Does Your 'Filtered' Water Still Have Fluoride? - Chasing Life with Dr. Sanjay Gupta - Podcast on CNN Audio

CNN

10-06-2025

Dr. Sanjay Gupta
00:00:03
Welcome to Paging Dr. Gupta, one of my favorite times of the week. I really love hearing from you. You know, we've been doing this for a couple of months now. I love reading your questions, hearing your questions, gives me an idea of what's on your mind. Whether it's something in the headlines, sometimes it's something happening in your own life, I'm here to help try and break it down. And we've got a great first question lined up. Kyra, wanna do the honors?
Kyra Dahring
00:00:30
Absolutely. So, Paula in West Springfield, Massachusetts asks, in our household, we use filtered water coming out of the refrigerator. Does that eliminate the fluoride in the water?
Dr. Sanjay Gupta
00:00:41
'Okay, Paula, this is a great question. There's been a lot of news about fluoride lately. So let me give you a simple answer and then explain it. Most water filters are not going to remove fluoride. Keep in mind that fluoride is a mineral and it dissolves in the water, so it's actually quite hard to remove, to filter out. Most conventional filters are not going to do this. Now, there are a couple of ways to filter out fluoride. One is using something known as reverse osmosis, a reverse osmosis filter. This essentially is forcing the fluoridated water under pressure through a semi-permeable membrane. Reverse osmoses is about 80 to 90% effective at removing fluoride. Another type is distillation, a distilling filter. Now, this essentially is boiling the fluorodated water and then capturing the water vapor, that steam that gets produced, and leaving the fluoride behind and that's nearly a hundred percent effective. Now again, I know there's a lot of discussion about fluoride lately, but two things I just want to make sure you know: in most places around the country around the United States, Fluoride is not going to be at a level that is high enough for concern. So despite the fact that we're talking about it a lot lately, there really isn't a lot of cause for concern. Second thing, there are ways to sort of figure out how much fluoride is in your water. There is something called a consumer confidence report that you can get from your water company, they're obligated to give it to you if you ask for it. That can tell you how much fluoride in your water. You can also go to the CDC's website and look for "My Water's Fluoride" and plug in where you live, that can also give you an idea of how much fluoride's in your water. But again, Paula, I just want to be clear for most people living in the United States, this is not a concern.
Kyra Dahring
00:02:37
Okay wait, now Sanjay, let's just say the fluoride is removed from the drinking water. We have a question from a listener named Lucia in New York who wants to know if brushing her teeth with a fluoridated toothpaste or rinsing with a flouridated mouthwash, is that enough to protect her teeth?
Dr. Sanjay Gupta
00:02:53
Okay, yes, this is a great question. The short answer here is yes, fluoridated toothpaste or rinses are really effective at protecting teeth. One thing I just want to point out, if you look at the sort of overall impact of fluoridating water, the public health community often refers to that as one of the greatest public health achievements over the last century. And for good reason, it's made a huge impact. But at the same time, really since about 1975, the incremental benefit of fluoride in the water has gone considerably down. Why is that? Because around that time, 50 years ago, we started to have fluoridated toothpaste and more widespread access to dental care. So fluoridate toothpaste can make a huge difference. When you think about fluoridatied toothpaste, first of all, for children under the age of three, you don't need very much toothpaste, about a rice grain size amount of toothpaste is good for children under the age of three. That's not very much. And for adults, about a pea size amount a fluoridated toothpaste. When you're thinking about the fluoride, you want to make sure that it's sort of sticking to your teeth. And you don't want to rinse your teeth for a period of time after you brush your teeth, just let that fluoride sit on your teeth that's what allows it to of cause remineralization. Don't eat for 10 to 15 minutes afterward either. So no doubt then that brushing your teeth with a little bit of fluoridated toothpaste can make a huge difference. Now I will say that the impact of taking fluoride out of the water is a little bit hard to know. There have been some modeling studies, one came from a group of researchers at Harvard that basically predicted that over the next five years, if you remove fluoride from the water, it would lead to about 25 million excess cavities. Over 10 years, it would lead to about 54 million excess cavities, cavities being defined by something that needs a filling. So again, fluoridated toothpaste, fluoride rinses, they do a great job, but there's an impact as well at taking the fluoride out of the water.
Dr. Sanjay Gupta
00:05:09
Okay, we're gonna take a quick break, but when we come back, we're gonna talk about foods to eat to keep your mind sharp. Stay with us.
Dr. Sanjay Gupta
00:05:23
Alright. I know that sound. Kyra, who's up next?
Kyra Dahring
00:05:26
Next up is Sam from Connecticut, and he has a question I think you're gonna love about brain food. Take a listen.
Listener Sam
00:05:34
