There is a clear link between your dietary choices and your health. What you put in your mouth can have significant implications for your brain and mental health specifically. Research analyses looking at multiple studies support that there is a definite link between what you eat and your risk of depression. One analysis concluded:
A dietary pattern characterized by a high intake of fruit, vegetables, whole grain, fish, olive oil, low-fat dairy and antioxidants and low intakes of animal foods was apparently associated with a decreased risk of depression. A dietary pattern characterized by a high consumption of red and/or processed meat, refined grains, sweets, high-fat dairy products, butter, potatoes and high-fat gravy, and low intakes of fruits and vegetables is associated with an increased risk of depression.”
The Brain In Your Belly
It’s a relatively recent scientific discovery that the bacteria living in your gut influence your overall physical health and your mental health too. Science confirms that your microbiome directly impacts your brain, and in turn, your mental health and behavior.
The bacteria inside you eat what you eat, and turn food into molecules that influence your brain through what’s known as the “gut-brain axis.” What goes into your mouth affects the bacteria inside you and, in turn, your health in a surprisingly short period of time. One study found that the bacteria in peoples’ guts shifted within three to four days of a major diet change.
From the time food hits your mouth and as it moves through your gastrointestinal tract, it’s causing a cascade of changes in your body and brain. In addition to the brain in your head, you also have a brain in your gut, called the enteric nervous system. This second brain consists of a network of some 500 million nerve cells and 100 million neurons – equivalent to about the size of a cat brain – lining your gut, esophagus to anus. Just like the brain in your head, the brain below uses over 30 neurotransmitters including dopamine and serotonin. In fact, the bowels contain 95% of the body’s serotonin.
Depression and Your Gut
Your gut and brain are closely connected and communicate directly with each other through the gut-brain axis. This gut-brain connection is a bidirectional highway that transmits critical data between the GI tract and the brain. It is made up of neurons, hormones, and proteins.
Scientists are learning that a big part of your emotions and mental health is influenced by the gut-brain through information carried from it to your head via the vagus nerve. It runs from your neck to your abdomen connecting internal organs to the brainstem. It’s the body’s major parasympathetic nerve responsible for basic functions, like the gag reflex, slowing the heart rate, controlling sweating, regulating blood pressure, stimulating the gastrointestinal tract, and controlling vascular tone. The vagus nerve is a physical pathway between the gut and brain. The gut-brain axis is a chemical pathway.
Living in your gut are tens of trillions of micro-organisms making up part of your unique microbiome. We’ve always known these little guys play a major role in digestion, allergies, and metabolism, but now we know that the bacteria in your gut aid in the production of vitamins and neurotransmitters and greatly influence your immune function. Science has also uncovered connections between intestinal bacteria and anxiety, depression, autism, Alzheimer’s disease, and other mental disorders.
Dietary Habits inked to Depression and Anxiety
In the article, “5 Dietary Habits connected to depression and anxiety“, the authors write:
In February 2019, researchers in Korea published a study in the Journal of Nutrition and Health, showing a connection between diet and mental health.
The researchers recruited over 3,500 participants for their study, all of whom were over the age of 65. They then analyzed their dietary information, addressed their anxiety and depressive states, and split them into two groups: those with anxiety and depression and those without.
They made quite a few findings as they compared diet and mental health between the two groups.
- Men who ate alone were more likely to have depression and anxiety than those who ate with others.
- Women who ate the evening meal less frequently were more likely to have depression and anxiety.
- Men who ate less—particularly less fish, shellfish, seaweed, mushroom, oils/fats, and seasonings—were more likely to have depression and anxiety
- Men who had poorer nutrient intake generally were more likely to have depression and anxiety
- Women and men who ate less dietary fibre, riboflavin (B2), niacin (B3), potassium, iron, and vitamin C were more likely to have depression and anxiety.”
Foods That Correlate with Depression
Science is proving that nutrition is a highly underrated lifestyle factor that can markedly improve some mental health disorders. A large body of evidence now exists suggesting that diet is as important to mental health as it is to physical health. There is strong evidence that poor diet is connected to depression.
