Research Update: Omega-3s and Chronic Kidney Disease

/in /by

Two recently published articles examined the link between omega-3 fatty acids from fish and two conditions; let’s begin with a study on fish consumption and chronic kidney disease (CKD). By definition, CKD is the loss of kidney function over time. The kidneys are the major blood filtering system, so continued decline can impact the entire body.

Researchers selected 19 studies from 12 countries to perform a meta-analysis. The key variables were measurement of omega-3 fatty acid levels and types—EPA, DHA, and DPA from seafood, plus ALA from plant sources—together with the estimated glomerular filtration rate (eGFR). The researchers identified 25,570 participants that met the criteria and were included in the analysis.

Over a median of 11.3 years of follow-up, 4,944 (19.3%) developed CKD. Higher levels of total seafood omega-3s were associated with a lower CKD risk. In comparing categories of omega-3 levels, subjects with total seafood omega-3 level in the highest quintile had a 13% lower risk of developing CKD compared with those in the lowest quintile. The association appeared consistent across subgroups by age, eGFR, and diagnosis of hypertension, diabetes, and coronary heart disease at baseline.

While this was an observational study, there appeared to be an inverse relationship between blood levels of omega-3s from seafood sources and the development of CKD. Do we know if this included supplementation with omega-3s? That wasn’t assessed in this study. We’ll look at another recent study on omega-3s on Saturday and ask the big question.

What are you prepared to do today?

        Dr. Chet

Reference: BMJ 2023;380:e072909. doi: 10.1136/bmj-2022-0729092

The Final Question on Ultra-Processed Food

/in /by

Here’s what we found out so far: When we eat ultra-processed food (UPF), we tend to eat way too much of them, upwards of 500 more calories per meal. We absorb more of those calories; the absorption starts sooner in the small intestine because of the simple carbohydrates in the UPF. Finally, we found out that we do not lose as many calories in our stool as we would if we had more fiber and more resistant starch in our foods.

But we need to answer one more question.

Is a Calorie Just a Calorie?

Despite the research that’s been done, all the clinical trials on UPF are on small groups of subjects. I’d like to see one more study similar to the one comparing the microbiome-beneficial diet with the Western diet high in processed foods. If researchers could do the same study on a group of overweight people and put them on one of two calorie-restricted diets—one following the microbiome-beneficial diet while the other used an ultra-processed food diet—we could see if there were differences in weight loss and other health markers between the two groups. Then we’d know whether there were any real differences between the types of calories we put into our bodies.

When thinking about weight loss, I always go back to the Minnesota Starvation Experiment. The subjects, all conscientious objectors, were given only the foods that would be available after WWII in war-ravaged Europe: bread, potatoes, and other root vegetables, little to no protein, and little fat. Normal-weight men lost weight and continued to do so for the entire six months of the study. If it’s just about the calories, then substituting UPF for the starvation diet and adjusting it on a weekly basis would get the same results today. But I don’t see that study happening any time soon.

Are UPFs Healthy?

Not in my opinion because of what they don’t have. No fiber. No resistant starch. No phytonutrients. Then add artificial flavors and colors and throw in sodium and umami flavoring to make us want to eat more of them. No, I don’t think they’re healthy. But if they’re a part of a total diet and consumption is controlled, then, while the research is not in yet, a calorie could be just a calorie.

The Bottom Line

It’s easy to be a demagogue and condemn UPFs as so many others have, but remember that protein powder is a highly processed food, whether from animal or plant sources. So is stevia, the “natural” sweetener. How about almond milk? Have you ever seen an almond teat? Neither have I.

What we need for good health today, not in 1900, 1930, 1950, or even 1970, is a balanced approach to nutritional intake. It’s as simple as eat better, but not perfect. Eat less, but don’t starve yourself on foods you don’t enjoy. And move more. It’s as simple as that.

What are you prepared to do today?

        Dr. Chet

Reference: https://doi.org/10.1038/s41467-023-38778-x

Ultra-Processed Foods: Losing Calories

/in /by

In our examination of the research on ultra-processed food (UPF), we’ve found out that we consume more calories and that we absorb more calories if we eat UPF. The final question is probably going to seem a little unusual. Do we actually lose more calories if we eat less UPF? In other words, do we actually eliminate calories if we eat a diet favorable to our microbiome? This is really interesting: we may actually not absorb every calorie we consume! I must admit that this one surprised me; I didn’t realize that we lost calories in our stool under healthy conditions.

Researchers wanted to test whether diet could influence the number of calories lost in feces among a variety of other variables. The researchers recruited 17 healthy, normal-weight to overweight men and women with an average age of 31. They designed a diet that could enhance the microbiome by feeding the healthy microbes that reside in the colon. They matched the diet for percentages of calories and macronutrients with a Westernized diet. The major difference was the fiber content and level of resistant starch; the Western diet included more highly processed foods.

At different points in the study, on both types of diets, they measured the exact calories consumed, calories used in exercise, rest, and sleep, and collected all urine and stool for 24 hours. The most interesting result was that the microbiome-friendly diet increased the calories lost in the stool by an average of 116 calories per day. The bacteria were using the fiber and resistant starch to manufacture more metabolizable calories, but they were lost in feces. They weren’t absorbed, so those calories do not apply.

What does it all mean? More than that, what is the question that hasn’t been answered by any study on ultra-processed food? I’ll cover that on Saturday.

And here’s one more reason to limit UPF, according to an article in the Washington Post: “…eating more pro-inflammatory foods, such as processed meats or sugary sodas, was associated with a higher risk of fecal incontinence. The authors hypothesized that pro-inflammatory foods could have negative interactions with the gut microbiome and diminish the function of the muscles and nerves of the pelvic floor.”

What are you prepared to do today?

        Dr. Chet

Reference: https://doi.org/10.1038/s41467-023-38778-x

Are Ultra-Processed Foods Absorbed Faster?

/in /by

The next question to consider with UPFs is this: Do you absorb more calories from UPFs than you would from minimally processed food? The answer appears to be yes, but requires some explanation.

Keep in mind that UPFs have been mechanically and chemically altered during the manufacturing process. The original grains of wheat, corn, or even something such as carrots bear no resemblance to their original form. The components, especially the fiber, have been torn apart. What’s the big deal? The normal chemical bonds that make up the food matrix are no longer in the same form as they were. Therefore, they require less digestion and potentially can be absorbed much faster starting in the small intestine.

That can mean a couple of things. The higher the proportion of UPFs in the diet, the more calories from carbohydrates can enter the bloodstream and get there faster. Blood sugar goes up more quickly; if the calories aren’t immediately used, the extra calories can be converted into fat for storage, and don’t we all love that!

It also means that the food that could have fed our microbiome is no longer present—we’ve taken in plenty of calories, but our microbiome is starving. What nutrient is missing? Fiber in the form of resistant starch. What does it resist? Digestion and absorption. That’s the food for probiotics in the microbiome, and without it, our microbiome is starving and not as healthy as it could be. The more UPFs you eat, the more you need a fiber supplement.

There is one more question that needs to be addressed, and I’ll do that in the next Memo. In the meantime, how about a bowl of steel-cut oats, bean soup, or a nice salad? Your microbiome will be so happy!

What are you prepared to do today?

        Dr. Chet

References:
1. https://doi.org/10.1016/j.cmet.2019.05.008
2. https://doi.org/10.1038/s41467-023-38778-x

Research Update: Ultra-Processed Foods

/in /by

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

/in /by

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!

/in /by

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

/in /by

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

/in /by

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

/in /by

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