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Meat and mental health

Interesting article … a systematic review of meat abstention and depression, anxiety, and related phenomena

https://www.tandfonline.com/doi/full/10.1080/10408398.2020.1741505

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Hmmmmmmmmmmmmmmmmmmm
Well… I’m probably not going to bother reading the article after perusing the abstract, which tells us that the sample size of meat eaters is a whopping seventeen times greater than vegetarians! What’s that, around 95% meat eaters and only 5% vegetarians? What a disparity!!

But Ok… I’ll skim a bit. Well. The authors admit that the studies they used included those with serious methodological flaws and severe bias, and this is after they limited the study to only 18 papers out of thousands of other studies - a decision made on the views of only 2 people.

Eighteen studies met the inclusion/exclusion criteria; representing 160,257 participants (85,843 females and 73,232 males) with 149,559 meat-consumers and 8584 meat-abstainers (11 to 96 years) from multiple geographic regions. Analysis of methodologic rigor revealed that the studies ranged from low to severe risk of bias with high to very low confidence in results.

So it’s no surprise to see the authors state upfront:

Our study does not support meat avoidance as a strategy to benefit psychological health.

However, at least the study does admit that there is uncertainty about whether diet is related to mental health at all. It also admits that diet would only be one factor in a myriad of other lifestyle factors already well known to influence mental health - including socio-economic status, unemployment, smoking, sedentary lifestyles, exercise, alcohol and drug use, and much more, but none of these incredibly important factors are taken into consideration, (which seems crazy right?!) a flaw admitted in the conclusion.

Another flaw is that the review excluded all non English language research, and for some reason seem to think that including China (a culture famous for its consumption of meat) somehow redresses the bias of not including largely vegetarian countries like India.

First, we excluded non-English language studies, that could potentially bias our results in favor of “Western” norms which include meat consumption. For example, our selection criteria excluded papers published in languages other than English. (e.g., Japanese, Hindi) and in non-English databases. Thus, our review may have omitted studies from geographic regions that follow predominantly vegetarian or plant-based dietary patterns. In these areas, the relation between meat-avoidance and psychological health may differ from “Western” nations. Nevertheless, our review included a large sample from China; so, this limitation may be trivial.

It also may be quite important, right?! I mean, they only have 5% vegetarians to begin with…

The journal has also published several other articles critical of vegetarians in the past. These sorts of studies always seem geared to generating preconceived conclusions, even when dressed up as respectable research! Just my opinion :wink:

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Here is a relevant part of the article:

This study was funded in part via an unrestricted research grant from the Beef Checkoff, through the National Cattlemen’s Beef Association. The sponsor of the study had no role in the study design, data collection, data analysis, data interpretation, or writing of the report.

It doesn’t mean the researchers did anything wrong in this case. Nonetheless,I am generally more skeptical of industry funded research, especially when the funder has a clear economic interest in the subject at hand.

Another thing worth noting:

All study designs were eligible (e.g., cross-sectional, retrospective, prospective, case control, randomized controlled trial (RCT), longitudinal).

Randomized controlled trials (RCTs) are generally considered the best type of evidence for estimating causal effects. RCTs are generally looked to to overcome the “correlation is not causation” problem.

The study included one RCT, which concluded:

Restricting meat, fish, and poultry improved some domains of short-term mood state in modern omnivores. To our knowledge, this is the first trial to examine the impact of restricting meat, fish, and poultry on mood state in omnivores.

I.e. the only RCT that is part of the review contradicts the conclusion of the review.

IMO, I would be skeptical of health research funded by the meat industry, beverage industry, alcohol, tobacco industry etc. or any industry with a clear financial incentive to prove that their product “is good” :slight_smile:

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Yeah. Well it’s a start, right?

Yeah. I read it more of possible evidence of some vague correlation. I could maybe see that there is perhaps a tendency for those who lean more towards vegetarianism to also maybe sometimes have a tendency to pay attention more to the suffering of other beings and perhaps without a way of dealing with that (e.g. Buddhism) they might fall prey to depression? That could be an area of study that may be interesting.

Yes. Wouldn’t it be great for someone to do just that and see where we go with it?

Unfortunately it’s the nature of the beast in science these days. :frowning: Very sad state of affairs.

Yes, that would be ideal. I guess it’s very difficult to do regarding long term trials with people self reporting what they eat and no clear definition of terms such as ‘vegetarian’.

That’s the problem with making science a commercial endeavour.

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It comes across to me as less science than developing ground for a position statement, or as an fodder to influence discussion.

Among other statements from abstract or study not (I think) previously highlighted:

Studies examining meat consumption as a continuous or multi-level variable were excluded.

the comprehensive term “vegetarian” may be used to describe individuals who avoid only red meat (e.g., beef), avoid both red and white meat (e.g., pork, poultry) or those who simply consume predominantly plant-based diets. Furthermore, investigators frequently subdivide vegetarians into several groups categorized by the types of foods they exclude. While no definition is definitive and categories vary significantly, “vegans” exclude all foods and beverages derived from animals (e.g., fish, eggs, dairy, or meat) and may also avoid using any animal-based products (e.g., leather clothing). Ovo-lacto vegetarians consume no meat but will eat eggs and dairy, whereas pescatarians eat fish but not red meat or poultry, and flexitarians consume a predominantly plant-based diet while occasionally consuming meat. These inconsistent and intersecting definitions in concert with self-reported dietary status may lead to misclassification because there is a clear and important distinction between merely reporting that one avoids meat and actual meat-abstention… To avoid inconsistent definitions of vegetarianism, our analysis sought to capture studies that clearly differentiated between individuals who reported consuming meat and those reporting to be meat-abstainers, while acknowledging that the overall dietary patterns exhibited by both groups (and most humans) are varied.

