Gut Health

Podcast with Healing Quest: “Probiotics for Depression” with Kiran Krishnan

Microbiologist Kiran Krishnan sits with the team from Healing Quest Radio to discuss new research documenting the power of probiotics to relieve psychological issues like stress and depression.

Read the interview below, or scroll to the bottom for a link to the live podcast. 

Judy Brooks: Hi, and welcome to Healing Quest. I’m Judy Brooks.

Roy Walkenhorst: And I’m Roy Walkenhorst. Our focus here on Healing Quest is holistic wellness and the latest in mind-body techniques to help us live longer, healthier and happier. First, from a study from McMaster University in Canada, published in the medical journal of gastroenterology.

Judy Brooks: This research showed that probiotics, those so-called good bugs that we’ve talked about here a lot on Healing Quest, cannot not only keep our GI tract and immune system healthy, but they may also relieve depression.

Roy Walkenhorst: You may have heard the phrase gut-brain connection, and that’s what this is all about. In fact, the study’s author says the research provides new evidence that the microorganisms in our intestinal tract are in direct connection with the brain.

Judy Brooks: Also, to help us understand all of that, we have with us today on Healing Quest Kiron Krishnan, who you may remember Karin from the interview we did with him several months ago after we returned from the Natural Products Expo in Anaheim.

Roy Walkenhorst: He’s the chief science officer for a new probiotic dietary supplement called Just Thrive. It got a lot of attention at Expo for its digestive benefits and also for its effectiveness in healing leaky gut syndrome and the inflammation that causes.

Judy Brooks: Well, he’s an expert on probiotics and the research being done on them all over the world, and he’s really good at putting the science into layman’s language, which I love that about him because he really helps you understand it. So when we saw the Canadian study, we asked Kiron to help us understand the significance of it. So welcome to the show, Kiron.

Roy Walkenhorst: We’re interested in this research out of McMaster University about probiotics and how it has an impact on depression. My first question is, the study involved doses of something called Bifidobacterium longum NCC3001. Now is that an essential ingredient for a probiotic that treats depression, or was that just what they used in their study?

Kiran Krishnan: What we’re seeing is that there’s a few different ways to manipulate the gut in order to get beneficial effects on cognitive health, whether it’s depression, anxiety, mood disorders, even things like ADD/ADHD. They all kind of go in the same realm of dysfunction within the gut. They happened to find a particular strain, and that strain number at the end is really important to indicate that that particular strain has an effect on anxiety and depression. What’s interesting is that there are other strains that have also been identified. For example, we work with spore-based probiotics. What the spores do is reduce leaky gut inflammation, which then also improves the cognitive benefit within the brain itself.

Roy Walkenhorst: So that would be the Just Thrive probiotic that I think Judy and I personally take and really feel like it’s benefiting us.

Judy Brooks: Yes.

Kiran Krishnan: Yeah, absolutely. Then a lot of it is just general dysfunction in the gut can lead to these cognitive behavior issues or mood disorders, again, both of which the dysfunctions are fairly similar. It starts with a disruption in the ecology, then an abnormal amount of inflammation in the gut and then the leaky gut. Then that all starts to snowball into mood disorders and so on.

Judy Brooks: In addition to depression, as one of the mood disorders you’re talking about, can probiotics actually help us deal with stress?

Kiran Krishnan: Absolutely. So there’s something called the HPA axis. It’s a fancy name. It’s called a hypothalamic pituitary adrenal axis, and it’s basically the communication between those three organ system in the body. That’s really what helps you deal with stress in life in general. When the imbalance of the communication between those three organ systems aren’t working the way they should, you have an inability to deal with stress. You produce excessive amounts of stress hormone, not enough of the happy hormones within the body, and the crazy thing is that whole axis is controlled by the gut and the gut bacteria.

Roy Walkenhorst: Well, how does the gut communicate with the brain?

Kiran Krishnan: The gut has direct contact with the brain that is completely independent of anything that we can do to stop it. So, for example-

Judy Brooks: Got a direct line, huh?

Kiran Krishnan: Absolute direct line, and it’s a two-way communication, which is really interesting. So our brain can talk to our gut, and our gut, in response, talks to our brain. There’s something called the enteric nervous system, so that’s the nervous system that coats the entire digestive tract. In fact, there’s more nerve endings in that enteric nervous system than in your spinal cord. So the density of nerves in that area is really, really amazing, and the microbes that live in your gut utilize all of those nerves to send messages through that enteric nervous system, an upper nerve called the vegus nerve which goes directly to the brain.

Kiran Krishnan: So think about it this way. Bacteria in your gut, regardless of your perceptions, your wants, your desires, if it needs something, for example, it’s a bad bacteria and it needs sugar, it can create a neurotransmitter, send it up that vegus nerve directly into your brain to make you crave sugar for its own purposes. That’s how amazing the connection is.

Roy Walkenhorst: Wow.

Judy Brooks: Sounds a little nefarious.

Roy Walkenhorst: Do we need to worry about GMO or pesticide contamination in probiotics?

Kiran Krishnan:That’s an absolutely critical question. I’m so glad you asked that because probiotics have tremendous amounts of benefits, but then if you’ve got contaminants in them, contaminants that are known to disrupt the gut ecology, then you’re kind of undoing any of the benefits that you could potentially have with the probiotic itself. So one of the main things is glyphosate. Glyphosate is the weed killer, the Roundup that they use basically everywhere in agriculture. Most production facilities have some contamination level of it. If that’s in the product, then you’re basically taking in a chemical that kills off bad bacteria along with your probiotic, and it also kills off good bacteria as well as bad bacteria along with your probiotic and causes more disruption that benefit. So very, very important to look for non-GMO. We’re now starting to get products that are being tested for glyphosate residue. (read more about glyphosate here and here)

Judy Brooks: Oh, that’s great. Well, I just have one more question, and then we have to wrap it up. But probiotics work in the intestines, but to get there, they have to survive the stomach acid. So how do they do that?

Kiran Krishnan: That’s really important. The stomach is a gastric barrier, and it’s a barrier against microbes in general. The vast majority of microbes die going through the stomach, so very, very few strains have actually adopted the capability to put an armor-like coating around themselves. So these are the spore-based microbes that we talk about a lot and we use in research. They put this armor-like coating around themselves which protects them through the stomach acid. When they get into the intestines, they pop out of that armor-like coating, and they go to work for you as a probiotic.

Roy Walkenhorst: Well, Kiran, thank you. We’ve been speaking with Kiran Krishnan, the chief science officer for and an expert on probiotics. He’s been helping us understand this really interesting new research about how probiotics can actually have a positive effect on all kinds of mental and psychological issues. If you want to learn more about the probiotics we’ve been talking about, we’ll have a link for you on our website,, or at Don’t forget a podcast of this and other Healing Quest shows are available at, on the iHeartRadio app and at


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