Research Update: Ultra-Processed Foods

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Ultra-processed food (UPF) has been in the news again with several research papers published in the last few months. After I read the press releases as well as several articles by health columnists, I found and read the research papers. I’ve narrowed it down to three questions about UPFs plus my own question, which I’ll save for the final memo in this series.

Let’s begin with a working definition of ultra-processed foods: substances extracted from foods that are altered chemically or mechanically, combined with flavor enhancers and other additives, and formed into consumer products that are highly palatable. They are generally high in calories and appeal to every taste sensation humans possess. The manufacturing techniques themselves can change the structure of the original component and include extrusion, molding, and preprocessing by frying. Simply stated, UPFs are designed to be irresistible to eat and keep eating; if you’ve ever been handed a bag of Cheetos, you know what I mean.

The first question is simple: Do UPFs in the diet contribute to an increase in calorie intake? The answer is yes. Population studies of nutritional intake have demonstrated that countries where UPFs are available show additional caloric intake when compared with people who have low intake of UPFs. These studies are based on food frequency questionnaires, which are not my favorite way to analyze diets, as I’ve said repeatedly.

However, the increase in caloric intake in well-controlled studies where people are offered a UPF-based diet was found to be up to 500 calories per day more than on a diet that doesn’t contain UPF foods. It seems clear that eating UPF foods can result in extra calories. I’ll tackle the next question on Saturday.

Tomorrow night is the Insider conference call. If you want to participate, simply sign up as an Insider no later than 8 p.m. Eastern Time.

What are you prepared to do today?

        Dr. Chet

References:
1. Food Funct. 2016 May 18;7(5):2338-46. doi: 10.1039/c6fo00107f.
2. Food Funct 2017 Feb 22;8(2):651-658. doi: 10.1039/c6fo01495j.3. https://doi.org/10.1016/j.cmet.2019.05.008

Beating the Heat

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Climate change is real, and it doesn’t really matter whether it’s man-made or a natural progression of the planet. At least for the foreseeable future, temperatures are rising, droughts are more common, and the storms are more severe. We will most likely see excessive temperatures for days, even weeks at a time. While everyone is at risk, especially those who work in the heat and humidity, children and those 65 and older are more at risk because one of their cooling mechanisms is not working effectively. Today we’ll look at signs and symptoms of heat stress as well as solutions.

Heat Stress in Infants and Children

These signs and symptoms may not all happen within the same child at the same time, but if you see more than one of these symptoms, it may be related to heat rather than fatigue or a possible infection.

Elevated temperature, usually between 100˚ and 104˚F

I don’t think I would have thought to check their internal body temperature to see if the internal cooling mechanisms were working, especially if they were experiencing the next couple of signs and symptoms.

Cool, clammy skin and goose bumps

Those seem more related to being too cool rather than too hot, so checking the internal temperature is a good idea.

Irritability

There can be other reasons such as teething, lack of sleep, or hunger, but this may be an important sign for little ones who can’t communicate well.

More serious signs and symptoms

  • Fainting, dizziness, or weakness
  • Headache
  • Increased sweating
  • Increased thirst
  • Muscle cramps
  • Nausea and/or vomiting

It may be difficult for babies and children who are just learning to talk to communicate a headache or muscle cramps, but I think we would all recognize that fainting, dizziness, and weakness—or vomiting for sure—means something is not quite right.

Heat Stress in Older Adults

Those who are older, generally 60 and up, have some similar symptoms as the young. While infants and toddlers may not be able to communicate effectively because they haven’t learned how to talk yet, those who are older tend to ignore symptoms that may be related to heat stress.

One of my favorite quotes from my father-in-law was his answer whenever I was trying to determine whether he might be having a cardiovascular event such as a heart attack: “Dad, do you have any chest pain?” And his classic response was, “Not too much.” With that stoicism in mind, here are the signs and symptoms of heat stress in older people.

Heavy sweating

If they are fortunate to still have a sweat cooling system, you may notice an unusual amount of sweat.

Cold, pale, and clammy skin

If the internal cooling system isn’t working well, you’ll see this symptom.

Fast, weak pulse

Elevated heart rate may go along with cold and clammy skin because the heart is working harder to pump blood to the skin for cooling.

