Science Friday - A Nutritionist Clarifies Some Common Health Claims

Episode Date: November 27, 2024

We recently asked our listeners which dubious health claims they’ve been seeing in their social media feeds or being circulated by friends and family. Unsurprisingly, we received a ton of questions about nutrition, including: Is seed oil bad for you? Does apple cider vinegar really lower blood sugar? What is the difference between processed and ultraprocessed foods? To answer those questions and more, SciFri producer Kathleen Davis talks with RDN Jessica Clifford, a nutrition specialist at Department of Food Science and Human Nutrition at Colorado State University. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Nutrition science is complicated, and it can be hard to separate fact from fiction. If the claim sounds too good to be true or maybe a little crazy, they probably are. It's Wednesday, November 27th, and you're listening to Science Friday. I'm sci-fi producer Shoshana Bucksbaum. We've recently asked you our listeners, which dubious health claims you've been seeing in your social media feeds or being circulated by friends and family. Unsurprisingly, we received a ton of questions about nutrition.

Sci-Fri producer Kathleen Davis talks with a nutritionist to help answer those questions and give advice on how to figure out if those claims really hold up. Jessica Clifford, registered dietitian and nutrition specialist at the Department of Food Science and Human Nutrition at Colorado State University based in Fort Collins. Jessica, welcome to Science Friday. Hi, thank you so much for having me. We're so glad to have you. So let's get right in to our listener questions.

The first one that we have is from Lynn S. She's based in Syracuse, New York. She asks, why are internet comment sections freaking out about seed oils? Okay, Jessica, first of all, what is a seed oil? Well, seed oils are those oils that are extracted from the seed of a plant, and generally, they contain unsaturated fats. Seed oils include oils like canola oil or corn oil, cotton seed oil, soybean oil, sunflower oil, among a few others. That is what a seed oil is. And so why are people concerned about these? Well, I think the biggest thing that we see across media platforms is that there's some concern

about the way that these seed oils are processed. And that is often through the form of like heat and the use of a solvent, which is commonly hexane. Now, hexane is a toxic compound, right? But research shows that really there's a very, very tiny amount in the oils that we're actually consuming. And so really, there's very little reason for concern with that level of the oil that we're eating. When you hear of a compound like hexane, you automatically might think, like, oh, my gosh,

this is horrible. Of course, we shouldn't be consuming it. But it's really not showing that it's harmful to our health in the amount that we're consuming. And in fact, the benefits that we see from some of the oils, right, because they're made up of these unsaturated fats can outweigh the risks that come with them as it relates to that hexane compound. And then another thing I think that draws concern for some people and maybe leads to some of this misinformation related to seed oils is the fact that they contain omega-6 fatty acids. So that might come up in discussions around seed oils, right? I was just going to say, omega-6 fatty acids are known to be, they're pro-inflammatory.

And so these oils do contain these omega-6 fatty acids, but it doesn't necessarily make them inherently bad. Okay. So how does canola oil compare to an olive oil, for example, nutritionally? So canola oil has unsaturated fats, so moni-unsaturated fatty acids as well as polyunsaturated fatty acids, which are heart-healthy, unsaturated fats, and so does olive oil. But the thing that differs with olive oil is that it also contains these other bioactive compounds, like phenolic compounds, which have anti-inflammatory and antioxidant properties. So there may be some advantage

that olive oil has over canola oil or maybe other seed oils, but the seed oils do also have heart healthy fats. So Jessica, give us a verdict. Overall, is seed oil bad for you? I would say no. It's definitely not bad for you. Again, everything should be consumed in moderation. So it's not like you want to rely solely only on one type of seed oil, but it definitely can be consumed as part of a healthy diet. Okay. So this next question that we have comes from David K. In West Richland, Washington. He asks, I am skeptical about the way all processed foods have been lumped into a single category from cooked mashed potatoes to hyper-processed hot dogs laced with preservative chemicals that I can't even pronounce.

Are all processed foods supposed to be bad for my health? Okay, Jessica, let's talk about this question. What does it actually mean for a food to be processed versus ultra-processed? Yeah, so a processed food, so the definition of just processed food in general is any raw agricultural commodity or food that has been altered from its original state or its whole food form, right? But there are, as you said, these various levels of processing. So you really can't lump them all together. Even like slicing an apple is a form of processing, but we all know that just cutting an apple makes it no less healthy, right? That's not going to change the nutrition of an apple.

