What’s Herd Immunity?

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Herd immunity is a way to protect a population against the transmission of an infectious disease from one person to another by increasing the number of people who are immune to the disease. This results in lower transmission of the disease and thus protects more people or “the herd”; herd immunity is the only way to protect people who can’t get the flu shot, such as the very young, the elderly, pregant women, and people with compromised immune systems.

There’s a lot written on the net about herd immunity, and most of it’s confusing or plain misleading, especially when it comes to vaccinations. I’m going to break it down to natural herd immunity and vaccination herd immunity. Today, I’ll define both terms.

Natural herd immunity develops as many people become infected, get sick, and generate antibodies to the virus or other pathogen. When a large number of people get infected and generate an immunity to the virus, those people can no longer catch that virus; thus they won’t be transmitting it, and that protects the rest of the herd. A side benefit is that it will also provide some immunity to similar viruses.

Vaccination herd immunity uses vaccines to help people become immune to a disease without getting sick. When enough people become vaccinated, the herd immunity goes into effect: those people can no longer catch that virus; thus they won’t be transmitting it, and that protects the rest of the herd.

In both cases, the issue is getting enough people to be immune to the disease. Estimates vary but the target is somewhere between 80% and 94%. The question is simple: do we want 80–94% of the population getting sick or do we want vaccinations? More on this question on Saturday.

What are you prepared to do today?

Dr. Chet

 

Further Reading:
1. http://www.pbs.org/wgbh/nova/body/herd-immunity.html
2. https://vector.childrenshospital.org/2017/03/social-media-mumps-herd-immunity/

 

What’s Viral Shedding?

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Based on the response to my email about the flu vaccination, people raised a few questions and I had one of my own. The first question is about viral shedding. Your first thought is probably “What’s that?”

Viral shedding is the period of time when you’re infected and can transmit the flu virus to someone else—it’s when you’re contagious. The question from the reader wondered whether someone who has been vaccinated will still be contagious to others if they’re infected with the flu. The answer is yes; being vaccinated against this year’s flu will not inhibit your ability to infect others if you get the flu. Remember, some people who are vaccinated will still get the flu.

The problem with the flu is that you can be shedding the virus while you still feel fine. You can be infectious up to a day before the onset of symptoms and up to 24 hours past the end of the fever. The difference may be related to the form of flu, whether influenza A or B. However, the data are not completely clear.

The point is that you should still be cautious if you begin to feel symptoms, whether vaccinated or not. While you can’t catch the flu from the vaccination because the virus used is dead, you might still get the flu. The goal is to protect others. Speaking of others, we’ll talk about herd immunity on Thursday.

What are you prepared to do today?

Dr. Chet

 

Reference: https://www.cdc.gov/vaccines/hcp/vis/vis-statements/flu.html

 

A New Commitment

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The numbers are in and the U.S. is fatter than ever: 39.6% of all adults over 20 years old are obese based on the Body Mass Index. That’s a rise of close to 2% since 2015, the last time the statistics were released. This isn’t affecting only adults; children 2–19 are also fatter than ever with 18.5% now considered obese. If we throw in those who are overweight, more than 70% of the population is fatter than ever.

I could review the causes, from refined carbohydrates to chemicals with estrogenic properties. I could talk about all the diets that could help. I could talk about supplements that may help to give people an edge. I’ve done that all before. There’s no single diet nor exercise program nor supplement that works for everyone. We all just have to find our own way. Instead, I’m going to tell you a story and issue you a challenge.

One of my best friends for the past 30 years, Dick Heller, died last week; he’d fought off cancer several times, but it finally got him just before his 80th birthday.

Dick and I were professors together in Buffalo. He was an excellent swimming coach and a competitive swimmer throughout his life. He was also a great teacher, especially when it came to helping people change their habits; he would help people identify what they wanted to achieve in the health and fitness classes he taught, have them write it down, develop a plan, and track the progress. Their grade was not based on how they compared to others; it was based on the goals they set.

To honor Dick, Paula and I are going to use that approach as we continue to improve our diet. Getting enough vegetables is a particular problem so we’re going to add at least one serving per day, every day, until it becomes a new habit.

Here’s my challenge to you. Pick one small health habit you want to improve, write it down, and start doing it every day until it becomes a new habit. Whatever small habit, if done repeatedly, that will help you achieve your goal. It may be related to your weight because, like I said, 70% of us are overweight or obese. It may be a different health goal. If people you know have died because of a health challenge, do it to honor them.

Identify. Write it down. Plan. Execute. Evaluate. I can’t think of a better tribute to Dick than that.

What are you prepared to do today?

Dr. Chet

 

Reference: https://www.cdc.gov/nchs/products/databriefs/db288.htm.

 

Flu Shot: Yes or No?

