Most replayed moment: Reduce anxiety by improving your gut health | Uma Naidoo

Summary

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Podcast Summary: ZOE Science & Nutrition

Episode: Most replayed moment: Reduce anxiety by improving your gut health
Host: Jonathan Wolf (ZOE)
Guest: Dr. Uma Naidoo, Harvard Nutritional Psychiatrist
Date: March 24, 2026

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Episode Overview

This episode examines the profound connection between gut health and mental health, with a special focus on how supporting your microbiome can reduce anxiety and improve emotional wellbeing. Dr. Uma Naidoo, a leader in nutritional psychiatry, explains the latest research on the gut-brain axis and provides actionable, evidence-based strategies for listeners looking to take charge of their mental health—with simple changes to diet and lifestyle.

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Key Discussion Points & Insights

The Gut-Brain Axis: Science & Mechanisms

• The Microbiome and Mental Health

  • Dr. Naidoo details how the gut houses trillions of microbes that not only assist digestion, but are also crucial in the production of neurotransmitters like serotonin and GABA, both fundamental to mental wellbeing.
  • Quote [00:46], Dr. Naidoo:
    “The trillions of microbes that live in our microbiome, in our gut, as they're helping with the process of digesting our food, their breakdown products are also in the same environment as 90 to 95% of serotonin receptors.”
  • 90-95% of the body’s serotonin receptors are found in the gut, not just the brain, highlighting a major link between what we eat and how we feel.

• Neurotransmitters Beyond Serotonin

  • The gut also influences levels of GABA, an inhibitory neurotransmitter associated with relaxation and anxiety reduction.
  • Quote [03:45], Dr. Naidoo:
    “We found in a research study that a certain type of bacteria is associated with GABA production. And this type of bacteria's name is Bifidobacterium adolescentis. When the production... is low, GABA is low and anxiety is high.”

• Inflammation’s Role in Anxiety & Depression

  • A major UK Biobank study showed those with anxiety and depression had higher levels of inflammatory markers (interleukin-6, C-reactive protein).
  • Inflammation in the gut, influenced by poor diet and ultra-processed foods, may contribute to these mental health challenges.

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Practical Advice for Reducing Anxiety via Diet

Introducing the “SAW” Method

Dr. Naidoo presents a simple 3-step mnemonic (SAW) for lifestyle changes:

• S – Swap:
  Replace one unhealthy food habit with a healthier alternative.
  E.g., swap nightly ice cream for a fruit-based version.

  • Quote [05:32], Dr. Naidoo:
    “Swap at least one unhealthy food habit that you have.”

• A – Add:
  Introduce healthy elements—especially colorful vegetables, cruciferous veggies, and leafy greens—to your meals for antioxidants, fiber, and anti-inflammatory benefits.

• W – Walk:
  Incorporate movement, in any form that feels accessible (walking, Zumba, yoga, even just walking the dog), to help break the paralytic cycle of anxiety.

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Addressing Anxiety Around Diet & Dieting

• Food Anxiety From Restriction Mindsets

  • Many people feel anxious about their dietary choices due to pervasive “eat this, not that” messages and restrictive rules.
  • Dr. Naidoo recommends a more inclusive perspective:
  • Quote [08:39], Dr. Naidoo:
    “I argue against the ‘eat this, not that’ mentality as often as I can so that people feel they can embrace all foods. Maybe it's the quality and quantity of the food, the source of the food that becomes important.”
  • Focus on quality, the source, and making gradual, sustainable changes rather than labeling foods as 'bad'.

• Common Food Confusions

  • Example: Fruited yogurt as marketed in the US often contains as much as 6–8 teaspoons of added sugar per half-cup.
  • Advice: Swap to plain yogurt with real fruit and cinnamon for a healthier option ([10:10]).

• Emotional Roots of Food Anxiety

  • Restrictions can trigger anxiety due to how deeply intertwined food is with our primal human instincts and memories.
  • Quote [11:10], Dr. Naidoo:
    “Food anxiety is a very big thing... Understand you’re on a healthy path. Think about calming foods.”