A food becomes ultra processed when there are things added like preservatives, flavor, colors and other food additives, such as like added salt, sugars, and fats, particularly for flavor and shelf life. So really, you can think of it like a spectrum of processing. So on the left side, you might have that sliced apple. And then all the way to the right might be that hot dog or that cellophane packaged cupcake. There has been a lot of research into quote-unquote ultra-processed foods recently. What do we know about their effect on our health? research shows that people who eat more processed foods gain weight, you know, maybe more weight and more quickly. And it's interesting because it's not just because they're eating more

energy-dense foods, right, that are higher in calories but lower nutrients, but also because the way the foods are engineered is actually making people eat more of them, right? It's that perfect concoction of like sugar, salt, and fat that really makes people want more. And it's actually triggering something in our brain to making us want to eat more of them. And so, and then research also shows that greater exposure of those sort of ultra-process foods is associated with increased risk of heart disease-related death, as well as diabetes, among other things. We want to have a healthy relationship with food, and really all foods can fit into a healthy diet. And so we don't want to make it about, like, demonizing certain foods and saying you can never eat this food or this is horrible and you should never have this. because really, I think having even some of these ultra-processed foods that some people might enjoy once in a while can be okay and can fit as part of a healthy lifestyle and a healthy diet.

But I do think from a public health sense that, you know, I really do think our food industry could use a little work in terms of providing or making less ultra-process foods for sure. So once in a while my McDonald's quarter-pounder is okay to eat, but in moderation. Absolutely, yeah. Okay, so let's move on to something that I've heard about for quite some time, and that is the health benefits of apple cider vinegar. People have attributed this to weight loss, lowering blood sugar, lowering cholesterol. Is there evidence to support these claims? Yeah, so this sort of information has been out for such a long time, you know, in the media and even in research around this. There is some evidence. I think, you know, Apple cider vinegar has been touted to have so many benefits. And while I think some are true to some degree, they may not be to the degree

that some media or people are saying. I think, first and foremost, the one thing where there's the most research or the strongest research to support is that apple cider vinegar can help to lower blood glucose levels or A1C levels, but the effect is minimal. So it's nothing huge. It's nothing earth-shattering. If someone has prediabetes or diabetes, this should definitely not replace any medications they're on or other lifestyle changes that would be recommended. But it could be used in addition or, you know, an adjunct to medication and or healthy eating or exercise. And then you mentioned weight loss.

So there is some research showing that it can help possibly with weight loss as well, but the research doesn't seem to be as strong as that with its effects on blood glucose. And really with weight loss, it's so complicated. So, you know, it's not necessarily a sustainable solution, I think, to weight loss. And it definitely wouldn't be like a silver bullet here, right? It could maybe help a little bit, but it's not to the degree that's being presented in the media. And I do want to say one more thing related to that, if that's okay. With that said, you know, even despite some of these minor benefits,

apple cider vinegar is very acidic. So it can cause damage to, like, tooth enamel in your esophagus. so people might experience some sort of upset, stomach upset or acid reflux. So if people do choose to consume this, it should be diluted, or I would recommend that it be diluted with water or, like, added to a tea or maybe a salad dressing as opposed to consuming it directly. But again, this should be in conjunction with a healthy diet, right? You can't just drink apple cider vinegar and expect to lose weight or reduce your blood glucose.

But why does it seem that apple cider vinegar specifically has these modest health benefits? So apple cider vinegar is made by fermenting apple juice with yeast and bacteria, in particular bacteria, the class of bacteria called acetic acid bacteria to make the vinegar. And so a lot of it, from what we can tell in, the research is due, I think is due to the effects of that fermentation and how that is impacting, at least related to the blood glucose decrease, it's affecting the absorption of carbohydrates into the blood or the slowed breakdown of the carbohydrates into sugars in our body. And so I really think a lot of it is attributed to the effects of the fermentation. So is it possible that other fermented foods have similar benefits?

Maybe, yes. I think it really depends on the bacteria present in the fermentation process and the impacts that those specific bacteria or their byproducts have. So it can really vary, from product to product, depending on what the food is and what the bacteria are that are doing the fermenting and the impacts that those bacteria or their byproducts would have. But yeah, there could be some of those benefits seen, yes, from other fermented foods. After the break, why it seems like nutrition recommendations keep changing, and how do that, what you read on social media? Okay, so let's move on to our next topic.

