Classic: Type III Error

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You know that eating fruits and vegetables is good for you, right? I tell you that all the time because that’s what the research indicates. But according to an editorial piece in the Journal of the American Medical Association (JAMA), maybe we’ve been wrong all this time (1)—at least as it relates to reducing our risk of cancer. Here’s a recap of the editorial and my take on it.


The Editorial

Mike Mitka is a well respected senior writer for JAMA; he’s published numerous articles that are well researched and contain interviews with the authors and other experts. In a 2010 JAMA article, he writes that an article from the European Prospective Investigation into Cancer and Nutrition (EPIC) clearly demonstrates that high intakes of fruits and vegetables do not reduce the risk of cancer, at least not very much.

Based on the study published in the Journal of the National Cancer Institute, increasing fruit and vegetable intake by six ounces per day reduced the risk of cancer only 3% (2). A couple of well-known researchers supported the notion that research does not support plant intake reducing the risk of cancer, including the director of nutrition for the American Cancer Society.

The problem is that it’s just not true, at least not in that study. The way it’s written, the study suggests that when subjects increased their intake of vegetables and fruits by six ounces, the reduction of cancer risk was a paltry 3%. This was an observational study, not an interventional study. No one kept track of who increased or decreased their plant material intake, and there’s no way to know that from the data collected.

The way I read the article, the EPIC study is central to this new belief about plant consumption not being related to decreased cancer risk. The first articles from the study were published in 2003, and that’s when scientists suggest the evidence grew weaker supporting reducing cancer by plant consumption.

I’ve written about EPIC before; it’s one of the largest observational studies ever conducted with over 520,000 subjects from 23 different centers in 10 European countries. While I suggested that there was strength in numbers when you want to try to tease out subtle effects, I mentioned that the researchers gathered nutritional information at the beginning of the study with a Food Frequency Questionnaire; subjects were asked as many as 256 questions about what they had eaten in the past year. There are two problems with that when you’re looking at the rate of cancer.

First, you have to assume that this one-time questionnaire on diet applies to the patterns of the way the subjects ate and will continue to eat. By the validation studies that were done for the EPIC study itself, that certainly was not true (3). Correlations between what people ate one year apart were as low as 36% in a sub-sample of the subjects. Researchers chose to adjust levels statistically, but that just isn’t the same as actually collecting the data. But when you’re dealing with a half million subjects, you just can’t collect dietary histories on every subject.

Second, the assumption is that the levels that the subjects ate were actually adequate to reduce the rate of cancer. In the study, the average fruits and vegetable intake for men was 17 ounces per day and about 19 ounces per day for women (4). Using an example from the editorial, a medium apple is 10 ounces and a serving of broccoli is about 3.5 ounces. That’s just two servings and that’s close to what the subjects actually ate.

The fact is that most subjects in the study did not eat very many vegetables and fruits and it got worse the further north the country was located. That should have been the overwhelming conclusion of the study to begin with before any other analysis was conducted.


My Take

Trying to explain statistics is not my strong suit, but I adapted this from a blog by Satoshi Kanazawa, an evolutionary psychologist in London and a contributor to Psychology Today (5).

There are two types of errors in statistics. There’s the error of a false positive: you think that the data reflect your hypothesis when it doesn’t. Then there’s the error of false negative: you think the results do not support your hypothesis when it does. Statisticians call the former type of errors “type I errors” and the latter type of errors “type II errors.”

My feeling is that Mitka and researchers who are using the EPIC study to make suggestions about the relationship between plant intake and cancer risk are committing a “type III error.” What’s that? An unwavering belief in statistics: you don’t look at anything but the numbers, and that rules what you believe. Maybe a better way of describing a type III error is hubris, an overbearing pride in statistics. These researchers are very smart people. Did no one consider that the way the data were collected didn’t make sense when tracking diet’s effect on cancer risk? That’s hard to believe unless pride gets in your way.

But when you get right down to it, if you eat an apple and some broccoli on a typical day and someone told you that adding a banana or a tomato would reduce your risk of cancer by 3%, doesn’t it seem like a great idea to add that banana or tomato? Imagine what you could do if you actually ate the recommended eight to ten servings!


The Bottom Line

This will not be the last time I write about EPIC because there are over 500 articles published to date. I still think that eating more vegetables and fruit reduces the risk of all disease including cancer based on the thousands of other studies that say that it does. It seems like the larger the study, the less beneficial effects anything seems to have whether it’s diet, exercise, or supplementation. Maybe someone should start considering whether the effects are being washed out by regressing to the mean. But that’s a message for another day. Time for some berries!