Other symptoms

  • Muscle cramps
  • Nausea or vomiting
  • Tiredness or weakness
  • Dizziness
  • Headache
  • Fainting

As you can see, there are many similarities in symptoms between the young and the old. The difference in what causes the symptoms is that the children’s systems are developing while the adults’ systems are degenerating.

Heat Action Plan for People at Risk

In the research, the most common recommendations are to stay in the air-conditioned indoors if possible. If that’s not possible, still stay indoors, preferably with fans; if the air is off at home, take a trip to the mall, the movie theater, the library, or another place where you can stay cool for a while. Another recommendation is to drink liquids; mostly water but depending on sweating, a sports drink has electrolytes that can replace those lost while sweating. Too much plain water can dilute electrolyte balance and cause hyponatremia, the lack of sodium in the body.

If you don’t have to go outdoors, don’t. If it can’t be avoided, go outside in the early mornings or the evenings. From the Midwest to the East Coast, we also must deal with poor air quality due to the fires in upper Canada. Again, staying indoors and out of the sun is a great prevention strategy.

Finally, observation is critical for both children and older adults. As a grandparent, I know it’s nice when the kids are outside and the house is quiet; but some children are not old enough to tell you what’s wrong or just don’t know that what they’re feeling isn’t normal, so it’s critical to observe them. That also applies to the older adults in your life; check in with them frequently to make sure they’re doing okay.

The Bottom Line

What happens if you suspect heat stress? Check the symptoms. Try cool baths or showers, and wear as few clothes as is realistic. Drink cold fluids and use ice compresses. Get the kids to sit in the shade and eat a popsicle, thus attacking the problem in two ways.

But if you get as far as the symptoms of dizziness, weakness, or fainting, it may be time for a visit to the ER, especially if there are other health challenges. We can deal with the heat if we just play it smart and look out for each other.

What are you prepared to do today?

        Dr. Chet

Reference: https://www.cdc.gov/disasters/extremeheat/heat_guide.html

No Sweat!

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I don’t know exactly when it happened—suddenly I don’t seem to sweat. Disappointing, because it was something that I looked forward to, believe it or not. To me it symbolized getting a good workout, whether during exercise or working in the yard, but it stopped as I approached 70. That means one of my cooling mechanisms isn’t working well during exertion. It also seems to happen in the heat, and it’s not uncommon in people past middle age. How about you? Have you noticed any changes?

I’m not alone. There’s another at-risk group: babies and children, especially during the kind of heat we’re facing in many areas of the country. The question is why are these two groups more at risk than others? There’s little to no research on the heat response in the young and the old with one exception: during exercise. Other than that, it’s a topic that doesn’t seem to attract much attention.

Research has found that the cause relates to the lack of development and aging. The very young haven’t yet developed their skin’s sweating mechanism, but it improves as they continue to develop.

The problem as we age is that our skin declines, along with other physiological mechanisms. Our skin loses sweat glands, our heart doesn’t pump as much blood, and it goes downhill from there.

What can we do about it? More important, what are the signs and symptoms of heat stress? I’ll cover that on Saturday.

With Paula’s knee surgery on Thursday, we’ve delayed the Insider conference call until July 26. You still have time to become an Insider before then.

What are you prepared to do today?

        Dr. Chet

References:
1. Eur J Appl Physiol. 2018 Oct;118(10):2233-2240.
2. J Athl Train. 2021 Aug; 56(8): 801–802.

On the Road Again

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To say that I’ve had a little agony over not running would be an understatement. I certainly don’t want to do anything that’s going to impact the new joint in my knee; on the other hand, my frustration continued to grow over the inability to exercise as hard as I want to exercise. I did what I always do: I looked at the research. Here’s what I found.

Total Knee Replacement and Revision Rates

I decided to look at the most recent research on revision rates in people who ran or started running after total knee replacement. Revision is the word used to describe replacing the original knee replacement because it has loosened or gotten worn. I wanted to see the most recent research because the prosthetics themselves have evolved over the years, as have surgical techniques. There were two research papers that were large enough for me to help make a decision. The references are both open access if you want to read them.