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Every year I get asked the same question: Should I get a flu shot? Most of the time, I tell people that it’s really up to their health. Do they have a compromised immune system? Are they older? Are they pregnant? Do they have small children? Most people decide that they probably won’t. I would have included myself in that group but not any more. I’m getting a flu shot this year and every year because of an article Paula forwarded to me from Popular Science.

You typically hear the same arguments about why you should or shouldn’t get a flu shot, but the author in the article used a different approach: the flu shot is not to prevent you from getting the flu, it’s to reduce the risk you pass it along to one of those at-risk groups I mentioned earlier. If you’re healthy and young, you probably won’t get very sick if you get the flu and the risk of getting hospitalized or worse is low. But for your children, your parents, your grandparents, friends or coworkers with compromised immune systems, and even strangers whose paths you cross, the results could be very different.

I checked the CDC stats on the cases of flu, hospitalizations, and death from the flu. While the numbers vary due to the severity of the flu in any given season, every year between 9 million to 36 million people will get the flu, 140,000–710,000 will be hospitalized, and 12,000–56,000 will die. The author estimated that it would take vaccination of 80% of the population to protect the most at-risk groups, and we get nowhere near that many people vaccinated.

You’ve probably heard a lot of misinformation about the flu shot, but the article reminds us:

  • You can’t get the flu from the flu shot.
  • It takes a few weeks for the vaccine to kick in, so if you get sick right after the shot it was just a coincidence.
  • If you still get the flu, the vaccine helps you fend off life-threatening complications.

So now my questions will be different. Do you know anyone with a compromised immune system? Do you know anyone who’s older? Do you know anyone who’s pregnant? Do you know anyone with small children? Do you ever see anyone out in public who would fit into any of those categories?

Unless you can answer no to all those questions, get the flu shot every year. It may or may not prevent you from getting the flu, but it might keep someone you care about from getting it.

What are you prepared to do today?

Dr. Chet

 

References:
1. https://www.popsci.com/you-should-get-flu-shot
2. https://www.cdc.gov/flu/about/disease/burden.htm

 

Update: Tattoos and Cancer

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This week it’s time to update prior memos given. The first is a case study on tattoos. It seems people, especially young people, are wearing a lot more ink then they used to. I’ve written about the relationship between tattoos and cancer, but didn’t find enough data to make a recommendation. This memo is about a recent case study on tattoos and lymphoma. Or so the physician thought.

A woman noticed a couple of lumps under her armpits. She waited a couple of weeks but when they didn’t go away, she went to the doctor. The doctor examined her. The lumps were swollen lymph nodes. They did a scan of her upper body and found more lymph nodes, similarly swollen, a condition usually consistent with lymphoma. When they excised the lymph nodes, they were surprised to find that they were full of ink. Black tattoo ink. She had gotten a large tattoo on her back some 15 years prior and another one recently. No cancer, just an extreme reaction to the ink.

Skin is live tissue and it’s part of the immune system. As the physician told the media, this was an extreme immune response to an invasion by a foreign substance. The white blood cells did what they do and sequestered the ink in the lymph nodes. Why? The physicians couldn’t explain. The question is will it happen more frequently with more tattoos in the future? Only time will tell. But if you have a tattoo, this is another reason to get any lumps checked immediately.

What are you prepared to do today?

Dr. Chet

 

Reference: Ann Intern Med. 2017. DOI: 10.7326/L17-0424.

 

CO2 and Plant Nutrients: Proceed with Caution

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The Memos this week have examined a potential problem with the nutrient content of the plants we eat due to increasing CO2 levels. What does the research show? Part of the problem that Dr. Loladze had was that no one was doing much research on the issue of CO2 and nutrient content. That’s going to change based on some of the research that has been published.
 

Mineral Content Has Decreased

In a study published in 2004, researchers examined the nutrient content—13 nutrients and water—of 43 garden crops as reported by the U.S. Department of Agriculture in 1950 and 1999 (1). They reported declines in six nutrients: protein, calcium, iron, phosphorus, riboflavin, and vitamin C. The reductions ranged from 6% for protein to 38% for riboflavin. The researchers concluded that the decline could be explained by changes in the types of cultivated plants. Okay. If we’re now planting crops that have lower nutrient content, maybe they’ve been selected for size or appearance or the ability to be transported long distances. Do we think that’s okay?

In a study published in 2014, researchers used a creative approach to test the affect of increased CO2 on grains and legumes (2). They mimicked the predicted CO2 levels expected in the middle of this century in grains and legumes grown under field conditions. They set up an outdoor system that allowed more CO2 to be released on the plants. They found that grains and legumes had decreased levels of zinc and iron and grains had lower levels of protein.

Dr. Loladze also published an article on mineral loss in plants. He examined every research paper that examined atmospheric CO2 on plants that we eat as well as trees and grasses. Remember that he is a mathematician; he used some very sophisticated techniques that are beyond me. However, to put it simply, the better the study was designed, the more the plants showed a decline in mineral content, averaging about 8% (3).
 

