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RHR Research Review: Dietary Intake Reporting, Caloric Restriction, Insomnia, Lion’s Mane, Lifestyle-Lifespan Correlation, Antibiotics & the Gut, and Aspirin


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In this episode of Revolution Health Radio, Chris examines studies related to the tendency of all body types to underreport their caloric intake, how our circadian rhythm potentially impacts the results of calorie restriction, how insomnia in middle age impacts cognitive function later in life, using lion’s mane mushrooms to slow the progression of Alzheimer’s disease, how making healthy diet and lifestyle choices can positively and significantly impact our lifespan, the impact of antibiotic use on the gut microbiome and how it can lead to systemic fungal infections, and whether people should be taking low-dose daily aspirin to help prevent heart attack and stroke.


In this episode, we discuss:

  • Underreporting of caloric intake across individuals of all body weights
  • The impact of circadian rhythm on caloric restriction efficacy and the benefits and downsides of caloric restriction
  • The prevalence of cognitive issues later in life among those who suffered from insomnia during middle age
  • The neuroprotective properties of lion’s mane mushrooms and their potential benefits in preventing the progression of early-stage Alzheimer’s disease
  • How positive diet and lifestyle choices can significantly impact our lifespan
  • How antibiotic use can lead to systemic fungal infections due to their effect on the gut microbiome
  • Recent changes to guidelines on taking low-dose daily aspirin for the prevention of cardiovascular events

Show notes:

Chris Kresser:  Hey, everybody, Chris Kresser here. Welcome to another episode of Revolution Health Radio. This week, I have another solocast episode for you with some of the most interesting recent research and headlines that I’ve come across over the past few weeks.

We’re going to talk about a study showing that most of us dramatically underestimate our food intake. I’ll talk about what that means for nutrition research and for anyone on a weight loss diet. This is something that I have mentioned a number of different times [before], [and] it’s one of the biggest weaknesses of nutrition research. This is a really interesting new study on that topic. Then we’ll review a study that looked at how our circadian biology, which is our daily rhythms of sleep and wakefulness, impact[s] the results of calorie restriction in mice, and the practical implications of that for human beings. We’ll talk about new research showing that insomnia during middle age leads to cognitive issues later in life. This isn’t a big surprise, but I think it’s another really good reminder for us to take insomnia seriously and address it when it arises. We’ll discuss a recent study on lion’s mane mushroom compounds and their potential impact on Alzheimer’s disease, both prevention and treatment. We’ll review a study that might seem too obvious to [even] talk about, at least on the surface, [which] found that making good lifestyle choices extends our lifespan. I want to talk a little bit about it because I think this doesn’t get the attention it deserves, and most people underestimate the impact that good lifestyle choices [have] on our health span.

We’ll cover a study on how antibiotics can lead to a much greater risk of fungal infections because they impact the gut microbiome adversely. I always smile when I see studies like this because, in the past, the idea that you could even have a fungal infection or fungal overgrowth like Candida was considered to be a quack idea in the conventional medical world. Now, I’m seeing studies like this almost every week. So [I’m] looking forward to talking about that. Then last but not least, we’ll talk about a change in the U.S. recommendation to take a low-dose aspirin every day for cardiovascular disease prevention for people who are middle-aged and older. This is really significant. Definitely stick around for that last piece because this has really important implications for middle-aged and older adults [who] are currently taking a low-dose aspirin. Alright, let’s dive in.

Underreporting of Caloric Intake Across Individuals of All Body Weights

The first study was called “Obese individuals do not underreport dietary intake to a greater extent than nonobese individuals when data are allometrically-scaled.” What the researchers were trying to study here is [the] idea, [which] was based on some earlier studies, that obese and overweight individuals tend to underreport their food intake more than lean individuals. And this study found that that’s not the case. Lean individuals underreport their calorie intake to the same extent that overweight and obese individuals do. What I found to be most interesting about this study is that everybody across the board, no matter what their body weight, pretty dramatically underreports their calorie intake. In fact, on average, everybody eats the equivalent of three cheeseburgers a day more than they admit to eating. So we’re not talking about small differences; we’re talking about pretty big differences. The reason that this is such a big issue is that in most cases, with nutrition studies, researchers use something called a food frequency questionnaire, or other methods that depend on the individual’s memory of what they ate, and [on them] reliably reporting what they ate on some kind of a questionnaire.

