The growing area of research known as nutritional psychiatry examines how the food choices we make influence our mental state and behavior. In addition, because studies have shown a connection between food, inflammation and mental illness, this rapidly evolving science also focuses on how doctors can use food and supplements to help treat mental health disorders.

A related area of inquiry is the exploration of the equilibrium between good and bad bacteria in our digestive system, or gut, which scientific evidence confirms can affect digestive function, inflammation in our bodies and mood and energy levels. 

Elisa Shankle, co-owner of HealHaus, a wellness center and café in Brooklyn, learned this fact the hard way. She now knows that healthy bacteria benefit the gut, which regulates many bodily functions. “If bacterial balance in the gut is off, toxins can seep into your organs and bloodstream,” says Shankle. “This is why it’s important to keep your gut bacteria under control and as neutral as possible.”

When she was in her 20s and worked in a stressful corporate setting, Shankle suffered from depression and anxiety. “I was also dealing with something called candida, an overgrowth of yeast that happens in your gut,” she explains. “It’s usually a reaction to a lot of your healthy flora being killed off. It happened to me because of antibiotics I was taking at the time. These meds really messed up my gut bacteria, but I didn’t really know what was happening. I was just having all these digestive issues.”


In addition to getting therapy for her depression, Shankle started going to a naturopathic doctor who advised her to begin an elimination diet. The objective was to stop consuming any substances, such as gluten, sugar and alcohol, that might be overloading her system with yeast. “That was when my life changed,” she recalls.

At the same time, Shankle began to study healing herbs. “I started making my own teas and tinctures for anxiety and depression,” she says. “But when I changed my diet, that’s when my depression started to lift.”

Shankle hasn’t suffered from chronic depression since. “I owe a lot of that to changing my lifestyle, my work environment and the foods I ate,” she explains.

Certified nutritionist Mindy Lu, founder of the website, agrees that taking antibiotics may lead to depression. “These medicines have a tendency to wipe out our gut microbiome, which is where most of our neurotransmitters related to mood are created,” she explains. “Lately, there has been significant research about just how responsible neurotransmitters—such as serotonin and dopamine—which are produced largely by our gut microbiome are for mood. That’s why it’s really important to have a healthy gut system.”


Lu advises people to avoid strict eating regimens. “In my experience, [these kinds of] diet plans increase anxiety for people and often lead to disordered eating,” she says. “I try to encourage people to listen to their bodies and mood.”

Additionally, she believes food deprivation can contribute to depression. “Without nourishment, our brains and bodies have difficulty processing information, finding motivation and functioning in a way that feels balanced and healthy,” she says.

“Food cannot be reduced to ‘what we eat equals how we feel,’ but it is a very layered relationship,” Lu continues.

“Oftentimes, it’s not just about what we eat but how and when we eat it and what else we eat it with. For example, caffeine’s impact on the body is quite complicated. When consumed throughout the day in large amounts, this stimulant can increase anxiety and depressive symptoms—from the inevitable crash—and influence sleep quality. However, an individual’s body will respond to caffeine differently depending on their tolerance for it, if they ingest it with other foods, how active they were that day, what their stress level was, etcetera. That said, I have noticed that caffeine and sugar seem to impact people’s moods the most.” 

While Shankle eliminated such inflammatory foods as dairy, she incorporated fermented foods and probiotics into her diet to increase healthy gut bacteria.

“Generally, individuals have experienced an improvement in mood when incorporating probiotics into their diet,” Lu says. “Probiotics as a whole food can include miso, live-culture yogurt, sour cream or kefir, or fermented veggies, such as sauerkraut or kimchi. In addition, you can find probiotics in supplement form in grocery stores.”

Lu has discovered that probiotics seem to help lessen the effect of antibiotics on people’s moods. “If individuals go the supplement path, I encourage them to rotate different brands to diversify the probiotic strains in their digestive systems,” she says. “The reason for this is because most of our neurotransmitters are created by the microbiome that lives in our gut and is essential to nurturing people’s moods.”

