Tag Archive for: blood pressure

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

SFCA, Sodium Intake, and High Blood Pressure

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Researchers in the United Kingdom recruited people with elevated systolic and diastolic blood pressure for a randomized, placebo-controlled, crossover study on diet and blood pressure. The scientists put all 145 subjects on a low-sodium diet for six weeks. Half the subjects was given a placebo while the other half was given a slow-release sodium supplement. After six weeks, the subjects were crossed over to the other group for another six weeks. The objective was to see if sodium intake impacted the microbiome and short-chain fatty acids (SCFA) production to reduce blood pressure.

In a perfect world, researchers would take stool samples under all conditions to test for changes in microbe content, but that approach is expensive and time-consuming. Instead they chose to monitor changes in SCFA because they’ve been associated with blood pressure.

Researchers found that while taking the placebo, subjects on the low-sodium diet saw all SCFA increase; 2-methylbutyrate, butyrate, hexanoate, isobutyrate, and valerate were significantly increased. The increases in SCFA were associated with reductions in blood pressure and arterial-wall stretchability.

What does it mean? We’ve known for decades that sodium plays a role in blood pressure. This study demonstrated that sodium reduction directly increased the production of SCFA, which then lowered blood pressure. What we don’t know is the specific beneficial microbes affected or exactly how sodium negatively impacts them. Research continues and I’m sure we’ll find that out eventually.

The Bottom Line

On the other hand, it may not be necessary to find out. Scientists like me always want to know the specific bacteria and the mechanism by how it works. We know that fluid retention is involved somewhere. But we already know that if we reduce sodium, we’ll positively impact our blood pressure. We also know that fiber is the essential food for these SCFA-producing bacteria in our microbiome. If we focus on a more fiber-rich diet as well as take a fiber supplement, we may be able to increase our odds of reducing blood pressure without medication. If we need the meds, we take them, but if we can do it by feeding our microbiome, that’s even better.

What are you prepared to do today?

        Dr. Chet

References:
1. Hypertension. 2020;76:73–79.
2. Benoit Chassaing, Andrew T. Gewirtz, in Physiology of the Gastrointestinal Tract (Sixth Edition), 2018.

Not So Smartphones

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Many variables that were included in the smartphone study weren’t reported, and there’s a good reason for that: they were non-significant. I don’t mean not statistically significant—I mean not significant in the real world either. In fact, I don’t think I’ve ever seen a study with so many variables that were non-significant.

The one that surprised me the most was that simple tracking of blood pressure or the use of the artificial intelligence (AI) application did not change the percentage of people who took their BP medications regularly. Neither approach shifted the scale one little bit. I would have expected that at least some people would have started taking their meds regularly, but they didn’t in either group. In next Tuesday’s Memo, I’m going to give you a good reason to take your meds based on a recent COVID-19 study.

Many of the variables were from questionnaires, and as I often remind you, self-reporting is always suspect. But it raised a few questions about the reported results.

Questions

The first question I had was related to the statistical analysis they ran. Instead of looking for differences within groups, they ran comparisons only between groups. I’m not saying that any differences were profound, but it did appear that there were some that were interesting.

For example, the control group demonstrated no differences in servings of processed meats per week, but the app group decreased servings by about one-half portion. The servings of sugar-sweetened beverages decreased by about a half-portion per week as well, while there were no changes in the control group. That would seem to be a benefit and if a statistical analysis were run, it might have been statistically significant—take a win wherever you can get it. You shouldn’t overstate the findings, but it does support the idea that reminders about a healthier diet might be effective.

I don’t understand why the researchers used an application that was being beta-tested for use in the study. If the number of subjects was limited, and AI requires a lot more data points to really “learn” enough to decide what the subjects need to know and how best to present it to them, it seems the study was destined to fail before it began. If they had called it a pilot study to gain insight to propose a major clinical trial, that would be more logical because that’s what pilot studies are for: to decide whether larger studies are warranted. They came to the same conclusion, but focused on what they didn’t show instead of what they did.

The Bottom Line

The use of smartphones, tablets, and laptops together with applications designed to monitor health are growing in use. Paula recently had a consultation with a specialist and her first telemed physical. I think there’s a place for these types of electronic services, especially during this unusual time. But no matter how many subjects are used to train AI, I think it will always stop short of what they hope applications will do, because there’s no app that will get people to do what they don’t want to do. No logic. No mini-goal setting. No reasoning.