Whenever I talk to people about this, they’re shocked [that] that’s how nutrition studies are performed because they are well aware that memory is not a very reliable tool when it comes to reporting food intake. If I ask you what you [had] for breakfast this morning, chances are, you’re going to remember that pretty well. If I ask you what you had for lunch two days ago, you might also remember that, but if I asked you to list all of your food intake from several days ago, you’re almost certainly not going to remember that, and you’re certainly not going to be able to report it accurately. I may be exaggerating a little bit here, but this is generally in the past how food intake has been assessed for nutrition studies. There’s such huge potential for introducing all kinds of error and bias here. Most people not only underreport their calorie intake, [but] they underreport their intake of foods that they perceive to be unhealthy because they don’t want to be judged by the researcher. It’s just a natural human tendency. A lot of people in the studies are susceptible to that, and [it’s] another reason that the data collected for these studies tend to be quite unreliable.

In terms of how this relates to day-to-day life [for] those of us who are paying attention to what we eat, and for folks who are trying to lose weight and maybe even engaging in voluntary calorie restriction in order to do that, it’s just a reminder that using our memory to determine how much we’re eating is not a really reliable tool. If you are trying to carefully track what you eat and reduce the amount of calories that you eat, then it’s probably best to use one of the many apps that are out there and be pretty methodical about recording what you eat and using something like an app to determine your calorie intake rather than just winging it and relying on your memory. Because as we see in this study, that’s not a reliable metric.

Regarding calorie restriction, I’m going to talk a little bit more about that in the next study, but I should mention that most research has shown that voluntary calorie restriction where you’re intentionally reducing calories is not a very effective strategy for weight loss. I’m not getting into the debate about calories in-calories out versus macronutrients like low carb [and] low fat. I’m simply commenting on the research that looks at whether calorie-restricted diets are actually effective in the long term. And generally, they’re not. Because most people are not able to overcome the hardwired biological mechanisms that kick in when we eat fewer calories than our brains think we need. In an ancestral environment, food scarcity was a much bigger problem than food abundance, which is the biggest problem in our current environment, at least in the Western world. Most of our ancestors didn’t have to worry about eating too much; they had to worry about not getting enough food. So our brains have several different mechanisms for ensuring that we don’t eat too little food. These include things like, if our calorie intake starts to fall below what our brain thinks is required, then our appetite will go up; we can start absorbing more calories from the same amount of food that we eat, so we actually become more efficient at extracting those calories, and then our basal metabolic rate, our resting energy expenditure will decrease as the body tries to conserve energy. All these mechanisms work against any kind of effort toward voluntary calorie restriction. It’s important to know that the brain may be defending a weight that is unhealthy or higher than we think it should be, than our doctor thinks it should be, [or] than health guidelines think it should be. But that doesn’t matter. From the brain’s perspective, it’s protecting us against starvation, and it has some pretty powerful tools to do that, and most human beings are not able to successfully override those hardwired mechanisms for more than just a short period of time. That’s why voluntary calorie restriction is not typically that effective for most people.

Impact of Circadian Alignment on the Effectiveness of Caloric Restriction

Let’s [move] on and talk about the next study, which is somewhat related. This was called “Circadian alignment of early onset caloric restriction promotes longevity in male C57BL/6J mice.” I want to emphasize [that] this was a study in mice, not in humans, but it was a pretty interesting study. They looked at the effects of circadian rhythm on biology. This is a very hot topic in the research world and, in particular, in people who study the neurobiology of weight loss. We know from a lot of previous animal studies that calorie restriction can extend longevity. But this study suggests that the body’s daily rhythms may play a pretty significant role in that. The researchers followed hundreds of mice over their lifespan and found that in the mice that were restricted [in] calories, those who ate only in the most active part of their day had an extended lifespan compared to mice that were also eating in the less active part of the day. This can shed light on the mixed results that we see in time-restricted eating studies in humans. For example, there have been some studies that have come out recently [showing] that time-restricted eating doesn’t necessarily lead to weight loss, and doesn’t always lead to metabolic improvements in things like blood sugar or insulin levels. What this study suggests is [that], even if that’s the case, there may be other mechanisms that time-restricted eating engages that can extend lifespan, even when weight loss or changes in blood sugar levels aren’t happening.