Far From Complete

The research in this area is really just beginning; scientists are just becoming aware of this nutrient decline. Perhaps that will attract research dollars. Dr. Loladze was never able to get significant funding for his work. Still, he persevered.

Here are two issues that I’d like explained or examined. First, why would an increase in carbohydrate content affect the mineral and protein content? If the minerals are in the soil, it would seem they would end up in the plant. That was never explained very well.

Another issue they raised was the protein content of goldenrod pollen. The researchers were able to examine it over the decades because samples are saved at the Smithsonian Institution. The protein content of goldenrod pollen has decreased by a third over the decades. They suggested that was important to bees; they need the pollen for the hive to survive. Is the lack of nutrients contributing to the collapse of bee colonies? Obviously, more specific research needs to be done before we really know the implications, if any. It’s going to be years until there’s enough research to make definitive statements about this.
 

Proceed with Caution

There is still every reason to eat your vegetables, fruits, and whole grains, even if the vitamin, mineral, and protein contents have declined somewhat—if anything, this a reason to eat even more to make sure you get your phytonutrients. Water and fiber are two more good reasons.

This also reinforces the need to do one more thing: take a multivitamin-multimineral that contains plant concentrates every day. If the nutrient content of plants is declining, that’s an excellent way to prevent nutrient deficits in your own body. It’s the simplest way to proceed with caution until the science catches up.

What are you prepared to do today?

Dr. Chet

 

References:
1. J Am Coll Nutr. 2004 Dec;23(6):669-82.
2. Nature 510, 139–142. doi:10.1038/nature13179.
3. Loladze. eLife 2014;3:e02245. DOI: 10.7554/eLife.02245

 

Does More CO2 Create More Carbohydrates?

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Why do you eat broccoli? Why do you eat blueberries? How about sweet potatoes? While you might simply like them, an important reason we eat them in modern countries is for the nutrients they have, such as vitamin C, beta-carotene, and of course those phytonutrients. They’re a source of calories, for sure, but also minerals. But what if the increasing levels of CO2 reduced the amount of those nutrients?

If you remember your high school biology, plants use CO2 and water (H2O) to make sugars and starches in a process known as photosynthesis. As the H2O is broken down for use in making sugars, the oxygen is released into the atmosphere. Then photosynthesis continues, with CO2 and the remaining ions combining with energy from the sun to make sugar.

Here’s the issue. When CO2 levels increase, as they have since the Industrial Revolution, the plants can convert more CO2 to sugar. Why is that a problem? Because it may be at the expense of other nutrients such as minerals. In addition, the protein content of the plants may also be reduced. Plants provide protein for most of the earth’s population, so if the protein content of plants is reduced and the carbs increase, people may get plenty of a grain such as rice but little nutrition other than calories.

But is it true? Does the research support the hypothesis? That’s what Dr. Loladze and others attempted to find out for the past 20 years. I’ll cover the research on Saturday.

What are you prepared to do today?

Dr. Chet

 

Reference: www.politico.com. The Great Nutrient Collapse. 09-13-2017.

 

Does Rising CO2 Harm Plants?

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What do algae, a mathematician, and carbon dioxide have in common? A 20-year quest to see if CO2 changes are affecting the nutrient content of our plants.

The Memos for the past two weeks were about eating more vegetables and fruit because they have the vitamins, minerals, and phytonutrients we can’t get from animal products. But what if there are fewer nutrients in those plants? That’s what a recent article entitled “The Great Nutrient Collapse” in Politico examined.

The mathematician is Dr. Irakli Loladze. While a graduate student, a biologist shared an observation with a group of biology students: exposing a specific type of algae to more light caused them to multiply faster. That increased the food supply for the plankton that ate the algae. The problem is that instead of thriving, the plankton began to die. How could that be? The algae grew faster but contained fewer nutrients, thus causing the plankton to starve.

Dr. Loladze spent the next 20 years wondering and researching whether that’s happening in our food supply as well. While the amount of sunlight has remained fairly stable, atmospheric CO2 levels have increased. Could that be impacting the nutrient content of our food supply? We’ll take a look at the science this week.

What are you prepared to do today?

Dr. Chet

 

Reference: www.politico.com. The Great Nutrient Collapse. 09-13-2017.

 

The Bottom Line on “What the Health”

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“What the hell is going on around here?” That’s one of my favorite sideline videos of Vince Lombardi as he’s talking to his players, and that’s the way I felt after watching this movie. As I said, I’m going to cover one of the studies that was cited several times, but there’s a whole lot more science that warrants explanation; it’s available for Members and Insiders as a Straight Talk on Health audio. Now to the study.
 

