The Brain-Gut Connection: How to Improve Your Mood With Food

The Brain-Gut Connection: How to Improve Your Mood With Food

There are trillions of reasons to be happy. Many of them, it turns out, are in your gut.

The bacteria living in the digestive tract outnumber your human cells 10:1. You probably intuitively understand that keeping your microbiome healthy can improve your digestion and immunity, but most wouldn’t expect it to influence your mental health.

According to the  American Psychological Association, gut bacteria produce about 90% of the serotonin (the neurotransmitter regulating mood and impulses) in your body, along with neurochemicals that the brain uses to moderate physiological processes – including learning and memory.

This explains why people with gut issues like Irritable Bowel Syndrome actually have higher levels of anxiety and depression, and why a high fibre, plant-based diet can be part of the treatment for mental health issues.

So while you walk around, there are trillions of microbes hitching a ride with you. Every time you eat a meal, pet an animal, or put on cosmetics, you’re affecting the environment they live in. And this, in turn, impacts your psychological wellbeing. So let's look at a few ways you can keep them happy and improve your physical and mental health.


Regular physical exercise provides many health benefits, including protection against chronic disease and improved mental health. And if you follow a regular workout routine, you know that you simply feel better when you’re active.

The surprising thing is that this seems to be at least partially caused by the exercise modifying and improving your gut flora.

Scientists have proposed that physical exercise is able to modify gut microbiota in a way that promotes well-being. In other words, people who move more have a more diverse microbiome. Getting the recommended 150 minutes of exercise per week increases health-promoting bacteria in your gut, and, in turn, your well-being.

Eating behaviors

Cravings for foods high in fat and sugar are a fact of life for many people. Unfortunately, these unhealthy eating patterns can increase our risk for health problems like obesity, diabetes, heart disease and cancer.

Changing eating habits and fighting cravings is a challenge for most people. We tend to blame lack of self-control when we fail, but the reason might actually lie in the microbiome. In other words, your cravings might not be your own, but the cravings of your gut bacteria!

An evolutionary conflict is said to exist between human hosts and microbes in our gut, because those microbes in the gut may have differing food preferences than the host. And these gut microbes can manipulate the host’s eating behaviour in ways to promote their own fitness to survive – even if this is at the expense of the host's health.  

This is one challenge that arises from an otherwise symbiotic coexistence between our bacteria and us: the food preferences of the microbiome aren’t always in the best interest of the human host. The good news is that, just like the microbiome, cravings can be changed.

Strong resolve helps, but the real trick is replacing unhealthy food with plenty of food that promotes healthy gut bacteria, such as the whole (i.e. unprocessed) plants. It’s a positive reinforcement cycle that ultimately leads to healthier cravings, and with the right recipes, it can be just as delicious as the empty, junk food calories.

Plant-based Foods, Pre- and Pro-biotics

The most important nutrient your gut needs is fibre, which can only be found in plant-based foods, particularly those that are unprocessed or minimally processed. Plants literally give your gut microbes something to chew on.

Most people lack this important nutrient, but hardly anyone talks about it. Increase the fibre in your diet and you and your gut will start feeling happier right away. It’s a prebiotic, and even though it’s not digested, it promotes the growth of good bacteria.

Another great way to help your microbiome are probiotics. These are foods that actually contain healthy, or "good," bacteria, and can have beneficial effects when eaten in the right amounts. Once they’re inside your body, the good bacteria multiply and help keep your microbiome in balance.

5 Microbiome-Boosting Foods

  1. Sauerkraut, an Eastern European staple, is packed with probiotics. You’ll get the most benefits if you can find it unpasteurized, or make your own, because pasteurization kills some of the good bacteria. Please do ensure that you follow proper food safety procedures when preparing your own fermented foods.

  2. Sourdough bread is made with a fermentation process that uses a sourdough starter, which contains a probiotic called ‘lactobacillus.’ You can find it at farmers’ markets and most health food stores.

  3. Olives have serious probiotic potential. They are fermented and then cured with brine. It's the curing process that allows the probiotic cultures to multiply, making them a gut-healthy garnish for salads, pastas, and pizzas.  

  4. Kombucha is a slightly sweet and fizzy liquid that has been brewed for thousands of years. You can buy it or make your own. Kombucha comes from fermenting black tea with a mushroom-like colony called "scoby." There’s been a surge in popularity lately, so you're likely to find a variety of brands producing a range of flavors in your local grocery.

  5. Tempeh is a fermented soybean dish that originates from Indonesia. It’s firmer than tofu with a mild, nutty flavor and texture. It’s less processed than tofu, and thanks to the fermentation process, it’s a good source of probiotics.

Improving your microbiome and your mood is just one of the benefits of a whole-foods, plant-based diet. Try these simple shifts and you should start noticing the changes within a few weeks.

Written by Dr. Pamela Fergusson, RD, PhD.

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