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Jun 3, 2009 05:36 AM

new studies about vegetarians - moved from General Chowhounding board

ok the way people here will respond to this may prove them right
several new studies have shown a link between high IQ in children and vegetarianism(not nessessarly veganism) in their adulthood me i like my meat but so i am not expressing any opinion here has anyone heard anything more

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  1. Where might one find information about these "several new studies"? It's hard for me to have an opinion about something when I don't know what that something is.

    29 Replies
    1. re: small h

      Here's the study.

      The study attempts to show a relationship between high IQ in CHILDHOOD with vegetarianism in ADULTHOOD. It appeared in the British Medical Journal in 2007.

      BMJ. 2007 Feb 3;334(7587):245.

      IQ in childhood and vegetarianism in adulthood: 1970 British cohort study.

      Gale CR, Deary IJ, Schoon I, Batty GD.

      Medical Research Council Epidemiology Resource Centre, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD.

      OBJECTIVE: To examine the relation between IQ in childhood and vegetarianism in adulthood.

      DESIGN: Prospective cohort study in which IQ was assessed by tests of mental ability at age 10 years and vegetarianism by self-report at age 30 years.

      SETTING: Great Britain.

      PARTICIPANTS: 8170 men and women aged 30 years participating in the 1970 British cohort study, a national birth cohort.

      MAIN OUTCOME MEASURES: Self-reported vegetarianism and type of diet followed.

      RESULTS: 366 (4.5%) participants said they were vegetarian, although 123 (33.6%) admitted eating fish or chicken. Vegetarians were more likely to be female, to be of higher social class (both in childhood and currently), and to have attained higher academic or vocational qualifications, although these socioeconomic advantages were not reflected in their income.

      Higher IQ at age 10 years was associated with an increased likelihood of being vegetarian at age 30 (odds ratio for one standard deviation increase in childhood IQ score 1.38, 95% confidence interval 1.24 to 1.53).

      IQ remained a statistically significant predictor of being vegetarian as an adult after adjustment for social class (both in childhood and currently), academic or vocational qualifications, and sex (1.20, 1.06 to 1.36).

      Exclusion of those who said they were vegetarian but ate fish or chicken had little effect on the strength of this association.

      CONCLUSION: Higher scores for IQ in childhood are associated with an increased likelihood of being a vegetarian as an adult.


      Obviously, there are huge problems with the study.

      The number of vegetarians in the study was 366 people, or 4.5% of 8170 people.

      The number of true vegetarians was even less, 243 people, or 2.9% of 8170 people.

      How was the IQ measured in children?
      What test was given?
      How accurate was the test?

      A followup article published shortly after the study was published
      said that the association between vegetarianism and IQ
      was not about health, but about NONCONFORMITY.

      "Non-conformity may be hidden driver behind [the] relation[ship]."
      Kobe Millet and Siegfried Dewitte, BMJ 2007 334: 327-328.

      Another followup article was titled
      "Childhood intelligence and being a vegetarian"
      Please note thay several statistics have since been corrected.
      Marcus Richards, BMJ 2007 334: 216-217.

      Finally, Dr. Ramakant Sharma, a physician in India, makes an excellent point in his rebuttal letter to BMJ when he ponts out that vegetarian cultures and countries
      are not, as a whole, more intelligent than meat-eating countries.

      In his letter he writes that "IQ has nothing to do with vegetarianism." Sharma said that 60% of his fellow Indians are vegetarians and they are not more intelligent than his Western counterparts who eat meat.

      Sharma goes on to state that vegetarianism is a cultural phenomenon and it should be looked as that only. He gives the interesting statistic that in spite being vegetarians, Indians have a 7 times higher incidence of Coronary Artery Disease than Westerners.

      1. re: maria lorraine

        Thanks! Much as I would like to feel super-smart, as a fish-eating woman with high academic qualifications that are not reflected in my income, Dr. Sharma's response makes an awful lot of sense to me. And I share your suspicions about the IQ test itself. Standardized tests are a good measure of how well people perform on standardized tests. And not much else.

