How Depression & Gut Bacteria Are Connected - Ask a Nutritionist

Transcript:

Kara: Welcome to “Ask a Nutritionist”. This is our weekly mini episode of Dishing Up Nutrition. I'm Kara Carper. I'm a Licensed Nutritionist and a Certified Nutrition Specialist. Today we're diving into a fascinating topic. It's getting a lot of attention in both nutrition and mental health research, and that is the connection between depression and gut bacteria.

You may have heard people say things like trust your gut or listen to your gut feeling. Well, science is starting to show that your gut may actually influence your mood, emotions, and mental health more than we once believed. Now, if you've been listening to Dishing Up Nutrition for a while, you've probably heard us talk about how food affects brain health

Today we're diving even deeper into that idea by exploring how bacteria that live in your gut may influence your mood, your emotional health, and risk for depression. This is a really exciting area of research and it's helping us understand why nutrition can play such an important role when it comes to mental health.

Basics of the digestive system

So let's start with the basics. Inside your digestive system lives a massive community of microorganisms, mostly bacteria called the gut microbiome. Now, trillions of bacteria live inside our gut, and they play an essential role in overall health. These bacteria help with not only digesting food, but also making vitamins, supporting your immune system, and protecting your gut lining.

But here's where things get interesting. Your gut microbes also interact with your brain. We now refer to this relationship as the gut/brain axis, and it's essentially a two-way communication network between your digestive system and your central nervous system.

Your gut sends signals to your brain through several pathways, one of those being neurotransmitters produced by gut bacteria. Yes, gut bacteria actually produce neurotransmitters, otherwise known as those chemicals that influence your mood. You've probably heard terms like serotonin, dopamine, norepinephrine, and GABA.

So how does this relate to depression? Research over the past decade has found that people experiencing depression often have different gut microbiome patterns compared to people without depression. And studies show lower diversity of beneficial bacteria and higher levels of inflammatory microbes.

This is how nutrition comes into play because healthy dietary patterns are going to support healthy bacteria. And of course, the more healthy bacteria we have, that's going to support our feel good neurotransmitters. For example, you may have heard of serotonin as our feel good neurotransmitter. Serotonin helps to regulate mood, sleep, appetite, and emotional balance, so you can see how all of those things are closely related to depression if someone is low in serotonin.

Here's the surprising part, about 90 to 95% of the body's serotonin is produced in the gut, not in the brain. Gut bacteria influences serotonin production, which means that the health of your microbiome affects how much serotonin you're producing. And here's some fascinating science.

Researchers conducted a study. They transferred gut bacteria from people with depression into laboratory animals. The animals began showing depressive like behaviors and symptoms, which suggested that gut microbes themselves may influence mood regardless of other factors.

Other research has found that improving gut bacteria through diet alone, or with supplementing specific probiotic strains that that can help support mental health in some people. Now, this doesn't mean to downplay the complexity of depression, which is influenced by many factors, including genetics, life experiences, stress, sleep, and overall health.

But what the research is showing is that gut health is one important piece of the puzzle. There's so much to talk about when it comes to gut health, but our topic in this episode is primarily focused on that bacteria connection to depression. Now, all this being said, let's talk about how to support the good bacteria to thrive.

The good news is that diet and lifestyle habits that support a healthier gut microbiome are the same habits that support overall mental health. And you may be surprised to learn that some of the most powerful foods for supporting mental health aren't fancy supplements.

Prebiotics support gut health (& where we get them)

They're everyday foods that feed that beneficial bacteria in your gut. Let's start with prebiotics. Prebiotics are fibers that act as a fuel for those good bugs living in your digestive tract, so again, they're a type of fiber and they're found most commonly in foods such as garlic, onions, apple skins, unripe bananas, oats, legumes, asparagus and flax, and chia seeds.

And while your body can't digest these fibers directly, your gut bacteria can. And when they break down, prebiotic fibers, they produce compounds that help reduce inflammation, strengthen that gut lining, and again, support the gut/brain axis, that critical communication path between the gut and the brain.

So when you regularly include prebiotic rich foods in your meals, you're not just feeding yourself, you're feeding the beneficial bacteria that helps support a healthier, more balanced brain and mood. I also like to suggest adding a scoop of fiber powder. It's called Sun Fiber, into your daily routine, and that just gives an added boost of prebiotic fiber; tends to be very well tolerated compared to some other fiber supplements that might cause gas and bloating.

Include fermented foods &/or probiotic supplements

Next, we want to include fermented foods. Fermented foods contain live probiotics, which are the good bacteria to support the gut/brain axis. Fermented foods can actually increase microbiome diversity and reduce inflammatory markers that have been linked to depression.

