High-Intensity Walking Is Better for Peripheral Artery Disease

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As I said in Tuesday’s memo, high-intensity walking was better than low-intensity walking in terms of physical measurements after one year; subjects were able to cover more distance in a six-minute walk and they were able to walk for a longer period of time on a treadmill. Another important outcome was that there was no damage to muscle fibers in response to the high-intensity walking as was found in other studies.

There are a couple of other factors I think were significant about this study. Let’s take a look.

High-Intensity Walking Saved Time

High-intensity walkers performed better on the physical tests in spite of the fact that they actually exercised half the time as the low-intensity walkers. I think that that’s a solid positive for people who really dislike exercise because they will save time: more benefit in a shorter period of time.

Even though there was a similar improvement in subjective quality of life assessments, what we don’t know is whether each individual session was more painful for the higher-intensity walkers.

Subjects Were Coached the Entire Year

The primary difference between high-intensity and low-intensity walkers was pain. Both the high-intensity and low-intensity walkers had assigned coaches who could track progress through the subjects’ accelerometer readings. Having done a similar type of study myself, it’s important that people can get answers to their questions, especially related to the significance of pain versus discomfort, and therefore push on. I believe subjects also feel obligated to a person, their coach, more strongly than to the study itself.

While it would be very difficult as a public health initiative, I think the approach would work for any type of physical-limiting condition whether it was cardiac rehabilitation, type 2 diabetes, or as in this case, PAD.

The Bottom Line

This analysis of high-intensity versus low-intensity walking for PAD might seem to be narrow in focus; after all, most of you probably don’t have PAD. But the greater question to me is determining what will be more effective to help recovery or even prevent disease from occurring. If high-intensity exercise can be beneficial for people with severe PAD, then there’s no question that it can be beneficial for just about everyone. And the key is coaching: having someone available to encourage you when you need it and to answer questions when they become important to you.

What are you prepared to do today?

        Dr. Chet

Reference: JAMA. 2021;325(13):1266-1276. doi:10.1001/jama.2021.2536.

Exercise for Peripheral Artery Disease

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Peripheral arterial disease (PAD) is a narrowing of the arteries in the arms or legs, usually caused by the build-up of plaque similar to what can happen in the arteries of the heart or the neck. The result is pain in the muscles of the legs, sometimes mild, other times severe. As you might expect, the harder you exercise, the more potential for pain. Termed “intermittent claudication,” it can reduce mobility, or rather, the desire to be mobile.

Higher-intensity exercise such as fast walking is typically avoided due to the resulting pain. The prevailing recommendation is slow walking. But as several studies have determined, people won’t do it because it hurts. So why recommend it?

Researchers from several universities across the U.S. recruited over 300 subjects with a mean age of 69 to participate in a yearlong study on the effects of low-intensity versus high-intensity walking. This was a massive undertaking due to the extensive training and coaching for all subjects. I won’t keep you hanging until Saturday: the high-intensity walkers did better on physical tests than the low-intensity walkers or the control group. But there was one other critical point, and I’ll talk about that on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: JAMA. 2021;325(13):1266-1276. doi:10.1001/jama.2021.2536.

Fasting: Another Piece of the Puzzle

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Fasting is gaining popularity. Actually, periods of complete abstinence from food within a 24-hour cycle is what really seems to be gaining in popularity, but this study doesn’t address intermittent fasting. It examines fasting for a specific period of time before a dietary change—in this case, to the DASH diet. We don’t know if the results would be the same if someone were switching to a ketogenic diet or a paleolithic diet. These are the major results of the study we began examining on Tuesday.

The Results

  • The five-day fast prior to beginning the DASH diet appeared to have positive effects on blood pressure. There was an average drop of eight points in systolic BP and a reduction in the use of medication to lower blood pressure.
  • Subjects adhering to the DASH diet lost weight as well. However, it was not the reduction in weight loss that caused the drop in systolic blood pressure based on their analysis.
  • The immunome, a portion of the total proteome I talked about a few weeks ago, improved. While the exact mechanism is not known, the positive changes in immune proteins appeared to have a positive effect on lowering blood pressure.
  • Researchers also discovered genetic differences between those who responded to the fast and the subsequent DASH diet by lowering their blood pressure and those who did not. The key seems to be in the bacteria that produce short-chain fatty acids. Fasting was identified as a way to increase the bacteria producing those SCFAs.

