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Welcome to The Dr. Kumar Discovery, a health and wellness podcast hosted by Dr. Ravi Kumar, a board-certified neurosurgeon. This is the medical podcast for anyone who wants honest, evidence-based answers to the health questions that matter most. No corporate influence. Just a physician who reads the research, questions the dogma, and breaks it down in plain language so you can make better decisions about your own health.
Dr. Kumar is a practicing neurosurgeon who brings a surgeon's precision to topics most doctor podcasts only scratch the surface of. Each episode dives deep into the science behind metabolic health, cardiovascular disease, heart disease, hormones, nutrition, brain health, mental health, pain, inflammation, weight loss, aging, blood pressure, sleep, and longevity. Whether it's the truth about seed oils, the real data on GLP-1 drugs and weight loss, the science of cold water therapy, how light can heal the body, or why your testosterone is declining, Dr. Kumar goes straight to the peer-reviewed literature and tells you what the evidence actually shows, not what the headlines say. This is evidence-based medicine in plain English.
The show features three formats. Solo deep dives explore a single health topic from the ground up, covering everything from the biology to the practical takeaways you can use today. Expert interviews bring on leading researchers, clinicians, and forward-thinking voices in health and medicine for in-depth conversations you won't hear anywhere else. The Tribulations series tells the true stories behind medicine's greatest breakthroughs, from the discovery of penicillin to the invention of vaccines to a father's fight to save his son's life. These are the stories of the doctors, scientists, and patients who changed the course of medicine.
Topics covered on the show include testosterone and hormone optimization, sleep science, photobiomodulation and red light therapy, exercise with oxygen therapy, creatine, uric acid and gout prevention, gut health and probiotics, cardiovascular risk and Lp(a), cholesterol, PANDAS in children, PTSD and trauma, acetaminophen safety, glyphosate, foot health, and much more.
If you're tired of generic health advice and want to hear from a neurosurgeon who actually reads the studies, The Dr. Kumar Discovery is your podcast. New episodes drop regularly. Subscribe and join the discovery.
For show notes, references, and more, visit drkumardiscovery.com/podcast
Welcome back to the Doctor. Kumar Discovery podcast. I'm Doctor. Ravi Kumar. Earlier in the week, I interviewed Doctor.
Ravi Kumar MD:Nathan Bryan on the biology of nitric oxide and how it fits into human health and wellness, and I got a bunch of very thoughtful questions. So I picked five of the best ones to do little mini deep dives on. I think this will tie together most of what we learned earlier. So let's get into it. Okay.
Ravi Kumar MD:The first question is, I've been using mouthwash twice a day for twenty years. Is the damage per minute, or can my oral microbiome actually recover? This is a great question, and the good news here is that the answer is yes, you can recover, and it happens pretty fast. The key paper on this was published by Doctor. Brian's team in 2019.
Ravi Kumar MD:They took 26 healthy people and did a baseline measurement of their blood pressure and their oral microbiome. Then they had everyone use chlorhexidine mouthwash twice a day for seven days, and predictably, blood pressure went up and the nitrate reducing bacteria took a big hit. But here's the interesting part. Then they had everyone stop the mouthwash, and then they remeasured after just a few days. Within that short window, their blood pressure normalized, the bacterial diversity on the tongue actually came back, and in some cases, the community looked healthier than it was originally at baseline.
Ravi Kumar MD:These bacterial communities are remarkably resilient. They're basically waiting for the chance to repopulate. So what this means practically for you is that you should stop using mouthwash and switch away from fluoridated toothpaste if you can, then wait about a week. Many people notice the difference in energy and workouts within days. And now, there are actually nitric oxide friendly toothpastes and mouth rinses that are being developed specifically to support these bacteria instead of nuking them, which is what happens with the traditional mouthwashes.
Ravi Kumar MD:This paper that I talked about is open access, so if you want to read it for yourself, just search Tribble, that's t r I b b l e, Brian, Tongue, Microbiome, 2019, and you'll find it. Okay, next question. I already eat a ton of leafy greens, and I exercise regularly. Do I really need to supplement with nitric oxide? So, is a very common question.
Ravi Kumar MD:I had this question myself. In a perfect world, diet and lifestyle alone should be enough. The human body is designed to do its job when you give it what it needs. But here's where reality doesn't work with that concept. Doctor.
