Many people believe that if someone cites a scientific study, their message becomes more credible. It’s important to be evidence-based, but citing studies can go awry when the person citing them does not understand what they are citing. Physiology is very complex, so that is understandable: I certainly don’t know exactly what’s going in all the papers I read.
In the health-blogosphere where many authors have no credentials and don’t regularly read full-text science articles, citations can serve as a mere marketing strategy. Of course, someone with credentials discussing nutrition or health can be completely wrong, but that’s besides the point. I only have a college degree after all, but I’ve read many articles where people throw around citations that don’t even support their point, showing me that they’re not being scientific despite citing science articles.
I read a horrendous ebook recently with a high number of citations but the author simplified the concepts too much and showed that he lacks a science education. Based on that experience I decided to write this post and elaborate on some mistakes I’ve noticed over the years from following the health blogosphere. I hope these ideas give you a fresh perspective on reading new material. Feel free to correct me or add more as well.
A -> B, B -> C: A-> C
If A causes B and B causes C, A must cause C. This not necessarily true. This adamant vegetarian argued with me on youtube a while ago and claimed that fish causes diabetes, because Dr. Michael Greger (he has cool youtube videos for sure) made a video about fish and diabetes. No where in the video did he say fish causes diabetes. Instead he discussed PCBs in fish and their link with diabetes.
This one youtube commenter, and others who replied to the discussion, wanted to believe so badly that fish inherently causes diabetes. I saw myself in them; I too wanted to believe certain things that weren’t true at one point and it took some practice to be unbiased. So I gave this commenter my argument and he cited a study that protein causes a greater insulin response per gram of glucose compared to the same amount of glucose by itself. He then cited a study that eating more protein is correlated with diabetes. It was a perfect example of this fallacy but he was unable to realize his folly because his belief-system was akin to a religion. The body doesn’t always work like a domino effect where one thing causes another in a linear fashion.
Some people say cod liver oil is unhealthy. They don’t have studies linking cod liver oil with poorer health, or even anecdotal evidence that it is bad for us, but instead they reduce it to its parts: DHA, EPA, vitamin A, vitamin D, etc. These people say that DHA and EPA aren’t actually essential for us and that they go rancid due to the nature of polyunsaturated fatty acids (PUFAs). PUFAs have more double bonds which react more, so consuming them may be bad for us. Yes, in the form of vegetable oils that hide themselves into the most innocuous of foods like bread, that may be true. But all whole foods to my knowledge that contain PUFAs contain antioxidants that have been shown to protect against that oxidation, like vitamin E.
Cod liver oil is not a whole food (although it’s wapf proponents say it is) but it has been consumed for a long time with health-promoting effects in various regions of the world, so without evidence showing that cod liver oil, and not DHA, or EPA consumption is unhealthy, one cannot conclude that cod liver oil is unhealthy. I trust the wisdom of traditional peoples much more than this reductionist attempt at being scientific. Green Pastures cod liver oil is the best by the way: whenever I took it I felt more energized and focused, and warmer.
By specificity I am referring to the specific effects of hormones, neurotransmitters, and other substances in different tissues, as well as the definition of being specific in our prose. If I were to say for example, testosterone increases sex drive, I am not being specific. If I said on the other hand, 10mg of testosterone supplementation increases sex drive in hypogonadal men, I’m telling specific story. The who, what, when, and where are often skimmed over on the internet and let me illustrate this with some more information on testosterone.
Testosterone is the male health-nut’s favorite hormone and we would measure it everyday if we could. We don’t like things that lower our testosterone, like licorice root, but it may be more complicated than we realize, as aromatase inhibitors show us. Aromatase inhibitors are a popular topic because aromatase inhibitors prevent testosterone from being converted to estradiol. Inhibiting aromatase however does not have the desired consequences, as many who have taken aromatase inhibitors have experienced.