The first study was a meta-analysis of research done on the difference between low physical activity and high physical activity in people who had total knee replacements. While the focus was not on running alone, there were no differences in revision rates in over 4,000 subjects who participated in high physical activity versus low physical activity over a follow-up period of 12 years.

The second study was a cross-sectional study of over 4,000 people who had total knee replacement or total hip replacement. The researchers used online questionnaires to determine activity modes and intensities, postoperative characteristics, revision surgeries, and the Commitment to Exercise Scale and Brief Resilience Scale. The patient-reported follow-up reached five years.

Of the 549 subjects who described themselves as runners before knee replacement, 65 subjects either returned to running or started running after the surgery. After the follow up, 6.2% of those who took up running again required revision surgery while 4.8% of those who didn’t run required revision surgery. The results were not significantly different—about one person. The prevailing recommendation from physicians was to stay active, but don’t run.

On the Road Again

I made the decision to start running again on July 1st. The research that I found was sufficient to give me the confidence to know that if done properly, a return to running can be safe.

What does that mean? Start slowly. While I like to think I’m running, I’m actually talking about a very slow jog. One of the reasons that I decided to return to running was because my fitness level had reached rock bottom, in my opinion. I also know it’s going to take some time.

I began with 20 seconds of jogging about every five minutes. On the day that I wrote this, I did 30 seconds every four minutes. And that’s about the way I’m going to progress: slowly. I’m not interested in running continuously anymore. I got used to a combination of walking and running before the replacement and before my knee got so bad I couldn’t run.

The Bottom Line

I’m glad that my irritation level got high enough to check the research on revision rates after knee replacement. Perhaps it was really more about gaining confidence that, after a year and a half of recovery, the healing of bone to prosthetic was at a point that could support running as I’ve described it. I’m not suggesting that anyone else should do it without checking with their physician. This is my decision and my decision alone. I’m basing it on the best information available today. However, I’d recommend walking or jogging over tennis or pickleball, which include a lot of side-to-side movement; even golf with its twisting motion would be more problematic. You should definitely resume exercise after knee replacement, but talk to your doctor first and make a plan to get where you want to be.

No matter what health, weight loss, exercise, or nutrition goal you set, basing it on the most current scientific information is the best that you can do. I’ll keep you posted on my progress.

What are you prepared to do today?

        Dr. Chet

References:
1. The Knee 2022; 39: 168–184
2. JAAOS Glob Res Rev 2023;7: e23.00019

Knee Replacement Update

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It’s great to be back! I hope your 4th of July holiday was great. Spending some time in Nashville with a few thousand of my closest friends just before the 4th, one of the questions that I was often asked was “How about an update on your knee?” I’ll tell you how I’m doing, but before I do, I just wanted to let you know that Paula will be getting her left knee replaced later this month and probably the right one next year. My knee was bad because of the 20-degree sideways deviation of my lower leg. Paula’s knees are much worse due to arthritis, and she’s really going to benefit from having them replaced.

As for me, I think the thing that surprised me the most was the length of time it took to gain the confidence in the knee to return to full mobility. I had reached the range-of-motion target within a few weeks. Strength I’m still working on. But the fine muscle control necessary for side-to-side movements, turning, posture, and especially balance took at least a year. That doesn’t mean I was inhibited from walking, climbing steps, and doing yard work, but walking downstairs, moving quickly side to side, and even turning sharply is not always there yet. I feel like I’m at about 95% right now.

I’m also terribly frustrated. I’ve been using the recumbent bike, elliptical trainer, and upright bike to exercise. I’ve also been walking outside when the weather permits in the winter and most days of the week now that it’s summer, but for me there’s nothing like running. Could I go back to it, even in some limited capacity? We’re told we can’t run after a knee replacement, but is that accurate? I’ll tell you what I found on Saturday.

Next Wednesday is the next Insider conference call. You have plenty of time to sign up for an Insider membership so you can participate. Get your questions answered and listen to the answers to other Insiders’ questions. Sign up by 8 p.m. on the 19th and you can participate live or listen to the rebroadcast at a later time.

What are you prepared to do today?

        Dr. Chet

Yes, Intensity Matters

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Can you get away with less time exercising and still protect your cardiovascular system? We know from Tuesday’s Memo that more time spent on physical activity will provide more protection. Can we save some time? Or perhaps better stated, can we do something in short bursts of time that can increase the moderate to intense exercise we get?

