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BBC: Science Suggests That Being a Vegan Will Make You An Idiot

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How a vegan diet could affect your intelligence

The vegan diet is low in – or, in some cases, entirely devoid of – several important brain nutrients. Could these shortcomings be affecting vegans' abilities to think?


Instead, the only research that comes close involved the reverse. It was conducted on 555 Kenyan schoolchildren, who were fed one of three different types of soup – one with meat, one with milk, and one with oil – or no soup at all, as a snack over seven school terms. They were tested before and after, to see how their intelligence compared. Because of their economic circumstances, the majority of the children were de facto vegetarians at the start of the study.

Surprisingly, the children who were given the soup containing meat each day seemed to have a significant edge. By the end of the study, they outperformed all the other children on a test for non-verbal reasoning. Along with the children who received soup with added oil, they also did the best on a test of arithmetic ability. Of course, more research is needed to verify if this effect is real, and if it would also apply to adults in developed countries, too. But it does raise intriguing questions about whether veganism could be holding some people back.

In fact, there are several important brain nutrients that simply do not exist in plants or fungi. Creatine, carnosine, taurine, omega-3, haem iron and vitamins B12 and D3 generally only occur naturally in foods derived from animal products, though they can be synthesised in the lab or extracted from non-animal sources such as algae, bacteria or lichen, and added to supplements.

Others are found in vegan foods, but only in meagre amounts; to get the minimum amount of vitamin B6 required each day (1.3 mg) from one of the richest plant sources, potatoes, you’d have to eat about five cups’ worth (equivalent to roughly 750g or 1.6lb). Delicious, but not particularly practical.

And though the body can make some of these vital brain compounds from other ingredients in our diets, this ability isn’t usually enough to make up for these dietary cracks. For all of the nutrients listed above, vegetarians and vegans have been shown to have lower quantities in their bodies. In some cases, deficiency isn’t the exception – it’s completely normal.

For now, the impact these shortcomings are having on the lives of vegans is largely a mystery. But a trickle of recent studies have provided some clues – and they make for unsettling reading.

“I think there are some real repercussions to the fact that plant-based diets are taking off,” says Taylor Wallace, a food scientist and CEO of the nutrition consulting firm Think Healthy Group. “It’s not that plant-based is inherently bad, but I don't think we're educating people enough on, you know, the nutrients that are mostly derived from animal products.”

One of the most well-known challenges for vegans is getting enough vitamin B12, which is only found in animal products like eggs and meat. Other species acquire it from bacteria which live in their digestive tracts or faeces; they either absorb it directly or ingest it by snacking on their own poo, but unfortunately (or fortunately, depending on how you look at it) humans can’t do either.

Later in life, the amount of B12 in a person’s blood has been directly correlated with their IQ

To see how crucial B12 is for the brain, take what happens when we don’t get enough of it. In children, the consequences of B12 deficiency can be life-altering. “There are some tragic cases of children whose brains failed to develop because of their parents being ill-informed vegans,” says Benton. In one example, the child was unable to sit or smile. In another, they slipped into a coma.

Later in life, the amount of B12 in a person’s blood has been directly correlated with their IQ. In the elderly, one study found that the brains of those with lower B12 were six times more likely to be shrinking.

Even so, low B12 is widespread in vegans. One British study found that half of the vegans in their sample were deficient. In some parts of India, the problem is endemic – possibly as a consequence of the popularity of meat-free diets. 

Another nutrient that’s scarce in the typical vegan diet is iron. Though we often associate it with blood, iron also plays prominent role in brain development, and is essential for keeping the organ healthy throughout our lives. For example, one 2007 study found that giving young women iron supplements led to significant intellectual gains. In those whose blood iron levels increased over the course of the study, their performance on a cognitive test improved between five- and seven-fold, while participants whose haemoglobin levels went up experienced gains in their processing speed.



Though there are small amounts of taurine in some dairy products, the main dietary sources are meat and seafood. “Some species have the ability to make all the taurine they need,” says Jang-Yen Wu, a biomedical scientist at Florida Atlantic University. “But humans have a very limited capacity to do this.”