Studies have shown that mice who are deficient in estrogen have almost no sex drive and don’t ejaculate. A recent study on hypogonadism in men concluded that low estrogen levels may explain some symptoms of hypogonadism such as decreased sex drive, independently from testosterone. Aromatase inhibition also increased body fat in hypogonadal males. This evidence really crushes the simple idea that aromatase inhibitors will somehow make men more masculine by lowering estrogen levels. Building on my point that we need to be specific, let’s just look at estrogen’s different effects in different tissues. First of all, there are three estrogens, such as estrone (E1), estradiol (E2), and estriol (E3). Estradiol is the most ubiquitous one. Quoting from this paper, hopefully you can see my point:
“Estrone (E1) is a significant estrogenic hormone contributor in both reproductive (~0.5–1 nM) and postmenopausal (150–200 pM) women and in men; estriol (E3) levels are significantly higher in pregnant women (~10–100 nM) than in nonpregnant women (<7 nM; ref. 4). Decreased E3 levels in pregnancy have been associated with complications of eclampsia (5) and the incidence of Down’s syndrome in offspring (6). Fluctuations of ovarian hormones in perimenopause consist of intermittent high and low E2 levels, followed eventually by chronically lower levels, and the predominance of E1 (7); these changes can be correlated with behavioral and other disturbances, as can pubertal and menstrual cycle-based fluctuations (8). All three of these estrogenic compounds (see Fig. 1) are also produced by aromatases in placenta (especially E3; ref. 9) and other nonreproductive tissues (brain: ref. 10; fat cells: ref. 11), where their effects may extend beyond reproductive functions (12). For example, E3 has protective effects against the development of arthritis in certain experimental models (13), as was known previously for E2. Effects in the brain, bone, the cardiovascular system, and many other tissues could be affected differentially by all three of these endogenous estrogenic compounds during different life stages.”
This paragraph defined the who (post-menopausal, reproductive, and pregnant females), the what (E1, E2, E3), the where (placenta, brain, bone, cv system, fat cells), and the when (puberty, menstruation, menopause, pregnancy, and perimenopause), as expected of a scientific paper. Many bloggers want to make it simpler and following their advice can be dangerous when they try to discuss science. The level of detail and specificity in a scientific paper (for the most part) is not matched by the blogosphere.
The internet is a great place in the health-worlds for people to market their businesses . . . just realize that when reading an article on a website that also sells products. I’m also selling an idea, so I promise to be as unbiased as possible.
I’m not saying that bloggers should turn into scientists now; I specifically am referring to bloggers who cite scientific articles and attempt to be scientific but may have very little understanding of what they are sharing. I understand that these people are excited to share information and want to learn, but we need to reserve our judgement and not believe everything we read on the internet, or even in a science journal for that matter (this includes what I say too).
I think it’s great to put in the effort and cite a scientific article, but if someone who cites articles regularly starts to pretend they understand the material when they don’t or is attempting to come to theories and does not realize that they are off the mark, I have a problem.
Notice that scientists often say things like “may” rather than thinking in absolute terms (A causes B which causes C). I rarely see that in the blogosphere. I admit that I may be wrong in everything I discuss. I like sharing my thoughts and receiving feedback so I can learn but I do my best to be accurate.
Only reading the abstract
Sometimes the full-text isn’t available, so this one isn’t completely bad, and sometimes we don’t have to read the full-text if we’re just looking for a citation on something that is common knowledge. But in general, it’s best to read the full-paper or at least look at the figures. Often, the story in the paper may differ slightly from the conclusions presented in the abstract. When someone only read the abstract but still cites the paper, I tend to notice the following: they will say very little on the subject and the paper was actually about other things than what they cited it for.
Rats and mice are useful for medical research for many reasons but it’s not easy to draw conclusions from those studies. Oftentimes these studies sound really complicated because the researchers are studying some isolated protein or a specific receptor or cell line, so it really bugs me when someone draws a conclusion about human health, like protein consumption or something, and cites a reductionist (not a bad thing to be reductionist) rat study that looked at some liver cell line.
You may be wondering why anyone would do this but I’ve seen it a LOT. People will act as if they understand something and cite a rat study that seems like it has something to do with their point but isn’t complete enough to really buttress it. Sometimes these studies confirm human experiences, but the human studies are needed to be able to draw conclusions. I just cited a mouse study on estrogen receptor knockout mice and how the results may explain the low sex drive men have experienced from taking aromatase inhibitors, but that alone isn’t enough. I did cite a human study afterwards so that helps but it still isn’t definite proof (that’s another conversation altogether).
Speaking in absolute terms
I just touched on this but scientists often speak cautiously in their writing. Health bloggers don’t much of the time. Beware.
There are many other mistakes people make all the time including a long list of logical fallacies, but these are the common ones I’ve noticed when it comes to citing science. It’s great that bloggers try to be scientific, but not when they use it to market their products or seem more knowledgeable when they don’t have a science education.
Here the argument gets complex because people with a science education may be completely brainwashed and these bloggers may just be very passionate and be trying to help. But there is a distinction between that and believing you know what you say is true, so don’t be fooled by people who present science in a way that makes it seem as if they understand it, and that what they’re saying is completely true.
The next question is, do we even need science to be healthy? Do we need to deliberate over our physiology to find true answers to our health? It depends, and I’ll cover that idea next time.