“A Vegan Diet Is Better Than ADA Diet”

One of the films experts may be recognizable to some readers: Dr. Neal Barnard, president of the Physicians Committee for Responsible Medicine. He’s a leading proponent of a vegan diet. He led a research group that conducted a study to compare a vegan diet with a diet based on the American Diabetes Association diet guidelines (2). In the film, there were several references to the study that claimed it was more effective than the ADA diet—in fact, twice as powerful at controlling or reversing diabetes as the ADA diet, which included meat and dairy.

Researchers gave both groups dietary guidelines to follow for each diet as well as training with a registered dietician; 49 subjects began in the vegan group while 50 began in the ADA group. The study went 22 weeks and then continued through 74 weeks with the subjects tested periodically. I don’t know the significance of the 22 weeks; those results were not included in the paper.

Here are the results that didn’t quite make the movie:

  • There were no differences in the decrease in blood sugar; both diets reduced fasting blood sugar a similar amount.
  • Fewer than half the people in both groups completed the study.
  • The subjects in both groups claimed to reduce their caloric intake over 400 calories per day. However, weight loss was just ten pounds in the vegan groups and seven pounds in the ADA group. Really? In 74 weeks? Those results are simply not possible unless the subjects did not accurately report what they ate.
  • Finally, this study didn’t show that a vegan diet was twice as beneficial as the ADA diet; it showed that they were both ineffective at achieving reasonable goals for weight loss and a reduction in HbA1c over an extended period of time. While it was statistically significant, a reduction from 8.1% to 7.7% in over a year is not much improvement. Yes, it was better than the ADA diet in which the HbA1c stayed the same, but I wouldn’t start touting the benefits for diabetics just yet.

 

What the Movie Did Right

The only expert who comes through this movie unscathed is Dr. Caldwell Essylstein, the physician from the Cleveland Clinic who has demonstrated in a large clinical trial that severe CVD can be reversed using a low-fat vegan diet. I’m a fan of his work and education program. He was in only a couple of scenes and did not corrupt science in anything he said.

No so for many others in the movie. I just don’t understand why these medical and healthcare professionals would say the things they said. I have more to say, and it’s in the Straight Talk on Health audio for Members and Insiders.

What the movie got right was to provide the research that the experts cited in the movie. It was done scene by scene and makes it easy for anyone to check where the experts got their research facts. Unfortunately, that didn’t stop the research from being misinterpreted by people who know better.
 

The Bottom Line

“What the Health” is a mess of a documentary. It’s not an objective examination of what constitutes a healthy diet; it’s a critique of the food industry and health organizations that get funding from that industry. The problem is that it’s not done very well and never quite gets around to proving what it claims. Maybe they’ll do better next time.

I know a vegan diet is a very healthy way to eat if you do it right. We must move to a more plant-based diet if we’re going to be healthy, and it’s better for the planet as well. While I don’t think it’s the only healthy diet, it’s certainly great if you take the time to learn how to follow it correctly. The problem is that the plants we count on for nutrients may continue to have fewer of them. That’s the topic for next weeks Memos.

What are you prepared to do today?

Dr. Chet

 

References:
1. What the Health. Directed by K. Andersen and K. Kune. 2017.
2. Am J Clin Nutr 2009;89(suppl):1588S–96S

 

“What the Health”: False Sugar Claims

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“Sugar doesn’t cause diabetes!” So says just about every expert in the film “What the Health.” Of all the misstatements in the film, this one is the worst and most dangerous. It isn’t because the statement is false; it’s because of the way it’s presented. Expert after expert looks into the camera and says that excess sugar intake does not cause type 2 diabetes. On top of that, the explanations that they give to justify their position are misleading.

One expert said that sugar will be stored as glycogen in the liver and the muscles and the rest used for energy. That’s correct. Another talked about the Duke University Diet which included rice, sugar, and some fruit and fruit juices; one physician used it to help many people who were too sick for other treatments. All the experts filmed agreed that neither sugar nor carbohydrate caused type 2 diabetes. It just couldn’t.

They are stopping short of telling the truth or intentionally misleading the audience. Sugar doesn’t cause type 2 diabetes if the person does not overeat. The statement about glycogen? True, as I said, but when a person overeats carbohydrates, the liver stores as much glycogen as it can and then converts the rest to fat.

Excess carbohydrates lead to insulin resistance and eventually, type 2 diabetes. The Duke University Diet? That was from the 1940s. It was an ultra low-fat diet with no salt, and was used to treat the sickest patients but only under the care of a physician.

The section on sugar and diabetes was by far the worst. It intentionally misleads people to think that overeating is fine as long as it’s carbohydrates. But there was one study that was cited over and over that’s even worse in my opinion. I’ll cover that on Saturday.

What are you prepared to do today?

Dr. Chet

 

Reference: What the Health. Directed by K. Andersen and K. Kune. 2017.