Anxiety and depression are mental health issues that have increased exponentially over the past several decades. Antidepressant medication distribution has nearly doubled in less than 15 years (JAMA) and has become the third most common drug prescription in America (CDC). Furthermore, nearly 18% (~40 million) of the American adults suffer from anxiety disorders which are now some of the most common mental health issues in the United States. There are many theories on why mental health issues such as anxiety and depression have skyrocketed such as societal and economic changes. A less recognized etiology of these escalating mood disorders is poor nutrition. We often tend to think of our brains and our body as two separate entities. But what if you could improve your mental health by changing what you eat? I am going to preface this post by saying, please, do not toss all of your medications at once, thinking a diet change will cure all of your problems. My point is to consider nutrition as a tool to manage anxiety and depression alongside psychological therapy and prescribed medications. Like most nutrition research, there is still a lot we do not know about the connection between food and brain chemistry. However, there is a growing body of evidence that suggests a clear relationship between nutrition and the development, treatment, and avoidance of mental health issues. Additionally, there are certain foods that exacerbate symptoms of anxiety and depression and certain diet changes that have been shown to mitigate them. So how is my diet affecting my mental health?
Standard American Diet (SAD)
Let’s start by addressing the elephant in the room: the standard American diet (AKA the SAD diet). Most of us are raised on sugary cereals, goldfish crackers, chicken nuggets, frozen pizza, and macaroni & cheese. Even the health conscious parents succumb to the “organic”, “healthy” versions of these processed foods. Then we grow up and add caffeine and alcohol.
The combination of processed carbohydrates, toxins, and lack of proper nutrition produces inflammation, oxidative stress, and impaired gut health. These effects of poor diet have been shown to induce depression and anxiety by decreasing the neurogenesis (the increase of neurons) of the hippocampus which is the part of the brain responsible for mood regulation. Hippocampal neurogenesis is of interest because the adult brain is limited in its capacity to create new neurons. In fact, the hippocampus is one of two segments of the adult brain with ongoing neuronal proliferation. The SAD has also been shown to decrease an important neurotrophin (a group of proteins that promote growth, adaptation, and survival of neurons) called brain derived neurotrophic factor (BDNF) which is thought to regulate the increase of neurons in the brain. Those diagnosed with depression actually have decreased hippocampal volumes than those without depression. Putting this is into perspective, while we often feel as though sugar makes us feel better because of its acute effect on serotonin we are actually intensifying our mood disorders. Sugar does, in fact, increase serotonin. However, sugar also causes your body and brain to become inflamed, which as we talked about earlier can lead to decreased brain chemicals leading to anxiety and depression. Even though sugar provides a short lived “high”, the long term effect on your mood caused by your chronic go-to processed food vice is significantly problematic. Aside from causing brain inflammation and affected brain chemistry, irregular blood sugar can cause symptoms that may provoke underlying anxiety.
Before we go into how to adjust our diets for better mental health, let’s take a closer look at the brain-gut connection.
The Brain-Gut Connection
If you haven’t noticed by now from my other blog posts, gut integrity, and prevention of dysbiosis is really important to your overall health. Mental health is not to be excluded. We’ve already discussed quite a bit in previous blog posts regarding the effect of gut bugs on hunger regulation and food cravings. They are also extremely influential in mood regulation. Gut integrity and microbiome balance are greatly impacted by what you eat and more importantly for this post, how you feel. The brain and the gut are so interrelated that it’s hard to determine what came first, the sick gut or the sick brains. The gut is often called the “Second Brain” because of its pervasive neuronal network. Your gut is lined with about 100 million neurons. This is more than your peripheral nervous system or your spinal cord. These neurons make up their own nervous system, the enteric nervous system. This complex neural structure allows food to be digested, nutrients to be absorbed, and waste to be discarded. Your brain and your gut are in constant communication with each other. Just think about how your stomach hurts before and/or during something stressful like taking a test. Your brain is responsible for the regulation of gastric juice secretion, intestinal blood flow, and intestinal peristalsis. Brain activity is stifled when you are stressed, anxious, or depressed and therefore all these gut functions are negatively affected which can lead to “bad bacteria” overgrowth. Small intestine bacterial overgrowth (SIBO) causes the systemic inflammation which not only affects your body but also, as discussed above, your brain. Heavy stuff. To recap: strong negative emotions such as anxiety or depression can lead to an overrun of bad bacteria which then leads to chronic inflammation which then causes anxiety and depression. SIBO also increases food cravings for refined carbohydrates and decreases absorption of what little nutrients your diet is providing. Decreased intake of nutrient rich foods, paired with decreased absorption of nutrients can lead to nutrient deficiencies that are correlated with anxiety such as Omega-3 fatty acids, vitamin D, zinc, b vitamins, and magnesium. This will be a never ending cycle of food cravings, dysbiosis, nutrient deficiency and mood disorders.
