Stress and sugar. In our post-modern society’s orthorexic narrative, these are two of the biggest villains. So combining them into a diabolical duo reinforces their evil even more.
Dr Caroline Leaf is a communication pathologist, self-titled cognitive neuroscientist and Christian life coach. In her latest newsletter to her adoring fans, Dr Leaf has accused sugar and stress of mass murder, with our soul’s approach to stress as their accomplice.
I’m sure Dr Leaf means well, but just because she’s not trying to frighten sales out of the gullible and vulnerable doesn’t mean she gets a free pass on the accuracy of her information.
To boil it down, Dr Leaf’s argument goes something like this:
Our choices turn good stress into bad stress
Bad stress releases excess cortisol which leads to disease and death
Therefore our choices to stress causes disease and death
We control our choices through our minds
Therefore, our mind is the key to stress illness
(oh, and sugar …)
The arguments seem plausible on the surface. Most people have heard enough about stress to know about ‘good’ stress and ‘bad’ stress. It doesn’t seem too much of a stretch to say that ‘bad’ stress is a significant cause of disease and death. In the middle of her essay, Dr Leaf jumps from stress to sugar with no preceding link, but again, most people have heard that sugar is unhealthy, so they would probably just accept that statement too.
Unfortunately for Dr Leaf, her article has several critical errors which turn her well-meaning educational essay into a science-fiction short story.
To start with, her essay is built on the dysfunctional premise that the mind controls the brain, so each higher argument or premise is fundamentally skewed from the outset, and in doing so, Dr Leaf simply creates a circular argument of distorted factoids.
For example, her opening sentence: “The hypothalamus is a central player in how the mind (soul) controls the body’s reaction to stress and foods.” The hypothalamus is a part of the limbic system deep in the brain. It’s the main pathway from the brain to the endocrine system as Dr Leaf goes on to correctly assert, but essentially it runs on auto-pilot, responding automatically to information already being processed at a level beyond the reach of our conscious awareness and control. For example, the hypothalamus regulates our body temperature, but it does so without our conscious control. We can not consciously will our body temperature up or down just with our minds.
It’s the same with the stress response – there are many times where people have a subconscious stress response, where their mind feels like there’s nothing to be afraid of, but their hypothalamus is still priming their system for fight or flight. White coat hypertension is a prime example. White coat hypertension, or “White Coat Syndrome” is the phenomenon of people having high blood pressure in their doctor’s office but not at home. Patients will say to me all the time, “I don’t know why my blood pressure is so high in here. I feel fine. I know there’s nothing to be afraid of here.” But while their conscious mind is relaxed, their deeper subconscious brain remembers those injections that hurt, or that one time a doctor stuck the tongue depressor too far down their throat and they felt like they choked on it, and their hypothalamus is preparing them for whatever nastiness the doctor has for them this time.
Dr Leaf’s statement fails because she wrongly equates our brain with our mind, a subtle perversion which doesn’t just invalidate her premise, but significantly skews the essay as a whole.
As a quick aside, Dr Leaf also says that the hypothalamus “integrates signals from the mind and body, sending them throughout our bodies so that we can react in an appropriate and functional manner, ‘so that the whole body is healthy and growing and full of love’ (Eph. 4:16 NLT)”. Ephesians 4:16 isn’t talking about the physical body, but about the body of Christ. You don’t need to be a Biblical scholar to know this, you just have to be able to read. Here is what the Bible says, “And He Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry, for the edifying of the body of Christ, till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ; that we should no longer be children, tossed to and fro and carried about with every wind of doctrine, by the trickery of men, in the cunning craftiness of deceitful plotting, but, speaking the truth in love, may grow up in all things into Him who is the head — Christ — from whom the whole body, joined and knit together by what every joint supplies, according to the effective working by which every part does its share, causes growth of the body for the edifying of itself in love.” (Ephesians 4:11-16, emphasis added).
