There’s a new skepticism in the air about health claims. I can feel it.
It started around 2011 with the discovery of a fraudulent study linking the MMR vaccine to autism, fueled more recently with the measles outbreak. Then, in 2014, researchers found more than half of Dr. Oz’s health claims were not supported by scientific evidence. Now 10 key doctors are asking that his medical license be revoked. And more recently, The Food Babe’s toxic and dangerous ingredient claims have been called into question by someone calling herself the Science Babe.
From where I sit, the lesson this teaches about nutrition and health in the 21st century is loud and clear. With the internet allowing anybody to write about any topic and sell most anything, people need to demand something extremely important: EVIDENCE.
Why evidence is so important
When you purchase anything you want to know that it works, right? Maybe you check reviews to see if that piece of furniture you want is sturdy or you visit Consumer Reports to get the lowdown on different car ratings. With nutrition products, whether it’s a new book, trendy superfood or supplement, it’s important to understand if it will actually do what its supporters promise it will do.
But how can you tell for sure? Of course, the person selling it will tell you it works and often will include testimonials. While that might be good enough for a pretty blouse, it’s not enough where health is concerned. That’s because strong claims are more likely to make people believe and therefore act on them, making them seem very real.
Take a 2007 study published in Psychological Science. Half of over 80 room attendants were told that the amount and type of activity they get cleaning hotel rooms meets the surgeon general’s exercise recommendations. Four weeks later, when compared to the room attendants who did not receive this information, they lost more weight, decreased their blood pressure and perceived themselves as getting significantly more exercise than they did at the beginning of the study.
While that study shows a perk to this particular health belief, it’s easy to see the potential downsides. People who believe they need something special to maintain health may find their habits go down the toilet when they stop. Or they may delay much-needed medical attention because of their strong belief in natural remedies. Some can become so scared of certain bad foods that they develop disordered eating. And most importantly, it’s important to know if a product (or not doing something, like getting vaccinations) is safe. This is especially true with dietary supplements that are not regulated by the FDA.
In short, there’s no getting around the need for evidence to make informed decisions.
From theory to evidence
Nutrition trends start with a theory to solve a particular health problem. For example, it was thought that delaying the introduction of food allergens, likes nuts, would help prevent food allergies. But this practice did nothing to tame food allergies. In fact, they only increased. With more research, scientists found that those at risk may benefit from early introduction of food allergens so the immune system is less likely to reject it. A total 180!
This shows that no matter how good a theory sounds, it needs to be tested. But scientific evidence can be — and often is — easily manipulated or taken out of context (often called pseudoscience). When I research anything I stay mindful of bias, including my own. I think most people have good intentions but when they get caught up in their cause, they can embellish the results. I’m not just talking about non-health professionals either. According to one review, nearly 10% of nutrition and obesity-related research articles overstated their results.
You may think you’re getting an accurate summary of evidence when in reality you might only be getting get pieces of the research that tell one side of the story. A healthy dose of skepticism and asking the right questions can go a long way. Below are some tips on how to check for evidence on different nutrition-related products.
Getting to the truth
In an article in the Atlantic, Dr. David Katz makes this important point:
You’re only being a good scientist if you say, ‘I’m going to try to read the literature in as unbiased a manner as I possibly can, see where it leads me, and then offer the advice that I have based on that view from an altitude.’ I don’t see that going on here, and again, I think it’s kind of sad because I think the public is being misled.
So maybe we can tackle this challenge together. I want to take on popular nutrition trends comparing the theory to the evidence in an ongoing series. But I need to know what you want to learn more about. What are some nutrition topics that confuse you the most?
Let’s talk about it in the comments.
Here are just a few of the problems with the “evidence” you are seeking. And, it’s always interesting to see who is funding the studies. To say the people you mentioned are ignoring the evidence is false. There are enough studies out there to prove any position on a nutrition trend. Im not saying we should stop looking for evidence, but studies need to be thoroughly dissected and well replicated. Finding sources should also be considered. Coca Cola would never allow a study they funded to produce negative outcomes. I’m very interested to see what evidence you find. http://www.forbes.com/sites/henrymiller/2014/01/08/the-trouble-with-scientific-research-today-a-lot-thats-published-is-junk/
Thanks for your comment. I’m not saying they are ignoring the evidence but the type of evidence they are providing is getting called into question as it should. Int he process of researching you are right, it is important to see who is funding studies, but bias can come from more than that. I ALWAYS look at both sides of the issue. Also, looking at different review studies and really getting an understanding of the pros, cons and limitations of different research is important.