There is a group of fruits and vegetables that people are, sometimes suspicious of, and these are nightshades. So these are potatoes, tomatoes, eggs, and some people incorrectly argue that they cause inflammation. But it's my understanding that the opposite is actually true, right? Yes. Yeah, that is true. I think, you know, like you said, people believe or claiming that these cause inflammation and maybe even other health issues have been mentioned as well. You know, some people may associate this with alkaloids, which is a compound found in these plant foods, but in very small amounts, though there really is not a large amount of evidence demonstrating that association. So

those experiences or what people are saying that, you know, is happening here are generally individual experiences and they're not generalizable. And it's not based on research that has been seen, right? There's really no conclusive scientific evidence to support those claims. And like you said, yep, it's quite the opposite that these foods can actually most of them, if not all of them, can help fight inflammation and have very many positive health benefits. So it's possible that some people, some individuals are experiencing inflammation when it's really, that's their body and that's their gut versus the entire population. Yes, exactly. And so some people do have an intolerance for certain foods that they might

relate to something that in truth is really something else. And so in those cases, you know, I would really suggest they meet with a registered dietitian to maybe do an elimination diet or something like that to figure out exactly what it is because it may not be a whole category of foods or, you know, the whole family of nightshade plants. Right. So every few years, it seems like there's a whole new fad diet. So first, it was low fat back in the 90s. And more recently, we've seen keto and low carb diets.

Why does it often feel like what is healthy is constantly? changing. I really think this has to do with, I mean, we always hear this, right? We're always like, nutrition is so hard to understand because, like you said, it's always changing. But I think it's hard for folks to navigate because research is constantly underway, right? And there are people out there who might hear something about one small research study that was done on one small thing and really blow that out of proportion or misrepresent what is actually being said. And then they may make it seem like things are changing or there are new recommendations when there are, in fact, not, right? True recommendations are ones that we as registered dietitians and maybe some other,

you know, physicians and other healthcare practitioners might recommend are usually, you know, true recommendations anyway, are usually based on years and years of research that has shown repeated results over time. So I think this idea that it's constantly changing is really just due to some of this spreading of misinformation because research is counsel underway, even though it's not ready to make a recommendation yet, if that makes sense. So what is your advice to listeners who come across nutrition information online and they maybe have a gut feeling that it's not correct and they want to vet it? What do you recommend that people do?

If you're looking to make a decision on your own, if you come across some information online, well, I've got about five tips that I might recommend. And I think first, people should consider who's offering the information, right? Who is this coming from? What are their credentials and what's their purpose? Right. And even if someone has credentials, I think folks should consider if those individuals or that individual represents a for-profit or if they're an influencer trying to make money or

garner a following, right? Really think critically about who that is. Number two, I think folks should think critically about the recommendations that promise a quick fix or provide any sort of dramatic advice, right? If the claim sounds too good to be true or maybe a little crazy, they probably are. Number three, think about if this suggestion or this advice is providing lists of like black and white lists, like good or bad foods, or maybe they use the word toxic, or they talk about removing foods or even whole food groups from the diet. That's another red flag for sure. And number four, folks should determine if they're

recommendation is based on solid research, right? And the word solid here is key, because if it's not solid, if it's based on, for example, like a personal or non-science-based testimonial, that can be concerning, right? Because that's not science. And even if it is based on research, people should be cautious if those recommendations are based on, like, just one single study or research, you know, where they're stating, like, research is currently underway, which really indicates that there's no current completed research, right? Any sort of worthy nutrition recommendation should be based on robust and repeated research. And then, you know, I just want to say kind of related that to that, despite some of this guidance, people may find it kind of hard,

nonetheless, despite these recommendations, right, to kind of wade through and navigate all that information. And in those cases, I recommend they meet with a registered dietitian who can help talk through some of the issues or concerns that they have related to any nutrition issue. Well, that's all the time that we have for now. Jessica, thanks so much for taking the time to be on the show. Yeah, thank you so much for having me. It's been a pleasure. Jessica Clifford, registered dietitian and nutrition specialist at the Department of Food Science and Human Nutrition at Colorado State University based in Fort Collins. And we want to hear from you. Is there a piece of health information that you've seen recently that makes you skeptical about its accuracy? you can email us or send a voice memo to SciFri at ScienceFriday.com.

You can also leave us a voicemail at 646-767-6532, or you can go to ScienceFriiday.com slash health info to submit a topic. In the coming weeks, we'll bring on another expert to help answer your questions. That's just about all the time we have for today. Lots of folks help make the show happen, including John Dan Kosky, Dee Petersmith, Robin Kassmer, Danielle Johnson. Tomorrow, we're talking meat and potatoes.

We'll dig into the science of the humble potato and how to make plant-based meat taste more like the real thing, including how to get a marbling effect. I'm sci-fry producer Shoshana Bucksbaum. Thanks for listening. We'll catch you next time.