So what do we make of this? As I said, we know that calorie restriction extends lifespan in a whole range of animals from worms and flies to mice, rats, and even primates. But that’s been difficult to confirm in humans because humans have pretty long lifespans relative to other animals, and it’s not possible to lock someone in a metabolic ward for their whole lifetime and restrict their calorie intake and perform a controlled study. Those conditions just don’t exist, and they won’t happen. So we’ve been left to wonder, to some extent, whether some of these impacts that we see in other animals would transfer over to humans. And it’s not just about extended lifespan. Calorie restriction has also been shown to lead to weight loss, improved blood sugar regulation, lower blood pressure, and even reduced inflammation in those animal studies. I think there’s a reasonable assumption that calorie restriction in humans may produce some of the same effects. And I think we could also perhaps reasonably assume that the same effect that was observed in this study with mice, where all of the mice were eating a calorie-restricted diet, but the best effects were found in the mice that were only eating during the most active time of day. If we put that in practical terms for humans who are following a time-restricted eating approach, the best window for food intake would likely be in the morning and during the day because that is typically the most active time for humans. Of course, it varies now; people are working different schedules and shifts. But let’s say you’re generally awake and active during the daylight hours and less active during the nighttime hours. Then doing your food intake window from something like 10:00 to 5:00, or 10:00 to 6:00, is probably better than doing it from like 12:00 or 2:00 in the afternoon until 8:00 or 10:00 at night. Because those daylight hours regulate the exposure to sunlight through our eyes, impacts our chronobiology, and leads to a whole bunch of changes in the body that make us more primed for food intake. I think that’s an important takeaway from this study. If you’re following time-restricted eating, it’s best to do that during the hours that you’re most active, whatever those hours are.

Now, going back to what we talked about in the last study, is it a good idea to follow a calorie-restricted approach to extend your lifespan and get these other benefits? I think there’s a challenge with voluntary calorie restriction that I mentioned, where there tends to be a bunch of rebound effects that are somewhat undesirable, and then [also] just sticking with the voluntary calorie restriction over time can be difficult. The third thing is that, while restricting calories might extend lifespan and lead to some of those other benefits, it doesn’t mean that it’s not without potential downsides. Many years ago, my friend and colleague Robb Wolf, who was a research biochemist as an undergrad and one of the modern fathers of the Paleo movement, introduced a framework for thinking about this question that really stuck with me and I still use, which is that if you imagine a triangle, on the top of the triangle is performance, on the lower right of the triangle is longevity, and the lower left of the triangle is health. It doesn’t matter where those things are in the triangle, but those are the three points of the triangle. Robb argued, and I agree with him on this, that it’s impossible to optimize for all three of those points of the triangle simultaneously. For example, if you want to optimize for performance above all else, and you’re a competitive weightlifter or something like that, and you’re not concerned with rules or regulations, or health or longevity, you’re probably going to take steroids or do a bunch of other stuff that will totally [boost] your performance at the expense of your health and longevity.

Likewise, if you prioritize health over all else and by health, I mean the full spectrum of health—how you feel, your well-being. I would include performance and health and longevity as factors in health, but not the only factors. You’re just trying to live the best life you can, a balanced life. You may not have the same level of performance, going back to the weightlifting analogy, as someone who’s taking performance-enhancing drugs and pulling out all the stops, because they don’t care about their health or longevity. Coming back to the study we’re talking about now, if you optimize for longevity, you might make choices like significantly reducing your calorie intake, and that could definitely lead to a longer life, if the animal research holds true for humans. But you might be cold and miserable for a lot of your life and not really enjoying your life as much in the present and perhaps not feeling quite as healthy. So that’s really how I think about this. Everybody has to decide what’s best for them in that triad and what they’re optimizing for. For me, I optimize for health because I believe that will [still] lead to very high levels of performance and great longevity, but [also] a life that’s much more enjoyable and rewarding while I’m living it. That’s just my approach. Yours may be different. But I think that’s a helpful framework and way to think about it.