You are cherrypicking a study to cherrypick other studies. In reality, science does reach consensus, not from one study, but usually dozens if not hundreds of study that provides evidence that supports a conclusion. Yes, one off studies don’t amount to hill of beans about 90% of the time.
For example, we have boatloads of evidence that smoking causes small cell lung cancer. And by boatloads, I mean several huge ocean liners. We have boatloads of evidence that HPV causes cancer. We have nothing that shows us that blueberries cause cancer. We have no evidence that marijuana can cure any cancer, but we have some evidence that it causes it.
And this whole thing about study sponsors? You’re assuming that scientists can be bought off by Coke, or Big Pharma or whomever. I don’t know why you have such a low opinion of science, but it’s not justified by very much. Yeah, you can cherry pick someone who was unethical, but I can cherry pick an honest politician and then assume all politicians are honest. 🙂
Yes, we do have boatloads of evidence against smoking. That is a very good point and relevant here. It has also been proven in court that the tobacco industry funded studies to undermine all of this evidence against cigarette smoking for years. How do you think that happened? The tobacco industry was eventually ordered by a federal court to admit that they “deliberately deceived” the American public. I don’t think all science is bad and I think we need science, but I don’t think people like Dr. Oz and the Food Babe are teaching us a lesson about science (or bad science) as the article suggests. Despite their claims, we should all know this is possible in science in general and we need to be very careful when interpreting science. And yes, funding is a factor that I consider when I read a research study. And if someone wants to use a study to prove a point to me, I do want to know who is funding it. That’s just me : )
So many people in the US are developing type 2 diabetes – what exactly is causing it? Processed foods? What exactly about the American diet makes us unhealthy? I think the tide is turning on saturated fats – but what about eating plain old bread? Do we need carbs to be healthy? Some say yes, some say no. It’s confusing sometimes to know what to eat to be healthy and keep yourself out of the hospital and off of meds as you get older.
What about the evidence in favor of GMOs? Don’t these people have the right to call it into question too? Unfortunately, it just becomes a vicious cycle. Maybe GMOs would be a good trend for you to explore in your new series?
Of course people have the right. This is really about qualification of evidence. It’s one thing to call something into question, it’s another thing to misrepresent science. The stronger the claims, the more evidence we really need to demand from people. I will try to tackle GMOs but it is quite complex.
I think we agree on the need for science and careful interpretation. However, I think misrepresentation of science is not limited to one side when it comes to the people you call out specifically in your article. I have a hard time finding that the evidence in favor of glyphosate is true. Evidently, the WHO agrees as well. They didn’t put out a strong clear message, but they said enough to question all the evidence in favor of GMOs. Yes, more research is definitely needed, but until then, I don’t want to take a chance with the health of my family. If I trusted the tobacco company, maybe I’d still be smoking today. I wonder how that would have turned out for me.
You forgot GMO’s! 🙂 Word-wide opinion about GMO’s is trending far away from the evidence in support of their safety – which is actually doing quite a bit of harm (there’s a good example in this opinion article http://www.nytimes.com/2015/04/25/opinion/sunday/how-i-got-converted-to-gmo-food.html). Then again, GMOs are an even hotter topic with more negative public opinion than vaccines, etc – so I could see why you’d avoid them.
As a relatively new Mom (my son just turned 1), the plethora of pseudo-science out there is really overwhelming, with people screaming about the dangers of things when scientific evidence says otherwise (or the reverse). I am lucky to work for the Federal Government in a science-focused Office, and have a science background myself – it helps me see through some of the pseudo-science. I’ve gotten fooled before, though – lesson learned!
Thanks Cara. Having a science background helps a lot. I will try to tackle GMOs but its quite a complex topic. Thanks for the article!
I would be interested in the evidence for treating mental health issues in children (and adults) with dietary restrictive interventions. OCD with a wheat-free diet, ASD with a cassein and gluten free diet, ADHD with omega-3 and artificial-free diet, and we may as well throw in ARFID, as it’s only a matter of time before someone suggests curing that with a carb-free diet.
What I’d really like to know is what drives the “fear of food” machine – why is it so very easy to convince a public with access to unlimited amounts of information that food is “toxic” and “poison”, and anything you can’t pronounce is not edible. When did phonetics become the most influential factor in food selection?
That’s a good idea Skye. I have already looked into many of those topics but it would be good to really dig into the evidence.
