The Oldest Fossil, Colon Cancer Rates, and Foodie Fads

IRA FLATOW: This is Science Friday, I’m Ira Flatow. A bit later in the hour, we’ll talk about using DNA to store digital information. But first, up near the Arctic Circle entombed in Canadian bedrock, researchers say they have found– they have dug up– the oldest fossil to date– fossilized bacteria, estimated to be between 3.7 billion and 4.2 billion years-old. The study is published this week in the journal Nature. But, of course, extraordinary claims require extraordinary evidence, so there is some pushback by critics.

Sophie Bushwick is here to fill us in on that story and other science headlines from the week. She’s Senior Editor at Popular Science. She joins us here in our [INAUDIBLE] studio. Welcome back, Sophie.

SOPHIE BUSHWICK: Thanks.

IRA FLATOW: Let’s talk. What exactly did the researchers find in this rock? Was it a whole bunch of bacteria that were in there?

SOPHIE BUSHWICK: So what they specifically found were these filaments of hematite of oxidized iron, that they think could have been left by these bacteria that processed iron, that oxidized it. The problem is that when you find a dinosaur fossil, you find bones, and that’s pretty clear evidence that an animal was there. When you’re looking for evidence of these bacteria, you’re really looking for the evidence of their past presence in these types of microscopic formations, which makes it more difficult to prove that something was definitively there.

IRA FLATOW: Just something that was left behind then, and they found the evidence.

SOPHIE BUSHWICK: Right, exactly.

IRA FLATOW: If it was 4.2 billion years-old– a long, long, long time ago– how would this alter our idea about how life evolved on earth?

SOPHIE BUSHWICK: Well, the oceans on earth only formed about 4.4 billion years ago. So this would really compress the timeline. It would say life arose way earlier than we thought it would, in less friendly conditions for life, which would mean that it was more resilient than we thought– although, we already know life is pretty resilient. But, also, that it formed in conjunction with our planet developing.

IRA FLATOW: Now, the runner-up until this time, the runner-up for the oldest fossil was just a few months ago, right? How much older is this one than that one?

SOPHIE BUSHWICK: So that fossil was found in Greenland, and it was, I think they said it would have been 3.7 billion years-old. This one is at least 3.77 billion years. And that extra decimal point might sound like nothing, but bear in mind that when we’re talking billions of years, that adds up to a pretty big difference.

IRA FLATOW: Yeah, sooner or later you’re talking big numbers. What kind of evidence will researchers need to dig up, now, to prove this theory that it was actually bacteria?

SOPHIE BUSHWICK: Well, I think they’ll need to find more of this type of formation dating from the same time period to support it. Although, some other researchers who study this type of early life, they’ve found these types of bacterial formations dating back to 3.3 billion years, I think. They said that these new formations are too large, that there wouldn’t have been enough oxygen to sustain bacteria making such large formations, back at the time period we’re talking about. And so there is a lot of back and forth about whether these are a natural formation, or one actually caused by life on earth.

IRA FLATOW: You know, that reminds me of a discovery on Mars made years ago, where they found some rock formations which had sort of, like, other things left over by the bacteria. And they thought, oh, maybe this is signs of old life, but they could never prove that, either.

SOPHIE BUSHWICK: Yeah, that’s the problem when you’re looking at such huge time scales. I mean, billions of years is that the evidence is less definitive.

IRA FLATOW: Let’s move on to this uptick in colon cancer in younger age groups. That’s really not typically seen there, is it?

SOPHIE BUSHWICK: No. So, in fact, colon cancer, colorectal cancer in general, rates have been going down since 1975. But when researchers looked at which age groups are getting this cancer, they found that in people under age 50, that it is actually on the rise. And that’s both people in their 40’s and people in their 20’s and 30’s.

IRA FLATOW: Among all age groups, of all socioeconomic levels in general?

SOPHIE BUSHWICK: Mhm.

IRA FLATOW: Do they have any idea why there’s such a higher incidence in younger age groups?

SOPHIE BUSHWICK: They’re got a few different ideas. The increase in rates of cancer is tracking pretty similarly with increasing rates of obesity, which could be upping people’s odds of developing this cancer. Of course, they haven’t proven that’s a causal link, but it seems like one of a few different, potential culprits. Another thing that they’re looking into is it could be binge drinking.

IRA FLATOW: Binge drinking?

SOPHIE BUSHWICK: Yeah, younger people are more likely to drink at those heavy rates, and so that could be contributing. Alcohol can increase your risk of several different kinds of cancer, including colorectal cancer.

IRA FLATOW: Well, one question about screenings is that having more screenings might lead to more false positive cancer results– maybe that has something to do with it? People getting screened more?

SOPHIE BUSHWICK: You would think that’s a possibility, but in fact, while people over 40 are getting screened more, people in their 20’s and 30’s aren’t. It’s not recommended that they get screened.

IRA FLATOW: Yeah, that’s true.

SOPHIE BUSHWICK: What we should maybe do is have those types of screenings happening more. Or at least teach people more about the symptoms of these cancers so that they can go get diagnosed sooner.

IRA FLATOW: Yeah. Finally, your last story looks at foodie fads, the science behind foodie fads. What’s the latest? What are some of the latest foodie fads?

SOPHIE BUSHWICK: So a group of cardiologists looked at a bunch of different fads to see well, what’s the actual scientific evidence for this being helpful? And one of the big things they found is that– sorry, juice fans, but juicing is not good for your heart health. It encourages you to consume more calories, and they are more sugary. You’re taking the fiber out of these fruits that you’re eating, which means that you can consume more calories without feeling full. And, also, you’re losing out on those health benefits.

IRA FLATOW: Yeah, you want the fiber. I mean, that’s the thing.

SOPHIE BUSHWICK: You do.

IRA FLATOW: When you juice the fruit, the fiber’s gone. In fact, they make a little puddle of it at the end.

SOPHIE BUSHWICK: Yeah, exactly.

IRA FLATOW: But people who are big into food say, no, you don’t want to break it all up. You need that fiber to catch some of the bad stuff.

SOPHIE BUSHWICK: Yeah, absolutely. Fiber helps move foods through your system, and it’s also got proven health benefits like that. And the other thing is that I wouldn’t sit down and eat three giant apples in a row, but I might drink a glass of juice that had that much sugar in it. So if you’re actually eating the fiber, you’re going to feel fuller sooner. And the act of chewing, actually, tells your brain that you’re eating. When you’re just drinking, your brain isn’t likely to tell you, hey, slow down.

IRA FLATOW: Yeah. What about people who are on these cleanses? Did you look into cleansing?

SOPHIE BUSHWICK: The problem with cleansing is– yeah, the idea that you’ve heard that maybe drinking juice helps you detox–

IRA FLATOW: Yeah.

SOPHIE BUSHWICK: Uh-uh. Your body cleanses itself, really. You’ve got organs like the kidneys that help filter out bad stuff out of your body. And that you can excrete that as urine. And there’s other systems in the body that help you keep it clean. And the problem with juicing is it can cause your blood sugar to spike, which is not something that you want.

IRA FLATOW: Well, the good news about food fads is that if you didn’t like this one, there’ll be another one around tomorrow.

SOPHIE BUSHWICK: I’m sure there will be.

IRA FLATOW: Thank you, Sophie. Sophie Bushwick is Senior Editor at Popular Science, and she was here in our [INAUDIBLE] studios.

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