One study from Lancet Psychiatry confirmed that nutrition is a significant component of the high prevalence of common mental health disorders like depression. The quality of a person’s diet is a determining factor in both physical and mental health. The reason is simple; a human brain requires certain nutrients to function properly and stay healthy.
Science has confirmed the positive effects of healthy nutrition on mental health beyond any doubt. The Nutrition Journal published a paper showing that the prevalence of mental health disorders has significantly increased in developed countries in correlation with the Western diet.
Whether you want to ease a current depressive state or prevent one in the future, you can help your mental health and mood by reducing the following foods in your diet according to the book This Is Your Brain on Food by Uma Naidoo, MD, a nutritional psychiatrist at Harvard Medical School:
Science shows that the more sugar you eat, the more likely you are to be depressed. In science, a perfect correlation is one. Researchers almost never hit this mark. In one study, the correlation between eating sugar and having depression was .95, and this proved true in six countries!
There are a couple of reasons sugar might cause depression:
Your brain relies on glucose, a form of sugar, from the food you eat to function. So, it is not all bad. The problem is too much sugar is harming our brains. Over a 24-hour period, your brain needs around 62 grams of glucose. In 2012, the average adult daily intake of sugar in the U.S. was 77 grams per day. This excess sugar can lead to inflammation in the brain which may result in depression.
Research also shows that high blood glucose levels are linked to lower levels of brain-derived neurotrophic factor (BDNF). BDNF is a key molecule involved that plays an important role in the maintenance and survival of neurons and in synaptic plasticity. Several lines of evidence suggest that BDNF is involved in depression, and BDNF is decreased in depressed patients. Other research found that people with glucose metabolism problems – pre-diabetics and diabetics – have low levels of BDNF. Those levels decrease as sugar metabolism worsens.
Consistently eating added sugar begins a chain of events in your body that reduces BDNF, and lower levels have been shown to contribute to insulin resistance which leads to Type II diabetes and metabolic syndrome (high blood pressure, high cholesterol, coronary artery disease, and many other health problems. Low BDNF levels are linked to depression and dementia and may be a critical factor in Alzheimer’s.
High Glycemic-Load Carbs
Your body processes high carbohydrate foods in much the same way as sugar. However, the type of carbs you eat matters greatly here because it determines how quickly your body breaks the food down into sugar. The glycemic index (GI) is a measure of that.
There are better-for-you carbs, which rank lower on the GI scale, and high-GI carbs which your body converts into glucose quickly resulting in a blood sugar spike. Simple carbohydrates, like potatoes, white rice, and white bread, are high-GI foods. Green vegetables, most fruits, beans, and lentils are low-GI foods.
In order to lower your risk of depression (and many other health conditions), you want to aim for a diet high in low to middle GI foods with an emphasis on good sources of whole grains and fiber. But, you do not want to overindulge in low-GI foods either, which can contribute to a high glycemic load and correlate with depression and all the other mentioned adverse health conditions. The bottom line is that you want to aim to lower your overall glycemic load by choosing good carbs in healthy amounts.
Artificial Sweeteners – Especially Aspartame
Artificial sweeteners, such as saccharin, aspartame, sucralose, erythritol, lactitol, maltitol, sorbitol, xylitol, and stevia are promoted as healthy alternatives to sugar. And while they do not cause the glycemic spikes that sugar does, they do have varying effects on the brain. Several studies implicate artificial sweeteners in depression because they alter brain concentrations of mood-regulating neurotransmitters.
Aspartame: Very common in sugar-free food products, especially sugar-free gums and drinks. Research shows that aspartame acts as a chemical stressor by elevating plasma cortisol levels and causing the production of excess free radicals. High cortisol levels and excess free radicals may increase the brain’s vulnerability to oxidative stress which may have adverse effects on neurobehavioral health.
Sucralose (also known as Splenda): Sucralose is an artificial sweetener that is popular in sugar-free products, especially sugar-free drinks. When the body breaks down sucralose, it releases toxic chemicals as part of its chemical bond with chlorine. Neurological side effects of prolonged sucralose consumption may include nerve damage, headaches, dizziness, anxiety, depression, tinnitus, and brain fog.
