As discussed in Making Sense of Nutrition News, Part I, nutrition research and knowledge over the past few decades grew at a staggering rate.
I’ve been adjunct (part-time) faculty over 20 years and have a unique perspective of hearing what my students know and understand about nutrition as they learn key concepts. Early on in my teaching career (pre-internet), I assigned students a project requiring them to summarize a nutrition-related current event from a newspaper or magazine. They presented their summary in class and we deciphered reliability, learning what’s credible and what’s questionable.
As the internet evolved and became the go-to place for information, our learning advanced to a virtual platform including discussion boards. A favorite discussion board topic was (and is) answering this question: Why is nutrition so confusing?
My nutrition students’ confusion over nutrition claims in media
Over the years, my students’ responses include comments like this:
- “Nutrition is confusing because it’s applicable to everyone. Everyone has their own experience and opinion and can say anything on the internet. People try to educate themselves but it’s an endless cycle of misinformation and opinion pieces.”
- “My sister won’t eat some vegetables anymore. She read somewhere they cause cancer. I’m not sure what she’s reading. I know that’s not true and told her it’s the opposite—how veggies may prevent cancer.”
- “News articles or reports get out there and maybe facts aren’t verified. The reports turn out to be untrue, yet the information is already out there. People don’t find out the truth and stick with the first info they learned.”
- “Articles written are exaggerated to get our attention. Some of the headlines are true, but researchers are testing on rats, not humans.”
- “Many studies make a bold claim and then make note about needing further research to substantiate it. One must always notice these disclaimers.”
- “One thing surprising me is that too many studies try to account for many things. From the day I started taking science classes and learning about the scientific method, my teachers made it clear that variables need to be controlled during experiments. So, why do many scientists, etc., forget the basics when performing their own experiments?”
- “One question I ask myself is why do people continue to believe these claims even after people claim they are not real?”
Good insight—score one for my students!
A closer look at nutrition news
But the abundance of information online makes it hard to sort through all the articles on any given nutrition topic and find the truth.
When looking at nutrition news, I don’t take the words in the article for face value. I take a closer look. For instance, when I reviewed references from a website touting coconut oil, many studies were either completed on rats or used an oil that is not coconut oil.
It’s important to look at exactly what is being studied and who the results apply to. While animal models are important in research, and studies might yield promising results, the research is preliminary and not definitive without human clinical trials.
In human trials, I also look at how many people were involved in the study. Studies performed on small sample sizes may hold less weight than studies involving hundreds, if not thousands, of people. To rule out a finding being “chance,” sample size ought to be large enough. If you’re averaging out the odds of something, 1 in 10 would be very different than 1 in 10,000.
Correlation is not causation
Although large sample-size studies called observational studies, like the Nurses’ Health Study, are important and add to our body of knowledge, they may provide weaker associations as opposed to the validity of a clinical study involving treatments and control groups. Correlating evidence does not prove a cause and effect. (Many things correlate as highlighted on this website. For example, as consumption of cheese rises so do the number who die getting tangled in bedsheets…hmmm.) 
You might be surprised to know some headlines in the news come from information compiled in a press release. It’s important to look at news stories and find the source(s) for the nutrition news article. For example, various food associations send press releases to editors and reporters; while their press releases may cite studies, it’s not going to provide a comprehensive review of the food or product—only supporting studies.
Many study results are preliminary, like those of a phase I clinical trial, which involve under 100 people and is highly experimental. In contrast, the results of a study involving a phase IV clinical trial is not preliminary and the treatment is already being used by the public.
Other studies have yet to be peer-reviewed. The study may be online, and written by an established researcher or doctor, and posted with other research articles, but it may not have the vetting of other medical peers, as it would, say, if published in a peer-reviewed medical journal.
So, as I tell my nutrition students each semester, take a closer look. With a little research, you’ll be able to decipher what is reliable, or not. With some effort, you’ll understand what is nutrition noise and what is factual nutrition news.