What Does It Mean?

What are we to conclude? With only 71 total subjects, there’s not a lot of data to generalize to entire populations, but here’s what I think is important.

First, fasting does have a role to play in the health of our microbiome; it also has role to play in our immune function. It’s not completely clear why these changes can occur, but research shows that they do. It may be that eliminating food for a period of time helps the naturally occurring bacteria to function better.

Second, it doesn’t seem to have anything to do with intermittent fasting. It very well may be that complete abstinence from food could get you similar benefits if you were to withhold food for 18 or 20 hours a day and only eat in a very small block of time. But until fasting for a specific amount of days is compared with hourly intermittent fasting, we just don’t have the best answers yet.

The Bottom Line

Fasting, however you define it, appears to have some beneficial effects. If you find a way that fits into your lifestyle, there doesn’t seem to be any reason that you shouldn’t do it unless you have a metabolic disorder and must eat. For example, if you have problems with your blood sugar or take meds that must be accompanied by food, fasting may not be for you.

Here’s my plan: now and then, I’m going to try a reduction to 500 to 800 hundred calories per day for one to three days. That seems to be supported by the most science. It also appears to benefit immune function the most.

Anticipating questions from those doing a ketogenic or paleolithic diet, is the diet after the fast important? Maybe if you select the right foods, such as going vegan during those fasting days, you may get the positive changes in your microbiome. What would happen if you then went on a ketogenic or paleo diet after that? We just don’t know whether the changes would last. This study provided a few pieces of the puzzle, but there’s much we still need to know.

What are you prepared to do today?

        Dr. Chet

Reference: Nat Comm (2021)12:1970. https://doi.org/10.1038/s41467-021-22097-0

How Fasting Affects the Microbiome

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How did you do? I asked you to reduce your caloric intake to fewer than 1,200 calories and keep it vegan if you can. Paula and I did okay, but not completely vegan.

Before I describe the study, you need to know that wasn’t the actual fasting part of the study—that was the fasting preparation phase. The actual fast was 300 to 350 calories per day of vegetable juice and vegetable broths. If you’ve ever done a detox just drinking tea and broths, that’s very similar.

There were multiple parts of the study, but we’ll focus on just two. The purpose of the two portions of the study was to examine changes in the microbiome and immunome as well as blood pressure after 12 weeks on the Dietary Approach to Stop Hypertension (DASH) diet. Before the dietary changes were begun, researchers randomly assigned 71 subjects to either the fasting-plus-DASH diet or just the DASH diet alone. All the subjects had diagnosed hypertension as well as metabolic syndrome.

This was one of the most complicated analyses I’ve ever seen because there were so many genes examined related to the bacterial composition of the gut as well as the immune system. The first question is simply this: were there changes in the microbiome after the initial fast? Yes, but the changes were reversed once normal eating resumed.

I’ll cover the post-DASH diet changes in Saturday’s Memo. Until then, unless you have metabolic issues or must eat at specific times of the day with medications, give the fast, the real fast as described above, a try for just one day.

What are you prepared to do today?

        Dr. Chet

Reference: Nat Comm (2021)12:1970. https://doi.org/10.1038/s41467-021-22097-0

Summer Body Prep Time

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This week culminates with the first outdoor holiday of the summer season, and for many of us, the first family cook-out in over a year. Next week I’m going to review a study on the benefits of intermittent fasting, but I want to challenge you to mimic part of the study before the weekend to see how you do. Here’s the task.

For any two consecutive days, cap your eating at 1,200 calories. If you can get by on 1,000 calories, great, but no more than 1,200 and no fewer than 800. The second part is to make them vegan days as well. Don’t think only salads and carrot sticks: beans, legumes, nuts, root vegetables, and every other vegetable and fruit you can think of as well as whole grains. Two days—that’s all. Then you can resume your normal eating if you want. That will give you at least part of experience of the subjects in the intermittent fasting study I’ll review.

The irises in the photo are from our yard. Two years ago, we dug up entire iris beds and replanted them until we ran out of space. This year, they produced more flowers than ever, and they’re just beginning; the ones pictured are hand-me-down yellow ones we got from Paula’s dad and another called “Red at Night.” There are more colors to come, including an electric blue called “Blue Suede Shoes.”