It was disheartening for me to discover that even stevia had some potential brain issues. Researchers found that it affects pleasure centers in the brain of animals that chronically ingested small amounts. Low-dose intake of stevia reduced enzyme activity that affected dopamine gene expression in the brains of rats lowering the dopamine-reward system activity in the brain. Studies in humans showed diminished dopamine activity in the brain as well.
One study raised the possibility that artificial sweeteners in diet beverages may increase the risk of dementia and stroke. It compared people who didn’t consume diet drinks with people who had at least one per day. Researchers found that diet soda drinkers had three times more strokes and were three times more likely to develop dementia. Consumption of regular (non-diet) soft drinks was not linked to a higher risk of these brain problems. Even when other factors were considered, like age, gender, diet, smoking, and physical activity, the results did not change.
Fried and Processed Food, Nitrates, and Bad Fats
Studies show that people with diets high in fried and highly processed foods, saturated and trans fats, and nitrates tend to score worse on tests measuring cognitive skills. These foods can cause inflammation in the brain, which can damage the blood vessels that supply the brain with blood.
Highly Processed Foods
According to the Science Daily article, Feeling anxious or blue? Ultra-processed foods may contribute to depression and anxiety:
More than 70 percent of packaged foods in the U.S. are classified as ultra-processed food and represent about 60 percent of all calories consumed by Americans. A study in 10,359 adults 18 and older found those who consumed the most ultra-processed foods as compared with those who consumed the least amount had statistically significant increases in the adverse mental health symptoms of mild depression, ‘mentally unhealthy days’ and ‘anxious days.'”
In a study published in Public Health Nutrition, researchers reported that people who consumed higher amounts of ultra-processed food had more adverse mental health symptoms.
“The ultra-processing of food depletes its nutritional value and also increases the number of calories, as ultra-processed foods tend to be high in added sugar, saturated fat, and salt, while low in protein, fiber, vitamins, minerals, and phytochemicals,” said Eric Hecht, M.D., Ph.D., author of the study and associate professor in Florida Atlantic University’s Schmidt College of Medicine.
Fried Foods and Bad Fats
When it comes to depression, it can help to reduce the number of fried foods you eat. Foods cooked in unhealthy fats, which almost all fried foods are, contribute to depression. Not all fats are bad though. The human brain is approximately 60 percent fat. To function optimally, your brain needs to maintain this level of fat.
Your body’s cellular integrity and nutrient exchange depend on fats. Your cells would literally collapse and starve to death without them. Cholesterol, unsaturated, and even saturated fats are all crucial to vital bodily processes. It’s important for you to give your body the different kinds of fats it needs in the right amounts.
Fat is your brain’s friend.
Your brain needs essential fatty acids (EFAs) to function properly. Because your body can’t produce them, you have to get EFAs from your diet. The two primary EFAs are linoleic acid (omega-6) and alpha-linolenic acid (omega-3). You get omega-6 mostly from plant oils such as corn, soybean, and sunflower, as well as from nuts and seeds. Omega-3 fats are especially important for improving brain function, inflammation, and vision among many other things. A variety of nuts, seeds, and marine foods, such as fatty fish, shellfish, and algae, contain Omega-3s.
Omega-6 fats from vegetable oils — like their cousins, the omega-3 fats from fish — are good for the heart and brain. However, the typical American diet contains 14 to 25 times more omega-6 fatty acids than omega-3 fatty acids. You need both in the right balance. An overabundance of omega-6 fats has been proven to lead to diseases involving inflammatory processes such as cardiovascular disease, obesity, IBD, rheumatoid arthritis, cancer, and neurodegenerative and psychiatric illnesses, such as Alzheimer’s and depression.
Bacon, salami, and sausage are examples of cured and deli meats that contain nitrates as a preservative. Studies show they may be connected to depression. One study even showed they can alter gut bacteria in a way that may encourage bipolar disorder.Share this article!