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Bonus: Acronym for Calming Foods

Dr. Naidoo quickly shares her "CALMING" acronym for foods that help support emotional health and combat anxiety:

• C: Choline (eggs, legumes)
• A: Antioxidants
• L: Liquids (water, teas like chamomile or passion flower)
• M: More omegas (omega-3s), magnesium-rich foods

Encourages listeners to focus on what positive foods they can ADD, not what they must avoid.

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Notable Quotes & Memorable Moments

• [00:46] Dr. Uma Naidoo:
  “There’s serotonin in the brain and other parts, but there’s 90 to 95% of the receptors in serotonin production happens in the gut. So... as our food is being digested, it’s also in the same environment as where these neurotransmitters are being produced, where the receptors are located.”

• [03:45] Dr. Uma Naidoo:
  “When the production... of [Bifidobacterium adolescentis] is low, GABA is low and anxiety is high. So there’s all of these different connections... anxiety is not just one thing. The food you eat can impact these microbes and can thereby, over time, not always immediate, can impact your anxiety.”

• [05:32] Dr. Uma Naidoo:
  “Food is one of the things that can help you, including things like breath, work, exercise, and other things, even sunlight are important. I have three steps... I have the mnemonic SAW.”

• [08:39] Dr. Uma Naidoo:
  “I argue against the ‘eat this, not that’ mentality as often as I can so that people feel they can embrace all foods... you are trying to work on consistency, which is one of the biggest things that will help you.”

• [11:10] Dr. Uma Naidoo:
  “Food anxiety is a very big thing. And I feel like understand you’re on a healthy path... Think about calming foods because I have an acronym calming and I also add in foods based on that.”

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Timestamps for Key Segments

• 00:00 – 00:45: Introduction and overview of gut-brain axis topic
• 00:46 – 03:45: How the gut influences neurotransmitters and mood (serotonin, GABA, inflammation)
• 05:13 – 07:26: Dr. Naidoo’s “SAW” steps for improving anxiety through diet and lifestyle
• 07:26 – 11:10: Addressing anxiety about dieting; practical strategies to shift mindset and embrace positive food habits
• 11:10 – 12:28: The “CALMING” acronym—foods that support emotional balance

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Summary Takeaways

• Diet isn’t just about physical health—it’s intimately linked to mental health, especially anxiety.
• Support your gut health with a focus on fiber-rich, colorful, and whole foods.
• Don’t succumb to restrictive diets—embrace the addition of positive foods into your lifestyle.
• Remember SAW: Swap a habit, Add healthy foods, and Walk (move!) every day.
• If you feel anxious about diet changes, talk with a nutrition counselor and focus on consistent improvements over perfection.

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For practical mental health improvements via nutrition, shift your focus from restriction to the positive power of what you’re adding to your plate—and recognize that supporting your gut is supporting your mind.

Transcript

[A]

Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today, we're looking at a novel way to improve our mental health. If I've learned anything from hosting this podcast, it's just how interconnected all the systems in our body are. Nothing works in isolation, which means we often have to step back and look at the bigger picture if we want to improve a particular aspect of our health. With this in mind, let's shift our focus on mental health. Can we approach it from a different angle? Harvard nutritional psychiatrist Dr. Uma Naidoo is here to explain the science behind the gut brain axis and how you can help one to help the other.

[B]

Nutritional psychiatry, and certainly what I practice, nutritional, lifestyle, and metabolic psychiatry, is an evolving size. It's nascent, and there's new evolving evidence every single day. But what we do know is that the trillions of microbes that live in our microbiome, in our gut, as they're helping with the process of digesting our food, their breakdown products are also in the same environment as 90 to 95% of serotonin receptors. Now, serotonin is often called the happiness hormone. There's serotonin in the brain and other parts, but there's 90 to 95% of the receptors in serotonin production happens in the gut. So the linkage that I make that's been backed up by science is that as our food is being digested, it's also in the same environment as where these neurotransmitters are being produced, where the receptors are located. So we are therefore really understanding more and more that mental health is not this impact of just the brain. It's the brain in connection with the gut and other parts of the body.

[A]

And can you explain a little bit more, like, what is a serotonin receptor? And if it's in my gut, how's that linked to my brain? And how does that then make me feel different? I think I was brought up, you know, sort of stiff upper lip. Like, whatever happens in the outside shouldn't really affect how you feel. I think that the science doesn't really seem to support this as much now what is going on?

