Vegetarians more likely to be depressed than meat-eaters, but why?

[Bryn]

https://theconversation.com/vegetarians-more-likely-to-be-depressed-than-meat-eaters-possible-reasons-191707?utm_medium=email&utm_campaign=Latest%20from%20The%20Conversation%20for%20October%206%202022%20-%202422424212&utm_content=Latest%20from%20The%20Conversation%20for%20October%206%202022%20-%202422424212+CID_acecc5fa430e0702792cfaf26f67b305&utm_source=campaign_monitor_uk&utm_term=Vegetarians%20more%20likely%20to%20be%20depressed%20than%20meat-eaters%20%20possible%20reasons

[smittims]

I haven't read thi subject in any depth, but I'm always sceptical about conclusions drawn from a 'study'. It's difficult to know how representative was the sample, and how many factors weer taken into consideration .

There are many reasons why one person is more depressed than another. I imagine I'd feel life was dull if I denied myself meat, even though I eat only a little (two sausages with a lot of vegetables, for instance).

The only vegetarian I knew well was a very red-faced, excitable man who spoke passionately on the subject. he was also short-tempered in daily life. I couldn't say if this was a result of his vegetarianism or the reason why he adopted a vegatarian diet, to try to improve his equanimity.

[Joseph K]

Thanks for the thought-provoking article, Bryn. I'm vegetarian and have been since I was 16, fortunately I'm not depressed, though I have been in the past.

[Eine Alpensinfonie]

We get “studies” like this seemingly all the time, usually in places like the Daily Express, and hardly worth the electrons they’re imagined on. As a teenager, I became very depressed when the gulf of agricultural land use was, between feeding meaty eaters and vegetarians was revealed to me. I felt much better when ai dropped the meat at the age of 20, and have felt much more optimistic since then.
Socially, it hasn’t made any difference. It’s sometimes necessary to tell people you’re a vegetarian, but that can be interpreted by some as the equivalent of saying you have perfect pitch. However, nowadays vegetarianism and vegan Ian are so common that it’s become widely accepted.

[Dave2002]

I haven't read thi subject in any depth, but I'm always sceptical about conclusions drawn from a 'study'. It's difficult to know how representative was the sample, and how many factors weer taken into consideration .

There are many reasons why one person is more depressed than another. I imagine I'd feel life was dull if I denied myself meat, even though I eat only a little (two sausages with a lot of vegetables, for instance).

The only vegetarian I knew well was a very red-faced, excitable man who spoke passionately on the subject. he was also short-tempered in daily life. I couldn't say if this was a result of his vegetarianism or the reason why he adopted a vegatarian diet, to try to improve his equanimity.

The study referred to only identified 82 members of the vegetarian group according to the article out of a very much larger population of people identified as not being vegetarian. The total sample size was over 14,000, so the vegetarian group was less than 1% of the total sample population.

[Bryn]

We get “studies” like this seemingly all the time, usually in places like the Daily Express, and hardly worth the electrons they’re imagined on. As a teenager, I became very depressed when the gulf of agricultural land use was, between feeding meaty eaters and vegetarians was revealed to me. I felt much better when ai dropped the meat at the age of 20, and have felt much more optimistic since then.
Socially, it hasn’t made any difference. It’s sometimes necessary to tell people you’re a vegetarian, but that can be interpreted by some as the equivalent of saying you have perfect pitch. However, nowadays vegetarianism and vegan Ian are so common that it’s become widely accepted.

At least the study referred to was based on more than one person's experience. To me, the main point is that the study, through its methodology, ruled out the potential role of nutritional properties of the competing dietary approaches. A useful reminder of the problems of attributing cause and effect, too.

[duncan]

An association between vegetarianism and low mood has been reported for at least 40 years, although not all studies find this. I suffer from low mood intermittently and I was once advised by a psychiatrist to eat more meat. Most of the research has been done in high income countries where, until recently, eating meat was the norm and vegetarians are the dietary avant guard (or experimental!). It would be interesting to look at countries where vegetarianism is the rule rather than the exception.

If meat eating was protective against low mood it is likely there would be a dose-dependent response: the more meat you eat, the jollier you become. Despite the image of Falstaff, this has not been reported. It is therefore unlikely that vegetarianism causes depression, more likely another factor (a confounder in the jargon) separately 'causes' both vegetarianism and low mood. If I had to guess - and this hasn't been investigated yet - this factor would be something to do with moral commitment aka giving a damn about the world.

[LHC]

This appears to be another instance of the difference between causation and correlation; a common factor in many studies such as this.

I was also going to say that Brazil might be an odd choice of location for a study of vegetarianism as I assumed it has a predominantly meat-based diet. A little bit of research suggests that around 14% of its population is vegetarian, which apparently is a similar percentage to the UK (I would have thought the numbers in the UK would be higher than this). In any case, as Bryn has noted the higher incidence of depression can't be attributed to nutritional factors, so vegetarianism doesn't cause depression. It is more likely that there is another factor shared by vegetarians and those with depression.

[richardfinegold]

The best estimates are that 50% of people will have at least one major depressive event in their lives, and most will have more than one. One frequent time for the first episode to occur is late teens/early twenties. My guess is that this is also a time when many people first adopt vegetarian lifestyle. I doubt that there is causation, more likely a correlation

[french frank]

The study explicitly says the study did not show a nutritional connection between vegetarianism and depression ("the new study suggests that this link exists independent of nutritional intake"). Joseph K has his own reasons for being a vegetarian. He might pigeonhole me, accurately, as a flexitarian

The total sample size was over 14,000, so the vegetarian group was less than 1% of the total sample population.

I think the base point is that the smaller the 'population' size (as in very small) the larger the sample needs to be. The larger the population, the smaller the sample size (if not random). A larger than necessary sample adds nothing to the accuracy of the result.

When I want to amuse myself I count the number of forum members online and work out what percentage of those known by me to have been 'registered' FoR3 supporters and it almost always turns out to be about 20% (but the fewer online the more likelihood of a blip). Currently of 36 online, I can count 8 FoR3ers, or 22%.

[Sir Velo]

I think the base point is that the smaller the 'population' size (as in very small) the larger the sample needs to be. The larger the population, the smaller the sample size (if not random). A larger than necessary sample adds nothing to the accuracy of the result.

Regardless of whether your sample population of 14,000 is larger than necessary, you should at least have a representative cohort of vegetarians if your study is to stand up to scientific scrutiny. In this case, however, it seems that the sample was not representative given that 14% of the wider population of Brazil are vegetarian as opposed to 1% of the sample population.

[french frank]

In this case, however, it seems that the sample was not representative given that 14% of the wider population of Brazil are vegetarian as opposed to 1% of the sample population.

But wouldn't they compare the two sections separately: frequency of depressive episodes among vegetarians compared with frequency of same in meat-eaters?