The alternative title for this newsletter edition would be: Don’t believe sensational headlines in major news outlets or on social media. Because if you’ve been following the headlines over the last few days, you certainly came across something like this:

A diet rich in fruit & vegetables might increase lung cancer risk? Really?

That’s a shocking headline and in my opinion, pretty irresponsible because:

Even though the topic is a bit outside the scope of psychology & neuroscience, I needed to address it in my newsletter because I find it outrageous how it’s spreading online (plus, I actually taught research methodology for many years, so dissecting scientific studies is one of my hobbies!).

Ok, without further ado, let’s dive in.

The source is a conference abstract.

This is also the first critical issue because:

The early dissemination of results is common because writing the full paper and peer review are time-consuming and delay the communication of new findings. But as long as there’s no officially published paper in a specialized journal, the results are considered preliminary and should be treated with caution.

Based on the limited information currently available, here’s what the study authors did:

First of all, while some media outlets (see screenshots above) use causal language and discuss a healthier diet as a cause of lung cancer in non-smokers, the study authors are more careful and just discuss a potential “role”, specifically mentioning pesticides/herbicides. So, the causal, sensational language used by popular media is an over-interpretation of the study.

The study only says that young lung cancer patients eat, on average, a healthier diet than the general US population.

That’s all.

Apart from the fact that the study isn’t officially published yet, let’s also consider some crucial methodological aspects:

The exact questionnaires and methods used in this study aren’t mentioned (we’ll have to wait for the full paper), but generally, food frequency questionnaires list different foods or food groups and ask people to indicate how much they consumed of each in a given timeframe.

If you only try to recall your food intake over the last 24 hours, you’ll notice it’s not that easy, especially when it comes to portion sizes or snacks you had in between. And it gets even more inaccurate if you try to remember what you ate a week ago or so.

So, the diet data in this study came from self-reports, which are limited in accuracy. And there’s yet another problem with self-reported food intake: Some people might intentionally report a better diet than they actually have to make a good impression.

Comparing the results from a specific group of study participants (the sample) to a population average is risky because they may not share the same characteristics (also see my next point). Also, the exact measurement methods used to obtain the US population data may differ from those used in the present study.

It would be better to recruit a matched control group that is as similar as possible to the patient group in terms of age, gender, education, etc., but without a lung cancer diagnosis, and then use the same measurement tools at the same time in both groups.

The sample consisted of patients with diagnosed lung cancer, meaning they have access to healthcare and use it. They also volunteered to take part in a scientific study. This could mean they’re generally more educated, wealthier, and more health-conscious than the average US population they were compared to, which could explain their healthier eating habits.

In other words, the diet differences between the cancer patients and the general US population may be completely unrelated to the disease.

Imagine you receive a cancer diagnosis. Do you just continue your life as if nothing happened? Probably not.

It’s the same here: Patients might have changed their eating habits as a result of the diagnosis, and then we have the reverse pattern: A diagnosis of lung cancer would lead to healthier eating.

The authors mention that they considered the “contaminant residue potential” of certain foods, that is, to what extent certain food groups are contaminated with pesticides/herbicides based on previous studies. They didn’t directly measure exposure in the cancer patients (e.g., through blood or urine samples).

To sum up, I’m not saying that there is no link between fruit & veggie intake, the associated pesticide/herbicide exposure, and lung cancer in young people. This link might exist (or not). I’m just saying that the present study has been overhyped in the media, and that it cannot establish a causal relationship between the intake of fruit, veggies, and whole grains on the one hand and lung cancer on the other.

So far, we only have a conference abstract summarizing some interesting findings, but we don’t know the study’s details, and it hasn’t yet passed science’s quality-control mechanisms.

My advice is definitely not to reduce your intake of fruit, veggies, or whole grains based on just one overhyped study. There’s also plenty of evidence showing the protective effects of healthy food on cancer.

If you were concerned about this study and the headlines, I hope my analysis helped you calm down. It sure makes sense to wash fresh produce well or rely on organic, but there’s no reason to panic.

Feel free to share this with other people who might need it!

And please be careful with sensational headlines. If you find any other sensational headline and would like to know what’s behind it, send me a message (just hit reply). I’ll look into it and might address it in a future newsletter edition.

That’s it for today!

And now?

Until next time!

Best wishes,

Patricia (Dr. Schmidt) from creatorschmidt.com

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