[B]

So I think the best way to think about it is in this way, the microbes, the microbiome is associated and anatomically, physiologically and biochemically connected to the brain through the vagus nerve, through the enteric nervous system, and through the transmission of these neurotransmitters. So serotonin exists in more than one place. When I said serotonin is the happiness hormone. Medications like selective serotonin reuptake inhibitors or SSRIs are the medications that are used to treat conditions like depression and anxiety, but they also manipulate serotonin. So think about it this way. Serotonin is involved in conditions like depression, anxiety and more. It's first line medication in mental health that people are prescribed. But, but food is also involved. And food is involved because it's being digested in the same place where the serotonin is being stored, manufactured and the receptors are located. And it therefore can mediate emotion through how those interactions happen as food is being digested. For example, if you are mostly eating ultra processed foods and sort of a poor diet, not only the breakdown products of that food are really gonna lead to conditions like inflammation in your gut. And studies of inflammation in actually a big UK Biobank study of more than 144,000 participants showed that participants who had anxiety and depression also had increased markers. And these markers were inflammatory markers, interleukin, sick and C reactive protein. So we know that inflammation is also involved. I want people to understand that there's this gut brain connection, there's the mechanism for how food is being digested. Serotonin is right there, as well as other neurotransmitters in that environment. Another neurotransmitter, for example, is gaba. And GABA is associated inhibitory neurotransmitter. It's also associated with anxiety, it's associated with the hippocampus, it's associated with the brain. Well, we found in a research study that a certain type of bacteria is associated with GABA production. And this type of bacteria's name is Bifidobacterium adelocentis. And when the production for whatever reason of that bacterium is low, GABA is low and anxiety is high. So there's all of these different connections. I mentioned serotonin because of those receptors, but there are also these other neurotransmitters. And it's a more complex way to understand that anxiety is not just one thing, that the food you eat can impact these microbes and can thereby over time, not always immediate, can impact your anxiety.

[A]

And uma, if someone's listening to this now, they say like, I'm sold, I wanna make changes. I am living with anxiety. Or even if it's not clinically diagnosed, like I feel like I have a lot of anxiety in my life. What is the sort of specific advice you would give thinking about food to someone who wants to make changes that would maximize the benefit.

[B]

If I could just also add to what you said, as I answer the question, that it may not be that you have a diagnosis, but you're feeling this way. And this is a very powerful tool that can help you. Food is one of the things that can help you, including things like breath, work, exercise, exercise itself, and other things, even sunlight are important. So I have three steps that I ask people to take and I have the mnemonic saw. So the one is swap. So swap one unhealthy food to get started. So maybe you started eating ice cream every night during the pandemic. Can you create a recipe that I have, for example, for ice cream made from fruit and swap that out, or can you start to eat less of it? So the first thing is swap. Swap at least one unhealthy food habit that you have. It may be that you're not drinking enough water, it could be that the second is add. So add in a healthy food. An easy way to start is adding in lots more vegetables, colorful vegetables to your diet. Things like colorful peppers, lettuces, greens, spinach, whatever it is you might like. Adding those in are low calorie. So cruciferous vegetables like cauliflower and broccoli and brussels sprouts, low calorie and can be added in to your meals that are both going to help you feel full, but they also giving your body nutrients and antioxidants and anti inflammatory substances that your body and your brain need. And the third W is walk. And by walk, I mean movement, exercise, a Zumba class, a yoga class, whatever appeals to you to get you going. Because remember, through the lens of mental health, someone who's anxious may not even want to take a walk. So getting them to take a walk, to buy the newspaper, get a cup of coffee, walk their dog, is a way to get them moving and move from that almost paralyzed state of feeling so anxious.

[A]

I'd love to talk about people feeling anxious about their diet and how they can avoid that. And I think it's particularly relevant on this podcast. Like most of the long term listeners to this podcast will be Zoe members. They'll have been paying for this personalized nutrition program that helps them to feel better and be healthier. And one of the things that we've discovered is that we have to spend a lot of time and effort to trying to sort of retrain people because they've been told that lots and lots of foods are off limits, that like these foods are bad and that sort of if they want to improve. It's all about sort of restriction, like calorie restriction, removing bad foods and the way that Zoe membership works. It's really all about focusing on adding things to their diet to be healthier. There's no calorie count, all of this. And also there's no, you know, one of the core ideas which comes from the. A lot of nutrition's have been involved in it is that sort of nature. No food is off limits. But what we find is that lots of people are still feeling really anxious about this even if they've been on the program for quite a while and they're feeling much better, I guess. What's going on around that? Anxiety about diet. And do you have any advice to anybody listening about how they can reduce that?