Additionally, Lu suggests incorporating prebiotics, in the form of fruits and vegetables, which probiotics need in order to thrive.

Sugar can also put folks at risk for depression and anxiety, says Trudy Stone, a certified culinary nutritionist. “People who are depressed have low levels of the hormone serotonin, 90 percent of which is produced in your gut,” she says. “If you have poor gut health due to eating too much sugar, you’ll run into issues with important gut functions, such as serotonin production, in addition to digestion and immune cell formation. “Also fluctuating blood sugar, especially when your blood sugar crashes, can trigger anxiety attacks,” she adds.

Stone recommends eating certain foods to reduce cravings for sweets. “Avocados are a great source of healthy fat that will help to beat sugar cravings and also help to improve your mood,” she says.

“As for food that’s added to help with moods, I just ask people to make sure they are getting grains and proteins in all their meals throughout the day,” Lu says. “I have noticed a large improvement in people who integrate an afternoon snack that includes both a grain and protein.”

In addition, Lu advises eating meals and snacks that include all food groups throughout the day. For example, consuming proteins and grains at all three meals (breakfast, lunch and dinner) and as part of snacks may help with anxiety—particularly in the afternoon.


“Depression can often feel like fatigue—or vice versa—so I also encourage people to make sure they are well-nourished throughout the day,” Lu says. “One nutrient that I focus on is protein because neurotransmitters are all made from amino acids, which are proteins. To make sure our bodies have everything they need to make neurotransmitters, we need to make sure we supply the protein they need.” 

Lu doesn’t believe any foods should be completely eliminated from one’s diet. “I’ve found that that is not sustainable,” she cautions. “Who wants to cut sugar out of their lives completely?”

Still, the standard American diet (the acronym, appropriately, is SAD) is “lacking in many vitamins, minerals and nutrients that are important for the brain to function well,” Stone observes.

She notes that a study in the British Journal of Psychiatry found that consuming processed foods, such as refined carbohydrates, increases the risk of depression by 60 percent. Other findings show that a good quality diet is key to preventing mental disorders.

Lu suggests that people simply notice how their bodies feel after they ingest foods with ingredients such as caffeine and sugar. “Then make decisions based on the data you collect,” she says. “This is a way for us to have ownership over these foods, not the other way around.”

Meals and Moods

Some nutrients affect how we feel.

Trudy Stone, a certified culinary nutritionist, believes certain foods, such as eggs, fish and dark leafy greens, are key to brain health and can help regulate our mood. “Our brain cells depend on certain nutrients, and when we don’t get them, we don’t function as well,” she says.

The following are some of the powerhouse substances found in the foods we consume:

B Vitamins

“Vitamin B-12 and others in this family of nutrients help to produce brain chemicals that affect mood. A B-12 deficiency causes irritability and depression,” Stone says. “Vitamin B-6, in particular, helps manufacture neurotransmitters, such as serotonin, which aids in the body’s ability to cope with depression, stress and anxiety.”


“Known as the antistress mineral, magnesium eases your nerves and mind and has been used to treat clinical depression. A deficiency can lead to fatigue, insomnia, anxiety and depression. Almost 70 percent of the U.S. population is deficient in magnesium,” Stone says. “Studies show that there is a greater prevalence of magnesium deficiency among African Americans compared with other populations.”

Vitamin D

Also called “the sunshine vitamin, this nutrient helps improve mood and relieves anxiety and depression.”


“Iron is vital for creating the mood-regulating neurotransmitters serotonin and dopamine,” Stone notes. “An iron deficiency can cause extreme fatigue, irritability and mood swings.”

Omega-3 Fatty Acids

An omega-3 deficiency has been associated with bad mood, cognitive decline and poor comprehension.


Findings show that lower levels of zinc are associated with mood disorders, including depression.