Why We Should All Be More Suspicious
We see reports of game-changing research every day. Can they all be true?
Posted October 15, 2014
"New research shows that eating chocolate daily can increase your life span by 50 years."
Of course, being told to eat more chocolate sounds like just about the best thing ever. But here's the thing: There's only one way to truly know if chocolate makes you live even 5 years longer—carefully select two groups of babies at birth, assign one to be the chocolate group consuming chocolate each day, and assign the other to the no-chocolate group. Then, observe them until they die, being sure to measure every bit of chocolate consumed by members of the chocolate group, and the type, and what they consume it with. And be sure to control every other factor that could influence how long they live.
In other words, there aren't any studies that can show this, at least not yet.
This might lead you to conclude that all research about increasing our lifespans is useless. But I can assure you that it's not. We've actually learned a significant amount. We just have to take into consideration the limitations of what we can learn from any individual study. Scientific advances are almost always based on piecemeal discoveries—rarely on one study alone. Research is a process, designed to produce an accumulation of information about the relationships between different factors and different outcomes. When a whole bunch of people study the same thing and observe the same outcome, we come to strong conclusions. For example, many studies have examined the effect of exercise on health and longevity. All come to the same conclusion: Exercise is good for you. Separate studies have demonstrated that it appears to be good for your brain, your heart, your bones and muscles, and your mental health—in fact, some studies have even assigned some people who were previously sedentary to start exercising, and discovered that it led to astonishing health gains. And so, researchers safely conclude that exercise has a range of health benefits. As we continue to learn more, we are beginning to figure out exactly how much and which types offer the biggest bang for your buck, so to speak.
But we're not there yet.
Here's the kicker: Associations between this factor and that outcome, even when observed over and over, isn't always evidence of a causal relationship. Let me offer a silly example: Suppose someone was interested in learning whether owning a Prius was related to decreased fertility rates. Such a study would very likely show, as observed by multiple people over a long period of time, that there is a consistent, negative relationship between owning a Prius and fertility. Does this mean that hybrid cars cause infertility? Or perhaps that people who own them don't attract mates? Probably not. Here's why: It is more likely the case that people who own a Prius tend to have fewer children than, for example, people who own Suburbans. They also tend to have higher levels of education, which tends to be predictive of lower fertility. This example might seem ridiculous, but it's not that different from other research in which people seem to draw similar conclusions.
Several months ago, a friend of mine posted a link to a natural health website that described results from a recent study about fluoride in drinking water and cancer rates. The study involved several different communities in China. Some of the communities had normal amounts of fluoride concentrations added to the drinking water; others had four times the normal concentrations. The researchers examined overall cancer rates in each community over the last year, and concluded that the communities with four times the fluoride in the drinking water had higher cancer rates. The natural health website, in reporting these results, deployed the headline, "Fluoride Causes Cancer," and then went on to argue why we should not consume fluoride. But not only did the study authors not indicate this in the study, the purpose of the study was to determine if high concentrations might be related to cancer, not whether normal levels of fluoride was good or bad. While it is certainly plausible that fluoride causes cancer, this particular study couldn't have commented on such a relationship.
It's hard though: I mean, if you personally believe that fluoride is awful for you, then, even if the science doesn't actually show this, you might be happy to have some evidence that appears to prove it. Aha! Do you see, fluoride supporters? I told you it was bad stuff! But alas, this is irresponsible consumption of information. At a time when health and aging research is splashed across the news on a daily basis, it is more important than ever to be cautious about jumping on any bandwagon of "research-based" recommendations presented by the media. When you hear a study that seems to support your cause, you might be inclined to believe what you hear, but you should always carefully consider the information presented. Even studies conducted under gold-standard research designs—randomized case control studies—have limitations.
Here's how to be a smarter consumer of information:
Look for information that challenges your ideas, not just reports that support them. And consider how the research was done: Did researchers just look at people who tried the mushroom-banana-mango extract, or did they compare them with people who just ate bananas? How many people did they look at? Was it only 15? (If you picked 15 people off the street who said they believed that mushroom-banana-mango supplements would make them feel more energetic, the study would probably show this, even though it wasn't really the supplement that made them feel better.)
We all need to be more cautious about data, or advice columns, or so called "expert" descriptions of, well, The Top 5 Reasons You Should Eat More Chocolate—particularly in an era when "big data" is everywhere, and even the timing of our morning bathroom breaks is being measured. Also, trust that the piecemeal accumulation of data that is the true scientific process will offer more and more insight with time, but don't hold your breath: There's probably never going to be a silver-bullet pill or lab-designed superfood that is going to extend life or reverse aging. You may not want to do the work, but exercise, fruits and vegetables, better sleep habits—you know, all of that stuff you've heard over and over but aren't doing—that's probably going to remain your best bet.
But have some chocolate now and again, just in case ...