target of many antidepressant medications. To produce this neurotransmitter, the brain must complete several steps inside the gastrointestinal system that require certain nutrients, including but not limited to vitamin B1, copper, riboflavin, and calcium.

What happens when you don’t get enough of these nutrients? A tug-of-war for nutrients happens. Some systems will lose.

Gut Microbiome

Your intestinal microbiome includes billions of beneficial bacteria that can produce certain vitamins when you don’t get them in your diet. It can create B1 and neurotransmitters like serotonin.

The bacteria in the gut communicate with the brain about what they need from the body to stay healthy. The body tells the gut what it needs to produce more of for various functions.

While the link between gut health and overall health has long been assumed worldwide, researchers are just beginning to understand the importance of gut health to mental health.

A study at Deakin University gathered information about the diets of 213 pregnant women in their third trimester as well as gut microbiome samples. They then followed the new mothers and their children until the age of two. They found that the women with the most diverse intestinal microbes during pregnancy had toddlers who had fewer depressive, anxious, or withdrawn characteristics.

This doesn’t show a direct cause-and-effect relationship. However, all studies are building blocks in our overall understanding.

Combine this study with serotonin’s impact on mood and mental health. This demonstrates the importance of a healthy gut. Consequently, it shows how important it is to maintain a healthy microbiome with nutrition.

Another 2019 study targeted the gut as a means to improve outcomes of patients with mood disorders. This provides further support for the importance of nutrition when therapeutically treating mental illness symptoms.

The bacteria in the gut love fiber, especially the insoluble fiber found in foods like broccoli stems, asparagus, dark leafy greens, beans, whole seeds, and fruit peels. The better fed the microbiome is, the more diverse it becomes.

A diverse microbiome is more adaptable and healthier. A less diverse microbiome can easily be overtaken by harmful bacteria, become inflamed, and lack the necessary components to support mental health.

Immune System Function

Inflammation is a natural tool the immune system uses to fight threats in the body. Certain foods increase inflammation, primarily saturated fat, sugar, and food additives that the body can’t recognize.

Current research suggests that this increased inflammation may explain why those who eat a lot of ultra-processed food also experience brain health challenges like cognitive decline as well as dysfunction in areas of the brain like the hippocampus and amygdala.

The hippocampus helps you manage stress through dopamine production. The amygdala regulates the fight or flight response through adrenaline and epinephrine.

Most of this research has historically looked at how food that may contribute to inflammation can impact people’s physical health. For example, researchers have long known that rampant inflammation increases the risk of developing type 2 diabetes or cardiovascular disease.

However, it’s becoming clearer now that this inflammation also impacts mental health.

One 2010 study found that those with type 1 or 2 diabetes also have abnormalities in their hippocampus, amygdala, and other brain structures that directly impact mental health.

Nervous System

The nervous system includes your brain, spinal cord, and peripheral nerves. This neural network sends and receives messages throughout the body. These communicate instructions for systems to follow.

The efficiency with which nerves transfer these messages depends on the brain’s neuroplasticity—the brain’s ability to create new neural pathways and remove ones that are no longer needed. This allows the body and mind to adapt to changes in the environment or inside the body.

For this reason, a poorly functioning nervous system could lead to or worsen mental health conditions such as anxiety, depression, bipolar disorder, obsessive compulsive disorder, and attention-deficit/hyperactivity disorder, among others.

This complex system depends on nutrients to build proteins and create and maintain nerve fibers. This requires certain amino acids, minerals, fatty acids, and carbohydrates.

For example, omega-3 fatty acids can reduce inflammation in the nervous system and are used therapeutically to help manage many neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases. Omega-3s are found in fatty fish like salmon and sardines, as well as plant sources like walnuts, chia, and flax.

The Bidirectional Link Between Food and the Mind

As humans, our relationship to food is complex. Food can be nourishing, enjoyable, social, and soothing. For this reason, there is a bidirectional relationship between diet and mental health. This means that mood can influence eating habits, and in turn, eating can impact mood and psychological well-being.

When you’re not getting proper nutrition, you might feel very stressed in an otherwise mildly stressful situation. As a result, you may turn to less healthy foods for comfort or as a time saver to mediate the feelings.

Because this food is less healthy, it further reduces your ability to adapt to stress. This can create a vicious cycle of eating foods that can worsen anxious feelings.

A similar cycle can happen with depression. You may feel depressed and low energy, so you turn to soothing foods or those that don’t require any work. These are often high in sugar and low in nutrition. You may feel worse after eating the foods, perpetuating the circle of worsening diet and mental health.

A 2020 article published in The British Medical Journal hypothesized this relationship in three pillars and demonstrated their interconnectedness:

• Good quality diet – nutrition, limiting fast food, etc.
• Physical health – good insulin sensitivity, healthy cardiovascular system, healthy weight, etc.
• Mental health – better mood, less stress, lower risk of getting sick, increased cognitive function, etc.

Each of these impacts the other, creating a loop that can lead to worsening mental and physical health as well as diet. Improving mental health with nutrition comes down to breaking a negative cycle.

That’s exactly what the research shows is possible.

