Study finds vegetarians have smaller brains

December 3, 2008 in Food & Nutrition | 18 comments

brainFrom a brief article at Barry Groves’ Trick and Treat blog:

Scientists at the Department of Physiology, Anatomy and Genetics, University of Oxford, have discovered that going veggie could be bad for your brain – with those on a meat-free diet six times more likely to suffer brain shrinkage.

The study involved tests and brain scans on community-dwelling volunteers aged 61 to 87 years without cognitive impairment at enrolment, over a period of five years. When the volunteers were retested five years later the medics found those with the lowest levels of vitamin B12 were also the most likely to have brain shrinkage. It confirms earlier research showing a link between brain atrophy and low levels of B12.

Vegans are the most likely to be deficient because the best sources of the vitamin are meat, particularly liver, milk and fish.

This study confirms other findings, covered in Trick and Treat, which shows that overall human brain sizes have reduced by an average 11% since we adopted an agricultural diet based on cereal grains rather than the meat-based diet of our Palaeolithic ancestors.

Vogiatzoglou A, et al. Vitamin B12 status and rate of brain volume loss in community-dwelling elderly. Neurology 2008; 71(11): 826-32.


Gianna December 3, 2008 at 6:02 pm

I didn’t see a link to a study anywhere??? and couldn’t find one when I did a google search??

did you look for the study? I’d like to cite this on my blog but won’t do it based on what some random blogger says…I’d like the source if you have it?

Gianna December 3, 2008 at 6:04 pm

sorry…I found the pubmed absract here:

you did give the source at the end of your piece but no link and that is what I was looking for….I’m too damn internet based…didn’t even see it…


resa_challender March 31, 2011 at 4:44 pm

Chuckled at this, since I do the same thing often myself.

zak December 20, 2008 at 5:54 pm

interesting and potentially compelling, but doesn’t this study seem a bit limited due to the fact that they were looking at brain sizes in elderly people?   i’m also curious to know the sample size.

it seems that much more research would be required in order to make statements as far reaching as the title of this post…. 

Ben August 31, 2009 at 4:39 pm

I used to believe stuff like this…but it’s REAL easy to see why they are flawed.

The author is making a false comparison of people with low B12 with being vegans. Vegans are NOT more likely to be deficient in B12 if they are eating correctly. We find meat eaters and vegans alike with deficiency. In other words, claiming “Study shows vegetarians have smaller brains” is just plain lying.

resa_challender March 31, 2011 at 4:47 pm

My first thought was to think “racist” And I’m a VLC/ZC/Paleo kinda eater me’self.

Dana Seilhan April 1, 2011 at 11:05 pm

You have to supplement as a vegan to get B12. It’s not present in plant foods. And if you don’t know you’re supposed to get the methyl form instead of the cyano form, you’ll burn through your reserves and wind up in trouble.

At least if you eat beef you get the proper form. One of my favorite cuts is flat iron and that’s a great source, for being a muscle meat (somewhere in the vicinity of the shoulder, I believe).

Noah F July 1, 2010 at 12:50 pm

The author could use a little help “challenging mainstream myths about nutrition, health and disease,” notably the assumption relied upon in the title: that vegans or vegetarians are deficient in B12. Every vegan or vegetarian that has a brain knows that these are important vitamins to supplement as they are of the few that are insufficient in plant based foods, especially if they are raising kids. If you go to the actual study:
You will find there is no reference to “vegetarians” in the study description, only to B12 levels, so even though you skillfully copied the title and speculation of another article, there is no basis for your assumption that any of the elderly community studied was vegetarian and the study only has bearing on B12 deficiency. So, yes, there are negative consequences to vitamin deficiencies, thanks for the brilliant conclusion.

Chris Kresser July 1, 2010 at 1:12 pm

Countless studies demonstrate that vegetarinans, and vegans, are B12 deficient. Some studies show up to 58% of vegetarians are deficient. Despite your claim that they know they need to supplement, they obviously aren’t supplementing enough.

I think that’s enough to make the point.

Dana Seilhan April 1, 2011 at 11:04 pm

And when they do they probably supplement with cyanocobalamin, which is the more commonly available supplemental form, even though it doesn’t do you as much good and it blocks absorption of the methyl form of B12, which is the form we actually need.

Yeah, it’s a supplement dealer, but the description and explanation are pretty good.

Pamina July 8, 2010 at 10:08 pm

does it matter? Some of the most influential and effective thinkers on earth were vegetarian. One of the mentally sharpest nation on earth – India – is traditionally and culturally vegetarian.

andy July 9, 2010 at 2:26 pm

In a study published three years ago, also in the American Journal of Clinical Nutrition, she found that nearly 40% of 3,000 adults under age 50 had blood levels of vitamin B12 low enough to cause problems.
So b12 is not vegan problem and it can be easily avoided taking b12 supplement.

ani July 9, 2010 at 3:18 pm

My understanding is that there are actually less vegetarians than not in India, and most of those who are, are lacto-vegetarian.

M C September 12, 2010 at 9:28 pm

This is complete fiction; the study says nothing about vegetarians or vegans.

Dana Seilhan April 1, 2011 at 10:58 pm

They’re less likely to get the proper form of B12 in their diets. You have to supplement B12 particularly on a vegan diet, and if a vegan doesn’t know they should supplement with methylcobalamin, they’re kinda screwed.

Linda Fox April 15, 2011 at 12:58 pm

Chris, there are vegetarians, and then there are VEGANS. And there are vegans who SUPPLEMENT, and those who are sadly too ignorant to do so.

Please make it clear what you are presenting … I am a vegetarian (who supplements B12), but I also want clearly-stated, well-reasoned support for Low-Carb diets, including Paleo!

Otto Gerardo Gómez Pernía April 21, 2011 at 5:51 pm

I would like to see more data related to this article. Meat eater´s Capuchine monkeys in Venezuela´s llanos have larger brains and are very much smarter than their leaves eaters relatives Howler (Araguato) monkeys. Meat´s sugar fuels the brains.

Mark Sip April 22, 2011 at 6:18 pm

Considering that there is a substantially greater percentage of vegetarians/vegans who are liberal progressive Democrats as a opposed to who are conservative Republicans, I often wondered if there wasn’t some type of cause and effect relationship here. This study which discovered impaired mental capacity in vegetarians as compared to meat eaters tends to confirm that suspicion.

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