Research shows that the food you eat can have a profound effect on your mental health. So, regardless of your mental health problem, the importance of addressing your diet simply cannot be overstated.

In a very real sense, you have two brains — one in your head, and one in your gut. Both are created from the same tissue during fetal development, and they’re connected via your vagus nerve, the tenth cranial nerve that runs from your brain stem to your abdomen.

It is now well established that the vagus nerve is the primary route your gut bacteria use to transmit information to your brain, which helps explain why mental health appears to so intricately connected to your gut microbiome — the bacteria and other microbes living in your gut.

For example, researchers recently found that fermented foods helped curb social anxiety disorder in young adults. Another study found that mice engaged in obsessive-compulsive repetitive behaviors were pacified when given a strain of the bacterium Bacteroides fragilis.

Gut bacteria also produce mood-boosting neurotransmitters like serotonin, dopamine, and gamma-aminobutyric acid (GABA). In fact, the greatest concentration of serotonin is found in your intestines, not your brain.

At the end of the day, if you’re trying to address your mental state, optimizing your gut health should be toward the very top of your list.

The Strong Link Between Sugar and Depression

A number of food ingredients can cause or aggravate depression, but the number one culprit is refined sugar and processed fructose, which feed pathogens in your gut, allowing them to overtake more beneficial bacteria.

Sugar also suppresses the activity of a key growth hormone in your brain called brain-derived neurotrophic factor (BDNF). BDNF levels are critically low in both depression and schizophrenia.

Diets high in sugar also triggers a cascade of chemical reactions in your body that promote chronic inflammation, which over the long term disrupts the normal functioning of your immune system and wreaks havoc on your brain.

Last but not least, refined sugar and processed fructose and grains are key contributors to insulin and leptin resistance, which also plays a significant role in your mental health.

One recent study found that high-glycemic foods (including those high in refined grains and added sugar) were associated with higher odds of depression.

Added sugar in particular was strongly associated with depression, reconfirming what William Dufty said in his classic best-selling book, Sugar Blues, first published in 1975. Sometimes it takes a while for science to catch up — in this case 40 years!