The human brain works 24/7, meaning it requires constant fuel. Our brains get this fuel from the food we consume, but not all food is created equal. The quality of our meals has a direct impact on the structure and function of our brains, as well as our mood.
In a recent post, Eva Selhub, MD, a physician of internal medicine and a contributing editor to Harvard Medical School's Harvard Health Blog, likened the fuel the brain needs to the fuel a car needs. Like an expensive car, the brain operates optimally when it gets premium fuel, or high-quality foods that are rich in vitamins, minerals and antioxidants. Similarly, like a car, your brain can be damaged if you ingest low-quality fuel.
Here are three ways your diet affects your brain and mood.
1. Examples of low-quality fuel include foods that are processed or high in refined sugars. These foods worsen your body's ability to regulate insulin and they also contribute to inflammation and oxidative stress. According to Dr. Selhub, multiple studies have identified a correlation between a diet high in refined sugars and impaired brain function, as well as worsening symptoms of mood disorders such as depression.
2. The digestive system is closely linked to emotion. About 95 percent of serotonin — the neurotransmitter that helps regulate sleep and appetite, mediate moods and inhibit pain — is produced in your gastrointestinal tract, which is lined with millions of neurons. The production of neurotransmitters like serotonin by neurons is influenced by the billions of "good" bacteria in your gut. What you eat has a direct impact on the amount of "good" bacteria in your intestinal microbiome, versus the "bad" bacteria, according to Dr. Selhub.
3. Studies have found people who take probiotics — supplements that contain good bacteria — improve people's anxiety levels, perception of stress and mental outlook, compared to those who did not take probiotics, according to Dr. Selhub. Other studies have compared "traditional" diets, such as the Mediterranean and Japanese diet, to a typical Western diet, and have found the risk of depression is 25 percent to 35 percent lower in those who eat a traditional diet. Researchers say this is because traditional diets are high in vegetables, fruits, unprocessed grains, fish and seafood, and contain little dairy and meat. In contrast, a typical Western diet is high in refined foods and sugars.