What are you prepared to do today?

Dr. Chet

 

References:
1. JAMA. 2010; 303 (21): 2127-9.
2. J Natl Cancer Inst. 2010 Apr 21;102(8):529-37.
3. International Journal of Epidemiology 1997; 26 (Suppl. 1): S26–S36.
4. Public Health Nutrition: 5(6B), 1179–1196.
5. www.psychologytoday.com/blog/bloggers/satoshi-kanazawa

 

Classic: Vitamin Dumb

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As Paula and I visit our son and his wife this week, I’m choosing what I call Dr. Chet’s Classics. This one from 2010 illustrates two points. First, mega-dosing vitamins and minerals can have consequences that someone might not expect, and “if some is good, more has to be better” is not a good idea unless there’s a genetic or other reason. Second, even with the best intentions, researchers sometimes don’t use their heads when designing research studies.

Researchers reported in JAMA on the effects of vitamin D on fractures and falls in a group of over 1,500 women over 70. The results were surprising in that the vitamin D group had more falls and more fractures than the placebo group. Well, maybe not so surprising.

Remembering to take medications as well as supplements is a problem. So how did the researchers choose to address that issue? Give the women a year’s worth of vitamin D once a year.

That’s right. They gave these subjects 500,000 IU vitamin D once a year. I was almost rendered speechless—500,000 IU? What in nature would give them a model to follow? If you spend all day in the sun without sunblock, your body shuts down the production of vitamin D automatically; that’s why you can’t overdose on D from the sun. But this was oral intake; in what universe did these researchers think this was a good idea? Would they give someone a year’s supply of cholesterol-lowering medication or pain medication in one dose per year just because the subjects might not remember to take their meds every day? And what earthly good would that do?

In an editorial in the same issue, the authors suggested that medical professionals examine how vitamin D is administered, and that maybe administering 50,000–100,000 IU doses isn’t such a good idea.

Do ya think?

Taking up to 10,000 IU vitamin D3 is safe and 2,000-6,000 IU per day is a good goal. But this study illustrates that there’s no need to megadose. Doing that is like taking vitamin Dumb.

What are you prepared to do today?

Dr. Chet

 

Reference: JAMA. 2010;303(18):1815-1822.

 

Men, Their Microbiome, and Infertility

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What role does a man’s microbiome play in infertility? Maybe a lot more than we thought. There are many more factors that affect fertility, with more studies published every day, but this week’s posts have focused on the microbiome. We’ll finish with a study on men.

Researchers examined the sperm of men who contributed semen to an in-vitro fertilization clinic before IVF with their partners. They wanted to determine whether there was a relationship between periodontal disease and sperm quantity and motility—how many sperm and how well those sperm moved. They found that men with periodontal disease had low sperm counts and the sperm were not as active. Those two problems can contribute to infertility.

Just as with women who have periodontal disease, the pathogenic bacteria appear to have an affect on fertility. The same type of treatment for periodontal disease may help fertility issues for both partners. But let me be clear: the microbiome is only one aspect of fertility; there are other issues that contribute to infertility that may also need to be addressed.

What are you prepared to do today?

Dr. Chet

 

Reference: J Clin Periodontol. 2011 Jun;38(6):542-6.

 

Your Oral Microbiome and Infertility

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Is there a relationship between the health of your teeth and your ability to conceive? Yes, and in today’s message, I’ll give you the latest research to come to that conclusion. This week’s messages provide insight into some of the health issues surrounding infertility. It’s also a kick-off of the second edition of my Healthy Babies CD and download.

In a review article, researchers examined the literature that was related to periodontal disease and women’s health. The examined systematic reviews, meta-analyses, and narrative reviews to evaluate all possible associations between periodontitis, systemic diseases, and women. The strongest association they found in the published literature was between infertility and periodontal disease, a growth in pathogenic bacteria in the gums surrounding the teeth. With open access to the bloodstream, these bacteria can affect many disease conditions such as heart disease. They can also contribute to infertility. And let’s be realistic: carrying a baby is a health challenge. You don’t need any rogue bacteria attacking your mouth or the rest of your body.

In this case, the solution for periodontal disease is simple: treat the periodontal disease and begin good oral hygiene including flossing, regular brushing, and regular dental check-ups. That will contribute to a healthy oral microbiome. There may still be other factors related to infertility that should be addressed, but you’ll have ruled out one possible obstacle as well as doing something great for your overall health.

