My previous article discussed a large systematic review which found vegans and vegetarians were more likely to suffer depression, anxiety and suicidal behavior.
This begs the question a number of readers have indeed asked:
Is the relationship causal?
In other words, do vegan and vegetarian diets impart a higher risk of these mental health problems, or are people with these mental health problems more likely to adopt vegan and vegetarian diets?
To answer this question, we’d need long-term, randomized clinical trials with mental health assessments performed at baseline and throughout the study.
These studies are yet to be done.
The systematic review by Dobersek et al analysed mostly cross-sectional studies, which can detect association but do not establish causation.
There was one RCT in the review, in which the diet periods lasted a grand total of 2 weeks each and therefore was as about as useful as mudflaps on a helicopter.
If you read the discussion section of the Dobersek et al review, the authors note some studies found the mean age of mental illness was younger than the mean age of commencing meat avoidance. However, the one longitudinal study in their review found the risk of mental health issues rose over time with meat avoidance.
Which would tend to confirm my suspicions that a mix of potential factors are at play:
- Extreme diets increase the risk of mental health disorders;
- People with/or susceptible to mental health disorders are attracted to extreme diets;
- People with/or susceptible to mental health disorders are attracted to extreme diets, then become even worse due to the nutrient deficiencies inherent in those diets.
Here’s What We Do Know
Vegans and vegetarians are far more likely to suffer vitamin B12 deficiency.
Vitamin B12 is critical for optimal brain and nerve health, and that low serum vitamin B12 levels are associated with neurodegenerative disease and cognitive impairment.
A 2002 analysis, involving 11,045 subjects followed for a mean 17.6 years, revealed death from mental and neurological diseases was a noteworthy (and statistically significant) 2.46 times higher among vegetarians.
This is a rare example of an epidemiological finding with a strong relative risk and a physiologically plausible explanation. Namely, deficiency of vitamin B12, a nutrient imperative for healthy cognitive and neural function but inherently deficient in meatless diets.
No-one can accuse that study of being a meat industry-sponsored hatchet job - the lead author was in fact Paul Appleby, a vegan activist from the intensely pro-veg*n Oxford collaboration that has published numerous papers on ‘plant-based’ eating.
More recently, Kaur and Kaur (2021) found a vegetarian diet was significantly associated with lower global cognitive scores among women (n=404) aged 40-65 years from rural areas of Punjab (North India).
A 2023 Taiwanese study of 1,285 subjects over 60 with mean follow-up of 2.3 years found a vegetarian diet was correlated with an elevated risk of all-cause dementia (HR = 1.68, p < 0.05).
Oh, and that Taiwanese study also found that “hypercholesterolemia” was negatively correlated with the incidence of incident dementia. It stuns me how so many people still fail to understand that the brain has a very high cholesterol content and therefore lowering your cholesterol via drugs and oddball diets is quite literally a stupid thing to do.
EEG Studies: This is Your Brain on Veganism
During the 1960s and early 1970s, researchers published the results of EEG studies showing diffuse (generalized) abnormalities in vegans (for examples see Smith 1962; West & Ellis, 1966; Kurtha & Ellis, 1971).
For some strange reason, this line of research has not been pursued.
In one of those early EEG studies (West & Ellis, 1966), B12 supplementation improved EEG scores in most of those registering abnormalities, but three of the vegans failed to respond to heavy supplementation with either oral or injected B12.
Leave. The. Kids. Alone.
What I find especially sad is when parents force their misguided dietary ideologies upon children, a vulnerable group that adults are supposed to protect.
In 1986, Dutch researchers observed that vegan infants participating in a large health study had markedly lower B12 levels and impaired psychomotor functioning when compared to control infants. (Dagnelie et al, 1989; Dagnelie et al, 1998) On the basis of these findings, the researchers made dietary recommendations to the families of the infants, who subsequently began switching their youngsters to lactovegetarian, lactoovovegetarian, or even omnivorous diets. On average, the children were six years old when the dietary change took place.
In 2000, follow-up examinations of these same subjects, who were now aged between ten to sixteen, were published (Louwman et al, 2000). Two-thirds of the formerly vegan adolescents still suffered from B12 deficiency, whereas all of the subjects in a similarly aged omnivorous control group had normal B12 levels.
When given a series of cognitive tests, the ex-vegan group achieved poorer results than the lifetime-omnivore group. A significant association was found between low B12 status and poorer performance on tests measuring fluid intelligence, spatial ability, and short-term memory.
Because fluid intelligence involves reasoning (something militant vegans clearly aren’t very good at), the capacity to solve complex problems, abstract thinking ability and the ability to learn, the authors pointed out that “Any defect in this area may have far-reaching consequences for individual functioning.”
