INTERVIEW BY KARINA GORDIN, MSc

Renowned cardiologist Steven Gundry, MD, has become one of today’s most influential voices in nutrition research—reaching millions worldwide through his bestselling books, podcast, and supplement line.

At seventy-five, he brings his insights into daily practice, maintaining a full patient schedule six days a week—translating cutting-edge science into care.

Over a glass of his signature “healthy soda”—a simple blend of sparkling water, vinegar, and a squeeze of lime—we sat down to discuss the surprising discoveries behind his newest book, The Gut-Brain Paradox.

Now, we invite you to pour yourself a refreshing, gut-friendly glass and join the conversation—cheers to good health.

Karina Gordin (KG): Dr. Steven Gundry, thank you for fitting in time between patients to share your insights with the Well Being Journal community—we’re grateful for this moment with you.

Steven Gundry (SG): Absolutely, my pleasure. Yes, I do keep a full patient schedule—even Saturdays and Sundays—and it’s still one of the most rewarding parts of what I do! New patients often ask why I’m still in practice, and the simple answer is, I learn something new almost every day. I get to see firsthand how research translates into real improvements in people’s lives—and then I can share those lessons with folks like you. So really, how could I not keep seeing patients?

KG: Exactly—and thank you for your continued work. What are one or two patient turnarounds you’ve seen over the past few years that stand out?

SG: I open The Gut-Brain Paradox with the story of a sixty-two-year-old physician and marathon runner diagnosed with Parkinson’s. When she first came to see me in 2023, she was experiencing the classic symptoms—pronounced tremors, stiffness, fatigue—and had been told, like so many others, that there wasn’t much hope beyond managing decline.

The medications prescribed by her neurologists hadn’t helped, and her symptoms continued to worsen. During our initial appointment, she remained seated, her face expressionless—a classic “mask of Parkinson’s.” Her speech was slow and halting so her husband did most of the talking.

We did a full workup and designed a treatment plan that centered on adjusting her diet, implementing a supplement regimen, and repairing her gut. The turnaround was remarkable. Within a year, her tremors eased, her energy returned, and she walked into my office with a big smile—a completely new person. Thirty years ago, I might have called that a miracle.

Another miracle I describe is the turnaround of a man in his thirties who sought my help after years of struggling with drug and alcohol addiction. He’d been through more than a dozen rehab centers and treatment programs, but nothing helped for very long. His mental health was deteriorating, he couldn’t hold a job, and his family lived in constant fear of losing him.

Yet when we started to focus on healing his gut—just as with the Parkinson’s patient—everything began to shift. As his gut health improved, his mental health stabilized—and with that, his life.

Now here is the surprising part: what if I told you that these patients were suffering from the exact same condition?

The tests we ran showed that these two—like nearly all my patients—were dealing with leaky gut, though the symptoms appeared very differently in each of them.

In the book, I make the case that whether you’re struggling with fatigue, acne, brain fog, dementia, mental health issues, addiction, or other cognitive and behavioral problems, chances are that the same root cause is to blame: the gut.

The good news is, when you repair the gut wall and restore microbial balance, the disease process is often resolved. I realize that’s a strong statement, but I’ve seen it time and again and published results on it over the past twenty-five years.

KG: Hippocrates—the father of medicine—was ahead of his time when he observed that “All disease begins in the gut.”

SG: That’s exactly right, and for the past twenty-five years, I’ve been trying to figure out how he knew that twenty-five hundred years ago! These days, I like to update his statement to: “All disease begins in a leaky gut.”

Dr. Steven Gundry on the Cause of Leaky Gut

KG: What do you see as the main cause of leaky gut today?

SG: Back in what I like to call the “dark ages” of my medical school training, three big changes happened that really fueled the rise in cases we’re now seeing.

#1 I was in medical school in the mid1970s when broad-spectrum antibiotics were introduced—and to us, they were miraculous! Before then, we had to culture the infection-causing bacteria and then test them against different antibiotics to see which one worked. That process could take days, and meanwhile, these were very sick patients.