What are you prepared to do today?

Dr. Chet

 

Reference: Curr Med Res Opin. 2017. Mar 24:1-11.

 

How Your Microbiome Affects Infertility

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Many couples struggle with infertility; they want to start a family but time passes with no results. This week, I’ll cover three recent studies that examine some factors that may affect fertility.

Researchers tested the fluids from the cervical-vaginal area in 96 subjects to examine the microbiome: were there any differences in the microbes in these women when compared to an established database of microbes typically found in that area? They found differences in the quantities of several bacteria. The researchers commented that the pattern of the microbiome was similar to women with bacterial vaginosis; it didn’t mean they had the condition, simply that there was a similar pattern in the microbiome. The researchers concluded that testing techniques could be developed along with treatment specific to the microbiome that could help infertility.

In this case, the researchers provided more questions and areas for further research. Where’s the solution? What can we do now? Ask yourself this: what makes the microbiome healthy in general? Without question, one of the primary ways is through diet. Eating vegetables, yogurt, and fermented foods contributes to a healthy microbiome.

What are you prepared to do today?

Dr. Chet

 

Reference: J Cell Physiol. 2017 Jul;232(7):1681-1688. doi: 10.1002/jcp.25806.

 

Pop Quiz on Fake Health News

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In last week’s posts, I gave you six questions to evaluate fake health news. Did I forget to say there’d be a quiz?

Below are three stories that you’ve sent me to check out. If you click on the link, it will take you to the story. As I take the rest of the week off to work on other projects, I want you to use what you learned last week, then send me an email about what you’ve found.

Here are the stories:

I know that some of you would not use any of these products, but choose one anyway. I want you to take out the emotion and just look at the facts you find.

I hope you’re healthy and well during Easter and Passover. I’ll be back with more health news next Tuesday.

What are you prepared to do today?

Dr. Chet

 

The Bottom Line on Fake Health News

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The final questions about checking fake health news completely depend on you—what you know and what your gut tells you. Let’s take a look:

5. Does it match your prior knowledge?
We all come to the table with a certain amount of knowledge. When it comes to health, it may be from a high school health class, listening to a lecture by a doctor, or other ways you’ve learned reliable health facts. Does what you’re reading seem to agree or conflict with that? Science changes as we get newer technology to examine things we couldn’t before, but it should still line up with what you’ve learned.

6. The final question is the simplest: does it make any sense?
What does your gut tell you? Is it reasonable that someone with no training in the sciences could discover something millions of trained scientists couldn’t? Sure, there’s always the exception, but it still should seem reasonable.

Those questions, along with the ones from Tuesday and Thursday, are what I ask every time I see something that promises too much. You know the old saying: if something seems too good to be true, it often is.

Keep in mind, too, that fake news is often click bait, and sometimes the owners of the site don’t just want to get paid for your click—they want to plant something harmful on your computer. It gives a whole new meaning to the term “breaking news.” If it doesn’t ring true, don’t even click it.

 

The Bottom Line

I thought the California teacher did his students a great service. If you read the article, you know they now fact-check him as well. I welcome you to do the same thing to me. That’s why I provide references for what I write. My goal is to always be one of those reliable sources. I gladly submit to anyone who wants to fact-check me—and now you know how to do it.

What about things that are complicated? Two that come to mind are soy and artificial sweeteners such as sucralose. In both cases, I’ve examined the research that Internet authors have used to say that they’re bad for us and given you what the research really says. Because they’re in a form you can reprint and give to your clients, your doctor, or your know-it-all cousin, they’re for sale on my website. All Bottom Line PDFs contain all the references I used to verify the facts, as do the zip files for the MP3 versions, and now all Bottom Lines are available as MP3s. Check them out today.

What are you prepared to do today?

Dr. Chet

 

Reference: http://bit.ly/2ozc2kC

 

When and Who: Spotting Fake Health News

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Let’s continue our look at how to check health news that you aren’t sure is real or fake. I hope you’ve had a chance to read the article by Stephen Hedley; if not, click the reference below to see what he taught his fifth grade class. One of my readers said he passed the article along to his niece, and I think that’s a great idea. Our kids are living in a world of fake news, and anything we can do to help them learn to spot it will make them savvier citizens and consumers, but as Mr. Hedley warned, prepare to be fact-checked.