Ravi Kumar MD:Brian's group published a paper in 2015 titled A Survey of Nitrate and Nitrite Concentrations in Conventional and Organic Labeled Raw Vegetables at Retail. So what they did is they basically bought 194 samples of broccoli, cabbage, celery, lettuce, and spinach from five major US cities. They brought them all back to their lab, and they measured the nitrate content. And the variability between these vegetables from different parts of the country was significant. The authors specifically noted that these geographic differences may actually undermine any attempt to estimate dietary nitrate intake because you just can't predict what you're getting.
Ravi Kumar MD:And then on top of that, soil depletion is a real problem. There's a well cited analysis that tracked USDA nutrient data from 1950 to 1999 and found statistically significant declines in protein, calcium, phosphorus, iron, riboflavin, and vitamin C. The modern food supply is simply less nutrient dense than what our grandparents ate. So that being said, some people might be getting enough nitrate from food. But if you're using mouthwash, if you're using fluoridated toothpaste, or if you're taking an antacid, you disrupt the downstream conversion steps that turn nitrate into nitrite, which turns into nitric oxide.
Ravi Kumar MD:Your body essentially can't turn dietary nitrate into usable nitric oxide. So, the foundation is still diet and lifestyle. I always believe that with everything. But you have to be realistic. And for most people in our modern environment, targeted supplementation makes a lot of sense.
Ravi Kumar MD:I really like Doctor. Brian's quote on this. He said, There are two people who should supplement with nitric oxide supplements: people who are sick and want to get well, and people who are well and don't want to get sick. That's pretty much everyone. But still, I certainly wouldn't be opposed to trying it naturally with the most nutrient rich vegetables you can find and then just seeing how you feel.
Ravi Kumar MD:I think that's a reasonable strategy. Okay, next question. I've been on a PPI for acid reflux for years. Doctor. Bryan said antacids block nitric oxide production.
Ravi Kumar MD:Am I stuck? Okay. This is a real clinical dilemma, and I wanna be careful here. Please don't stop any prescription medications without talking to your doctor first. This is educational and not medical advice.
Ravi Kumar MD:On that note, I did do a full podcast on GERD and how to wean off proton pump inhibitors when appropriate. That's definitely worth a listen if you're blocking your acid production with a drug. So let's talk about the mechanism here. Your stomach acid is what drives the final step that converts salivary nitrite into nitric oxide gas. If you shut down the acid production in your stomach, you shut down that whole pathway.
Ravi Kumar MD:And this isn't just Doctor. Brian's opinion this is actually established biochemistry. There's also growing literature on the broader harms of long term PPI use. This is something I've talked about a lot. In fact, they've shown that PPI users have a significantly higher risk of all cause mortality compared to H2 blocker users, and with the risk increasing the longer these people stayed on PPIs.
Ravi Kumar MD:PPIs were designed for short term use, originally two to eight weeks, but most people end up on them for years or decades. And then here's one other thing you should probably know about acid production in your stomach. A lot of reflux cases are actually caused by low stomach acid, not high stomach acid. You see, acid triggers your lower esophageal sphincter to close, So when you have low acid, that sphincter doesn't close and the acid splashes up into your esophagus causing pain. So acid blockers are essentially treating the symptom and worsening the root cause.
Ravi Kumar MD:So try listening to that episode I did on GERD and work with your doctor. Getting acid production back in your stomach can transform your whole body and bring nitric oxide production back online. Okay. Next question. My doctor told me cured meats cause cancer, and I should never eat bacon or deli meat.
Ravi Kumar MD:Doctor. Brian said the opposite. Who's right? Okay, so this is a good question, and it's a fascinating one, because it's a perfect example of how medical dogma can persist long after the underlying science has been totally figured out. The origin of the cured meat scare traces all the way back to 1956, when a paper in the British Journal of Cancer showed that nitrite cured fish could contain compounds called nitrosamines, which are genuine carcinogens.
Ravi Kumar MD:Dimethyl nitrosamine, in particular, causes liver cancer in animal models, and that's a real finding. Then in 1970s and 1980s, nutritional epidemiology studies linked cured meat consumption to slightly higher rates of stomach and esophageal cancer. That's the foundation of what most doctors were taught, And for years, I did not eat cured meat because I thought it would cause stomach and esophageal cancer. But the science has evolved substantially. Doctor.
Ravi Kumar MD:Brian published a rigorous risk benefit analysis in the journal Nitric Oxide in 2010, where he laid out several problems with the original hypothesis. First, about 85% of the nitrate and nitrate that we consume comes from green leafy vegetables, not cured meats. If nitrate itself were the problem, vegetarians would have massively high cancer rates than meat eaters, but they don't. It's actually the opposite. And second, in 1972, the US government changed the code of federal regulations to require that nitrite cured meats include ascorbic acid, which is vitamin C, or its analog, erythrobate, which blocks the chemistry that forms nitrosamines in the first place.