        1. re: maria lorraine

          >>He gives the interesting statistic that in spite being vegetarians, Indians have a 7 times higher incidence of Coronary Artery Disease than Westerners. <<<

          wow, that's astonishing.

          1. re: maria lorraine

            The non-conformity bit makes sense to me.

            1. re: maria lorraine

              Well, the things that struck me strange in the report (as reported here) is that there was no "control group" of children with "average" IQs to compare incidence of vegetarianism, and it also bothered me that the implication of the way things are worded is that children with a high IQ may or may not grow up to be intelligent adults. I could go on, but I quickly concluded that those who wrote and published the study must be in one of those "Publish or Perish" career fields. Not exactly a font of wisdom.

              1. re: Caroline1

                Its a study of a large cohort in which differences showed up over time. Perfectly OK.

                1. re: Sam Fujisaka

                  Right. That, and the differences that should have been obvious from the start. '-)

                  1. re: Caroline1

                    Yup. The starting point differences were defined by scores on standardized IQ tests. Monitoring of the stratified cohort over time found that there was a significant association between high early IQ testing and vegetarianism later in life. All legit!

                    1. re: Sam Fujisaka

                      I'm not saying it's not legit, Sam. And I am undoubtedly being something of a curmudgeon, but I don't like "data" passed to me in standard deviation format. I find it intellectually constipating.

                      But I did find this little morsel interesting: "Vegetarians were more likely to be female, to be of higher social class (both in childhood and currently), and to have attained higher academic or vocational qualifications, although these socioeconomic advantages were not reflected in their income." Is this a "glass ceiling" for women or for vegetarians? '-)

                      1. re: Caroline1

                        Standard deviations just tell you about the distribution of data around the mean. Although the statistical measures are OK, one would have to look at the study in more depth to be able to comment on the conclusions derived from the statistics.

                        1. re: Sam Fujisaka

                          Eggzackitally! Standard deviations are fluff.

                          1. re: Caroline1

                            Maybe you can be hired to deal with stuff like:

                            El Adlouni, Salaheddine and Taha B Ouarda. 2009. Joint Bayesian model selection and parameter estimation of the generalized extreme value model with covariates using birth-death Markov chain Monte Carlo. Water Resour. Res., Vol. 45, No. 6, W06403.

                            1. re: Sam Fujisaka

                              They're wasting their time, Sam. EVERYONE knows that EVERYTHING is 6 degrees from Kevin Bacon! As long as no one messes with my quark in a jar, I'm a happy camper.

                        2. re: Caroline1

                          Tidbits from the study:

                          There was a difference of 5 points in the IQ between vegetarians vs. non-vegetarians.

                          No differences were found between strict vegetarians and those who consumed fish or chicken.

                          Vegans' IQ scores were nearly 10 points lower than other vegetarians.

                          Vegetarians were more likely -- as caroline1 mentioned --
                          to be female
                          to be of higher social class (both in childhood and currently), and
                          to have attained higher academic or vocational qualifications

                          Maybe it's just me, but this makes me want to ask all kinds of questions.

                          5 whole points?
                          No diff in IQ between vegetarians and those who ate fish or chicken?
                          So vegetarians are smarter than vegans?
                          What happened to the men?
                          Does a study of 366 people prove anything that is definitive worldwide?
                          Is this study more a reflection of cultural programming in Britain than intelligence? (like dr. sharma was saying)
                          Were the Brit IQ tests given in 1970 accurate?
                          Is the vegetarianism a reflection of IQ or nonconformity, or of familial or cultural or peer programming? Or does it reflect a concern about health or calories or some other thing?

                          And, like I said, maybe it's just me...
                          but anything that infers eating a certain way makes someone smarter or better or more ethical makes me wanna scream.

                          The complete study (.pdf file) can be downloaded here:

                          1. re: maria lorraine

                            A causal relationship was not claimed. There was an association between high childhood IQ testing and adult vegetarianism. The study had nothing to do with eating something making you smarter. Your further queries are all good; and the researchers probably thought about all of the same things in order to explain that association. As to the five point difference, that is a simple statistical question as to if it represents a significant (i.e., non-random) difference.