Before I answer that, remember that physical activity means everything you do that requires movement: walking to the kitchen, gardening, cooking, and the activity involved in your job. Exercise is also a part of your overall physical activity. In the study, all activity was registered by the accelerometer the subjects wore.

Intensity Matters to Reduce CVD Risk

With that in mind, the answer is yes: exercise intensity matters when it comes to protecting yourself from cardiovascular disease (CVD). I must admit that the charts and graphs published in the study were challenging to understand. They used a percentage of calories used per day as the way to measure outcomes. For the exercise intensity analysis, they considered the percentage of calories at moderate to high intensity. They found that as the percentage of activity at moderate to high intensity increased, the rate of CVD events decreased.

Here’s an example. Let’s take a 180-pound guy who uses a low amount of energy in physical activity such as five calories per kg body weight. The total calories he uses daily would be about 400 calories, including any exercise he did. But let’s say the percentage of moderate to severe intensity exercise rises from 10% of total exercise to 20% of that total. His risk of a CVD event would be reduced from 2% lower to 20% lower. He hasn’t invested any more time, yet he gets a jump in benefit just from increased intensity.

What Does That Mean for You?

Does this mean that everyone should be doing high-intensity interval training? Not in the classic sense; what’s high intensity for you may be impossible for your elderly neighbor and a breeze for your kid’s soccer coach. You don’t have to do special workouts such as high-intensity interval training where you’re going to bust a gut for 60 seconds and then take it easy for five minutes. That is intense, but it takes less time overall and you could do that if you want; there’s more info at drchet.com if you decide to try it.

In physical activity, everything counts from housework to walking the dog to breaking into a run to catch a bus. Those would show up as mild or moderate intensity, or high-intensity exercise for the running. It doesn’t mean that all the exercise you do has to be high intensity, but investing time in higher intensity exercise may provide you with additional benefits. Working a little harder is going to reduce your risk of cardiovascular disease and, while not assessed in this study, your risk of type 2 diabetes, hypertension, and cancer would be reduced as well.

Of course, the question is what’s high intensity for you. The chart above is geared toward weightlifting, but it will give you some ways to think about how hard you’re exercising, no matter what you’re doing. If you’re running for the bus, could you run one more block? If you’re cleaning house, do you have enough juice left to go for a bike ride?

The Bottom Line

You must be fit enough and ambulatory enough to actually do moderate to high-intensity exercise. But you know something? I know of one physical therapist who encourages patients to do jumping jacks while sitting in a wheelchair. Of course they can’t do the actual jumping part of it but for 60 seconds, their arms are going up and down, up and down, up and down at a very high rate, and maybe their legs are moving, too—and that’s high intensity for them. For others of you, it may be doing a two-minute walk up a very steep hill. The intensity of the exercise stresses the heart in ways that a nice easy walk does not. And for that, you get additional benefits, no matter where you’re starting.

So check with your doctor to find out your limitations as it relates to exercise intensity, and then get after it. Not to lose a whole bunch of weight, not to win the next 5K, not every day—but often enough to make your heart stronger and fitter.

What are you prepared to do today?

        Dr. Chet

P.S. Happy Canada Day to our neighbors to the north! We’re taking next week off to enjoy the July 4th holiday and hope you do as well (even if you’re not in the U.S.) We’ll be back with new Memos the week of the 10th. Meanwhile, it’s a great time to try increasing your exercise intensity.

Reference: Eur Heart J (2022) https://doi.org/10.1093/eurheartj/ehac613

How Hard Should You Exercise?

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Exercise is my most favorite thing to talk about—not surprising for an exercise physiologist. There’s no question that diet is important to our health, but if I had to focus on just one habit that people should adopt, it would definitely be exercise first before anything else. I believe we should all eat more vegetables and fruits, take supplements for gaps in our diet, and try to reach a normal body weight. But aside from quitting smoking, the most important thing you can do for your health is to be physically active.

Let’s look at the study. The subjects in the study were a subgroup of people from the United Kingdom Biobank study. The data were collected from 88,412 middle-aged adults, with 58% women, who were specifically chosen because they had not been diagnosed with cardiovascular disease before the study.