Insomnia Symptoms in Middle Age Associated With Poorer Cognitive Function After Retirement

The next study is one that looked at the incidence of insomnia during middle age, and then the prevalence of cognitive issues in people who struggled with insomnia at that time in their life. It’s another very long title, “Trajectories of Insomnia Symptoms Among Aging Employees and Their Associations With Memory, Learning Ability, and Concentration After Retirement.” One of the good things about this study is [that] it was a very long, prospective cohort study with an extended follow-up period of 15 to 17 years. They followed the participants for quite a while, which means they were able to collect and analyze a lot of data, and it strengthens the validity of the results. The researchers found that long-term insomnia symptoms can pose a risk of poor cognitive functioning later in life, especially memory, learning ability, and concentration. I’m sure most of you listening to this podcast already know how important high-quality sleep is. It’s received a ton of attention over the past several years from myself and many other people in the health world, and I’ve come to believe that high-quality sleep is probably even more important than diet because you can live for quite a long time on a crappy diet, and many people do. But you can die from not sleeping [at all] for just a few days. There are so many studies now [showing] that even a single night of disrupted sleep can decrease insulin sensitivity, increase blood sugar levels, lead to poor choices around food, increase inflammation [and] oxidative stress, and so many other harmful effects. This study makes it even more clear that insomnia should be addressed when it’s present because cognitive issues and more advanced concerns like dementia and Alzheimer’s [disease] are on the rise. Alzheimer’s [disease] has been climbing the list of the top causes of death in the [United States], and it’s a scary condition for anyone who’s experiencing it themselves or for their loved ones who are caring for them. I think we can all agree that we want to do everything we can to protect our cognitive health as we age and our brain health and avoid conditions like dementia and Alzheimer’s [disease] if at all possible.

I’ve talked a lot over the years about tips for improving sleep, so I’m not going to go through the exhaustive list here. I have a recent article on this called “8 Tips for Beating Insomnia and Improving Your Sleep.” I’m going to briefly cover a few of them to jog your memory. I think a lot of this will be a review for many of you. One is restricting artificial light at night in the bedroom. I talked about [this] a few shows back. It’s really important, and it’s pretty easy to do. Replacing your digital alarm clock with an analog clock, getting blackout shades, wearing a sleep mask, whatever it takes to make your room dark is super important. Another is keeping your sleep environment cool. There’s a couple [of] different ways of doing that. One is to control the ambient temperature in the room [by using] air conditioning or opening windows or whatever. Another is to control the sleep surface, [which is] usually a bed. That’s even more effective because studies have shown that cooling the sleep surface will lead to greater reductions in core body temperature, which is what we’re going for. I’ve been a big fan of devices like the ChiliPad [which is part of the] OOLER [Sleep System by ChiliSleep]. This is a pad that you put on your mattress and it uses tubes with water circulated through the pad to cool [the] pad, and that’s the sleep surface that you’re on. That can be an absolute game changer for people.

Another approach is to eat your carbohydrates later in the day. It’s called carbohydrate backloading. We know that melatonin is synthesized in the pineal gland from serotonin, and eating carbohydrates at night can lead to a greater increase in serotonin, which might also increase melatonin levels. So that’s something to consider. Another tip is to manage your stress [throughout] the day. I’ve always said [that] if you run around like a chicken with your head cut off during the day and then you expect to just push a button, say it’s time for sleep, and then fall into a deep and restful sleep, that’s just not going to happen. That’s not how our biology and our brains work. Taking steps throughout the day to manage stress and regulate the nervous system, whether that’s mindfulness, meditation, yoga, Qigong, walks, spending time in nature, breathing techniques, whatever it is, doing even a little bit of that throughout the day can make a huge difference when it comes time to sleep. Likewise, exercise is key. I’m sure many of you have experienced that. For me, that’s one of the biggest factors. If I’m busy traveling for work, [if] I’m in a conference or something and I don’t have time to exercise like I normally do, it will definitely impact my sleep. It makes a big difference.

Getting exposure to bright natural light during the day is another key factor that helps entrain our circadian rhythms and ensure that cortisol production is solid during the day and melatonin production is strong at night. The [last] thing I want to mention here is [that] it’s really, really critical to identify and address any sleep-related issues like apnea or restless leg syndrome. Sleep apnea is extremely common, and the vast majority of people who have it don’t know that they have it. There are a growing number of at-home sleep tests that you can get now. It used to be a real pain in the butt to get a sleep study. You had to go into a formal sleep clinic, spend the night there, and get hooked up to tons of wires. It always struck me as being really artificial. It’s not the kind of environment that many people sleep in, it’s cumbersome, and it’s expensive, especially if insurance isn’t going to cover it. But there are tests like the WatchPAT that are [U.S. Food and Drug Administration] (FDA) approved now, and [while they] may not be quite as accurate as a formal sleep study, they’re still very accurate and more than accurate enough to diagnose obstructive sleep apnea. We used them on our patients for many years, and we’ve consistently found people who are struggling with sleep apnea who didn’t even know that they had it. When we correct that, either with a mandibular advancement device [or] a dental treatment, or if they get a [continuous positive airway pressure] (CPAP) [machine], or any number of other approaches, then [not only does] their sleep improve dramatically, but their overall health also improves dramatically. I think this is something that’s really important to pay attention to, and it’s something that’s often missed, so just keep that in mind. If you are struggling with insomnia, whether you’re in middle age or younger or older, definitely check out that article. I think if you employ even a few of those strategies [in my “8 Tips for Beating Insomnia and Improving Your Sleep” article], you should see pretty significant results.

