SGU Episode 370

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Introduction

I like big buttes and I cannot lie, you other brothers can't deny... Skeptics' Guide to the Universe, your escape to reality.

S: Hello and welcome to the Skeptics' Guide to the Universe, today is Wednesday, August 15 2012 and this is your host, Steven Novella. Joining me this week are Bob Novella.

B: Hey Everybody.

S: Jay Novella.

J: Hey Guys.

S: And Evan Bernstein.

E: Good evening everybody.

S: Rebecca is travelling so cannot join us this week, so Evan you're back in your old slot covering This Day in Skepticism.

This Day in Skepticism (0:27)

• August 18, 1986 - Seventy-two Nobel Prize-winning scientists filed a legal brief with the U.S. Supreme Court challenging as unconstitutional a Louisiana law requiring schools that teach evolution to also teach "creation-science".

E: Yep and the seat is still warm, I might add, thank you very much.

S: I remember it well.

E: I remember it well.

S: Unfortunately, yeah.

E: I was a junior in high school, man that was a long time ago.

J: Wow yeah. Actually, I think that was the year I graduated.

E: But on that day in 1986, 72 Nobel prize winners in science urged the supreme court to reject a Louisianna law calling for "balanced treatment" of evolution and creationism in public schools. So as you can tell it's not just a more modern phenomenon going on in our society these days, this dates back to the 1980s and even well before that. The news release described the scientists as the largest group of Nobel laureates ever to support a declaration on any subject so it's that important to them, that 72 of these people had to get together and make sure that this law got struck down, and sure enough it did. The supreme court ruled against the law on June 19th in 1987, so.

S: Yeah, this is the Edwards versus Aguillard case, this is now one of the pillars of supreme court law keeping creationism out of public school science classrooms, this pretty much ended the equal time creation science approach and then led to their next move, the intelligent design teach the weaknesses of evolution approach. So that was very important case law.

E: For the most part, good results coming out of the US court system when it comes to matters of creationism versus evolution and the teaching in the classroom. It's kind of sad that it has to get to that point that lawsuits are constantly being brought up, but so far we've done pretty well in defending science.

B: It's still scary though, I still think they're just getting slicker and smarter about it, they're kind of, they're evolving their approach and one of these days I just can't help but think they're going to slip some crap in and then that's going to be it, then I've got to move out of this country.

S: Yeah.

E: Yeah I hear you, you know judges are people too, and it may be just a matter of time if they do this and try to repeat it more and more and more over the years and decades, one of these courts is probably going to let something through, and that's going to be a sad day.

S: You're right Bob, we need to keep vigilant because they're constantly seeking ways around the constitution.

News Items

Eggs and Atherosclerosis (2:58)

http://www.sciencebasedmedicine.org/index.php/eggs-and-atherosclerosis/

S: All right so let's move on to some news items. The first one is about eggs and atherosclerosis. So what do you guys think after all of the research and the news back and forth, are eggs good for you or bad for you, what's the bottom line.

B: Well, I'm not familiar with this topic, still I think that eggs overall are good for you and I don't care what you say.

E: I think they're a good source of protein and other nutrients.

B: And riboflavin!

E: Right, well like anything, well almost anything, it's not without its negatives, but I think the positives outweigh the negatives.

S: Yeah, that's basically what I would say, the controversy is about the cholesterol. Now if you guys remember, again, going back to the 80s there was the whole oh eating cholesterol causes increases in your blood cholesterol and that's the killer, that causes hardening of the arteries and atherosclerosis and heart disease, and eggs for some reason were a huge focus, especially the egg yolks, but then it turned out that research was showing that well the cholesterol actually doesn't increase you serum cholesterol, it seems a little counter-intuitive.

B: Is that because of the nature of cholesterol in the eggs, or the nature of cholesterol itself?

S: I think it's the nature of cholesterol itself, eating cholesterol in general doesn't increase serum cholesterol.

B: Yeah I've always read that if you're looking to control your serum cholesterol, you worry about things like fat, just total fat intake rather than cholesterol itself.

