Mental illness is on the rise. In the US, the rate of suicidal ideation among adults has increased every year since 2011. Depression is also on the rise. Around 15.08% of youth in the US experienced a major depressive episode in the past year, a 1.24% increase from 2021. 1 Nearly one in five US adults live with a mental illness. 2
Currently, the healthcare system deals with mental health issues by following a certain medical model. Patients are offered psychiatric medications first, followed by therapies and other forms of support. In some cases, treatments such as psychiatric medications and psychological therapies save lives. However, looking at current mental health trends, the rate of mental illnesses is increasing instead of decreasing.
Some studies that examined the link between diet and mental health in the last decade have provided some strong evidence suggesting nutrition plays a critical role in mental health. But what exactly is the link between healthy eating and mental health? How does nutrition affect stress or depression? What types of food should one incorporate into their diet to improve their mental health?
According to nutritional psychiatry, the gut and the brain are closely linked both historically and physically, even though they are located at different locations in the body.
The historical connection between the brain and the gut begins in the womb, specifically in the developing embryo. In the developing embryo, the central nervous system is formed by special cells called neural crest cells. These cells move around the developing embryo, forming the enteric nervous system in the gut. The gut contains the largest collection of nerve cells in the body, somewhere between one hundred million and five hundred million neurons. Because of this fact many people call the gut "the second brain."
The two organs also share a physical connection via the vagus nerve, also called the wanderer nerve, which originates in the brain stem and travels to the gut, thus connecting the gut to the central nervous system. The nerve penetrates the gut wall and plays a critical role in the digestion of food and ensures that nerve signals travel back and forth from the gut to the brain in both directions. In other words, the brain needs the right balance of gut bacteria to produce the chemicals it needs to stay stable and healthy, and the gut needs the brain to be stable and healthy to maintain the proper balance of gut bacteria.
The link between food and mental health comes through the connection between gut bacteria and brain chemicals. Gut bacteria are responsible for making many of the brain chemicals vital for regulating mood, memory, and attention. For instance, 95% of serotonin is produced in the gastrointestinal tract. 3
The production of neurotransmitters like serotonin is influenced by the billions of "good" bacteria that make up the intestinal microbiome. In the absence of normal gut bacteria, the production of these neurotransmitters is impacted. Consequently, the deficit and imbalance of these chemicals can lead to a range of psychiatric disorders, such as depression and anxiety.
It has been found that some types of foods fuel the growth of helpful bacteria, while other types impede this growth. Eating foods high in vitamins and minerals, as well as complex carbohydrates and lean proteins, can help the gut produce healthier bacteria, which will encourage the production of all the neurotransmitters. Unhealthy food can do the opposite: cause the harmful bacteria to outgrow the good bacteria, causing a range of adverse health effects. For instance, high sugar intake can contribute to and worsen depression and increase the odds that depression will recur in a person's life.
Just as mental illness can increase the number of unhealthy bacteria in the gut, bad nutrition can cause a range of other problems as well.
There are several causes why one might be suffering from fatigue, and in many cases, food plays a critical role. One reason for fatigue is chronic low-grade inflammation. When the body is inflamed, less energy is available to the brain. To reduce inflammation, it is important to eat an anti-inflammatory diet. Foods that fight inflammation include fruits like cherries and strawberries, olive oil, green leafy vegetables like kale, and fatty fish like salmon.
Low magnesium levels can also contribute to fatigue. Increasing the levels of magnesium can increase one's energy levels. 4 Low zinc levels are also a hallmark of chronic fatigue syndrome, and increasing zinc can improve and prevent fatigue. 5
The lack of many vitamins is also connected with chronic fatigue syndromes, such as vitamins B6, B9, and B12.
One placebo-controlled study found that consuming glucose or table sugar can lead to a delay in completing cognitive tasks. Participants were divided into several groups and were given a drink that contained either glucose, sucrose, fructose (fruit sugar), or the placebo sucralose. According to the study's findings, participants who consumed glucose and sucrose were slower by up to 0.2 seconds in answering questions. 6
Poor nutrition can lead to poor decision-making. Some people who eat an unhealthy diet might experience a condition called brain fog, which is characterized by being unable to think clearly, having difficulty concentrating or multitasking, and losing short-term and long-term memory. Although the exact cause of brain fog is unknown, researchers believe it is due to excessive brain inflammation and can be alleviated by eating a whole-food-oriented diet.
Poor nutrition has also been linked with stress and depression. One 2002 study discovered a strong correlation between people who ate sugar and those with depression. 7 In 2019, a meta-analysis of ten previously published observational studies including 37,131 people with depression concluded that consuming sugar-sweetened beverages puts people at a higher risk for depression. 8
The gut plays an important role in cortisol release and is instrumental in making sure the body responds to stress effectively, which means that the wrong balance of gut bacteria can lead to a spike in cortisol.
Several studies have shown how nutrients and specific foods can positively affect a person's physiological, neural, and psychological stress response. One animal study found that eating a diet high in saturated fat and refined sugar leads to increased oxidative stress, which damages brain cells and reduces the efficacy of cell-to-cell communication in the hippocampus. 9
Additional studies have found that omega-3 fatty acid consumption normalizes abnormally low cortisol levels and protects against cardiovascular disease. 10 Consumption of fermented foods has been shown to be associated with reduced social anxiety. 11
Other population-based studies revealed that eating a whole food diet is associated with lower depression, anxiety, and stress, while a Western diet is linked with a higher risk of poor mental health. 12
Various studies, both older and more recent, have revealed the impact nutrition has on brain development. For instance, an early nutrient shortage can lead to a reduction in brain cell production, while later nutrient shortages can negatively affect cell size and complexity. It also seems like nutrient deficits can lead to less efficient communication between brain cells. Here is a more detailed explanation of how nutrition affects some of the most critical brain processes.