I also want to mention that when we release the ADAPT Naturals Core Plus supplement bundle in July, which you may have heard the announcement [about on] the past couple of podcasts or if you’re on the email list, we also built an app called Core Reset. This app is designed to help you get your diet and lifestyle totally dialed in. Because as amazing as our supplements are, you cannot supplement yourself out of a bad diet and lifestyle. We wanted to put our money where our mouth is, so to speak, and really give people the tools they need to clean up their diet and improve their sleep, their physical activity, and their stress management. We’re giving this [app] away for free to all customers who buy the Core Plus bundle. I’m really excited about that. I think it’s going to be an amazing resource. We’re definitely going to have a full week in that program that’s dedicated to improving sleep, with lots of videos, audios, guided meditations, guided relaxation exercises, [a] full Qigong series, and a bunch of other stuff that will help you take the next step toward calming and regulating your nervous system and getting better sleep. So look out for more on that in the weeks to come.

Tune in to hear my thoughts and insights on some recently published studies and headlines that I’ve found especially interesting in this episode of Revolution Health Radio. #chriskresser #educator #insomnia #lionsmane #antibiotics #aspirin

Lion’s Mane Mushroom and Alzheimer’s Disease

This next study is really exciting. This is about lion’s mane mushroom compounds and Alzheimer’s disease. As I mentioned earlier, Alzheimer’s [disease] is now the fifth leading cause of death, and the cases are increasing significantly and projected to rise pretty dramatically over the next several years. That’s really bad news because Alzheimer’s [disease] is a terrible disease. Not just for the people who experience it, but for all of their loved ones and people around them. I’m sure that many people listening to this podcast know someone in their life, perhaps even a loved one, family member, or friend, [who] has dementia or Alzheimer’s [disease], and you’ve seen firsthand the damage it can do. The other challenge with this, of course, is that we don’t currently have a lot of great treatments for Alzheimer’s [disease]. I’ve had Dr. Dale Bredesen on the show a few times. He’s done pioneering work in looking at how diet, lifestyle, and other factors contribute to Alzheimer’s [disease] from a Functional Medicine perspective and what we can do to prevent and reverse that condition. Definitely check out those episodes if you haven’t heard them already.

Having said that, there’s still a really big need for additional treatments, and particularly treatments that are safe and well-tolerated and natural and unlikely to cause harmful side effects and adverse effects over time. One of those treatments, or food compounds, is lion’s mane mushroom. We had a lot of cell culture in vitro studies in the past that suggested that lion’s mane has really potent neuroprotective properties, but until recently, there weren’t a lot of human clinical trials to back that up. That’s now changing, which is really exciting. This study was called “Prevention of Early Alzheimer’s Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study.” This was a 49-week, double-blind, placebo-controlled study, so [the] gold standard in medical research, and the patients were randomized into two groups. One group took a 5-milligram capsule [of] lion’s mane mushroom three times a day, [for] a total of 15 milligrams. The other [group] received a placebo. Those taking lion’s mane saw significant improvements in the scores that the researchers used to assess the progression of Alzheimer’s [disease]. One was called the Mini Mental State Examination score and the other was the Instrumental Activities of Daily Living score.

The people taking lion’s mane saw those scores go up, whereas the people who were taking [the] placebo did not see an improvement in those scores, and they actually saw a decrease in the cognitive ability screening instrument score. The placebo group also saw a decrease in biomarkers like calcium, albumin, apolipoprotein-E4, hemoglobin, and [brain-derived neurotrophic factor]. And they saw elevations in alpha1-antichymotrypsin and amyloid-beta peptide 1-40 over the study period. That’s probably a lot of unfamiliar terms, but the gist of that is that, in addition to seeing no improvement or a decline in cognitive abilities based on those scoring instruments, the patients who were taking placebo also saw a change in biomarkers that is consistent with a worsening of Alzheimer’s [disease], whereas the patients who were taking lion’s mane did not see that change in biomarkers. Again, this is a really exciting study. When we combine other diet and lifestyle interventions that I’ve talked about with Dr. Dale Bredesen, lion’s mane could offer additional help for supporting brain health as we age.