S: Yeah and even in the 80s we were still focussed on total fat but actually that's not even the answer, it's the kind of fat that you eat, you know the bad fat, the LDL raising type of fat, the saturated fats and the trans fats, those are the bad ones. But other kinds of lipids, of fats, are good, like anything that increases your HDL, your good cholesterol. So the question is, so it's not just that there's cholesterol in any particular food like eggs or that there's fat, it's what's the balance, what kind of fat is in it and how does it affect your lipid profile? And that's now been the focus on the research of the last 20 years in general and specifically with eggs and the literature has moved in the direction of yeah, cholesterol and eggs is actually not so bad, but a study came out recently by Canadian researchers looking at peoples' consumption of eggs and the amount of atherosclerosis or cholesterol build-up in their carotid arteries, the arteries that feed the brain. They looked at 1262 patients who were seen in a vascular prevention clinic, so they're starting with people who have all had studies of their arteries to see how narrowed they are, how much thickening of the arteries there is from atherosclerosis and then they give them a survey asking them about how many eggs they eat, about their smoking history, and a bunch of other questions that are relevant to that. Then they came up with this measure they're calling egg-yolk-years, which is the number of eggs per week times the number of years you've consumed those eggs, which is similar to when we take a smoking history, we usually record it in pack years, how many packs per day times how many years you've been smoking as sort of a rough estimate of your total risk or burden from smoking, so they were modelling it after that. Then they compared egg-yolk-years to the degree of atherosclerosis on the carotid studies and what they found was that there was a positive correlation that the more egg-yolk-years you had, the more eggs you ate basically the more thickening you had in your arteries.

E: Well how did they specifically attribute that to the eggs, I mean what the hell else are these people doing of the course of that time.

S: Well that's a very good question. Because this is an observational study, right? They didn't control for it prospectively, because it's a retrospective study, they're just using survey data. There's potentially many confounding factors in here. For example, there was a positive correlation with age, the average age of people who ate the least amount of eggs was 55 and who ate the most amount of eggs was 69, that's like a 14 year difference in age. Now they controlled for that when they looked at the data but because this is a retrospective study where you're not, where you can't control for variables, you just try to record as many as you can, who knows what else is going on with the data? The other thing is, and to me this is the killer for this study: they looked at total cholesterol, triglyceride, HDL and LDL and guess what they found?

J: What?

S: No freaking difference at all. No difference! So the eating eggs did not increase your total cholesterol, did not increase triglycerides, did not lower HDL (good cholesterol), did not increase LDL (bad cholesterol).

B: Well that doesn't that break any possible connection?

S: Well yeah, right?

B: Hello!

S: Doesn't that argue sort of strongly? So what's the mechanism then? So eggs cause atherosclerosis but not by affecting the lipid profile in any way?

B: (laughs)