So, when broad-spectrum antibiotics came along, we suddenly had an AK-47 with a 200-round clip set on fully automatic. We can just mow these bacteria down! Little did we know that, in the process, we were mowing down our microbiome—an ecosystem of beneficial bacteria, viruses, fungi, and other microbes essential to everything from digestion to cognition.

Back then, no one really talked about this community living in the gut—the term microbiome wasn’t coined until 2002, and the Human Microbiome Project didn’t wrap up until 2019.

#2 The second big change around that same time was the rise of NSAIDs—non-steroidal anti-inflammatories. Aspirin had long been a mainstay, but anyone my age remembers its major drawback: it’s notorious for causing gastric ulcers. Pharmaceutical companies tried to solve that pesky problem with newer NSAIDs like ibuprofen and Naproxen, but these too carried risks and were restricted to prescriptions—typically for no more than two weeks and with limited refills.

Fast forward to today, and more than thirty million Americans rely on overthe-counter NSAIDs daily for pain, headaches, and arthritis. The trouble is that these drugs have been shown to disrupt the gastrointestinal system and produce measurable shifts in the microbiome.

For example, studies show that NSAIDs increase pathogenic, pro-inflammatory bacteria such as Enterococcus. At the same time, they reduce Lachnospiraceae and Ruminococcaceae—protective species that produce the all-important butyrate: a shortchain fatty acid (SCFA) that protects both the gut lining and the brain.

And here’s the paradox: while NSAIDs may offer temporary pain relief, long-term use actually drives inflammation—and ultimately more pain.

#3 Finally, in the mid-1970s, glyphosate was introduced—a weed killer commercialized under the trade name Roundup. What many people don’t realize is that Monsanto actually patented glyphosate as an antibiotic.

The EPA has routinely found that there are “no human health risks of concern” from using glyphosate, but that language can be misleading. While it may not appear acutely toxic to humans when used as directed, studies show it poses real risks to the human microbiome.

Certain species are especially vulnerable. For example, glyphosate selectively kills Lactobacillus, which helps break down tryptophan into compounds that promote neurogenesis and strengthen neural connections. Another is Ruminococcaceae—an important family of bacteria whose decline has been linked to Parkinson’s disease and depression.

Glyphosate is now everywhere—on our grains, in our wines, sprayed across golf courses and schoolyards. And to think, I witnessed it all unfold—the weed killer, the antibiotics, the anti-inflammatories. It happened right under my watch.

KG: And thank you, Dr. Steven Gundry, for raising awareness about these issues and showing that solutions are within reach. What are some practical steps patients can begin taking today to restore and strengthen their gut health?

Strategies to Support Gut Health

SG: After nearly thirty years of working and learning alongside patients, I’ve identified several strategies that reliably support gut health, including the following three:

1. The first step is to get your vitamin D levels well above the current recommendation. As a baseline, everyone should be taking at least 5,000 IUs (125 micrograms) daily. The University of California, San Diego—home to one of the largest vitamin D research centers in the country—recommends closer to 9,600 IU per day for the average American to achieve adequate levels. In fact, they, like me, have never observed vitamin D toxicity at doses up to 40,000 IU per day. For my autoimmune patients—who tend to present with severe leaky gut—I often prescribe 45,000 to 50,000 IU daily, and they are not vitamin D toxic.

KG: Just to clarify, what is the current recommended dietary allowance (RDA) for vitamin D, and what’s the best way to take it?

SG: The RDA is woefully low: 600 IU per day for adults. In terms of how to take it, Michael Holick, MD, PhD, at Boston University—one of the leading vitamin D experts—has shown that, despite being fat-soluble, vitamin D does not require added fat for absorption. That’s one of the biggest misconceptions about vitamin D. You can take it with or without food, morning or evening, and there’s no need to split up the dosage.

Now, why does vitamin D matter so much? One of the main benefits is that it increases the abundance of beneficial bacteria like Akkermansia, along with two major butyrate producers—Faecalibacterium and Coprococcus. That means vitamin D gives your microbiome a big boost in butyrate production, which, as you may recall from earlier, is crucial for strengthening the gut wall and supporting brain health.