Positively Impacting Our Lifespan with Healthy Lifestyle Choices

The next study is perhaps a, “Duh, I already knew that,” study. But I think it’s interesting, so let’s talk about it. It’s called the “Impact of modifiable healthy lifestyle adoption on lifetime gain from middle to older age.” This was a study that used data from the Japan Collaborative Cohort, or JACC, Study Group out of Osaka University. It’s a really large research project with almost 50,000 people, [and] it was conducted from 1988 to 1990 in 45 different areas of Japan. The researchers looked at how a range of factors including diet, exercise, alcohol intake, smoking status, sleep duration, and body mass index (BMI) impact lifespan. What they found when they analyzed [these] data was that the factors that had [the] biggest impact were reducing alcohol intake, not smoking, losing weight, and increasing sleep. So again, we’re talking about the importance of sleep. That was right up there with alcohol, smoking, and losing weight as one of the top four factors that affected lifespan. People who did the best on those four factors added up to six years of life, starting from age 40 onward. They also found in this study that there were benefits [of] these healthy lifestyle choices, even in people who were 80 years old or greater, and for people who already had pre-existing health conditions.

Again, this is not a big surprise, right? It’s fairly obvious to most of the people who are listening to this show that making good diet and lifestyle choices is going to have a positive impact on our lifespan. But I’ve found, as I said in the intro, that people tend to underestimate just how significant that impact can be. And most people are not making the best choices because data from the [Centers for Disease Control and Prevention] (CDC) suggest that only 6.3 percent of Americans consistently engage in the top five health behaviors, which according to the CDC are never smoking, getting regular physical activity, drinking fewer than five drinks at one sitting, maintaining normal body weight, and sleeping seven to eight hours per night. So we’re not talking about super advanced health strategies here like infrared sauna and cold therapy and pulsed electromagnetic field (PEMF) therapy and meditating for an hour a day. We’re talking about [the] basics here like not smoking, getting enough exercise, drinking fewer than five drinks at a sitting, having a normal body weight, and getting enough sleep. Six percent of Americans consistently engaged in those five health behaviors. So we know there’s a ton of room for improvement here. I suppose that’s the glass half full way of looking at it.

On the flip side, a study in the journal Circulation a [few] years ago found that adopting five healthy life habits can extend lifespan by an average of 13 years. That’s even greater than what was found in this particular study out of Japan that we’re talking about. And those habits were very similar to the CDC’s top five health behaviors with one exception. They were not smoking, maintaining a healthy BMI, not drinking excessively, [and] doing 30 minutes a day or more moderate to vigorous physical activity. All four of those were part of the CDC’s criteria. But the fifth one in this study was eating a healthy diet. I’m doing air quotes here, “healthy.” They didn’t go into a lot of detail on what comprised a healthy diet. It was, I think, more of a whole-foods diet versus eating tons of processed and refined foods. So again, not getting really fine tuned here on these health behaviors. They’re just talking about the basics. And if you follow the basics, you can expect to live, on average, 13 years longer. That’s an average number, so for some people, it was a little bit less than that. But for some people, it was more than that. [And] you can imagine that in some cases, especially [in] people who were going beyond those five basic health behaviors and engaging in more physical activity, or eating a really healthy diet, or taking supplements to optimize nutrient needs, or doing things like occasional intermittent fasting or time-restricted eating, or infrared sauna, all the stuff that we talk about [and] that many of you are probably engaged in to some extent, it’s likely even more than that. [It] could extend your lifespan by 20 years, let’s say. That’s an enormous number. We’re not talking about a small increase. We’re talking about potentially living 20 years longer than the average lifespan in the [United States], which is already in the upper 70s in terms of age. And we haven’t even started talking about socioeconomic factors or other things like that, which are also known to impact lifespan.