Ravi Kumar MD:Studies looking at residual nitrite and nitrosamines in modern cured meats show essentially undetectable levels of nitrosamines. Doctor. Bryan's group has published multiple surveys confirming this, including a national survey of nitrite and nitrate concentrations in cured meat products that found levels substantially lower than those reported by the National Academy of Science back in 1981 when this whole scare was going on. And then third, your body concentrates nitrate in your saliva and reabsorbs it in your kidneys. Evolution doesn't design elaborate machinery to recycle a toxin.
Ravi Kumar MD:It does that for nutrients. And here's the irony, that uncured or no nitrite added bacon that a lot of health conscious people buy, including myself, is made with celery powder, plus a bacterial culture to convert the nitrate to nitrite synthetically. So it has nitrite anyway. It's just made in a less controlled way, and usually without the ascorbic acid that blocks the nitrosamine formation with more bacterial variability, shorter shelf life, and often double the price. The WHO classification of processed meats as carcinogens is based on old epidemiology that many in the field now consider fundamentally flawed.
Ravi Kumar MD:The science has moved, but the recommendations haven't fully caught up. So, to be completely honest on this one, this definitely caught me by surprise. This is one of those examples where conventional dogma still had my mind trapped in flawed thinking because I hadn't gone to the literature and looked it up myself. So investigate it yourself and be informed because doing that will unlock the truth on a lot of these things. Okay, so next question.
Ravi Kumar MD:How do I know if I'm actually nitric oxide deficient? Is there a test? This is a great question, and there are a few different angles here. First, listen to your body. Doctor.
Ravi Kumar MD:Brian described a hierarchy of symptoms, and there's solid literature backing this order. The first sign is usually sexual dysfunction. He called it the canary in the coal mine, and that's not hyperbole. There's a well known study published in JAMA in 2005 showing that erectile dysfunction is an independent predictor of cardiovascular events because the small blood vessels of the sex organs are the first to show endothelial failure. Elevated blood pressure is next, then insulin resistance, then exercise intolerance, and at the far end, mild cognitive impairment progressing towards Alzheimer's.
Ravi Kumar MD:In fact, some researchers now refer to Alzheimer's as type three diabetes because of the insulin resistance and hypoperfusion in the brain. There's a great paper by DeLamonte and Wands in the Journal of Diabetes Science and Technology in 2008 that lays out this whole concept in detail. And second, there's the question of whether nitric oxide really declines with age. And the short answer is yes, and this has been shown repeatedly. A foundational paper in the Journal of American College of Cardiology in 1994 used ultrasound to measure flow mediated dilation, which is basically how well your arteries open up when blood flow increases.
Ravi Kumar MD:And they found that endothelial function declines progressively with age. Another important paper in Hypertension in 2001 directly measured nitric oxide availability and oxidative stress in humans and confirmed that nitric oxide bioavailability dropped substantially with age. By the time the average person hits their sixties or seventies, they're running on a fraction of what they had in their early twenties. And lastly, if you're over 40 and eating a standard American diet, using mouthwash, using fluoridated toothpaste, taking an antacid, and not exercising regularly, you're almost certainly deficient. The science is clear on this, and in my opinion, you don't really need a test to justify taking action.
Ravi Kumar MD:The interventions we talked about in the episode are safe and beneficial for essentially everyone. So start there. And one last topic that I thought was worth bringing up but I didn't get a specific question on was that Doctor. Bryan mentioned that fluoride in drinking water lowers children's IQs, and this is based on the National Toxicology Program published report in 2024 that suggested this. It was followed up by a meta analysis in JAMA Pediatrics in 2025 that followed 74 studies and found a statistically significant inverse association between fluoride exposure and IQ, which held up when they restricted the analysis to only the highest quality studies.
Ravi Kumar MD:In September 2024, a federal court ruled that water fluoridation at the U. S. Public Health Services recommended levels poses an unreasonable risk to children's health. The science is converging on this, and if you want to read more about this, look up that JAMA Pediatrics paper because that's a good starting point. Well, that's it for today, folks.
Ravi Kumar MD:Keep the questions coming. And if you haven't listened to that full conversation with Doctor. Brian, please take a listen. It's one of my most favorite episodes so far. Okay, folks.
Ravi Kumar MD:Cheers, and I'll see you next week.