All those flowers don’t happen by accident; neither does a healthier and fitter body. It takes work and it may take a while to see the benefits, just like the irises. Take the vegan-fast challenge and see how you do. Just remember: no lower than 800 calories and no more than 1,200. It will give you a sense of how the subjects initially felt in the study on fasting, the microbiome, and blood pressure.

Paula and I are going to spend this week putting flowers in containers, so this is the only Memo this week. Enjoy the outdoors and if you’re traveling, be safe. See you next week.

What are you prepared to do today?

        Dr. Chet

Vision Health: Never Too Young

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Continuing with what I asked Dr. Laura Kenyon during my interview with her, the question is still “What are the mistakes people make related to retaining their vision?” Here are the rest of her answers as well as a program every parent needs to know about.

Eye Protection

The third mistake we make is not wearing eye protection when we should. Obviously you’ll want safety glasses if you’re working with a chainsaw. When you’re working with liquids such as paint, oil, and gasoline, protecting your eyes is critical then as well.

But let’s move beyond the obvious: wear safety glasses anytime you’re working in the yard. True, when you’re mowing the lawn or using the weed-whacker, eye protection makes a lot of sense. But when you bend over to pull weeds or prune trees or bushes, you might not focus on that tiny little branch that’s sticking out from the rosebush. That kind of stab or scratch can severely damage the eye.

The other is when you’re cooking. When you’re cutting foods such as onions and hot peppers, a squirt into your eye can certainly make your life miserable for a long time, even though probably not causing permanent damage. And you’ve probably heard that you shouldn’t cook bacon naked. I can tell you that you shouldn’t be without eye protection then as well. I can remember putting a piece of fish into a fryer, and in a perfect splatter, it came right from the tail end of that fish directly into my right eye. You’ll find out whether you can dance or not when that happens to you! So be sure to wear eye protection even for tasks that do not seem as obviously dangerous.

Eat Vegetables and Fruit

I was a little surprised that Dr. Kenyon said then another mistake that we all make in relation to our eyes is that we don’t eat enough vegetables with carotenoids in them such as lutein, alpha-carotene, zeaxanthin, and, of course, you probably know beta-carotene already. Those are all critical to eye health and we need some every day.

One little piece that I contributed was to mention that chopped or cooked vegetables with carotenoids will release more carotenoids than if you eat them raw. So those baby carrots (that we know really aren’t baby carrots at all), would serve you better if they were cooked and put in soup.

Never Too Young: InfantSEE™

When I said that it’s never too early to start with regular checkups, I meant it: if you’ve got a baby, it’s time to start. The InfantSEE program was started in 2005 with the support of former President Jimmy Carter. He had a grandson who was diagnosed with amblyopia, a condition that could have been easily treated had they been aware of it. The result of his effort, as well as the American Optometric Association efforts, has resulted in a free program for children six to twelve months old. The examination can identify conditions such as astigmatism, which in a single eye, can result in what we typically call lazy eye—easy to treat if you know the child has it at an early age but very difficult to treat later. You can search for a participating optometrist on the home page of InfantSEE; let’s all help spread the word to new parents.

The Bottom Line

There you have it, right from the optometrist’s mouth: the biggest mistakes we make when taking care of our eyes. Use this info to put together a list of actions you should take to keep your eyes healthy throughout your life.

If you live in the Grand Rapids area, Dr. Kenyon and her practice is taking new patients. The contact information is below (2). Also, for all Members and Insiders, I’ll be posting parts of the interview in the members section after it plays in Grand Rapids.

What are you prepared to do today?

        Dr. Chet

References:
1. www.infantsee.org
2. West Michigan Eyecare Associates. https://wmeyecare.com 616-949-8500.

Keeping Your Eyes Healthy

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When I interviewed our optometrist, Dr. Laura Kenyon, for my Sunday radio show here in Grand Rapids called Straight Talk on Health (you can listen live via the Internet by going to https://www.wgvunews.org/programs/straight-talk-health), I learned a lot about how to take care of your eyes. In this week’s Memos, I want to cover the things that you should do for good eye health, regardless of your current age. As you’ll find out, it’s never too early to start.

I asked Dr. Kenyon what were the biggest mistakes people make when caring for their eyes. Her answer rang a bell for me: most people believe they should see an eye doctor only when they need glasses, so they don’t get regular eye exams. That’s a mistake; whether they need glasses or not, very subtle changes that occur within the eye may not have been noticed because it hasn’t affected their vision yet. For example, I never would have known I had glaucoma if I hadn’t needed new glasses. Now, five or six years later, the pressure in my eyes is under control and I haven’t lost vision.