As for the “fear of food” tendency, I think its explosion has a lot to do with how people receive information these days. So many blogs and access to info/news — and most of all distrust for science and the government. But I think a new trend is coming and I hope more people demand better evidence so we see a change.
I ran across this article today, and I just want to give you kudos. Very well done and balanced scientifically.
I do have a small bone to pick. You are misusing “theory,” at least in a scientific sense.
Scientifically (and using the scientific method), a diet claim would start with an observation. Let’s use as an example, you observe that people who eat lots of blueberries have a lower rate of cancer.
So, your next step would be to write a hypothesis based on this observation. “A diet high in blueberries prevents cancer.”
Next, you would design an experiment or epidemiological case control study to answer that question. Now, it gets complicated. Do people who eat blueberries also eat a lot of cheese and smoke less? Or do people who eat blueberries stay out of the sun and drink red wine? it gets very complicated, so you need a huge population, maybe 100-200 thousand individuals. If it’s a double blind clinical trial (which may be impossible, since most people I know would notice the taste of a real blueberry and a placebo), maybe you can get 3000 people enrolled.
Let’s say you get positive results. People who eat blueberries show a 5% risk reduction in contracting one type of breast cancer (there are over 250 different cancers, so seeing a change in risk for all 250 is not possible in a typical research study). You present this data in a peer-reviewed paper, presenting it at a big science meeting. All the researchers jump up to ask you question, criticize your conclusions, but it’s all exciting.
Over the next 5 years, 50 other researchers publish similar results. Then someone writes a meta-review, which rolls up all the data from all the well-designed studies, and publishes that.
The next year after that meta-review is published, and if it’s positive, then the American Oncology Society will make a statement that “the scientific consensus is that eating blueberries leads to a lower risk of XYZ type breast cancer.”
From the moment of your observation to the date of that statement might be 20 years.
This is why I nearly always reject one-off studies whoever wrote it. I wait until 10-20 years of research supports the original idea.
But, never in this story do I use the word “theory.” That’s reserved, at least scientifically, for broad, overarching principles of science like evolution, germ theory, cell theory, gravity, Big Bang, etc. One wouldn’t say “the theory of blueberries preventing cancer.”
TL;DR I know. I’m not known for my brevity. 🙂
Thanks for your response and your website. I loved your article on pseudo-science. When I talk about theory I wasn’t referring to the research process but how nutrition trends start. Most are based on a theory that seems to make sense. But thanks for your research lesson. Maybe I can pick your brain for my ongoing series.
Would love to see an article about whole grains (and sprouted grains, and multigrain, and ancient grain …). I think something about carbs generally would be good too. Seems like they are really demonized these days, to the point that I’ve seen people on parenting boards talking about giving your kids Annie’s cheddar bunnies being like giving them trash to eat.
I would LOVE more articles clarifying recent food trends.
> Is fat good or bad? I changed from a low-fat focus to now saving my bacon grease! What’s the right balance?
> Whole wheat vs. Whole wheat white flour
> Sugar: what’s the right balance? I’ve even read things saying fruit juice (100%) equates to just sugar.
> GMO
> Buying organic, farm-raised, etc. It sounds like it would make sense, but it is SO much more expensive. Does it really provide that much of a health benefit.
You may have already addressed some of these on your website..I’m new to your blog so I haven’t seen many past posts.
Great topic to explore! When friends and clients ask be about health claims and new products, I teach them to become a skeptic and consider the source – is the person promoting the product benefitting from the sale of the product? Who funded the study to test the efficacy and has it been tested more than once? It’s important to teach our clients what we know as truth in this ever-changing science, but it’s equally important to teach them to be nutrition detectives as well.
Thanks for sharing!
I have been reading your blog for several years, and I just want to let you know how much I appreciate your calm, balanced approach to eating/feeding. Keep up the good work staying true to your focus on “enjoyable health.” I have noticed many blogs getting controversial or judgmental on the topic of food, but that defeats the whole purpose to me.
Thanks Jennifer. You made my day ; )
I would love to see more articles about popular “healthy” trends such as:
-coconut oil (compared to other types of oils/fats, and why people think of it as healthier, even though it is high in saturated fat)
-agave nectar (as well as honey and other types of sweeteners which are thought of as “healthier”, even though as far as I understand they are just another type of sweetener)
There are so many more interesting trends and fads that I feel need to be explained, and possibly “myth-busted”….
Thank you for opening this up for discussion!