A 2019 study has found that obesity due to a poor diet can result in changes in cognitive control and the function of the prefrontal cortex and its impact on working memory. 13 Saturated fat can also worsen brain inflammation, which is linked to cognitive decline in aging and the risk of developing Alzheimer’s disease. 14
On the other hand, some studies have shown that a well-balanced diet can improve memory. For example, several studies found that fermented foods such as kimchi and kefir improve memory and slow cognitive decline. 15 Also, one 2009 study among elderly patients revealed that restricting calories by 35% improves memory. 16
Nutrition can also affect attention. A 2006 study found a connection between ADHD and celiac disease. Patients with celiac disease were more likely to have ADHD and following a gluten-free diet improved their symptoms over six months. 17 Eating a lot of dairy foods that contain casein has also been shown to worsen ADHD. Certain foods can improve the symptoms of ADHD. For example, several studies have found that ADHD responds well to the Mediterranean eating pattern.
Recent studies show diets rich in saturated fats impair learning and memory. High-fat and high-glycemic-index foods may cause changes in the brain pathways critical for learning and memory, especially affecting neurons in the hippocampus and prefrontal cortex. 18
Some foods have been found to improve brain health and performance as well, such as berries, citrus fruits, dark chocolate, nuts, eggs, and avocados.
One study examined the connection between milk proteins and thinking ability. It was discovered that patients who drank milk containing A1 protein made more errors on an information-processing test, had slower thinking, and suffered from more gastrointestinal inflammation. 19
It seems like even the scent of certain foods can improve thinking. One 2012 study examined the effect of rosemary on cognitive function and found the scent of a rosemary essential oil leads to better attention and executive function. 20
Other foods have been found to enhance memory and thinking skills, such as pumpkin seeds. Broccoli contains vitamin K, which enhances cognitive function, while fish has high levels of omega 3, which can improve mental clarity.
If you are looking for a new way to improve your diet, consider adding healthier foods that affect mental health positively. Healthy foods are those that have low amounts of saturated fat, added sugar, and sodium. They are also rich in vitamins, minerals, and other nutrients. Healthy foods will keep you energetic throughout the day, but they will also help you to lose weight, reduce cravings, and improve your overall sense of well-being.
Complex carbohydrates include whole grains, legumes, fruits, vegetables, and even some nuts and seeds. They get absorbed slowly, increase blood sugar less dramatically than simple carbs, and contain many nutrients. Eating complex carbohydrates can help with weight loss and lower the risk of developing cardiovascular problems.
Lean proteins are lower in calories and fat and will leave you feeling fuller longer. Incorporating lean proteins into your diet can help repair your muscles, maintain your nerve impulses, and keep your metabolism running smoothly.
Poultry, seafood, and grass-fed beef are all good choices of lean protein to ensure you are getting plenty of protein and the essential amino acids that your brain needs to function. Organic tofu and tempeh are great plant-based sources of lean protein.
Fatty acids are essential nutrients found in plant foods such as meats, dairy, eggs, and nuts. They can reduce symptoms of depression and anxiety, alleviate gut inflammation, and block the growth of cancerous cells. Some foods rich in fatty acids include fish, flaxseed oil, extra-virgin olive oil, chia seeds, walnuts, and avocados.
Vitamins are essential nutrients that are required in moderate amounts to support normal body function. Vitamins play an essential role in protecting the brain and supplying energy. Although you can take a multivitamin to help bolster your levels of many vitamins, consuming vitamins through natural sources is critical as well. To ensure you are getting all the essential vitamins through your diet, you must maintain a balance of meat, fish, fruits, and vegetables.
The human body needs minerals in order to function properly. Minerals are needed for proper heart and brain function and for the production of enzymes and hormones. Some foods that are rich in minerals include nuts and seeds, cruciferous vegetables, eggs, beans, berries, yogurt and cheese, tropical fruits, and leafy greens.
Good nutrition is key for a healthy mind. In addition to providing the body with the needed nutrients, eating well can also help reduce mental health issues such as stress and depression. A nutrient-rich diet can even improve brain function and performance. Fortunately, there are plenty of healthy eating tips you can incorporate into your daily life.
Going grocery shopping on an empty stomach may result in more impulse high-calorie food purchases instead of buying whole, nutritious, and satisfying foods.
Incorporate vegetables in a variety of colors into your diet to consume all the nutrients that are beneficial to your brain. The same applies to fruits. Even though you should eat different-colored vegetables, the most crucial color is green. Green, leafy vegetables such as kale and arugula are rich in vitamins, minerals, and fiber, but low in calories.
By cooking at home, you will know exactly what you are putting in your meals and will not have to wonder about any unhealthy ingredients. Cooking at home is also associated with a lower risk of obesity and improved diet quality. If you are eating out, consider switching your favorite fast-food restaurant with one that offers healthier options.
Eat at least three meals a day with small snacks in between. Eating large meals can lead to overeating, and waiting too long to eat between meals makes it more likely to make unhealthy food choices. Keep healthy snacks in your home or in your bag when you are out to avoid eating unhealthily.
Highly processed foods lack important nutrients such as vitamins, minerals, and fiber. Some examples of highly processed foods include hot dogs, chips, cookies, and frozen pizzas.
The three macronutrients that are essential to your diet are carbohydrates, fat, and protein. All three are critical for our body to function properly. At least half of the plate should contain carbohydrates, one-quarter of the plate should be filled with protein, and one-quarter with healthy fats.
Here at Genesis Recovery, we help restore the lives of individuals who have struggled with a mental health disorder or alcohol and drug substance use disorder. We do so by implementing a spiritually therapeutic treatment experience that combines four distinct elements that we believe are crucial for obtaining lasting sobriety:
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