                            1. re: maria lorraine

                              'Scuze me while I say a few swear words. I had a longish, well-reasoned response written and hit the wrong key and it's now floating somewhere in cyberspace. Sh*t...!!!!

                              Okay. Calm yourself, Caroline.

                              Five points difference in IQ scores is ridiculous, and a good example of why I don't like results for any study disclosed by "standard deviation". Five fishes to feed a crowd is impossible to anyone except Jesus, but five IQ points is insignificant! "Standard deviation" can be used to obscure questionable conclusions, and I think that's the case here.

                              The thing that many people, including academics and researchers, don't seem to fully understand is that one's IQ is NOT an inflexible state. I can teach anyone with an IQ above 90 and older than four how to raise their IQ score by five points in a week or two. Some can learn in hours.

                              One's IQ fluctuates all through the day, as well as all through life. It's not a huge fluctuation (short of serious brain injury), but it does fluctuate. There are tons of factors that impact on how well or poorly one does on an IQ test. Things such as anxiety level, how rested they are, whether they have been listening to specific types of classical music (pastoral music doesn't work as well as a toccata, for example) just prior to the test, whether they are really hungry or really full, do they need to go to the bathroom? All sorts of things have an impact, and some can modify the end score of the test by 5 IQ points easily.

                              And then there is the thing that few take into consideration: An IQ score ONLY identifies the smart people who get the answers within the time frame. NO points given to those smart people who come up with 100% of the correct answers AFTER the bell rings! There is a Nobel Laureate in Medicine (names are my Waterloo!) who is quite proud of his 115 IQ. And rightfully so. On the other hand, I have an exceptional IQ, but no Nobel Prize! But he, with his Nobel Prize, or I, with my exceptional IQ, can get ourselves cup of coffee for around five bucks at any Starbuck's on the planet. Well, if they know who he is, more likely his coffee will be comped. Oh, and for the record, I consider my IQ my primary birth defect. Any time you're born with something outside the norm, it is technically a birth defect and can work as a handicap.

                              So back to an opinion I voiced above: This test looks like the work of "Publish or Perish" academicians and researchers. Or as Shakespeare put it, "Much Ado About Nothing."

                              1. re: Caroline1

                                Again standard deviation is simply a measure of distribution around the mean. Deciding whether or not five points is significant is a done using simple statistics, not by opinion. Significance simply says that something observed was not a random difference. All the research said is that there is an association between high childhood IQ testing and adult vegetarianism. What the result means can be debated; and that may have been the reason for publishing - to stimulate possibly usefull discussion, including the validity of IQ tests. But there is no need to criticize statistics and statistical analyses: all publications have to show the statistics used and how inferences or conclusions were drawn. Others who are interested can easily check if the stat analysis was done properly.

                                1. re: Caroline1

                                  Hey, buddy! It must be hot and high summer in Plano. Turn on the aircon because:

                                  I'm not attacking or arguing with you at all. The study in question may be seriously flawed. All I'm saying is that the statistics probably are not. What one infers from the statistics is another question. Stats are a way of dealing with often small differences that are quantitatively continuous but often patterned around a mean. How variable that distribution is and how much is clustered around the mean gives you the SD or coefficient of variance. Statistical significance simply means that an observed patterns was not random at specified confidence levels. Simple, innocent statistics.

                            2. re: Caroline1

                              "Is this a "glass ceiling" for women or for vegetarians? '-)"

                              Perhaps it reflects the possibility that vegetarians are less aggressive than meat-eaters, and this carries over to not pursuing higher power and pay in their careers.

                              1. re: BobB

                                Bob--you may have met different vegetarians; many of the vegetarians I know, particularly vegans, are far more aggressive than the omnivores I've met!

                                1. re: BobB

                                  Jfood has found that most meat eaters are much more accepting of vegetarianism than vice versa. Granted there may be a bit more fun-poking from the meat eaters but the quid pro quo is that many vegetarians are downright critical while eating with a meat eater than vice versa.

                                  1. re: jfood

                                    I've seen that too, and I did preface my remark with "perhaps." But other than vehemently (defensively?) insisting that theirs is the right dietary choice, I don't find most vegetarians overly aggressive in general, and many overtly espouse a "walk gently upon the earth and do no harm" approach of which vegetarianism is just a part.