Let’s chat. What confuses you?
-Neily
My boy Lex is so smart.
Image credits: pixabay.com and neilyonnutrition.com
Jennifer Neily, MS, RDN, LD, FAND
Registered Dietitian Nutritionist | Wellcoach® Certified Health Coach
NeilyonNutrition.com
@JenniferNeily Twitter
@NeilyonNutrition Instagram
Excellent!
Thanks Neva – did you see part 1?
Yes, I agree that nutrition is a very confusing subject. It is confusing because so much information about nutrition keeps changing, but the foods themselves do not change. For example coffee has been ground and mostly brewed the say way for hundreds of years. It is also confusing how some foods which are common and have been around for a long time, suddenly become nutritious super foods. Is it that people are consuming these foods such as wine and coffee in different ways or in larger amounts?
Thanks for your question Mweru! And you are correct, coffee HAS been consumed the same for centuries BUT it’s the research on it that is new. There has been a lot of research on coffee and also the phytochemicals in wine. Sometimes too it is marketing! -Neily
Hi Neily! Great post! I particularly enjoyed the discussion about correlation not equaling causation. Its so natural to assume the opposite, the amusing examples of correlations that can’t possibly indicate causation are a good reality check. (And Lex is real cute!)
Awww thanks Leah – Lex is my sweet sweet boy! 🙂
-Neily
I also learned a little about correlation is not causation in my psychology and stats class. With an observational study, the results/data are just observations. I believe observational studies can lead to experimental studies. After the experiment and all data is recorded, a conclusion is made and evidence is shown through a graph or diagram. I wonder if companies expand or decrease the values on the X and Y axises to manipulate the shape/direction of the line. The data would be correct but the ranges on the axes may throw the data off. My question is can companies change the way their data statics are perceived without technically falsifying data?
I hope that question makes sense,
Colleen 🙂
Thanks Colleen – I’m pleased you found the information interesting and have started learning about it in other classes.
Re: “My question is can companies change the way their data statics are perceived without technically falsifying data?” Although I am not a statistics expert it is my understanding data can be manipulated in many ways by how the data is statistically analyzed. The data itself does not change but how stats testing is completed. -Neily
I didn’t know there could be so many variable when testing out how food affects us. That’s interesting!
Thanks for your comment Vinny! Yes, I know, there is much to think about in the science of nutrition. -Neily
The graph about bed tanglings and cheese consumption really drives the point home that causation is not equal to correlation. Very clarifying.
After reading this second post I learned that there is constantly new information being put out to the public that is not always accurate. Also how while researching animals is a great source of study but is not always 100% applicable to humans. Then reading and learning that even with human studies, not all will have the same outcome because not everyone has the same body type. Which is why it is very important to do multiple tests.
-Emily Gonzales
Thanks for your post Emily! I’m glad you found the information useful. -Neily
I relate to most students confusion about nutrition because there is a lot of information and it gets overwhelming. And you also mentioned about correlation and cause in class today and after reading the article I have understood that just because two or more things are related doesn’t mean they caused each other or one caused the other
What confuses me is applicable correlation sometimes masks causation. Like I can see why some correlation can seem real, sometimes it can come from left field weird and have nothing in common or it can be somewhat muddy in the gray area. Sometimes it can be hard to tell and can be easily abused.
this was an amazing article. i really enjoyed reading it.
You pointed out most of young people’s assumption about the concept of food nowadays (or maybe it’s just me). It’s really confusing when it comes to correlation vs causation because I was still doing that until last week. (after you explained how different they were).
As you mentioned above, it’s interesting to know how food can benefit our bodies or gives our bodies the wrong instructions due to the lacking of information. Therefore, thanks for posting!
It is not just you Trang! Understanding that correlation is not causation is an inherent problem when trying to understand information we read on the internet. Appreciate your comment!
-Neily