There’s no subtlety about this misuse of scripture. Even non-Christians would be able to figure out that this verse has nothing to do with the physical body. Dr Leaf has demonstrated that she either doesn’t read the Bible or doesn’t understand it. Either way, this is a shameful indictment on Dr Leaf’s claim that she’s a “Biblical expert”, and should be ringing alarm bells for every pastor that is considering letting her get behind the pulpit of their church.
Dr Leaf rolls on with her list of medical misinformation. Some of it is subtle (the “stages of stress”, also termed the General Adaptation Model, is an outdated model of the stress response , and CRF and ACTH are released during all stages of stress, not just stage 1). Some of it is outlandish, like her claim that high levels of stress leads to Cushing’s Syndrome (see http://emedicine.medscape.com/article/2233083-overview#a4 for a list of the causes of Cushing’s Syndrome and note that stress isn’t on the list).
Dr Leaf’s also suggested that it was solely our perception of stress that was the key factor in the outcome of stress, making reference to “a study” showing a 43% increase in mortality if you thought stress was bad. This is an example of cherry-picking at it’s finest, where one study’s findings are misrepresented to try and support one’s pre-existing position. Dr Leaf didn’t bother to list her references at the end of the article, instead expecting people to find it for themselves, but I’ve previously seen the study she’s referring to. Keller and colleagues published the study in 2012 . Their survey suggested a correlation between overall mortality and the combination of lots of stress and the belief that stress is bad. But remember, correlation does not equal causation, a golden rule which Dr Leaf is quick to ignore when the correlation suits her argument. The Keller study, while interesting, did not control for the impact of neuroticism, the “negative” personality type which is largely genetically determined and is independently associated with a higher mortality [3-9]. It does not prove that thinking about your stress in a better way makes you live longer.
Dr Leaf went on to claim that “the researchers estimated that the 18,200 people who died, died from the belief that stress is bad for you—that is more than two thousand deaths a year.” Even here, Dr Leaf manages to get her facts wrong. The authors actually wrote, “Using these cumulative hazards at the end of the study follow-up period under the assumption of causality, it was estimated that the excess deaths attributable to this combination of stress measures over the study period was 182,079 (controlling for all other covariates), or about 20,231 deaths per year (over 9 years).”
Dr Leaf can’t even get her vexatious arguments right. Not that the number really matters, because notice how the authors described the magic number as an “assumption of causality”. Basically the authors said, ‘Well, IF this was the cause of death, then these would be the numbers of deaths attributable.’ They NEVER said that anyone actually died because of their beliefs about stress. Indeed, the results showed that just believing that stress was bad didn’t make any difference to the mortality rate as Dr Leaf suggested – it was the interaction of high stress AND the belief it was bad that was associated with a higher mortality. But why let pesky issues like methodological rigour get in the way of sensationalist hyperbole.
Then in the penultimate paragraph, Dr Leaf suddenly decides to throw sugar into the mix. Somehow without justification, stress is bad and therefore sugar is also bad, and they both throw the hypothalamus and the rest of the body into toxicity.
Dr Caroline Leaf is promoted, by herself and by many in the Christian church, as a Biblical and scientific expert, but in one short promotional essay, Dr Leaf makes multiple critical scientific and exegetical errors. In other words, her errors in discussing scientific findings and basic Biblical text are so massive that they are incongruent with her claim to be an expert.
Something needs to change – either Dr Leaf revises her knowledge and improves her accuracy, or she needs to stop misleading people from pulpits, both virtual and real.
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 Keller A, Litzelman K, Wisk LE, et al. Does the perception that stress affects health matter? The association with health and mortality. Health Psychol 2012 Sep;31(5):677-84
 Okbay A, Baselmans BM, De Neve JE, et al. Genetic variants associated with subjective well-being, depressive symptoms, and neuroticism identified through genome-wide analyses. Nature genetics 2016 Apr 18.
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