I choose to believe that red wine and dark chocolate are good for me. This is despite the fact that I am a professor and a researcher. I am well aware that claims that particular foods are good for you are often not backed up by solid scientific evidence. Indeed, I often hope that my students will develop the ability to separate valid from invalid information in the media. This is a skill that we could all exercise and use more often. We are often inundated with media claims that particular foods or activities are good or bad for us. In many cases, these claims conflict with one another. Sometimes, butter (or bacon or some other feared food) is good for us, and at other times, it’s bad for us, posing risk for cardiovascular disease and so on. Similarly, there have been recent articles in the newspaper discussing the relationship between processed meats and colorectal cancer. I for one have no interest in developing colorectal cancer. The fear of developing a terrible illness makes it easy to read something indicating that a food poses a scary risk and to take that as a fact. As human beings, our brains are set up to associate one thing with another. In particular, we are very good at associating people, things, events, and even food with danger. Our logical minds might say that the evidence for a link between prepared meats and cancer is shaky at best. But, as soon as a particular type of food seems linked with a dangerous illness like cancer, it’s hard for our emotional brains not to react.
I’m not suggesting that everyone should go out and immediately get a large pastrami on rye, but I am suggesting that readers should approach media articles with a scientific frame of mind. As an example, let’s say a newspaper article claims that eating bacon doubles our risk for colon cancer. It’s important to ask yourself what type of evidence supports this claim. With this a study with humans or with rats? If it was a study with rats, how much bacon did they get, how often, and in what conditions. Did the study involve randomly assigning some rats to a bacon diet and other rats to a regular diet? If the study focused on humans, it’s very likely that the research was simply correlational. What I mean here is that research on health risks in humans often simply involves asking people what they eat and correlating that information with their current or future health status. Even if there is a correlation between consumption of bacon and colon cancer, it’s always possible that this correlation might be accounted for by some other factor related to both bacon consumption and cancer, such as obesity. Let’s go back to the hypothetical claim that eating bacon doubles cancer risk. Let’s say researchers conducted a solid experimental study, randomly assigning one group of people to a diet rich in bacon and another group of people to a different kind of diet. Over time, the people on the bacon diet were is twice as likely to develop colon cancer. Do you stop eating bacon? That really depends. Do you know the prevalence of colon cancer? Among men, the prevalence is about .7%. Let’s say it went up to 1.4% among the bacon eaters? Would you decide to change your behavior based on this information (an absolute difference in risk of .7%). You might, but I’d still suggest that people consider these questions as they read claims about the effects of foods on health.
On the other hand, I am also a big believer in the placebo effect. This is why I, for one, will not be looking up and examining with scepticism the research on red wine, chocolate, and health. It’s enough for me to simply think that these things I enjoy are good for me. Although I encourage people to approach “facts” with a scientific mindset, there is something to be said for the idea that we don’t always have to have the right thoughts in our minds. The research on depressive realism emphasizes this point. Some studies have found that nondepressed people are actually unrealistically optimistic, and that to a limited extent, depressed people can sometimes be more realistic. Sometimes, it’s important to be scientific, logical and correct in our thinking. At other times, it may be more important to use our thoughts to make our lives better (even if we are not technically accurate or scientifically sound in our thinking). This is my approach to dark chocolate and red wine. What an incredible bonus! I get to enjoy them and feel good about enjoying them. Ignorance in this case is bliss.- Alexander L. Chapman, Ph.D., R.Psych.