The most important rule is to get regular eye exams. How often? A motto she used says it all: To see clearly, check yearly. I think that’s a good one to adopt.

The second eye health mistake we make is not wearing sunglasses. The sun’s rays can damage the lenses of the eye even without bright sunshine, so if you’re going outdoors put on sunglasses even in cloudy weather.

I’ll finish the list on Saturday. In the meantime, is it time for you to schedule your eye exam? Get to it.

Also, tomorrow is the next Insider Conference Call. Essential amino acids and fasting before starting to change your diet are on the agenda, along with answering Insider questions. Isn’t it time you became an Insider? Join today and you can be a part of tomorrow’s call.

What are you prepared to do today?

        Dr. Chet

Metabolically Healthy and Obese

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The researchers in Germany continued to determine which factors associated with being obese were the most predictive of mortality from any cause and from cardiovascular disease. While not explicitly stated, it seems to me that they attempted to use variables that were simple to assess. With that in mind, here are the variables which demonstrated whether someone was metabolically healthy or not, regardless if they were normal weight, overweight, or obese.

Criteria for Metabolic Health

  • Systolic blood pressure less than 130 and no use of blood pressure lowering medication
  • Waist-hip ratio less than 0.95 for women and less than 1.03 for men
  • No prevalent diabetes

These criteria are simple enough for most people to determine for themselves, no doctors necessary. People usually know whether they’re diabetic, and they also know whether they’re taking medication to lower their blood pressure. Most people have a home BP cuff to assess systolic blood pressure or have access to one in a store.

The waist should be measured at its widest point and hip should be measured at the bony process of the femur. Divide the second number into the first, and that gives you the waist hip ratio.

The Results

The subjects who were considered metabolically healthy and obese had no greater risk of mortality from all causes or from cardiovascular disease then did normal weight, metabolically healthy subjects. This study examined only the death rate, not the rate of disease. Still, I think that if someone is working towards becoming a healthier version of themselves, intermediate goals can be very motivating.

I like this study for two reasons. First, it confirms what I thought for many years: people who are overweight or obese can be metabolically healthy. Second, it means that instead of trying to lose all the weight a person needs to lose, there can be intermediate steps on the way to becoming the best version of yourself; in fact, you don’t even need to be trying to lose weight to start being healthier.

The study also found that some people who were metabolically unhealthy and normal weight or slightly overweight were at higher risk for cardiovascular disease and total mortality. Could it be that the reason for the reduced risk was exercise? It was not considered, but it would be interesting to see further analysis on the data to determine if fitness was a contributing factor in metabolic health.

The Bottom Line

This study provides a basis for assessing risk of mortality on more than just BMI. What it shows is that even though you may be carrying too much weight, that doesn’t mean that you’re automatically at risk for death due to cardiovascular disease or other causes. I believe regular exercise is critical to achieve metabolic health and thus reduce your mortality risk, so that’s your first step to becoming and staying metabolically healthy.

What are you prepared to do today?

        Dr. Chet

Reference: JAMA Net Open. doi:10.1001/jamanetworkopen.2021.8505

Can You Be Obese and Healthy?

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The research question that was most interesting to me as a graduate student was this: could you be overweight, even obese, and still be healthy? That question still interests me today, and for good reason: 70% of the U.S. population is overweight or obese, and we’ve just passed 40% of the entire population falling into the obese category. And it’s not just the U.S.; we’ve exported our poor fitness and diet habits around the world.

Research done decades ago from by Cooper Institute, most often under the direction of Steven Blair, demonstrated that you could be fat and fit. Their research showed that people who were obese, meaning they had a BMI greater than or equal to 30.0, were no more at risk for death from cardiovascular disease or all-cause mortality if they were in the high fitness category.

That’s not the same question as this: could you be metabolically healthy and at no more risk for death from cardiovascular disease or all-cause mortality than someone with a normal BMI (18.5-24.9 kg/m2)? Researchers from Germany decided to examine that question. They used data collected from the National Health and Nutrition Education Survey III, which included over 12,000 subjects, and the U.K. Biobank, which contained over 374,000 subjects. Then they examined the statistical relationship between many different variables such as triglycerides, total cholesterol, hemoglobin A1C, C-reactive protein, systolic blood pressure, and on and on. Once they had a series of statistical relationships between obesity and mortality, then they sought to derive as simple an algorithm as they could to develop a profile of someone who would be metabolically healthy and obese. I’ll tell you more about that in Saturday’s memo.