A 2019 study found that when people who have mental health challenges increase their fruit and vegetable intake, it reduces their symptoms.

Another study in 2022 looked at the effects of the Mediterranean diet on those with severe depression. In this 12-month randomized, controlled trial, the intervention group (those on the diet) saw a large 20.6-point reduction in depression symptoms on the Beck Depression scale. A 6.2-point reduction was observed in the control group (not on the diet).

The Mediterranean diet is built around a variety of whole foods rich in fiber, vegetables, fruits, legumes, healthy fats, and fish. It includes very minimal, if any, ultra-processed food.

While this diet has gained popularity, many diets around the world apply similar principles of eating a diet filled with a variety of whole foods and very few ultra-processed foods.

Western Diet vs. Traditional Diets

Traditional diets are diets that humans have been eating for hundreds or, in some cases, thousands of years. Throughout human history, these eating patterns have been built around a variety of nutrient-dense whole foods and meals prepared from scratch.

Conversely, the Western diet, sometimes called the Standard American Diet (SAD), is a newer invention. It’s built around convenience foods that no longer resemble whole foods, even if whole foods are on the ingredient list.

These highly processed foods are produced in factories and scientifically engineered to be extremely tasty and easy to overeat. They tend to be high in sugar and crave-inducing chemicals. At the same time, they are very low in fiber and other nutrients.

An estimated 73% of the U.S. food supply is ultra-processed, and yes, there is a clear indication that these foods are bad for mental health.

The Limits of the Western Diet

While it’s called the Western diet, this way of eating is not exclusive to the “West.” It has been exported throughout the world. Its name also doesn’t suggest that everyone in the West eats this way. It only indicates its origin and popularity in Europe, the U.S., and Canada.

Western society is highly dependent on processed foods because they’re accessible and taste good. Many people in Western countries did not learn to cook or even prepare easy-to-make, less-processed meals. For at least the past several decades, much of Western society has prioritized convenience and tastiness over nutrition.

This is not to say that nutritious foods don’t taste good or can’t be convenient. Instead, it shows that taste and convenience have been taken to an extreme. As a result, countries where the Western diet is dominant are seeing increased rates of physical and mental health conditions.

Foods that are high in sugar and low in fiber cause your blood sugar to spike and fall suddenly. This can lead to low energy, extreme hunger, and cravings for high-sugar, quick-energy foods soon after eating.

As a result, ultra-processed foods often replace more nutritious convenience foods like fruit, vegetables, and nuts. In the diets of some, highly processed food also takes the place of healthier meal options.

Ultra-processed foods can also lead to the development of a compulsive habit, where you continue to do something that you know is harming you but feel helpless to stop doing it. That helplessness is not because you lack willpower.

The sugar and chemicals in ultra-processed foods impact dopamine, another neurotransmitter. Dopamine is responsible for helping us form habits—for better or worse. For example, the use of hard drugs like cocaine and heroin leads to addiction by triggering dopamine release.

You can stop this cycle by managing your consumption of ultra-processed foods and learning to prepare more nutritious snacks and meals.

Health Benefits of Traditional Diets

Have you heard of the Mediterranean, Costa Rican, West African, Nordic, or Okinawan diets? These are all traditional ways of eating that have been shown to promote health and longevity.

The diversity here suggests that you don’t have to eat one way to improve your nutrition and mental health. You have options and can find an eating pattern that works for you.

With that said, these diets do have some things in common.

For example, black beans and corn are staples in the Costa Rican diet. In the Okanawin diet, you consume more soybeans and whole rice. The Mediterranean diet includes white beans, chickpeas, and lentils with whole-grain bread or pasta.

These are all diets based on legumes and whole grains.

Furthermore, the Okinawan, Mediterranean, and Nordic diets each prefer fish over other kinds of meat. The West African and Okanawin diet both rely heavily on tubers of orange and purple sweet potatoes, respectively.

And finally, all these diets make up the bulk of their meals with a variety of whole plants, including significant amounts of fruits and vegetables. These eating patterns include a lot of fiber and nutrient-dense food.

The Rise of Nutritional Psychiatry

Not long ago, the connection between diet and mental health was not well understood. Some traditional medicinal practices, like Ayurveda of India and what is commonly called “Ancient Chinese Medicine,” a health practice in many Asian countries, have long believed that what someone eats can impact physical and mental health.

However, Western medicine only saw a vague link of little significance until more recently.

Science did not yet know a mechanism that explained the correlation, so the nutrition component was dismissed by many. Psychiatric researchers have developed medications to directly influence brain chemistry, along with behavioral therapies such as dialectical behavior therapy (DBT).

It wasn’t until a 1998 study showed a strong multi-national correlation between fish consumption and lower rates of depression that more researchers began to start seriously studying diet and mental health.

This paved the way for many of the other studies previously mentioned. Each study is increasing our understanding of diet and mental health.

Many mental health experts see nutrition as an integral part of preventing the onset and worsening of mental health conditions and therapeutically managing the symptoms.

Nutrition’s Role in Mental Health Research

Various research studies highlight the connection between nutrition and mental health conditions such as depression, anxiety, and ADHD.