Hi, my name is Sam and I'm 68 in Norwalk, Connecticut. I don't know if you've covered this in one of the podcasts that maybe I've missed, but I'd like to know what are the best foods you could eat to nourish your brain? Memory, response time, accuracy? Thanks, have a great day and thank you for all the wonderful information. Bye.
Dr. Sanjay Gupta
00:05:58
Okay Sam, thank you for your question and I do love the fact that you're thinking about how to keep your brain sharp. As you know, I'm a neurosurgeon, I think about the brain all the time, the most enigmatic three and a half pounds of tissue in the known universe. Now, with regard to how we nourish ourselves and its relationship to brain health, there is some solid science behind certain foods that support memory and cognition. In fact, I sat down on a previous episode of Chasing Life with Dr. Uma Naidoo. She's a nutritional psychiatrist, by the way, how cool is that? A nutritional psychiatrist, she's also a professional chef and she really digs deep into how food affects the brain. Listen to what she told me.
Dr. Uma Naidoo
00:06:44
'Foods that will help cognition, we actually go back to those, those omega-3s, it's a group that's featured very frequently. Olive oil, also one that we lean into. The herbs and spices that showed up doing well for cognition and for thinking and for memory are turmeric with that pinch of black pepper, which makes it much more bioavailable, cinnamon, saffron, rosemary, ginger, sage.
Dr. Sanjay Gupta
00:07:13
I hope you caught that last part. It's not only the specific foods, but also these added spices, which can make the foods much more bioavailable. If you eat foods that are good for you, but they're not highly bioavailable, that means they're not circulating around the body and the brain and doing their job. Now, Dr. Naidoo also gave us some great advice on caffeine and how, in moderation, it can actually help objectively with focus and memory.
Dr. Uma Naidoo
00:07:41
Coffee was thought, if you keep your caffeine's consumption, or your coffee consumption, under 400 milligrams a day, it was thought to be healthy.
Dr. Sanjay Gupta
00:07:50
Now, I think it's important to point out that Dr. Naidoo's not just talking about these things as individual ingredients. Oftentimes we think of medicines as these single molecules, but when it comes to food, it's really about putting all these ingredients together into a meal that is tasty, but also brain healthy.
Dr. Uma Naidoo
00:08:10
You know, for me, this is some guidance. While I know that those foods have been identified as healthy, it's also part of an overall plate, right? It's not just eating the nuts or eating the olive oil, it's putting that together in a meal that's still tasty makes a very big difference to balancing that out for people.
Dr. Sanjay Gupta
00:08:28
'Beyond that, let me give you some of my thoughts on what the research shows about food and brain health. Studies have shown that eating just a handful of blueberries or a single serving of spinach or kale can slow cognitive decline by years even. There was this big study that tracked over 16,000 older women for 15 years and found that just a half a cup of blueberries, or a cup a strawberries a week, slowed memory loss by two and a half years. Another study found those who ate a serving of leafy greens, spinach, kale, collard greens, arugula, appeared many years younger in terms of their overall cognitive health compared with those who rarely or never consumed green leafy vegetables. Another one to add to the list, oily fish, salmon, tuna, mackerel, herring, trout, sardines. They are all rich in something known as DHA. DHA is a fat that can help protect your brain. And then there was a study showing that eating fish just once a week was associated with slower cognitive decline and a lower risk of Alzheimer's. You know, I also want to mention eggs. They are packed with something known as choline, which is a key nutrient for memory and learning that many people just don't get enough of, eggs can be a great source. So Sam, if you're at the store, think about these foods, look for color in your foods, berries, greens, those brain-boosting spices Dr. Naidoo mentioned, turmeric, cinnamon, saffron, rosemary, ginger, sage, and don't forget your salmon. That's a big one. But remember again, it's about building meals around these components. Make them tasty and pack them with these ingredients, that's great way to support your brain health over time.
Dr. Sanjay Gupta
00:10:19
'Alright, that's all the time we have for today, and thank you to everyone who sent in questions. I love hearing what you're curious about. If there's something health-related you've been wondering about, you can record a voice memo, email it to [e-mail], or give us a call at 470-396-0832, leave a message. Thanks for listening, and I'll be back next Tuesday. Chasing Life is a production of CNN Audio. Our podcast is produced by Aaron Matthewson, Eryn Mathewson, Jennifer Lai, Grace Walker, Lori Galaretta, Jesse Remedios, Sofía Sánchez, and Kyra Dahring. Andrea Kane Is our medical writer, our senior producer is Dan Bloom, Amanda Sealy is our showrunner, Dan Dzula is our technical director, and the executive producer of CNN Audio is Steve Lickteig. with support from Jamus Andrest, Jon Dianora, Haley Thomas, Alex Manasseri, Robert Mathers, Leni Steinhardt, Nichole Pesaru, and Lisa Namerow. Special thanks to Ben Tinker and Nadia Kounang of CNN Health and Wendy Brundige.