Meanwhile, have you examined that map that was part of the CDC atrial fibrillation primer? Here’s what I saw: I’ll call it the I-75 Corridor of A-fib. Starting in Flint, MI, if you follow the pattern of the deepest red, it follows I-75 through Detroit to Toledo, OH, then Cincinnati, OH, and all the way down through Georgia to Florida. That’s the I-75 Corridor of A-Fib. What does it mean? Nothing, as far as I know; it doesn’t correspond to race or income or temperature. It’s an observation, nothing more, but maybe some epidemiologist or statistician somewhere will look into in more deeply.

What are you prepared to do today?

        Dr. Chet

Reference: JAMA Net Open. doi:10.1001/jamanetworkopen.2021.8505

Omega-3s and A-Fib: More Analysis Required

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I hope that you took the time to review the paper on atrial fibrillation as well as the research letter on omega-3s and atrial fibrillation. If you haven’t, especially the primer on A-fib, please do it. It’s a serious condition that requires attention if you have it; in most cases, fixing it is surprisingly simple.

The research letter included five studies. I decided to look at each of those research papers individually to see how each trial was conducted, especially on the populations used in those experiments. Here’s what I found.

The Subjects

The subjects in the studies had several characteristics in common. First, they were, on average, in their mid 60s and older. Second, they had already had a myocardial infarction (heart attack) or were at high risk for cardiovascular disease due to factors such as obesity, hypertension, elevated triglycerides, and others. Third, most were taking multiple medications.

They definitely were not healthy and free of disease. The potential for a cardiac event increases if you’ve already had a cardiac event. On top of that, in the trials that used prescription fish oils, the attempt was to lower triglycerides in those patients who were taking a maximal dose of statins. There may be some interaction that hasn’t been identified yet between very high doses of omega-3s, equal to or greater than four grams, and statin medications or other pharmaceuticals the patients were taking to control blood pressure, heart rate, etc.

In short, this does not apply to everyone. In fact, in the concluding statement of the research letter, the researchers state that physicians should be cautious when prescribing high-dose omega-3s in patients with high triglycerides and an increased risk of cardiovascular disease.

Additional Analyses

As I alluded to in the prior paragraphs, I think the analysis should include factors such as exercise, diet, and especially prescription medications. It may be that the number of subjects might not be able to be broken down by statin intake, beta blocker intake, or ace inhibitors, but I think that it should at least be examined to see if there’s any trend.

Also, the data could be separated into those people who’ve had a heart attack and those that haven’t, even though they may have significant risk factors for cardiovascular disease. After a heart attack, there may be morphological changes such as damage to nerve conduction or the buildup of scar tissue that could impact how omega-3s impact the heart itself.

Are all of these possible? I would think it would be with over 150,000 subjects from all the studies included in the meta-analysis.

Two More Things

I still have not found a single nutritionist involved in any of this research. When you look at prior studies that seemed to benefit heart rhythms, it’s DHA omega-3, not EPA, which is the factor related to better heart rhythms.

Take a look at the map that’s in the primer on atrial fibrillation. It applies to those on Medicare who are 65 and older, but there’s an amazing and obvious trend. I’m even going to give it a name; I’ll tell you that next Tuesday. The only clue that I’ll give you is to think maps and what they’re typically used for.

The Bottom Line

While interesting, the Research Letter on the update of omega-3s in relation to atrial fibrillation leaves more questions than answers. So far, it applies only to people over 65 with high triglycerides and other risk factors for cardiovascular disease. If you already take omega-3 fatty acids, there’s probably no reason to stop, but it’s a discussion you should have with your physician.

It’s also obvious that if you do have high triglycerides, you can work on changing that by changing your diet first. Reducing refined carbohydrates is the key; eating more vegetables helps as well.

It always comes back to this: eat better. Eat less. Move more.

What are you prepared to do today?

        Dr. Chet

References:
1. European Heart Journal – CVD Pharm. 2021 doi:10.1093/ehjcvp/pvab008
2. Curr Atheroscler Rep. 2020. https://doi.org/10.1007/s11883-020-00865-5
3. Atrial Fibrillation Primer. https://www.cdc.gov/heartdisease/atrial_fibrillation.htm