One major limitation of all studies in this review was the use of self-reported dietary status. … The debate revolves around two major criticisms. First, critics of self-reported data state that without objective corroboration of dietary self-reports, it is impossible to quantify measurement error due to intentional and nonintentional distorting factors, such as deliberate misreporting (i.e., deception/lying), social desirability, reactivity, misestimation, and false memories of dietary intake … Second, critics argue that pseudo-quantification (i.e., the transformation of reported foods and beverages into estimates of nutrient and caloric intake) created a fictional discourse on diet-disease relations… This latter argument is based on the fact that ∼65% of self-reported dietary data have been shown to be physiologically implausible [i.e., respondents cannot survive on the amount of foods and beverages reported…The first criticism is potentially applicable to our analyses. Nevertheless, the dichotomous nature of our classifications (i.e., meat-consumers versus meat-abstainers) reduces both its importance and impact. The second critique regarding pseudo-quantification is not relevant to our review, nor is it relevant to qualitative assessments of dietary intake.

Study designs and/or a lack of rigor precluded inference of causal relations and none should be inferred.

Annecdotal comment: several (separate) friends of mine who lived in China for years repeatedly volunteered the information that what was considered vegetarian there often just mean no identifiable pieces of meat served in a dish. It was simply impossible (they reported) to maintain or become vegetarian there, without solitary cooking and eating.

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There appears to be a cultural battle going on over diet and its relation to mental health. I was able to find two studies presenting a contrary view to that in the OP and by Chinese authors, so that study is apparently part of the broader US antagonism towards China.

From virus to virtue: Veganism is growing fast in China following the trend in the West:

Tofu was invented in China.

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Yes. It’s interesting isn’t it. Although I don’t have access to the full science direct article that you link to, the abstract is suggesting that a high intake of fish (and low intake of animal foods) is included in their understanding of apparent association with a decreased risk of depression.

A dietary pattern characterized by a high intakes of fruit, vegetables, whole grain, fish, olive oil, low-fat dairy and antioxidants and low intakes of animal foods was apparently associated with a decreased risk of depression.

Looking at the op article this inclusion of fish flesh is less clear cut, but that’s probably because I can see more info.

In the second study that you provide it suggests

The quantitative synthesis of these observational studies showed that meat consumption might be associated with a moderately higher risk of depression. However, with respect to the prevalence of depression, no significant relationship was observed.

It then suggests

Obesity might mediate the effect of meat consumption on depression.

So that’s an interesting observation too. It is probably much easier to become obese as an omnivore.

I don’t understand your reasoning here.

I think the Dhamma diet has helped me most with my mental health :slight_smile:
Thanks for sharing friends.

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Maybe if dietary habits are addressed/researched within a certain culture a more accurate results can be produced. For example, if you spot a vegetarian within a community of meat consumers, it is very likely that there is something wrong with him/her as he/she would be off the chart. Whether we call him/her a genius or mentally sick does not matter as both are associated with eccentricity and melancholy.

And vice versa :popcorn:

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I have been a vegan for many years now (though I have started eating some tinned cod liver now, because of vitamin D which is supposed to help with covid 19) and I am very happy with my diet. I am probably a bit anxious (as shown by the fact that I started having more vitamin D in this stressful time :wink:) but I think I am all right.
Having said that I must admit that I once heard a very very great meditation master say that he got his best meditations usually when he ate steak, so perhaps meat does indeed have an influence on one’s mind.

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I wonder what hindrances are lessened by eating steak? I would’ve thought that for some eating a vegan diet would maybe reduce restlessness and remorse. Perhaps eating steak satisfied the meditation masters sensory desire temporarily? Or maybe it gave them some energy to dispel some sloth and torpur? :woman_shrugging:

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Yes I don’t know, perhaps it makes his body feel well and relaxed so that it can quickly disappear and he can go into his mind. Perhaps it’s not a universal thing because the monk in line after him is a vegan and claims that vegan food helps him with his own meditation, so probably it depends on one’s constitution.
I also must admit that I gave up being a vegan for a day when I heard that sentence about meat and good meditation, and went out and bought a steak to see if that helped me with my meditation, but it didn’t seem to, so I got back to being a vegan…

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I think this is relying on a good mood to get good meditation. When I eat tasty food I usually get a better meditation, and anything flavored with pork or bacon usually results in a good meditation for me because I love the taste.

I agree completely that it depends on your personal predilections on how food effects your mind and body and thereby your meditation. We know the Buddha drew a correlation with when you eat and eating healthy portions as important for practice. I also read in the Upanshids that is recommended people avoid eating spicy food (I think it appears in the Upanshid with Yama and boons?) because it gives them bad mental qualities not suitable meditation. I guess that spicy curries upset Indian stomachs sometimes too. :wink:

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That’s interesting. I also read about how flavours can affect mental qualities in Ayurveda. I certainly find that some types of food make me for example calmer than others.

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In DN.1, the Buddha dispelled all the views saying “conditioned by contact” tadapi phassapaccayā

Steak is good or veganism is good etc IMO fall under above category.
With Metta

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Visuddhimagga chap. IV, 34, 40:

[GUARDING THE SIGN]

  1. The arousing of the counterpart sign, which arises together with access
    concentration, is very difficult. Therefore if he is able to arrive at absorption
    in that same session by extending the sign, it is good. If not, then he must
    guard the sign diligently as if it were the foetus of a Wheel-turning Monarch
    (World-ruler.)
    […]

  2. Food: Sweet food suits one, sour food another.

  3. Climate: a cool climate suits one, a warm one another. So when he finds that
    by using certain food or by living in a certain climate he is comfortable, or his
    unconcentrated mind becomes concentrated, or his concentrated mind becomes
    more so, then that food or that climate is suitable. Any other food or climate is
    unsuitable.

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