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

New Research on Sucralose

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Everybody seems to be talking about sucralose. In the past week, I’ve gotten more emails about the artificial sweetener sucralose than I ever have before; I’ve also seen more commentaries on sucralose in health news feeds. The problem is that the issue really isn’t the sweetener itself—it’s a contaminant that may be found in the sweetener called sucralose-6-acetate. On top of all that, the primary author of the study is continually muddying the results of the study by using the term sucralose when she means sucralose-6-acetate.

The sweetener sucralose is as safe as it always has been. Some people are opposed to artificial sweeteners of all types, and that’s fine, but there’s nothing in this research update nor any of the other studies on sucralose that presents any type of major concern. That doesn’t mean it’s for everybody; genetic factors and microbiome issues may affect some people. But that aside, there’s nothing to be fearful of, so let’s check out the study that’s attracting so much attention.

Let’s start with what the researchers did. They attempted to examine six historical claims about sucralose:

  • Sucralose passes through the gut unchanged
  • It has no effect on the microbiome
  • It has no effect on intestinal tract
  • It doesn’t accumulate in human tissue
  • It has no effect on metabolism including blood glucose or insulin
  • It won’t disrupt the DNA

To say the tests to examine these questions were complicated is an understatement. I’ll give you my interpretation of the published results on Saturday. However, if you want to read the study yourself, click the link below.

What are you prepared to do today?

        Dr. Chet

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

Flavanols: The Real Brain Food

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As I suggested in the last memo, the researchers did not prove their hypothesis that there would be an increase in measures of memory in all participants of the clinical trial. While disappointing, the secondary hypothesis might have been even more important because it was statistically significant.

They found that those with the lowest intake of flavanols from foods and drinks had the most improvement in measures of memory function. Makes sense: people who did not eat enough fruits and other foods containing flavanols saw benefits by supplementing with a specific amount of flavanols every day.

Researchers didn’t test to see if eating little to no foods containing flavanol resulted in a decline in memory function; that would fall into the category of “first do no harm.” Understanding that flavanols are beneficial for more than just memory, it would not be responsible to have a person decrease intake of them.

They also did not find additional benefits of taking the supplement for those with the highest intake of flavanols from their diet. That means that a great diet has great benefits.

There are three points we can take from this study:

  • Regular intake of flavanols from supplements can compensate for weaknesses in the diet.
  • Eating flavanol-containing foods provides a wide variety of flavonoids including anthocyanidins, flavan-3-ols, flavanones, flavones, and isoflavones. In my opinion, eating and drinking plant-based substances is a better approach; using additional flavonoids from supplements is a great insurance policy.
  • The memory tests used in the study focused on one area of the brain: the hippocampal area. Supplementation did not appear to impact the prefrontal cortex component of cognitive aging.

If we want to age with a vengeance, I think we should look at it as though every little bit helps. I also think that the earlier we begin developing the habit of eating more fruits and vegetables, plus drinking teas, coffee, and cocoa drinks, the better our brains will be. And as a bonus, the rest of our body gets to enjoy the benefits as well.

What are you prepared to do today?

        Dr. Chet

Reference: PNAS May 2023. https://doi.org/10.1073/pnas.2216932120h

What’s Brain Food?

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If I ask what you think a good brain food would be, what would you answer? I think for most people, it would probably be fish, especially cold-water fish such as tuna and salmon. I don’t think we can discount how important omega-3 fatty acids are to the function of our bodies, especially our nervous system. But based on recent research, I don’t think we have to get quite as exotic as cold-water fish. I think we can find what we need in the produce section or at farmers markets. I’m talking about the phytonutrient class called flavanols.

Researchers recruited over 7,500 people—men over 60 and women over 65—as potential subjects. After meeting the criteria established for inclusion in this clinical trial, researchers ended up with just over 3,500 subjects. To test the theory that flavanols would improve memory, researchers used three different online memory tests. They used a form of the Healthy Eating Index to evaluate dietary intake of flavanols. They also used a test for the urinary excretion of flavanol by-products to confirm the amount of flavanols in the diet.

Half the subjects got a flavanol extract from cacao that contained at least 500 mg of cacao flavanols, including 80 mg of epicatechin; the remainder of the subjects received the placebo. Subjects were tested before the study began and then at the end of one, two, and three years.

The primary goal was not met; not all subjects saw an improvement in memory after the first year. The secondary goal was met, and it may prove to be even more important. I’ll finish this review on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference:   PNAS May 2023. https://doi.org/10.1073/pnas.2216932120

Diet: It Just Doesn’t Matter

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Long-time readers probably know I love using quotes from movies. One of my favorites is a Bill Murray line from the movie Meatballs. Although it’s part of a much longer rant, the key phrase is, “It just doesn’t matter!” That’s what I want you to remember from the study that examined the percentage of energy nutrients in the paleo diet. They found a significant difference in the range of nutrients, but the ranges are wide enough to incorporate the ketogenic diet as well as the Mediterranean diet.

