In my opinion, standard anti-depression drugs, SSRIs (selective serotonin reuptake inhibitors), are way over-prescribed even as more recent research has cast doubt on just how effective they really treating milder or moderate cases. And yet I know that a lot of my patients, a lot of my readers and just a lot of people are suffering the emotional after-effects of the pandemic. Some of them are thinking about going the pharma route to combat the depression and anxiety. My recommendation: before you reach for the pills, consider the plate, that is, the food you eat every day. It can have a major, and all too often, underappreciated, effect on your mood. Why? A lot of it has to do with the role of the bacteria in your gut, the microbiome, which play crucial role in maintaining your emotional well-being. Feed the good bugs in your belly what they want, they, in turn, will take care of you. Here’s the topline of what you need to know about the microbiome and your mental health – and how to use food to help them both:

Calling on your “happy chemicals”.

The neurons in the brain are responsible for producing neurochemicals like serotonin (which makes us feel contented) and dopamine (which produce lively, pleasurable feelings) and GABA (which lowers anxiety). Well guess what? The gut produces those same brain chemicals and the bacteria that live in the gut are essential cogs in the assembly line. The gut and brain are connected by the vagus nerve, which allows the brain to affect the way the gut feels (we’re all familiar with “butterflies in the stomach”) and the gut to affect our moods and emotions. We have fascinating studies that show, for instance, when you introduce the gut bacteria of a bold mouse into a timid mouse, you provide the mouse equivalent of a dose of courage. These kind of experiments are more difficult to pull off in humans but psychiatrists have observed for years that the onset of emotional disorders is often accompanied by, or preceded by, gut problems. The same out-of-balance gut bacteria that cause, for instance, IBS symptoms, are likely implicated in the emotional disturbance. It’s hard to know whether the emotional issues cause the gut problems or the other way around, or both. What I do know is: clear up your gut health, pump up the production of happy brain chemicals and your brain will thank you.

The stress connection.

The best recent research suggests that an out-of-control stress response plays as big, or bigger role, in depression as an imbalance in brain chemicals (i.e., too little serotonin), undercutting the idea that the SSRI drugs are the be-all-and-end-all when it comes to treating the problem. And, what do you know, gut bacteria are involved the production of the body’s primary stress hormone, cortisol. The gut-stress connection works both ways. A gut bacteria balance that is off-kilter because of a poor diet (usually the number one culprit) may help generate excess cortisol. Or, the brain tells the adrenal glands to produce a lot of cortisol which then alters the gut environment in such a way as to favor the “bad” bacteria that help promote that “stressed-out” feeling. The take-away: if you can reduce excess stress — by meditation, yoga, long walks, a warm bath before bed, whatever works – you’ll be doing your gut a favor which in turn will do wonders for your emotional equilibrium.

Immunity against mental health problems?

The microbiome can profoundly affect mental health via the immune system. A diet low in plant fiber and high in high-carb processed foods gives you a gut that lacks a diversity of bacterial species. And a gut with a depleted microbiome is more likely to contribute to food allergies and sensitivities, for instance, overreacting to the gluten in grains, triggering a systemic inflammation that can manifest as depression, anxiety, or “brain fog.” A subpar microbiome can trigger inflammation in a different way. When the good bacteria aren’t properly fed, they don’t ferment enough compounds (so called “short-chain fatty acids”) to help protect the lining of the gut wall, increasing the risk of “leaky gut” – microscopic bad guys leak through the wall into the bloodstream creating the inflammatory havoc that, once again, can be felt at the brain level.

The prebiotic prescription.

If you want to make friends with your microbiome, feed them plenty of vegetables. Human gut cells can’t digest plant fiber but the “good” bugs thrive on it. Veggies like asparagus, broccoli and onions contain a compound called inulin, basically a bacteria superfood. (If you have a sensitive gut, you may to go slowly and build up your tolerance – overactive bacteria can cause gut distress.) Pretty convincing proof that a well-fed microbiome protects mental as well as gut health? An Oxford research team fed study subjects a prebiotic powder every morning and measured lowered stress levels at the end of the three-week study than at the beginning.

The probiotic solution.

Another way to safeguard your mental health, besides tending to the care and feeding of your resident “good” bacteria, is to bring some new strains on board, preferably by eating fermented foods like sauerkraut and kimchi, or by taking a probiotic supplement containing a broad spectrum of helpful bacteria, millions of CFUs (colony-forming units) of them. An intriguing UCLA study fed one group of women a cup of yogurt, containing live bacteria, twice a day for a month and compared them to a group who didn’t get the yogurt. The yogurt-eaters showed subtle changes in their brain function, as shown in brain scans, and reacted more calmly when they were shown images of facial expressions.

Eating for a happier brain.

Fortunately, there’s not one way to eat for brain health and another way to eat for, say, heart health. A good diet is a good diet across the board: focus on whole plant foods like veggies and low-sugar fruits like berries, preferably organic or farmers’ market; protein, be it plant or animal; and healthy fats (after all the brain, is mostly fat). There is a nice body of research showing that omega 3 fats – small, oily fish are the richest source – can pump up “good” bacteria and lower the risk of emotional disorders. One family of antioxidant compounds, the polyphenols, provides an impressive gut bacteria boost, so feel free to load up on herbs and spices, green tea, and flax. When it comes to microbiome and mental health-friendly supplements, besides probiotics, I recommend vitamin D and B6 and B12, as well as magnesium. Studies have found that seniors are especially vulnerable to the emotional and cognitive effects of low levels of these essential helpers.

Nutritional psychiatry – the wave of the future?

That we have good evidence that a healthy gut can protect a healthy mind, and vice versa, is amazing enough. But the latest research is uncovering tantalizing links between bacterial strains and hard or impossible to treat psychiatric and neurological conditions. A team of Belgian researchers looked at over a thousand people suffering from depression and found their guts were lacking in two particular bacterial strains. Other work has turned up clues that specific bacteria may be playing a role in autism and Parkinson’s disease. I have a feeling that our growing understanding of the gut microbiome will, one day, help lead us to cures. Here’s to food as nature’s medicine.