I like to share these figures because in all the people I’ve worked with, and the coaches we’ve trained and doctors we’ve trained, I think people are often still surprised by the extent of the impact that making good choices can have in terms of their health span and their lifespan. [By] potentially 13 years in the Circulation study, and [likely] more than that if you’re doing other things. This is a great reminder that our choices do matter a lot. And also, from the Japanese study, that it’s never too late to start. People who are in their 80s who started making better lifestyle choices were able to extend their lifespan. Of course, the earlier you make those choices, the more of a benefit you could probably expect. But that’s not a reason not to start.

Antibiotics and the Gut Microbiome

[The] next study is one that found that antibiotics can lead to fungal overgrowth in the gut and consequently, systemic fungal infections because of the effect of antibiotics on the gut microbiome. So it was called “Long-term antibiotic exposure promotes mortality after systemic fungal infection by driving lymphocyte dysfunction and systemic escape of commensal bacteria.” I’m going to translate this into English. Researchers basically found that taking antibiotics disrupts the immune system of the intestines. Not a big surprise. We’ve known this for decades now. But a couple of things that were made even more clear by this study is that antibiotics lead to fungal overgrowth in the intestines, those fungal organisms poke holes in the gut, making it permeable, and then the fungal organisms can escape into the bloodstream and cause systemic fungal infections, which in immunocompromised people in a hospital setting can be fatal. It’s really difficult to treat invasive candidiasis in a hospital setting. This has been a big deal for many, many years. We don’t have great antifungal drugs compared to antibiotics, and those systemic fungal infections are much more difficult to treat. So this is definitely an area of interest, particularly in the hospital world, where people are immunocompromised and this is a much bigger deal.

The other piece of information that came out of this study is that the researchers found that gut bacteria from both friendly and harmful bacteria were able to escape in this situation. Because of antibiotic use and then the increase in fungal overgrowth [and] the gut becoming permeable, bacteria from the gut were able to enter the bloodstream, and that increased the risk of systemic bacterial infection. That’s not good either. Even though we do have better tools for treating those kinds of infections compared to systemic fungal infections, they’re still difficult to treat. And because of growing antibiotic resistance, they are a serious problem. Bacterial infections still kill many, many, many Americans each year and people around the world. As I said in the intro, I sometimes do a bit of an eye roll when I read these studies because, especially in the reporting around them, there’s a lot of hyperbole about what a phenomenal discovery this is. There’s never any mention of the fact that even just 15 or 20 years ago, if you walked into a room of conventional doctors and started talking about fungal overgrowth, whether it’s a side effect of antibiotics or anything else, and you mentioned the word Candida, you would have been immediately labeled as a quack and they would have been rolling their eyes. Yet, over the years, and especially in the past five years, there’s a growing body of research that confirms that, yes, fungal overgrowth is real. We all have some yeast in our digestive tract; that’s normal. That’s not a problem. But when we take antibiotics or do other things that disrupt the delicate balance of all the microorganisms in the gut, then fungal organisms can become over represented and you can get an overgrowth of fungal species like Candida albicans, [which] is one of the main species that can become opportunistic and take advantage of that situation. Now we have lots of studies showing that overgrowth of Candida and other fungal organisms in the gut is a risk factor for inflammatory bowel diseases like Crohn’s [disease] and ulcerative colitis. In this study, it can increase the risk of systemic fungal infections and also systemic bacterial infections and can cause a whole host of other problems.

I’m just happy to see that this is finally being recognized in the conventional medical establishment. We’re seeing a lot of studies that give us insight into all the problems that fungal overgrowth can cause. Hopefully, now people will be able to go see their conventional gastroenterologist and get testing for fungal overgrowth and treatment for it. Because until now, and even still now, in most cases, I think that’s been impossible. You may recall that a while back, I talked about SIFO, which is small intestinal fungal overgrowth very similar to SIBO, which is small intestinal bacterial overgrowth. As a clinician, I began to suspect that a lot of my patients with SIBO had something else going on because they weren’t responding to treatment for SIBO. I did a lot of research and started to discover some small but interesting studies on SIFO and believed, although we didn’t have a ton of research, that a lot of our patients who were not responding to SIBO treatment actually had SIFO and maybe that was even the more prominent condition. When we started treating them for SIFO, they got better. So [it’s] a fascinating area of research, and I hope to see more papers like this in the future, and I’ll definitely share them with you.