I always thought that education was the key. It isn’t. Even with my education, I have trouble doing the things that I know I should do for my health. The willingness to change has to come from within. Until people have that, no program, person, or application will help them achieve their health goals. It’s wrapped up in the third word in my tagline: what are YOU prepared to do today? It is and always be your choice.

Because we’ve talked about blood pressure all week and more is coming next week, this seems like an obvious time to offer you my High Blood Pressure download at half price; only a few CDs are left, also half price, and when they’re gone, they’re gone. Members and Insiders who log in first will get their discounts as well.

What are you prepared to do today?

        Dr. Chet

References:
1. https://bit.ly/39OmUCc.
2. JAMA Open. doi:10.1001/jamanetworkopen.2020.0255.

Limitations of the Smartphone BP App

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In the examination of a smartphone application to help lower blood pressure, the results were a little surprising. Take a look at the graphic representation above of the study, including the results. More and more journals are going to that type of graphic summary. They’re great summaries, but they don’t always tell the entire story.

A quick review on blood pressure: systolic is the upper number and indicates the pressure when your heart is beating; diastolic is the lower number and indicates the pressure when your heart is resting. The ideal BP range is 110/70 to 120/80.

In this case, as you could see on the graphic, there was a difference of only 3 mmHg in systolic BP between those using the AI-generated coaching application and those who didn’t use that app. One of the discussion points was that the number of subjects was not great enough to be able to discern the significance of less than a 5 mmHg difference in BP. Achieving statistical significance is pretty much irrelevant in the real world if the difference between the approaches was so small. Yes, in a population of 50 million, a 1 mmHg drop in systolic BP may save some lives, but who do you really want tracking your BP: an artificial presence or your physician?

What really caught my attention was that both approaches worked. The overall decrease in the AI group was 8.3 mmHg versus 6.8 mmHg in the control group. There were decreases in diastolic BP as well. Whether it was the automated BP reporting alone or not, it appeared that just paying attention got results. But that’s not all I got out of the study. I’ll let you know more on Saturday. By the way, how you coming along with your new habit?

What are you prepared to do today?

        Dr. Chet

References:
1. https://bit.ly/39OmUCc.
2. JAMA Open. doi:10.1001/jamanetworkopen.2020.0255.

What Happens if You Give Up Salt?

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The next category of foods that you could give up for Lent is salt and sodium. Why do I mention both? Because they’re not exactly the same thing. Salt is sodium-chloride, a one to one proportion of sodium and chloride; sodium is just sodium. The typical American takes in over three grams or 3,000 mg of sodium per day. The upper limit is 2,300 mg and the goal is 1,500 mg. In past centuries, packing a food in salt was one way to preserve it, but with today’s refrigeration systems, we don’t need salt as a preservative. We just like it.

Where do we find sodium? Salt is added to all types of chips, nuts, processed meats, and deep-fried foods. But sodium is also added to many types of prepared foods. With the emphasis on reducing fat and carbohydrates, the flavor is often enhanced with sodium.

What could you expect to happen if you reduced your salt and sodium intake? You would probably lose some fluids. You body must keep sodium in a specific ionic balance, and reducing sodium would reduce the need for additional fluid. That could result in the reduction of blood pressure, something almost everyone could benefit from. That eases the strain on the heart, which won’t have to pump as hard because the resistance would not be as great.

As I’ve confessed before, I’m a salt-aholic so I’m going to work on reducing my sodium intake—no salty crunchy chips or roasted nuts, and no added salt to anything. I’ll also limit my intake of processed meats such as ham and bacon. We’ve become used to salt and sodium and it’s jaded our taste buds. No substitutions for this one. Time to retrain our taste.

What are you prepared to do today?

Dr. Chet

 

Guidelines for Lowering Your Blood Pressure

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When guidelines for any condition are changed, especially one as common as high blood pressure (HBP), it raises several questions. One question would be: is this is just a way for the medical and pharmaceutical businesses to promote and sell more drugs? Another would be: will this throw more people into the pre-existing condition category and thus hinder their ability to get health insurance? I can’t answer those questions, but I can condense the American Heart Association’s 481-page guidelines to a few points.