S: Yeah, so that kind of calls into question a causal relationship there, so now we have a correlation but the causation that they're inferring here is very dubious and there's lots of potential confounding factors, so I don't know we could make too much of this study. The authors acknowledge that in your conclusion, you pretty much have to to get this past peer review, no peer reviewer worth their salt would allow that to go unnoticed, so the authors concluded, they say "our findings suggest that regular consumption of egg yolk should be avoided by persons at risk for cardiovascular disease. This hypothesis should be tested in a prospective study with more detailed information about diet and other possible confounders such as exercise and waist circumference." So they have to acknowledge that yeah, they need to control for confounders, it wasn't prospective, but still I don't that this study really shows anything that we can really draw any conclusion from, I mean the most significant data is the lack of any effect on the cholesterol. So I wrote about this on science based medicine, and yeah I did as much as I could, I looked, I tried to get up to date on the literature on eggs, cholesterol and atherosclerosis and heart disease, and damn, it's complicated, I mean the story really is complex. So there's so many variables, you could be looking at the general healthy population, patients who've had heart disease, patients with diabetes, men versus women and you get, the data is kind of all over the place, it's hard to pull a signal out. There was one review, actually by the same authors who really concluded that, and again they used the same thing of comparing the risk of eating eggs to the risk of smoking, but other than these authors, they seem to be out there kind of on their own now, the rest of the literature is sort of mixed and leaning against any significant role of eggs. I found studies that showed that eggs reduced risk of death or reduced risk of heart disease, studies that showed really no effect at all and studies that show that maybe for this sub-population or for that sub-population of maybe like with diabetes or maybe in women in other studies there may be a tiny risk, but there wasn't a clear consensus that there was a risk from eating eggs, these researchers seem to be off on their own. A 2012 review, so the most recent review that I found said this, "the findings are suggestive of a small but potentially important reduction in cardiovascular risk on modification of dietary fat but not reduction of total fat in longer trials. Lifestyle advice to all those at risk of cardiovascular disease and lower risk population groups should continue to include permanent reduction in dietary saturated fat and partial replacement with unsaturates. The ideal type of unsaturated fat is unclear." So this is looking at cholesterol, fat in the diet and risk. They're saying, mmm, maybe a small risk, sure you probably should avoid a lot of saturated fat in your diet but there really isn't a clear signal there so it's interesting. What I found also from reading around, there's definitely this anti-cholesterol school of thought, people who think that dietary cholesterol, and even just your serum cholesterol is not a risk factor for heart disease or vascular disease. I think they've gone too far, I think they have an agenda, I don't buy that position, I think there's enough evidence to say that having really high serum cholesterol, especially a bad profile, high LDL to HDL ratio, is a significant risk factor for vascular disease, heart disease, stroke and peripheral vascular disease. The story is more complicated than we thought 20 years ago but it's definitely real. But I'm not sure why these Canadian researchers are so anti-egg and are trying to go back to the 1980s view of cholesterol and eggs in particular. What I find interesting is, not just with this question, but any question of diet and health and longevity and risk factors for certain things, let's try a thought experiment, we try two approaches to the lifestyle choices you make and your life expectancy. You could take a maximally simple algorithm as a first approximation of the scientific evidence.

J: Wait wait, explain that again.

S: Yes so, in other words, what rule of thumb could you follow for your lifestyle choices that would be as simple as possible but still basically follow the scientific evidence. I would summarise that as follows: in terms of your diet, everything in moderation and have a varied diet. That's it. That's a pretty simple rule, nothing too extreme, don't eat a lot of any one thing, have a varied diet including fruits and vegetables, by definition, if your diet is varied enough, and you'll be fine. Right, so that's the simplest rule that gets pretty close to the scientific data. If you want to expand that to all lifestyles, I would say, have a varied, moderate diet, exercise regularly, have regular sleep, don't drink a lot of alcohol, and don't smoke. That's it. That's really what the last 50 years of scientific evidence have told us about lifestyle and risk factors. Again, this is for the general healthy population, to emphasise that, if you have certain diseases it gets more complicated as you have to accommodate certain diseases, like if you're a diabetic, you have to be on a diabetic diet. Now compare that approach, a person person following that approach, to somebody who obsessively follows the scientific evidence in as great detail as possible and tweaks their diet and their lifestyle to account for every new nuance of the scientific data, and I'm saying they're being scientific, they're following the evidence, but they're trying to tweak their behaviour and their diet specifically so that they're adjusting every macronutrient, every micronutrient, every vitamin, everything to its optimal range, avoiding things that should be avoided, really obsessing and basically dedicating their life to having the optimal diet. Honestly, I don't think there would be a significant difference between those two approaches. I don't think that, if you get any difference, if the obsessive approach is any different than the simple algorithm approach, I don't think it's that significant, I think the difference there is within the noise that we have. I don't think that we have enough scientific data to be that obsessive person, I think that the simple algorithm is really what we can say based upon the evidence.

B: Right I mean the quality of life that you would lose and the time you would lose obsessing over it wouldn't be worth it, right?

S: Yeah, it's not even clear that you would net a day of life from doing that, but even if you did, there's the other question, would it be worth it? And the other thing is that most people can't really comply with that obsessive lifestyle, worrying over every little detail, so honestly I think it's far better really just to emphasise the simple approach because that basically is what the scientific data is telling us anyway. Once you try to get more detailed than that you're into controversy and the limits of the data that we have and the noise of the data that we have so just keep it simple, I think that would be my prescription, that's Steve's Healthy Lifestyle, keep it as simple as possible, I can't get a whole book out of that, right? That's like on one sheet of one side of one paper. Keep it...