Changes in Low-Dose Aspirin Therapy for Prevention of Cardiovascular Disease

Last but not least, [we have] new guidelines from the U.S. Preventive Services Task Force, which is an independent panel composed of experts in disease prevention and evidence-based medicine, on whether people should be taking low-dose aspirin for prevention of cardiovascular disease. As you probably know, this has been a recommendation for many years in the [United States] and other countries that middle-aged people and older [people] should take low-dose aspirin every day to lower their risk of heart attack and stroke. I’ve been critical of this for many years because according to my reading of the research, the risks outweigh the benefits. So I was happy to see that the U.S. Preventive Services Task Force released an update. They are no longer recommending low-dose aspirin for people who are not at high risk of heart disease and, more specifically, for people who have not already had a heart attack or stroke. That’s a huge change. In the past, it was recommended that pretty much everybody middle aged and older take low-dose aspirin, even if they hadn’t already had a heart attack or a stroke. Now the task force is saying that they’ve reviewed the research, and they found that taking low-dose aspirin to prevent a first heart attack or stroke may have only a “small net benefit” for people aged 40 to 59 who are at higher risk of cardiovascular disease. For healthy people and even for people who are at high risk, the benefit is very small. Most importantly, they found that [the] benefit is often outweighed by the risk of significant bleeding events that can be caused or can be increased by taking low-dose aspirin. And those bleeding events can be fatal, especially in the elderly.

These new guidelines suggest that people who have not had a heart attack or stroke should not take daily aspirin, even at a low dose, although they do still suggest that for people who have already had a heart attack or a stroke. [It’s] really important, [this] new recommendation and [the] research [it’s] based on. Many people think that aspirin is safe, almost like a vitamin, and that [idea] has been encouraged. That belief didn’t come from nowhere. These are recommendations that came from public health authorities. But the reality is that aspirin can alter the natural structure and function of red blood cells, as well as how blood flows through our veins and arteries. This is called hemodynamics. These foundational changes that aspirin causes in hemodynamics and the structure and function of red blood cells explain why aspirin has such a wide range of adverse effects, even at relatively low doses like baby aspirin. Aspirin has been associated with everything from increased risk of ulcer to hearing loss and tinnitus, bleeding in the brain, [an] increase in influenza mortality, Crohn’s disease, Reye’s syndrome, [and] increased risk of Helicobacter pylori infection. And some of those effects are observed even at the lower dose, like 80 milligrams, rather than the full adult dose of 325 milligrams.

What do we do with this information? I think obviously, if you’re taking low-dose aspirin [daily] right now and you have not had a heart attack or a stroke, regardless of your age, these recommendations suggest that you shouldn’t do that anymore. You should talk to your doctor about it or your clinician, whoever made that recommendation in the first place, and point them toward these new recommendations. You can also consider other steps [to] take from a diet, nutrition, and lifestyle perspective that could lower your risk of cardiovascular disease without increasing the risk of adverse events that are associated with taking a baby aspirin daily. There are a whole range of things to consider. The long-chain omega-3 fats like [eicosapentaenoic acid] (EPA) and [docosahexaenoic acid] (DHA) have been shown to have a mild blood thinning effect without increasing the risk of bleeding. Increasing the amount of seafood [and] coldwater fatty fish that you eat and/or taking fish oil or cod liver oil at a moderate dose could be helpful. Dark chocolate has some anti-platelet effects on a milder scale. I’m sure you won’t be upset to hear me say that eating dark chocolate on a daily basis might help with that. There are some common herbs and spices that you can add to your food that are known to inhibit thrombosis without prolonging bleeding time. Garlic is one of them, turmeric is another, thyme, rosemary, [and] tarragon. All of those are readily available, cheap spices that you can use in your cooking to help. And curcumin, which is an extract from turmeric, and pycnogenol, which is a pine bark extract. These have been shown, along with other nutrients like sulforaphane, to have a mild blood thinning effect. And they have a number of other benefits, as well. If you’re taking those for any reason as anti-inflammatories, or for histamine in the case of pycnogenol, or if you want to take them for their mild blood thinning effect, you should check with your clinician or practitioner that you’re working with. Or you can experiment with those on your own, but be aware that those supplements would be contraindicated if you are taking a blood thinner. So you definitely want to be careful with that and at least check with your clinician before you start doing that on your own.

Okay, everybody. [I] hope you enjoyed the show. Please keep sending your questions to ChrisKresser.com/podcastquestion. Even though we haven’t been doing as many Q&A episodes, the questions actually inform the topics that I pick for these solocast research review episodes and the guests, as well. So we’d love to hear from you. Keep sending them in there, and I will talk to you next time.

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