Here's some common examples of fermented foods: plain yogurt with live cultures, plain kefir, another fermented dairy beverage; sauerkraut look for sauerkraut that's naturally fermented. Just cabbage, salt and water. Kimchi: it's a spicy Korean cabbage dish. Miso, a fermented soy paste, often made into a soup. And tempeh, which is also fermented soy.

Try to include at least one serving of those foods per day. I also recommend supplementing with a probiotic to boost that population of good bacteria in the gut. Probiotics can help restore balance to the gut microbiome, especially after factors like stress, illness, poor diet, or antibiotic use, because all of those factors can disrupt healthy bacteria in the gut, particularly if you've had a recent surgery;

And like I said, needed antibiotics or anesthesia or a lot of pain medications, narcotics, things like that, it's really important to replenish that good bacteria that's been lost in the process. And I mentioned earlier that people suffering from depression tend to have a different gut bacteria profile. That specific population in those who are depressed, it's often lower levels of bifidobacterium and lower levels of lactobacillus, which is one reason that those are two strains that are well studied and used as part of a supportive treatment plan.

If you're looking at different probiotic supplements, finding one that is multi-strain can be really helpful to diversify the gut bacteria and incorporate some of the bifidobacterium and lactobacillus.

Food dos and don’ts to support the gut microbiome

Getting back to diet, and this one might be the most influential when it comes to diet and mental health. Reduce highly processed foods. Highly processed foods are gut disruptors. Diets that are high in ultra processed foods, excess sugars, refined carbohydrates, and artificial sweeteners and chemicals have been associated with lower gut microbiome diversity.

Remember, we want that diversity and our real food message that we always talk about here on Dishing Up Nutrition, it's about much more than just the scale and weight. The quality of foods that you eat affects the bacteria in your gut, which affects every part of your health and how you feel. You can think of the gut microbiome like a complex ecosystem similar to a rainforest or coral reef.

In a healthy ecosystem, many different species live together, and each one plays a role in keeping the system balanced and functioning well. Your gut works the same way. Trillions of bacteria interact with each other and with your body to support digestion, immune function, and even brain health.

The foods you eat act like the resources that shape the ecosystem. A diet of high fiber foods rich in colorful antioxidants, high quality clean animal proteins and natural fats provide the nutrients that allow beneficial microbes to thrive and maintain that diversity.

But when the diet is dominated by ultra processed or highly processed foods and added sugars, it's really disruptive to that ecosystem. Certain microbes can overgrow kind of like weeds in your garden while other beneficial microbes disappear, and that can reduce the resiliency of that ecosystem.

So just like in a rainforest, you know, it depends on the diversity of good resources. A healthy gut depends on that same premise, the diverse microbiome that we get when we're eating nourishing foods and avoiding ultra processed foods.

And I see that when working with clients, when they start eating more of a real food, whole food diet and cutting out processed foods and added sugars, pretty quickly, they'll start to notice improvements in mood and energy and digestion, sometimes within a few days.

Realistically, I would say once you focus on a real food diet and cut out processed foods, you'll see digestion improve within a week or two, and you may notice signs of reduced inflammation and within a month or two you should notice consistent improvement with moods being more stable and balanced.

Lifestyle habits’ relationship to gut health & mood

Finally, I want to mention stress and sleep. Believe it or not, your gut bacteria are influenced by more than just what you eat. So chronic stress, poor sleep, and sedentary habits can all disrupt that gut microbiome. Prioritizing daily movement, quality sleep, and stress management can help support the microbiome and the gut-brain connection.

Although the research on the gut microbiome is still evolving, one thing is very clear. Our gut health and brain health are deeply connected. What we eat doesn't just fuel our bodies or make us gain or lose weight. It also feeds the trillions of microbes living inside of us, and those microbes can influence how we feel mentally and emotionally.

Supporting your gut through nourishing foods, balanced meals, good sleep and stress management can be a powerful step towards supporting mental health. And while good nutrition is important for mental wellbeing, depression is a medical condition that deserves proper care and support from multiple angles.

And nutrition is just one piece of a larger approach to mental health. But what's exciting is that the research on the gut microbiome is opening up new ways to understand how our bodies and minds are connected. The idea that caring for your gut might also support your mood, it's just a powerful reminder that mental health and physical health are deeply intertwined.

If you've been struggling with mood, brain fog, or digestive issues, working with a licensed dietitian or nutritionist can help you explore how nutrition could support your health.

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At Nutritional Weight & Wellness, we believe that real food is powerful medicine. And that small changes in what you eat can make a meaningful difference in how you feel. I'd like to thank you for joining me today on Dishing Up Nutrition. If you enjoyed this episode and found it helpful, please be sure to share it with a friend or a family member. Hope you have a great day.​