For this reason, vegans tend to have less taurine in their bodies. No one has looked into how this might be affecting their cognitive abilities yet, but based on what we know about its role in the brain, Wu says vegans should be taking taurine tablets. “People can become deficient when they restrict their diets, because vegetables have no taurine content,” he says.

In fact, the holes in our current understanding of what the brain needs to be healthy could potentially be a major problem for vegans, since it’s hard to artificially add a nutrient to yo



Take choline: in the brain, it’s used to make acetylcholine, which is involved in a number of tasks, including relaying messages between nerve cells. It’s fundamental to our ability to think – even insects have it in their tiny brains – and the body can’t produce enough of it on its own. 

And yet: “It’s a very understudied nutrient,” says Wallace. “I believe we've only considered it essential [something you have to get from your diet] since the late 1990s.”

There are small amounts of choline in lots of vegan staples, but among the richest sources are eggs, beef and seafood. In fact, even with a normal diet, 90% of Americans don’t consume enough. According to unpublished research by Wallace, vegetarians have the lowest intakes of any demographic. “They have extremely low levels of choline, to the point where it might be concerning,” he says. 

For vegans, the picture is likely to be bleaker still, since people who eat eggs tend to have almost double the choline levels of those who don’t. And though the US authorities have set suggested intakes, they might be way off.  

Wallace points to a 2018 study, which found that the babies of women who consumed twice the amount considered “adequate” – around 930mg each day – in the last third of pregnancy enjoyed a lasting cognitive edge. For comparison, the average vegetarian gets roughly a fifth of that amount.  



The latest nutrient in question is creatine – a white, powdery substance often found in fitness shakes. Its natural function in the body is to supply our cells with energy, so it’s revered by gym obsessives as a way to improve their endurance.

But it’s also important to the brain – and studies have shown that increasing your intake can provide a range of benefits, such as a better recognition memory and reduced mental fatigue. Recently it’s started to gain traction as a smart drug.

It’s well-established that vegans and vegetarians have significantly lower levels in their bodies, because plants and fungi don’t contain any.

This has led scientists to wonder whether a creatine deficit could be holding some people back. For one study, researchers tested how the intelligence of vegetarians and omnivores changed after five days on supplements. “We found that the vegetarians seemed to benefit particularly,” says David Benton from Swansea University, who led the research. 

In contrast, the omnivores were relatively unaffected. This hints that, unlike the vegetarians, they already had the appropriate amount of creatine in their brains.



Though vegans can take supplements, he thinks it’s unrealistic to expect that they all will. Consequently, he finds the recent shift towards plant-based diets troubling, though he’s sympathetic to the arguments for doing so. “Without question, veganism can cause B12 and iron deficiencies, and without question they affect your intelligence,” he says.


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The article lead in...



The vegan diet is low in – or, in some cases, entirely devoid of – several important brain nutrients. Could these shortcomings be affecting vegans' abilities to think?


Text from the discussion in the paper...



Although the results do not allow clear conclusions to be made about the mechanisms underlying the effects of supplementation on cognitive development, they suggest that meat provides a more bioavailable source of micronutrients than the other supplements. Alternatively, or in addition, meat may provide micronutrients that are particularly deficient in this population of children.




Although food intake is a crucial factor contributing to the cognitive development of children in developing countries, one of the primary deficits in many previous studies examining the associations between nutrition and cognitive development is the limited attention paid to contextual factors. In addition to nutritional intake, data from this study also highlight the important effects of SES and maternal literacy on child cognitive outcomes. Regardless of the supplemental diet, children from higher SES families and children with more literate mothers showed superior performance on all the cognitive measures. Correlations between SES and nutrient intake are generally strong, with children from higher SES families likely to have more and better quality food available in the household.


Truly shocking results.

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If we’re gonna use anecdotal evidence, one of my most intelligent coworkers is vegan. And another one of my very bright and creative friends is vegan.


And I will never understand how people put so much mental energy into caring about the diets of other people. Just eat what you want and let others live their own damn lives. Let vegans be vegans.

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13 minutes ago, sexy_shapiro said:

And I will never understand how people put so much mental energy into caring about the diets of other people. Just eat what you want and let others live their own damn lives. Let vegans be vegans.

Again, only anecdotally, but it’s not the neater eaters in my life constantly posting about the superiority of their diet on biological and moral/ethical grounds :p 

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