To add another nail in the coffin, your gastrointestinal tract is responsible for creating nearly 95% of your serotonin. Serotonin the neurotransmitter that we often associate with being happy (and if we do not have enough of it, being depressed). Serotonin is also influential in regulating anxiety. Many antidepressant and anti-anxiety medications work by manipulating this chemical. Long story short, if your diet is full of processed carbohydrates and gastric irritants (for example french fries and beer), those good bacteria will be suppressed along with their ability to aid in nutritional absorption and production of Serotonin. This is one of the many reasons that depression and obesity tend to go hand and hand.
Eating for Mental Health
Many reject the importance of eating a healthy diet. With depression and anxiety on the rise, it is crucial that we consider our diets as a possible cause and a probable reprieve. The evidence is continuously suggesting that what we eat not only affects our gut health which regulates our moods but also directly affects our brain chemistry. Just as there are certain foods that derail our mental health, there are foods that can help heal the gut, replenish good bacteria, improve levels of key neurochemicals and reverse nutritional deficiencies. The literature often utilizes the Japanese or Mediterranean diets as comparisons to the “western” or American diet. These comparisons consistently reveal a decreased risk of anxiety and depression in traditional diets versus the American way of eating. These diets are high in fruits and vegetables, essential fatty acids, and fermented foods and are very low in processed foods.
Our goal with eating for depression and anxiety should be to decrease foods that disrupt our microbiome and our blood sugar balance. Decrease foods that increase inflammation, dysbiosis and neurodegeneration such as processed foods (especially refined carbohydrates), alcohol, and caffeine. You may also want to decrease foods that you may be intolerant to such as wheat, dairy, or even grains. A good rule of thumb is to take these foods out for a few weeks while keeping a food diary. Track what you eat and how you feel physically and emotionally. Add foods back into your diet one at a time and note how you feel with each addition. In terms of controlling SIBO, elimination diets like the GAPS diet (Gut and Psychology Syndrome diet) with the avoidance of starchy vegetables is not backed by science. However, we are seeing that the low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) diet approach is beneficial as a short term intervention. For more information on FODMAPs, this is an easy to read explanation from Standford Univeristy (See Here). It may be helpful to work with an Registered Dietitian during any type of elimination diet.
Eating at regular intervals to maintain blood sugar is another important diet adjustment to consider. Studies have shown that blood sugar regulation promotes a feeling of “calm” and decreases the onset of anxiety. Your diet should ideally include, fermented foods and/or probiotic supplement, vegetables, fruit, fatty fish, lean protein, nuts, and seeds. These foods support gut health, decrease inflammation, reduce oxidative stress, and stimulate neurogenesis (growth and adaption of your brain). Some studies show that eating foods high in Omega-3 (salmon, walnuts, and flax seeds), foods high in antioxidants (berries, fruit, and green leafy vegetables), and fermented foods (kombucha, kimchi, and sauerkraut) decrease inflammation in the body and brain, support gut health, and promote brain health. Including foods that support healthy levels of Serotonin might also be beneficial. Serotonin is derived from tryptophan which is an essential amino acid. Essential amino acids, unlike non-essential amino acids, must be obtained from food sources and can not be made in the body. Including foods that are high in tryptophan such as turkey, chicken, eggs and green leafy vegetables may help improve serotonin levels.
Eating a healthful diet will not necessarily provide 100% alleviation of mood disorders in the same way it will not 100% prevent the onset of cancer. However, as you can see, the diet has an extremely impactful role in the development and continuation of depression and anxiety. It is important to understand that having a piece of cake once in awhile is not going to negatively impact your body or your mind. It is what you eat day in and day out that is going to have the largest influence. Moreover, you certainly do not need to make all of these changes at once. Slowly make changes over time, focus on foods that nurture your body, practice stress management techniques and work with a mental health professional. As always, if you need assistance putting these concepts into practice, I am more than happy to support you.
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