[B]

Well, I'll speak from the perspective of where I live in the US which is that we have a bay eat this, not that mentality which I argue against as often as I can so that people feel they can embrace all foods. Maybe it's the quality and quantity of the food, the source of the food that becomes important. We talked about sugar earlier on eating some berries or some, you know, a clementine, a mandarin. These are healthy choices as part of not only your fruit serving, but the fiber and other nutrients. Have faith that you're on the right path to trying to make things better. You may not be perfect, but you are trying to work on consistency, which is one of the biggest things that will help you. Discipline around your food will help you. The moment that someone starts to feel better, they want to do more of those healthy habits and that you can build on. If you're feeling anxious about the plan, maybe checking in with your nutrition counselor about it. What's driving that anxiety? Is it the quantity of food? Are you maybe not drinking enough water? Are you maybe eating something? Here's a common mistake that people make. I shouldn't say it's a mistake, it's more that they don't realize. For example, yogurt, rich in probiotics. Great food. Blueberries, delicious fruit. Great source of fiber and anthocyanins. Good for your diet. Fruited yogurt. So the fruit in the yogurt, not a good idea. Because in the United States a small half cup serving can have six to eight teaspoons of added sugar. So often someone might be eating something they think and have heard and read is healthy. But the food industry is not necessarily our friend and is labeling food in a way that you think it's healthy, but it's not because of those added sugars. A simple swap would be plain yogurt with berries and a sprinkle of cinnamon. Super delicious. You get all the benefits from every ingredient, including the cinnamon. So those types of things may be worth discussing with your counselor or whoever you speak to to check in about what's driving that anxiety. Or maybe it's that you have too much or too little food in your plan. It could be many different things. You know, I always take it back to when we were first, when we were first born. What happens when a baby is born. So if you've ever seen on television or you work in the ER or the labor and delivery, you know that you want the baby to cry, they take a deep breath and what happens next? Yeah, they clean them up and all of that, but they feed. So think about food as something very primitive. It's very primary to who we are as humans. And I think that when sometimes we're in situations where you can't eat this or there's a media report that you shouldn't eat that, it really drives anxiety. Like food anxiety is a very big thing. And I feel like understand you're on a healthy path. Remember sore swap, add walk. Think about calming foods because I have an acronym calming and I also add in foods based on that. So very quickly. C is for choline, choline is in eggs and legumes. A is for something like antioxidants, L is for liquids, calming teas like passion flower or chamomile, liquid water, very important. And M is more omegas and magnesium. So many more foods on every letter of the list. But just very quickly think about foods you can start to add in that help that anxiety. So if you're on the plan and you worried about the plan, ask yourself why. Maybe it's something related to questions you have that are not answered or information you need. But you can also add in foods that could help you even more.

[A]

As you can imagine hosting this podcast, running Zoe, juggling family life, it all keeps me pretty busy. So I try as best I can to stay energized and show up well in all those parts of my life by fueling my body with the right food, by exercising, and by adding a scoop of daily 30 to my meals every day. If you haven't heard of Daily 30 yet, it's the gut supplement designed by our gut health scientists here at Zoe. It's made of over 30 high quality hand picked plants including seaweed, fungi and different types of fiber. Better yet, it contains ingredients that support gut, health, digestion and energy, which is ideal for packed calendars and busy lives. Simply add one scoop a day to any meal for an extra boost of fiber and plant diversity. And because it tastes delicious on just about anything and adds a satisfying crunch, it quite quickly slots into your life, becoming a daily healthy habit you'll always have time for. By the way, whenever we talk about Daily 30 as a good source of fiber, we're required to say that it contains 4 grams of total fat per serving. Obviously, that's all amazing healthy fats from plants, so order yours [e-mail] daily30. Thanks for listening and see you next time.

[B]

J.