2. Next, don’t forget to fuel up on fiber. Many of your important gut microbes depend on it to grow and thrive—and some of the best sources come from the chicory family (radicchio, Belgian endive, escarole, and frisée). Whenever I travel to France or Italy, salads almost always feature escarole and frisée—these cultures have long made them a priority. And here’s the really cool and surprising part: even if you don’t love these foods at first, as your microbial community becomes more diverse, it will actually shape your cravings. Over time, you may find yourself reaching for a salad instead of a plate of empty carbs.
   
   What makes chicory so powerful is its richness in inulin, a soluble fiber your gut microbes love. They use it to produce important compounds like plasmalogens—special lipids that protect neurons and support healthy cognitive function. In other words, the right microbes can turn your food into brain-protective compounds.
   
   Finally, don’t forget your “animal fiber.” This refers to the parts of animal foods most people eating a Western diet tend to discard—ligaments, tendons, cartilage, and bones from meat and fish. These tough materials resist digestion in the small intestine and make their way to the large intestine, where beneficial microbes ferment and use them as fuel.

3. Fitness guru Jack LaLanne famously said, “If it tastes good, spit it out.” My PR team has urged me to stop quoting that line since readers might get a bad impression of my eating program. But that’s not what Jack meant at all! I got to know him, and what he was really saying is that we shouldn’t let a twoby-three-inch piece of muscle in our mouths—our tongue—be our guide. We should be eating for our good bacteria.
   
   One of the best ways to do that—along with getting enough fiber—is by adding fermented foods to your diet. Think apple cider vinegar, kefir, kimchi, and raw cheeses from Italy, France, or Switzerland. Even certain artisanal meats like pancetta and prosciutto, because they are cured (fermented), have been shown to have probiotic properties.
   
   Personally, I like to start my day with a splash of aged balsamic vinegar in sparkling water—my version of a “fake Coke.” To take it up a notch, I recommend Italian sparkling water such as San Pelligrino (in a glass bottle, please). I have absolutely no affiliation with San Pelligrino—I just prefer that brand because it has the highest sulfur content of any bottled water. And in Italy, sparkling water is required to fall within a specific pH range, so I’m a fan.
   
   For a little extra sweetness, try adding allulose. It’s a naturally occurring, low-calorie sweetener that works as a one-to-one substitute for table sugar, easy to bake with, and—unlike artificial sweeteners—is the real thing. (I say this as a recovering sweets addict who used to drink eight Diet Cokes per day. If I could have sterilized Diet Coke, I would’ve sipped it in the operating room!)
   
   Unlike allulose, artificial sweeteners wreak havoc on the gut microbiome. A Duke study found that just one packet of sucralose (Splenda) killed off fifty percent of gut bacteria. One dumb packet. That means even occasional use isn’t safe.

The good news is, we can begin reversing gut damage today.

While all disease begins in the gut, all disease can also be reversed in the gut—and that’s what’s really fascinating and exciting. Once you begin nourishing and taking care of your microbes, they will return the favor.

To me that’s truly empowering.

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Steven Gundry, MD, is the medical director of the International Heart and Lung Institute and The Centers for Restorative Medicine in Palm Springs and Santa Barbara. After a distinguished surgical career as a professor and chairman of cardiothoracic surgery at Loma Linda University, Dr. Steven Gundry shifted his focus to reversing modern diseases through dietary and lifestyle changes.

His bestselling books include The Gut-Brain Paradox, Gut Check, Unlocking the Keto Code, The Energy Paradox, The Longevity Paradox, and The Plant Paradox. He has also authored more than three hundred peer-reviewed articles on using nutrition and supplementation to address heart disease, diabetes, autoimmune conditions, and other chronic illnesses.

In addition to his writing, Dr. Steven Gundry hosts the top-ranked Dr. Gundry Podcast and is the founder of Gundry MD, a wellness brand offering a wide range of science-backed supplements, functional foods, and skincare products. Dr. Steven Gundry lives with his wife, Penny, and their dogs in Palm Springs and Montecito, California.

Well Being Journal adapted the above excerpt from The Gut-Brain Paradox by Steven Gundry, MD. Copyright (c) 2025 by Steven Gundry, MD. Reprinted with permission