B12 deficiency is a documented and plausible factor that could help explain the increased risk for depression, anxiety, suicidality and neurocognitive decline researchers have observed among veg*ns.
You’ll note that I have italicized “increased risk” - this is for the subset of (veg*n) dimwits who seem to think my recent article was a declaration that everyone who follows a veg*n diet will become depressed, anxious and suicidal. Anyone who bothered to read the actual figures in the article will know that is not even close to what I wrote.
Other Potential Dietary Factors
Much of the research focus in this area has centered around B12, but meat contains several nutrients that are either low or absent in plant foods (other B-vitamins, creatine, carnitine, carnosine, taurine, zinc, iron, long-chain omega-3 fatty acids, etc).
Insufficient LC-omega-3 fatty acid intake has have been implicated in mood disorders, but we don’t have a whole lot of research examining its possible role in the heightened veg*n susceptibility to depression, anxiety, and suicidality.
Psychosocial Factors
Compared to omnivores, vegans exhibit high levels of dietary-related embitterment (i.e resentment towards omnivores for not appreciating their allegedly more virtuous dietary path). They also have a higher perception of being discriminated against compared to vegetarians and omnivores.
Higher dietary embitterment among vegans is accompanied by higher moral motivation in regard to diet (think highly annoying, moralizing vegans).
Vegans exhibit higher dietary centrality, in which their self-identity revolves heavily around their dietary beliefs.
Numerous studies have also found that vegans and vegetarians are more likely to suffer eating disorders such as orthorexia (an obsession with eating only "healthy" or "pure" foods).
If the Truth Hurts, Too Bad
After posting my article, I’ve received angry correspondence from two clearly triggered and butt-hurt veg*ns ranting and raving about anything and everything except the actual data I discussed in the article.
One, “Maureen”, went off half-cocked in the comments below the article. This was despite the fact that, by her own admission, she only read a small part of the article. After I replied to the incoherent Maureen, she deleted her comments.
Then a peanut by the name of “Philip” sent me an email. I could tell right away Phil was an impartial stickler for science, because his Instagram moniker is “wicked_vegan_chef”.
Lolz.
Like Maureen, Phil subjected me to an incoherent diatribe that did everything but address the actual data in my article. Like Maureen, Phil told me his age, his interests, his past work history, and was clearly angry at me for daring to publish an article critical of veg*nism.
Phil’s email began thusly:
“What a complete load of tosh! Shame on you for publishing it.”
Note the moral angle there: I’m supposed to feel shame. For telling the truth.
Lolz².
“I think your article is based on irredeemably biased and factually highly dubious research especially in its portrayal of vegans.”
But Philip completely failed to explain just what in the peer-reviewed research I cited was “irredeemably biased and factually highly dubious.”
The reality is that Philip never read the research. Philip, whose proud past scientific endeavors include running pubs and those human zoos known as nightclubs, wouldn’t know science if it crawled up his keester and started a symposium.
This is one thing that really cracks me up about dietary zealots. Vegans and low-carbers might act like mortal enemies residing at polar opposite ends of the dietary spectrum, but their approaches to research analysis adhere to the exact same criteria:
Studies that support what we believe, no matter how sloppy and biased = AWESOME!
Studies that contradict what we believe, no matter how thorough and impartial = BAD, TERRIBLE, BIASED, EVIL!!!
Then comes Philip’s pièce de résistance:
“I would have expected better output after reading some of your more balanced polemics.”
What Philip really means:
“I liked you better when you were telling me what I wanted to hear. Now that you’re saying stuff I don’t want to hear, you’re a right prick!”
Have a cry about it, Phil. If the facts hurt, then the problem isn’t with me - it’s with that irrational character staring back at you in the mirror.
In closing, I’ll repeat what I told Maureen:
“I have presented evidence above linking meatless diets, not just to depression and anxiety, but to an increased risk of suicidal behavior.
You know what suicidal behavior is, Maureen?
It’s when people try to KILL themselves (sadly, they sometimes succeed).
Have you ever lost someone to suicide, Maureen? I have, and it’s not a very bloody pleasant experience. It’s heartbreaking.
If the link between meatless eating and veganism is causal, then this has HUGE public health implications. Lives could literally be saved by making susceptible people aware that these diets can increase suicidality.
It must take an incredibly selfish, self-centered and diabolical person to expect me to refrain from sharing this information, just because he/she doesn’t want to have his/her feelings hurt by someone posting critical information about their pet dietary beliefs.”
The facts don’t care about your feelings, folks.