Environmental Causes of HBP

The nice thing, if you can call it that, is that most of the causes of HBP, also known as hypertension, are environmental; they’re caused by the way we interact with our environment in a personal way. I’ve listed the causes in the order presented in the AHA’s guidelines; they’re not ranked by significance.

  • Being overweight or obese contributes to HBP. Going back to the insurance actuarial tables, there is a distinct relationship between excess body fat and HBP. This observation has been confirmed in several large epidemiological studies over the years. If you carry extra body weight, your risk for HBP is higher.
  • Excess sodium intake is associated with HBP. The reasons can vary, but let’s look at it this way. Cells must be in a specific ionic balance to function properly. If one ion, sodium, is increased, the body must retain more fluid to keep the ionic balance. When fluid levels go up, there’s an increase in the force exerted against the inside of the arteries to handle the extra fluid. Hence, blood pressure goes up.
  • One that may surprise you is that a decreased potassium level is also associated with HBP. As a nation, we are potassium poor because we don’t consume the necessary plant material in the form of vegetables and fruit. Potassium is also an ion involved in many strategic chemical reactions. Because we take in much more sodium than potassium, the balance is thrown off and BP increases.
  • Fitness level directly affects the cardiovascular system; when fitness declines, everything from the heart’s ability to contract to the number of small blood vessels is modified in a negative way. That can increase BP.
  • Finally, excess alcohol intake is related to an increase in BP. While a little alcohol may be beneficial to help reduce stress levels, too much can increase BP.

Let’s take a look at the treatment recommendations for Elevated and Stage 1 Hypertension.

Treatment Recommendations

The initial recommendations for Elevated BP and HBP Stage 1 are lifestyle recommendations. The goal in both cases is to see how the person responds to lifestyle changes first before any medications are recommended.

There is one exception: if the person’s 10-year risk for a heart attack and stroke is greater than 10%, the recommendation is lifestyle plus medication. You can take this assessment at the link in the second reference to determine your risk. However, most physicians will give you three to six months to change your lifestyle, and then reassess whether you need the medication at all.

The important point is that it’s lifestyle change that’s recommended first, not medications. So how are you going to reduce your risk?

Lifestyle Modifications to Lower BP

  • Lose weight. There’s no single correct way to do that. Use the DASH Diet or go low fat, follow the USDA MyPlate plan or go ketogenic, use the AHA guidelines or go low carb. Whatever you can do to lose weight and keep it off, do it. For every kilo (2.2 pounds) you lose, you can expect BP to decrease by 1 mmHg, both systolic and diastolic (top and bottom numbers).
  • Eat healthier by following the DASH Diet. It focuses on vegetables, healthier fats, more fruit, nuts, fish, and whole grains. You can expect to decrease BP from 3 to 11 mmHG.
  • Reduce sodium intake to 1,500 mg per day. If that’s too difficult, shoot for a reduction of 1,000 mg per day from your current intake. Expect to reduce BP between 2 and 6 mmHg.
  • Increase potassium intake by eating more foods containing potassium—and the best source is most vegetables. It’s more than just eating bananas! Expect to reduce BP by 2 to 5 mmHg.
  • Exercise regularly and that means 4 to 5 days per week. Aerobic gets the biggest results, but weight training and even isometric exercise will reduce BP between 4 and 8 mmHg. Fun activities like dancing, tennis, and playing with the grandkids count as exercise if you keep moving and increase your heart rate.
  • Reduce excess alcohol intake. Men should have no more than two drinks per day while women should have no more than one. Expect to reduce BP 3 to 4 mmHg.

Any one of these lifestyle changes doesn’t seem too hard, but you’ll get the best results by combining a few changes. As always, I’d advise a stepwise approach: change one thing, and a week or two later change another one. If you do that and stick with it, you can reduce your BP by 10 to 15 mmHg and that will get you into the desirable range—no medication necessary.

The Bottom Line

I think the new guidelines for diagnosing and treating BP are spot on. The emphasis is on lifestyle first and foremost, so these guidelines have put the ball squarely in your hands. Take the ball and run: change your lifestyle, for good. The real benefits will be how much better you’ll feel and the knowledge that you’ve reduced your risk of heart disease and stroke considerably.

