Recommended Reading: What Is Tryptophan? Tryptophan: Benefits, Side Effects, and Food Sources
B-vitamins primarily affect neurotransmitter synthesis and transmission, assisting in emotional regulation and stability.
Recommended Reading: What Are the Benefits and Side Effects of B-Vitamins? A Comprehensive Guide to Vitamin B
Omega-3 (Mainly EPA)
Omega-3, particularly EPA, can help combat inflammation, neutralize oxidative reactions caused by free radicals in the body, and further improve mood.
Recommended Reading: What Is EPA? What Are Its Benefits? How Does EPA Improve Depression?”
However, is it enough to simply supplement with these anti-anxiety and anti-depression health products? In addition to the so-called ‘happy nutrients,’ there are many factors that influence mood. Diet, as a source of energy for the body, also affects mood through blood sugar, immune response, and gut microbiota. 
High Glycemic Foods Lead to Blood Sugar Fluctuations and Possible Depression
When we are hungry, we tend to become irritable and have decreased focus as our bodies signal us to eat. When we eat and our blood sugar rises, we tend to feel better and can continue with our activities. This is a normal body mechanism. However, foods that cause rapid spikes in blood sugar can also lead to quick drops, causing fluctuations in mood-regulating hormones and potentially resulting in depressive feelings. 
Poor Food Choices: Processed carbohydrates like sugary drinks and desserts. Remedy: Avoid processed carbohydrates and consume nutrients, such as B-vitamins, that support blood sugar metabolism.
Fatty Foods Leading to Inflammation and Mood Swings
Excessive saturated fats can stimulate cellular inflammation in the body and also affect the brain, resulting in decreased cognitive function, impaired short-term memory, and even an increased risk of mood disorders. Of course, bodily inflammation doesn’t necessarily lead to depression or anxiety, but randomized trials have found that anti-inflammatory drugs can alleviate depressive symptoms. Reducing inflammation in the body can indeed help improve mood. 
Poor Food Choices: Fried foods, fatty meats, refined bread, and other high-fat diets. Remedy: Adopt a low-fat diet or increase consumption of anti-inflammatory nutrients like Omega-3.
Low Fiber Foods Leading to Poor Gut Microbiota and Reduced Attention and Depression
The gut microbiota ecosystem has been proven to be one of the most significant factors influencing mood. The gut is rich in about 70% of the body’s immune cells, 90% of the so-called ‘happy hormones’ like dopamine and serotonin, and through the gut-brain axis, discomfort in the gut can transmit signals to the brain, causing negative emotions and discomfort in hopes of prompting the body to improve. 
For the gut microbiota to function effectively, it needs to form a balanced ecosystem.
Poor Food Choices: A diet that is too limited and lacks sufficient fiber intake. Remedy: Consume a variety of vegetables and mushrooms to increase fiber intake and supplement with probiotics to nurture a healthy gut microbiota ecosystem.