Nutrition Tales – 4 Ways to Know Which Headlines to Trust
Updated: Jul 6, 2020
You’ve seen the news stories: alcohol is better for you than exercise; celery juice can clear your skin and prevent cancer; sugar is worse for you than heroine; or the ultimate debate of the century: EGGS. One day, they are a killer worse than cigarettes, and the next, meh, they’re aite. Especially in the field of nutrition and health, the internet is literally overflowing with conflicting advice and a lot of it sounds like it could be true. One day, you’re spending a fortune on goji berries because it’s apparently the “ultimate superfood", and the next, you hear that the sugar in fruit is the devil incarnate entering us through food.
So what gives? How can we possibly know who or what to trust? Well, let’s talk about the most glamorous topic of all: research.
Research is an ongoing process and no single study can ever thoroughly answer a question on its own…and this is where headlines go wrong. Oftentimes, writers report on the findings of a single research study, even if there are eighty other studies on the same topic that say the exact opposite. They do this because their main mission is to grab attention and get readers. And yes, it is possible for two studies looking at the same topic to arrive at opposing conclusions; this is inevitable and truthfully, it is actually a welcome part of the scientific process. At the same time, however, quality also matters. There are different types of research studies and some are objectively better than others. Additionally, a more recent study is not automatically superior to an older one.
What can you do with all this information I just threw at you? Well, I want to help you develop a radar to identify nutrition and health news stories that are actually reliable. Here are 4 things to consider when you come across the next headline:
1. What does the entire body of research say on the topic?
How does the reported study align (or not align) with all the other research done on that topic? Is this study generally contradicted or supported by the body of evidence? As mentioned before, a single study alone is almost never powerful enough to dictate nutrition or health recommendations. It can certainly inform future lines of inquiry in science, but if the reported findings are unique to a single study, it is likely not worth changing your lifestyle over.
2. How big was the study?
Generally speaking, larger studies with bigger sample sizes are more reliable or generalizable to the population than smaller studies.
3. Was it an animal or a human trial?
Despite some (valid) ethical considerations regarding the welfare of animals, a lot of health research is done on mice or another small mammal first in order to minimize potential harm or burden to humans. Typically, if some interesting finding is noted in an animal and it seems important or relevant to human health, a version of the experiment may be repeated in humans to see if the same outcome is realized. However, unless the experiment has been carried out in humans, we cannot conclude with absolute certainly that the observation made in animals is applicable to human health or human physiology.
4. What type of study was it?
There are different types of research studies and the scientific community has what we call the hierarchy of evidence. The diagram below is taken from The Logic of Science website and it shows that not all research is equal. Animal or in-vitro studies are lower on the hierarchy, along with observational studies, like cross-sectional, case control, and cohort studies. This is because observational studies cannot isolate variables and therefore cannot determine cause-and-effect relationships. Randomized-control studies are the gold standard, as they involve having controlled environments with precisely-manipulated variables. These types of studies are expensive and may even pose ethical dilemmas when dealing with health and disease, and are therefore not always feasible. Meta-analyses and systematic literature reviews are the most superior because they are a consolidation of multiple studies looking at the same research question.
If a headline is reporting on a research study that is lower on the hierarchy of evidence or if it is a single study that is contradicted by the entire body of research, don't believe the hype!
I would love to hear about any ridiculous nutrition or health headline you've seen recently, so feel free to comment below!