E: KISS.

S: ...a varied, moderate diet, exercise, don't smoke, don't drink to excess and get a good night's sleep. That's all you need to do.

E: It's the KISS concept, right?

B: Yeah. Right.

S: Right.

E: Keep it simple, stupid.

J: It's very easy to say, "get a good night's sleep". Because there's a few parameters here, and sleep is another topic that I think it would be interesting for us to really talk about. But there are people that just can sleep well but they're not giving themselves enough sleep time, that's one thing. And for the most part the good average is between 7 and 9 hours of sleep, but a real problem, and it's something that I suffer from, is I just don't sleep well. I can give myself an 8 hour clip or a 9 hour clip, I just don't get a lot of quality sleep during that time, it's probably because I have way too many things going on in my life that I can't possibly get to, but that's a different problem and a lot of people suffer from that and it's very hard to work your way through an issue like that.

S: Yeah that's right, Jay. The thing that is different about sleep is that you don't have total control over it. You have total control over what you put in your mouth, what you do, although people may have physical limitations that make it difficult to exercise as well, but you could always find something. You control if you smoke, how much you drink, but you can't control how much you sleep because you could have issues, you could have insomnia, or whatever, problems with your sleep, and I think it's a hugely under-diagnosed and under-treated problem. My advice is that if you have good sleep hygiene, that's the stuff you can control, basically, the lifestyle factors that you can control. If you have good sleep hygiene and you're still not sleeping well, then you have a sleep disorder and you need to treat that as a medical condition and you need to get diagnosed properly and treated properly for that, you shouldn't just accept, I have patients who come to me and are like, "oh yeah I get 3 or 4 hours sleep a night and it's been that way for a long time", and you don't see that as a medical problem? That's a medical problem, that needs to be addressed, we need to do a sleep study or whatever, we need to address it. But a lot of people just don't think of that as a medical issue that needs to be aggressively treated, and then they wonder why they're tired and gaining weight, and they have all these symptoms that are demonstrably related to lack of sleep, they just don't make that connection. So yeah, there definitely needs to be more public awareness about sleep disorders, it needs to be addressed more as a problem, I think it's related a lot to the obesity problem in this country, both cause and effect, apparently. Lack of sleep results in being overweight and being overweight impairs sleep, you get sleep apnoea and poorer quality sleep so it's a viscous circle.

Hacking the Rover (17:52)

http://www.gmanetwork.com/news/story/269564/scitech/technology/anonymous-hackers-may-be-targeting-mars-rover-says-security-firm

The Sneeze (26:16)

http://news.nationalgeographic.com/news/2012/08/120814-why-do-we-sneeze-health-science-sinusitis/

Google Pyramids (33:56)

http://www.foxnews.com/scitech/2012/08/14/long-lost-egyptian-pyramids-found-on-google-earth/

Occ Update (40:52)

http://www.kickstarter.com/projects/sgu/occ-the-skeptical-caveman-a-new-webseries

Who's That Noisy? (44:24)

Answer to last week: Alan Shepard

Questions and Emails (46:41)

Screwed ()

Critical Thinking and the Asymmetrical Apple Screw I thought this was kind of interesting... http://day4.se/how-we-screwed-almost-the-whole-apple-community/

Truckee Lynch, San Francisco

Science or Fiction (52:12)

Item number one. An instrument aboard the Lunar Reconnaissance Orbiter has detected helium in the Moon's atmosphere. Item number two. A recent lost letter study, in which stamped and addressed letters are dropped on the street and their fate recorded, demonstrates that wealthier neighborhoods are less altruistic. And item number three. Researchers have discovered the code by which the retina communicates to the brain, leading to a retinal prosthesis that has restored near normal vision to a blind mouse.

Skeptical Quote of the Week (1:08:07)

For having lived long, I have experienced many instances of being obliged by better information, or fuller consideration, to change opinions even on important subjects, which I once thought right, but found to be otherwise.

Benjamin Franklin

References