A 2014 randomized, controlled study found that reducing inflammation by increasing omega-3 intake could prevent some kinds of depression.

A 1993 study on blood glucose (sugar) levels found that when they systematically lowered human participants’ glucose levels, counter-regulatory hormones such as cortisol caused them to feel more irritable and anxious.

Eating a diet lacking nutrition causes the body to struggle to regulate blood glucose through a process known as insulin resistance. This can lead to elevated and severely low glucose levels and may contribute to anxiety in some people.

A 2018 randomized, placebo-controlled study hypothesized that providing certain vitamins and minerals to children with ADHD could improve aggression and emotional regulation.

The results found a clinically significant 47% of the experimental group improved “much” or “very much” compared to 28% of the placebo group. 32% compared to 9% improved in the area of attentiveness. They also saw greater improvements in aggression and the ability of the child to function compared to the placebo group.

Diet vs. Dieting

While prioritizing nutrition is beneficial for mental health, it’s important not to take it to extremes that could lead to unhealthy behaviors or dangerous outcomes.

“Diet” generally refers to the overall pattern of what you eat on a regular basis, reflecting your daily food choices. It’s a lifelong approach to nourishment, focusing on a balanced intake of nutrients for overall health. On the other hand, “dieting” often implies a temporary and restrictive approach aimed at achieving specific weight or health goals.

Choosing a healthy and balanced diet, rather than following short-term diets, promotes sustained health and vitality.

How Unhealthy Eating Can Lead to Eating Disorders

Dieting can lead to constantly thinking about food, feeling deprived, and struggling to control eating habits. Restricting your diet or other unhealthy food behaviors can lead to eating disorders and negatively affect your physical abilities, mood, concentration, and daily activities.

An eating disorder is a condition in which a person cannot maintain a balanced and healthy relationship with food. Depending on the condition, they may not eat enough, eat too much, or overly manage the calories they take in or put out.

People with eating disorders may also try to “control” their food, overexercise, develop rituals surrounding mealtimes, or refuse to eat with others. These are just a few examples of the ways eating disorders can manifest.

The overarching image of an eating disorder is an obsession with weight and appearance above health. People with anorexia, bulimia, binge eating disorder, and other eating disorders often come to see themselves as physically unappealing in ways that do not reflect reality.

If you think you or a loved one may have an eating disorder, reach out to a health care professional and/or a trusted outside resource. The best thing you can do if you’re concerned about yourself or your loved one is to get help immediately.

Is Your Diet Affecting Your Mental Health?

More research is needed to determine the best ways to combine nutrition and mental health treatment into the optimal diet. However, the number of well-conducted studies points overwhelmingly toward the importance of nutrition.

Future research may reveal more targeted and personalized methods doctors can use to systematically improve their patient’s mental health, but for now, those struggling with mental illness may find that following general nutritional guidelines can have a positive impact on their mental health.

Improving mental health nutrition requires a commitment to enhance your overall diet. At this time, no pill, powder, or supplement can replace that. It’s important to strive to get most, if not all, nutrition from real food.

Anyone looking to improve their mental health through a more nutritious diet should always start first by talking to their physician.

Changing your diet is a big decision. You may face societal, physical, emotional, and mental challenges. It will be easier to stick with changes if you know with relative certainty that specific foods or food components improve or worsen your mental health. How can you know?

Start a Food and Mood Diary

For a select period, such as four weeks, track everything you eat and drink. Log your mood each day or the severity of mental health symptoms if you’ve been formally diagnosed.

At the end of the period, review your data to look for patterns that could help you see a connection between your diet and your mental well-being.

Eliminate or Add One Thing Systematically

Your best strategy is to pick something that will be a significant change. For example, if you already avoid added sugar, completely eliminating it may not have much of an impact.

If you live with depression or anxiety and do not usually eat fatty fish, consider eating fish two to three times a week for four weeks. If you cannot eat fish because of dietary restrictions, choose plant alternatives.

Then, track your symptoms each day. Over time, do you notice a change in your mood?

Adding or removing one thing is a great way to transition into a new dietary pattern. You might choose to keep doing what you’re doing after the test period has passed because you feel better. Then, keep adding or subtracting foods to improve your nutrition and mental health further.

Take a Break From Fast Food and Ultra-Processed Food

This one will take a little more planning if you’re currently very dependent on ultra-processed foods. Plan ahead to have a nutritious alternative during this time.

Some people might benefit from getting nutritious whole food-based meal kits for a week or working with a supportive friend to learn to prepare some healthy, easy-to-make meals.

Continue to track your symptoms to note any changes in mental well-being when the foods are absent or reduced in your diet.

Reach Out for Help

If you are thinking about making major changes to your diet, it’s important to consult with your primary care physician (PCP) or seek assistance from a trained dietitian. This will help you to ensure you are making healthy choices.

Moreover, if you or a loved one are struggling with mental health symptoms, it’s important to seek help from a trained health professional. You can talk to your PCP about this too, or reach out to a mental health facility like McLean.

Mental health services can include a focus on nutrition, but may also require attention to addressing acute symptoms first.