Looking at the diets of hunter-gatherers in different parts of the world showed that the types of carbohydrates were dependent on what was available. In some cultures, digging up root vegetables and tubers was critical to the diet. But eventually, we learned to grow and process grains, and now we have an abundance of refined carbohydrates such as breads and pasta, often to our detriment.

What are the lessons?

Personalization

In one of the many commentaries I read on the merits and downfalls of the paleo diet, one researcher said this:

Ultimately, the best way to eat for your health is the change you can keep up with. Most people know what they need to do: limit calories, eat fruits, vegetables, whole grains, and lean proteins. The challenge is how to do it. There are lots of ways people can achieve this. The key is figuring out which is best for you as an individual that you can keep up with.

That uses a whole lot more words, but the message is the same as always: eat better.

When It Comes to Weight, It’s All About the Calories

Whichever way you decide to eat—and there are many ways to eat a healthy diet—losing weight is always going to be about how many calories you eat versus how many calories you expend. You can eat the carnivore diet, which is essentially all meat, although I wouldn’t recommend it. Or you can become a vegan. You can follow the DASH diet that I talked about a couple weeks ago, or you can eat the paleo diet. It just doesn’t matter. As long as you control the number of calories you eat, you can get to and maintain a normal body weight.

I believe you have to have vegetables and fruit as the foundation of your diet, but there’s a difference between maintaining a normal body weight and sustaining a healthy lifestyle. What we eat does matter. But quality aside, as always, it is and it will always be about the calories. Nothing else matters in controlling what you weigh. Eat less.

And if you can, eat better.

What are you prepared to do today?

        Dr. Chet

Reference:https://doi.org/10.1016/j.ajcnut.2022.12.003

Is Summer Paleo Diet Time?

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Now that we’re past Memorial Day, we’re officially in the summer season. For many people, that typically means they grill more than at other times of the year—I know that I do. It also seems like we favor more vegetables and fruit. In a way, it seems to mimic the paleo diet approach: we eat foods closer to nature before planned agriculture became common. I can’t say we’re hunter-gatherers because we mostly shop at the same grocery stores, but we may buy foods closer to the source due to the prevalence of roadside stands and farmers markets. With all the fresh food available, we also may eat fewer grains and starches, which also fits the paleo profile.

Or does it? Researchers at Simon Fraser University decided to examine the premise behind the paleo diet in terms of proportion of protein, carbohydrate, and fat. The current paleo diet approach consists of 19-35% protein, 22-40% carbohydrate, and 28-58% fat. While the range of percentages in each energy category are wide, it does focus on much higher protein and much lower carbohydrate, especially refined carbohydrates.

In a recently published paper, researchers at Simon Fraser University examined the percentage of energy nutrients in the diet of ten hunter-gatherer societies and in different locations. They derived the following percentage of energy nutrients: 14%–35% protein, 21%–55% carbohydrate, and 12%–58% fat. The percentages were significantly different—they incorporated a wider range in each nutrient category.

Are these differences meaningful in the real world? I’ll let you know on Saturday. Meanwhile, time to grill some burgers and veggies.

What are you prepared to do today?

        Dr. Chet

Reference: https://doi.org/10.1016/j.ajcnut.2022.12.003

BE FAST for Stroke

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So what did the Society of NeuroInterventional Surgery (actual brain surgeons) add to the mix? They added the acronym BE, which then makes the entire acronym BE FAST.

What do the new letters stand for?

B: loss of balance. I didn’t see any details about how to test that. It may be self-evident that someone cannot stand upright without tilting to one side or the other. Or it may be the while holding their arms to test their arm strength, they can be moved side to side to see how they respond.

E: loss of eyesight in one eye or blurry vision.

I think adding balance and eyesight are a good idea for the lay public. A physician or other healthcare professional may know to look for balance and eyesight symptoms, but it may not be as obvious to you and me. Here’s the whole list:

BE FAST

B: loss of balance

E: loss of or blurry eyesight

F: face drooping

A: arm weakness

S: speech difficulty

T: time to call 911

Commit those to memory and if you feel that you or someone you care about might be having a stroke, assess those symptoms and most important, take action immediately if necessary. I can’t stress that enough because the sooner treatment begins, the less function a person loses.

Enjoy your holiday weekend, and safe travels if you’re hitting the road. We’ll be back next week.

What are you prepared to do today?

        Dr. Chet

Reference: https://getaheadofstroke.org/call911/