                                    1. re: BobB

                                      Generalizations about vegetarians are rubbish. Vegetarians are simply PEOPLE. There are nice ones and nasty ones, some with high IQs and some with low IQs (as with omnivores). Some are vegetarians for moral or health reasons, others for fashion (and don't even get me started on the ones I've met and have known who wear high end leather, don't recycle, drive inefficient vehicles, the list goes on). Some only wear vinyl and recycled cotton. It's not an all or nothing lifestyle and there are variations.

                                      A well known dictator whose antics helped start WWII was a vegetarian and teetotaler who loved animals.

                                      1. re: Caralien

                                        I take it you don't subscribe to any of the arguments about diet affecting temperament, then?

                                        1. re: BobB

                                          : )

                                          Diet and lifestyle may affect health and digestion, but genetics and upbringing/environment (nature and nurture) are more likely to affect temperment.

                                          Steve Jobs is a vegetarian, and far from mellow or even tempered, but a creative genius, nonetheless.

                                2. re: Caroline1

                                  There are probably certain jobs/types of jobs (both high-paying and otherwise) that vegetarians are unwilling to take/don't want, depending of course, upon their reasons for becoming vegetarians.

                      2. It's a simple correlation. Deciding to become vegetarian is a decision based upon reason and knowledge. For example, one may decide not to eat meat out of concern for one's health or concern for the treatment of animals, etc. Each of those conclusions requires a deductive process. I would not be surprised if a significant number of those children with high IQs elect not to be vegetarians based upon the same process. The point that the data really proves is that children with low IQs are unlikely to become vegetarians, since they are unlikely to engage in thoughtful consumption.

                        Edited to disclose that I am a carnivore.

                        2 Replies
                        1. re: MGZ

                          Choosing to be a vegetarian is a personal decision, but doesn't necessarily require much intelligence or thought. I knew someone who blamed Arby's for becoming ill, and changed his diet to simply be the same garbage he normally ate without meat (Domino's 4-5x per week, for example, hold the pepperoni). I also knew lifelong vegetarians who were never particularly sharp (this group would have been avoided in the study, not being affluent).

                          There have always been eloquent speakers who can convince those of any intelligence level to believe something, true or not (look at trends and fashion, food or otherwise). This removes the need for deductive reasoning.

                          That said, vegetarianism in all forms is great when chosen for the right reasons and followed in a sensible, non-alienating way.

                          1. re: MGZ

                            Plenty of people are veg because that is what their culture dictates, and it's no more a "decision" than the daily bath. Becoming veg *is* a decision in Western cultures where meat is widely consumed and available, like the United States or Great Britain, yes, but not everywhere.

                          2. My guess based on no research whatsoever (so take it for what it is), is perhaps that it is simply more likely that persons with higher IQ's are more likely to evaluate their diet and have a reason for choosing as they do, which would increase the chance of changing it (for instance eliminating meat).

                            So I'd agree with MGZ when he/she says that it is the dietary evaluation that is the main correlation, vegetarianism being a secondary caused by the primary. There's an "extra step" there for the tangent of people who after careful consideration remain omnivorous.

                            1. The original comment has been removed
                              1. Well since people are trying to purport this as a more intelligent choice, I'll offer up the notion that it's because higher IQ people hang around in loftier circles more often than not. They're more likely to be the kind to keep up with the Jones's. Or more to the point, they feel the need to have a holier than thou attitude.

                                The mere fact that I had originally spelled intelligent wrong should be enough to show you I'm a meatitarian.


                                1 Reply
                                1. re: Davwud

                                  So wait- people with higher IQs are more likely to try to keep up with the Joneses and be holier than thou? Where the heck do you get that conclusion from?!

                                  It's been said, and I generally agree, that a high IQ means nothing more than being really good at doing IQ tests.

                                  But to bring it back to the question of food, I must say that the vegetarians I've met here in England are way less likely to be holier than thou than the American vegetarians I've known. They seem to have a way more un-preachy, live-and-let-live attitude, whereas the many American vegetarians I have known can't seem to resist trying to make people feel bad for eating meat. Not sure why that is.