The researchers broke the data into three equal groups by activity level. The average age of the subjects in the study was 62, and the average BMI was 27. They tracked the subjects for 6.8 years, and in that amount of time there were 4,068 cardiovascular disease (CVD) events: ischemic heart disease (reduced blood flow to the heart) or cerebrovascular disease (reduced blood flow to the brain).

Their findings were interesting and confirmational. Using no or differing covariates in the statistical analysis, as the amount of physical activity increased, the incidence of CVD decreased. That would confirm what we would expect: regardless of intensity, the risk of CVD decreased and it continued to decrease for every level tested.

How does exercise intensity impact all this? We’ll take a look at intensity on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: Eur Heart J (2022) https://doi.org/10.1093/eurheartj/ehac613

More Taurine, Longer Life

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The researchers next step was to supplement the diet of several species with taurine to see if the lifespan of various species would be increased. While they didn’t include humans in the study (we live too long), they did note in other studies that some factors related to aging declined with taurine supplementation.

Taurine supplementation significantly increased the lifespan of worms, mice, and rhesus monkeys, but researchers didn’t determine the originating mechanism involved in the protective process. Certainly, genes have to be impacted in some way, but the only conclusion they could make is that supplementing with taurine extended the lifespan of the species tested.

Combine that with the decline that occurs with aging in humans and the associated increase of degenerative conditions, and it appears that taurine is critical for improving human health as well decreasing some of the manifestations of aging.

Increasing Taurine Intake

The only real question is the best way to increase taurine levels. Would there be any downside to taking a taurine supplement? Or should we focus on increasing the protein in our diet, specifically the animal protein? Here’s something else to consider before we get to that point: one of the characteristics of aging is a decrease in protein intake. There’s no reason that I could find for that to happen. It just does.

I think it should be a combination of both sources. Protein intake should be increased once a person reaches 50 to at least one gram per kilogram body weight. That would mean it would be roughly half a person’s body weight in grams. If you weigh 200 pounds, you should probably get 100 to 120 grams of protein per day. It may be prudent for those over 70 to exceed that amount, not just for the taurine but also to stem the loss of muscle mass. It may require a concerted effort to eat that much protein.

Let’s turn to taurine supplementation. Taurine is typically offered in 500 milligram capsules. When you look at the research, the amount used in studies ranges from 500 milligrams per day up to six grams per day. A couple of studies lasted at least six months long. Taurine supplementation seems safe.

Starting with one gram of taurine per day for a minimum of 60 days is a good place to begin. Depending on where you began, you may or may not feel anything, so you can increase the amount. Or you may find it’s having a profound effect on you because it impacts so many different organ systems in the body, and you may decide to hold the line.

How about your diet? What foods contain taurine? The highest taurine levels would be found in shellfish, eggs, soy products, and liver as well as—surprise, surprise—energy drinks if you want to use them. But don’t forget, all animal protein will count because it will have the two primary amino acids that taurine is made from: methionine and cysteine.

The Bottom Line

Is taurine the fountain of youth? No. But it’s one of many strategies we can use to age well. Living long is not good enough. Living well longer should be our goal. Increasing taurine levels is another step in aging with a vengeance.

What are you prepared to do today?

        Dr. Chet

Reference: https://www.science.org/doi/10.1126/science.abn9257

Taurine’s Effects on Aging

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A recent research paper examined the amino acid taurine and its connection to aging; in fact, the title of the research paper is “Taurine as a Driver of Aging.” It was published in the journal Science in June 2023; it’s open access if you’re interested in reading the article itself.

Taurine is a sulfur-containing amino acid that can be made from the amino acids methionine or cysteine metabolism. It plays a role in several essential body functions, such as regulating calcium levels in certain cells, manufacturing bile salts, balancing electrolytes in the body, and supporting the development of the nervous system. There is one more way that taurine may benefit us: taurine appears to be important in mitochondrial health as well. And when you think mitochondria, think energy.

In the first part of the study, the researchers examined taurine levels at various ages during the lifespan of several species. They looked at mice, macaques, worms, yeast, and human beings. The results were absolutely clear: as these species got older, the taurine levels decreased substantially. While all species had other metabolic functions going on, the stark drop in taurine certainly appeared to be related to the decline of many body systems.