Let’s continue with questions three and four:

3. When was the news story published?
That seems simple enough but many fake health articles don’t have a date. In one article I recently checked, the author published it as though it were her own. The problem was that it just seemed way too familiar. Way at the bottom, it was something she had found on the Internet and reposted. I recognized it from 15 years ago. Dates also apply to research citations. Research should stand the test of time but if an author uses a single study from 20 years ago on a topic such as supplements or a disease, that’s a warning they may be picking research to suit the message.

4. This one’s a big deal: what is the author’s expertise and background with the subject?
That’s a big problem on the Internet. People lose weight or find a diet that “heals” their irritable bowel disease, they start a blog, and are now “experts.” Even if they do seem to have some credentials, are they talking about something within their area of expertise? Do they have the training in statistics and research methods to understand the research they’re using? I may be getting beyond what you can do, but you can check someone’s education, training, and resume online in places such as Linked-In. Be suspicious if you find nothing there or elsewhere.

One thing: you don’t have to do these in the order that I’ve presented them. Sometimes, it’s easier to check the date something was posted or do a quick search on the author. We’ll finish it up on Saturday.

What are you prepared to do today?

Dr. Chet

 

Reference: http://bit.ly/2ozc2kC

 

Spotting Fake Health News

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Would you like to know whether a health news story is fake? Should you be worried and stop eating the deadly food they’ve identified? On the other hand, should you be excited? You know, if you do this one thing, you can lose your belly fat, or this exotic fruit prevents Alzheimer’s disease!

This week I’m going to adapt what a teacher taught his fifth graders on how to spot fake news. He developed seven questions that his students should answer, but I think I can do it in six. He tells them that it won’t guarantee something is true, but it can eliminate the “fakiest” news. I’ll give you two questions per day and explain how to look for answers with the same goal in mind.

1. Can you verify what’s being said from multiple sources?
Fake health news is often passed from one fake website to another, so it’s a little more complicated. Check the bottom of the article to see if this was an author from the website posting the information or whether it was taken from somewhere else. Keep drilling down until you can find the source. That allows you to see whether the originator may be credible or not. Another way is to check it on Snopes or some other fact-checking website.

2. Is the source of the information credible?
Every legitimate article related to health should have references. The references may be scientific journals or press releases from journals; yes, there are fake journals, but they’re rare. Fake press releases exist, but you can check their source as well. The important point is that you can find and read the original sources. Sites such as WebMD and PubMed are almost always reliable, but check whether it’s a research report or just someone’s opinion. Government sites such as the National Institutes of Health publish legitimate health stories as do major organizations such as the American Heart Association.

That’s enough to get started. More on Thursday.

What are you prepared to do today?

Dr. Chet

 

Reference: http://bit.ly/2ozc2kC

 

Sleep More and Quit Eating Sooner

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Sleep more, eat the same, and lose weight. Seriously? That’s what researchers are going to try to find out. At this point, there’s little question that for most people, lack of sleep messes with the circadian rhythms and negatively impacts glucose metabolism.

But a different research team is looking at another element: how long you eat every day can impact your ability to lose weight. Researchers have done a pilot study looking at eating intervals: the time you eat your first meal until you stop eating for the day. For people devoted to their evening snacks, it can be 16 to 18 hours per day.

In the pilot study, subjects restricted their eating to a period of 10 to 12 hours per day. Over 16 weeks, subjects lost an average of seven pounds. One more thing: they didn’t have to restrict their eating. They ate what they wanted, just in a shorter time interval every day.

This was a pilot study using an app that the researchers developed; they’re recruiting 10,000 subjects to see if the idea will work on a greater scale while collecting additional data. Such as what? Well, maybe you actually eat fewer calories when you eat in smaller time frame even if you eat the same foods. By the way, if you want to be a subject, check out www.mycircadianclock.org to see if you qualify.

Back to the sleep portion. The part that interests me the most is the messed up carbohydrate metabolism by eating when your clock says it’s time to sleep. Getting more sleep is not easy these days, but it just might be worth it.

We’ve all heard people say they cannot lose weight no matter what they do. Well, maybe getting a little more sleep and eating over fewer hours may help. Of course, if you’re a diabetic or hypoglycemic, talk with your doctor. But here’s something simple and cheap you could do: sleep more and eat the same over fewer hours. Will you lose weight? We don’t know, but it’s worth a try.

What are you prepared to do today?

Dr. Chet

 

Reference: doi:10.1001/jama.2017.0653