What are you prepared to do today?

Dr. Chet

 

References:
1. Hypertension. 2017;00:e000-e000.
2. http://www.cvriskcalculator.com.

 

Blood Pressure: Getting It Right

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The change in the clinical guidelines for diagnosing high blood pressure, as described in Tuesday’s memo, requires that your BP reading is done correctly. That could be a problem.

In a JAMA Medical News report published in August, medical students were asked to take the BP of volunteers. Only one out of 159 got all the steps correctly. It’s not that they were poor at the actual mechanics of taking the BP, but they didn’t follow all 11 steps. Yes, 11 steps. Here they are:

  1. Five minutes of rest; that eliminates the rise in BP from getting to the office, checking in, getting weighed, etc. This is the step most often missed.
  2. The correct size cuff should be used. If your upper arms are large, and the nurse or doctor doesn’t use a large cuff, your BP reading will be higher. That’s because the bladder inside the cuff will have an artificially high pressure, which is reflected in the reading.
  3. The cuff should be placed over a bare arm, not over clothing. It’s your job to remember to wear something with a loose sleeve that won’t get in the way.
  4. The arm should be supported on a desk or a table, not hanging free.
  5. The patient should be asked not to talk. The doctor has to be able to hear the sounds clearly to get an accurate reading. This is not the time to discuss new restaurants.
  6. Legs should be uncrossed because that can affect blood flow.
  7. Feet should be flat on the floor.
  8. No reading or cell phones during measurement. There are a couple of reasons for this one. Holding the phone or book is an isometric contraction albeit a small one; nevertheless, it can raise the BP reading. The other reason is that if you’re checking email or something like that, it can affect your reading if your heart rate gets elevated.
  9. The BP in both arms should be checked.
  10. The arm with the higher reading should be noted.
  11. Finally, the physician should note in the records which arm is to be used in future readings.

Who knew taking a BP was so complicated? The photo above gets at least three steps wrong. Now that you know, you can make sure you do your part whether you’re told to or not.

But what’s going to happen if you hit higher numbers? I know many people suspect this is just a way to push more BP meds. We’ll look at treatment regulations on Saturday.

What are you prepared to do today?

Dr. Chet

 

Reference: JAMA Online. Abassi 08-30-2017.

 

Do You Have High Blood Pressure?

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On Monday November 13, you may have awakened with normal blood pressure, and by that afternoon, you may have joined the ranks of those with high blood pressure (HBP). That’s when the American Heart Association (AHA) released their new HBP clinical practice guidelines at their national conference. With the new guidelines, close to half of all adults will be diagnosed with HBP.

The guidelines are the topic for this week’s Memos. I downloaded the entire document—all 481 pages—and three important parts warrant discussion. The first is AHA’s new guidelines for diagnosing HBP, and those numbers are in the graphic above.

While there are numerous questions, the first one is this: is your BP being taken correctly? That’s the topic for Thursday’s Memo, and you’ll be surprised at how often it’s done poorly.

What are you prepared to do today?

Dr. Chet

 

Reference: Hypertension. 2017;00:e000-e000.

 

Research on Nature and Health

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I’m back on the deck to write today’s message about the benefits of spending time with nature (1). Researchers tested over 1,500 subjects who live in urban settings; they wanted to quantify visits to parks in cities with physical measures such as depression, blood pressure, social interactions, and physical activity (2). If you’re a long-time reader, you know I prefer studies with solid measurements such as body weight or cholesterol levels. Surveys and questionnaires are subject to how a person feels at any given moment, but these researchers used the best instruments available.

They found . . .

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Blood Pressure: Lifestyle First

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Today I’m going to share a caution from one of the lead authors in the Mayo Clinic arm of the study and tell you what I think is the biggest mistake the researchers made in announcing the preliminary results of the SPRINT Study.

The Mayo Clinic posted a video from Dr. William Haley, a lead researcher in the SPRINT Study; remember there were 102 different clinical sites that provided data for this study. What he said was significant. Here’s my interpretation: The results of a large study such . . .

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If you're already a DrChet.com Member or Insider, click on the Membership Login link on the top menu. Members may upgrade to Insider by going to the Store and clicking Membership; your membership fee will be prorated automatically.