But how do you test that? You supplement the diet of the particular species with taurine. That’s what the researchers did, and I’ll tell you what happened on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: https://www.science.org/doi/10.1126/science.abn9257

The New Research Isn’t Really About Sucralose

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Those of you who actually read the research paper mentioned in the last Memo didn’t have to go past the title to find out that it was not about sucralose—it was about a contaminant called sucralose-6-acetate that may be found in commercially available sucralose used in drinks and baking products. I said the tests were complicated; I’m going to give you the results of the eight tests in everyday terms as much as possible.

Test Results

Researchers were able to test only half of the questions on their list; in the other cases, they relied on prior research on sucralose, not sucralose-6-acetate. Here’s what they found:

  • The first test assessed the potential for altering DNA; the results indicated that sucralose-6-acetate was genotoxic, but sucralose was not.
  • The second test assessed the potential for DNA damage in specific types of cells called TK6 cells; the results for sucralose-6-acetate were that it was genotoxic. They didn’t test sucralose, but prior studies demonstrated that it doesn’t damage DNA in these cells.
  • The third test also assessed the potential for causing damage to DNA. The results for sucralose-6-acetate were somewhat positive, while the results for sucralose were not.
  • The fourth test assessed DNA mutations in bacteria; neither sucralose-6-acetate nor sucralose induced mutations.
  • The fifth test assessed electrical resistance and permeability in the colon’s epithelial cells. Both sucralose and sucralose-6-acetate affected monolayers of colon cells grown in test tubes.
  • The sixth test attempted to examine the same type of colon cells for damage to RNA sequencing. A total of 12,553 genes were analyzed. There were changes with sucralose-6-acetate but in no specific pattern. In other words, we don’t know what many of those genes do, so we don’t know whether this is impactful or not. As for sucralose versus the control group, only two genes out of over 12,000 seemed to have some sort of variation.
  • The seventh test examined the stability of minute cellular structures called microsomes in liver cells from a variety of animals including humans. There seemed to be some impact of both chemicals on this single layer of cells.
  • The eighth test looked at the inhibition of cytochrome P450 detox enzymes in human liver microsomes. Sucralose-6-acetate seems to impact two of the detoxification genes, while sucralose had no impact.

What Do the Results Mean in the Real World?

As I pondered that question, I ended up with dozens more questions. I’m not a bench chemist, so it’s difficult to know whether the tests used are the correct ones; I’m not sure that all the authors are familiar with the testing procedures either. They didn’t do the testing in their own laboratory; they hired laboratories to do it. From one perspective that excludes any bias the researchers may have had; on the other hand, they may or may not have the experience with specific testing methods to fully understand the results.

My major question is related to the chemicals used in the testing. They contracted with chemical companies to have sucralose made to a standard level of 0.5% sucralose-6-acetate. They also had sucralose-6-acetate made to a standard level of 0.3% purity. Neither of those are used commercially. The little yellow packets are primarily fillers such as dextrose and maltodextrin because the sucralose is so sweet, only a tiny amount is required.

Another question is about the potential genotoxicity. When the body makes a mistake in DNA, that mistake usually is addressed and the chemicals are recycled before any mutation becomes permanent. When you do bench studies, there is no such defense mechanism present. We have no idea how the body handles it.

As I said, I had many questions but these are the primary ones. If you’re interested to hear more, become an Insider; I covered this study in the call for this month. The Insider Conference Calls are available on-line for six months.

The Bottom Line

I think this study demonstrates that human trials are needed to confirm or refute some of the impact of sucralose-6-acetate on DNA and the microbiome performed in these bench studies. While there is evidence of DNA damage and impact on the microbiome, we don’t know if that causes any health issues. Further, they need to include scientists with expertise in nutrition as well as bioengineering.

As I said on Thursday, not everyone can use artificial sweeteners such as sucralose due to pre-existing genetic mutations and compromised microbiomes, but we have 35 years of experience with sucralose as a sweetener. To date, there have been no large-scale studies that have raised any question about its impact on the health of humans. When there is more to know, I’ll be sure to keep you informed.

What are you prepared to do today?

        Dr. Chet

Reference: https://doi.org/10.1080/10937404.2023.2213903