You ARE what you eat. At least, your brain is. Anyone surprised?

Jul 20 2011 Published by under Behavioral Neuro, Neuroscience

A tweet via @Vaughnbell yesterday shared this paper, and I just couldn't let it go by. Sigh. So very much to blog, so very little time.

I don't know how you all feel about breakfast, but for Sci, it's a little essential. I NEED it. If I don't get breakfast by 10am I am a ravening hunger beast appeased only by large amounts of coffee and Snickers. In fact, even WITH breakfast this happens. There's just no way to really be sure.

I wasn't always this way. In fact, in middle school and high school, you were lucky if I also ate LUNCH. No breakfast, no lunch. Yeah, by the end of the day I often had no energy, was grumpy, and no fun to be around. But I was also a teenager, so I have to figure most people didn't notice anything. 🙂 In fact, it wasn't until grad school that I began to really comprehend the importance of having something with the coffee in the morning. It made me feel better, gave me higher energy...and it even made me a little sharper.

But now I look back upon my breakfast-less ways with suspicion. Could they have hurt more than my energy? Could I have missed out on something important?! Was a little lady-Einstein just SITTING in my head waiting to get out, and I will never know because my breakfast...CHANGED MY BRAIN?

Taki et al. "Breakfast Staple Types Affect Brain Gray Matter Volume and Cognitive Function in Healthy Children" PLoS ONE. 2011.


I think we've heard this one before.

(Source. Used under Creative Commons License)

(Also, I'd like to all to know that Sci ate breakfast as she read this paper. Just in case, you know.)

We all want our kids to succeed, to achieve to the best of their potential. Heck, I'm sure we all wouldn't mind if our kids were really smart. We want them to do well in the world, and smartness often helps there. We know some aspects of academic success can be affected by things like practice, homework, individual attention, genetics, etc, etc.

But what about the part controlled by breakfast?

Here's the deal. Breakfast is good for kids. There's lots of studies out there showing that a good breakfast improves cognitive performance in school children. The question then becomes one of HOW this works. IQ performance is realted to grey matter size in several other studies and in several brain regions. So the authors of this study took three groups of school kids (ages 5-18), and asked what they generally ate for breakfast. They gave them cognitive tests, and stuck them in an fMRI.

This was in Japan, so the major breakfast staples were white rice and white bread. Rice? This actually isn't unusual, only in the US and other Western countries is breakfast composed of items you wouldn't eat at any other time of day. In most areas of the world, breakfast is just what you have on hand. In this case, their groups of kids tended to eat either rice, bread, or both.

They did various kinds of IQ tests, including verbal and performance, as well as assessing verbal comprehension, processing speed, and working memory. And here's what they got:

The kids who had rice for breakfast showed higher grey matter volumes than those who had bread. The authors of the study related this to cognitive performance, and said that the rice group had higher IQ scores and POI scores compared to the bread group. The authors believe this to be because rise has a lower glycemic index score than white bread. Glycemic index is a measure of blood glucose after you eat something. High glymcemic index scores are for things like sugar, there and gone in a few minutes, creating a high blood glucose spike and then disappearing. Low glycemic index scores are for things like peanut butter, lots of protein, takes longer to digest. It's a slower blood glucose increase, but it'll stay around a lot longer. The idea is that things of low glycemic index are better for keeping your energy and cognitive levels up over the long term, because the low sustained increase in blood glucose keeps a steady supple of glucose going to the brain.

How does this relate to this study? The authors hypothesize that lower glycemic index foods provide better glucose support to the brain and thus better cognitive function, and that these lower glycemic index foods will...increase your grey matter. Change your BRAIN.

How many times have I heard this before. Hormones change your brain. Exercise changes your brain. Breathing changes your brain. Did you know that after reading this blog post, you will show increased grey matter in the cynicus nucleus of the sarcastic complex? It CHANGES YOUR BRAIN, people.

But of course, these are our kids, right? We want to give them the best possible edge, and so we want to make sure their breakfasts have low glycemic index, increasing their grey matter, and enhancing the odds that 100% of our little tykes will go to Harvard.

As you can tell, I've got a few issues with this paper. Here we go.

1) The breakfast was SELF-REPORT. They just asked the kids what they GENERALLY ate for breakfast. These are kids, kids ages 5-18. And I'll be honest, I can't remember what I had for breakfast freakin yesterday. I think the variables in this study would be much better controlled if they provided breakfasts of various types to the kids.

2) They didn't state WHEN they did the fMRI and IQ testing, etc. Was it in the morning? How can they really be sure, even though they controlled for things like socio-economic status, that it's really BREAKFAST that's doing it, if they aren't feeding them breakfast themselves, and then checking them at a specific time point afterward? I think this would be a lot cleaner if they fed the kids breakfast every day for a month or two and then did some cognitive testing before and after, along with the fMRIs. Get some baselines, see if people improve or not.

3) How does this compare to no breakfast at ALL? Many high school age children in particular don't eat breakfast. Does this impact things? Definitely possible to take this variable into account.

4) What about higher glycemic indexes? Sure rice is lower than white bread (most things are) but what about, say, eggs? Another study has shown improvement in attention with low glycemic index breakfast foods in kids. But these were all CEREALS. Always with the carbohydrates. What about eggs? Maybe an egg McMuffin just beats em all. This is a variable that's easy to introduce, as long're feeding them breakfast and not relying on self-report.

5) And speaking of self-report. They studied the correlations only with the MAIN GRAIN the kids consumed. None of these kids were just eating white rice or white bread for breakfast. Many were having protein, fruit, tea. These will change the overall glycemic index of the MEAL and may have a bigger impact on cognitive functioning than whether your base was rice or bread.

6) I don't find the fMRI stuff all that compelling. Ooooh, changes in grey matter. You're going to find that if you compare red and blue Matchbox toys at this point. No, it's the cognitive performance that is important here. Though they SAY they got significant differences in various IQ measures (specifically full IQ and POI), I don't see that graphed anywhere, and the numbers they present in the table of IQ findings actually don't appear to be significantly different (and in fact aren't even listed at significantly different). Observe:

7) Are the changes in grey matter effective because of BREAKFAST? Or because the people who show them are eating mostly foods that have a high glycemic index? And additionally, does this mean we should change breakfast? Or change the whole diet? How does this impact lunch and dinner?

And finally, this study raises more questions than it answers. There is no way to tell if this is really permanent, or how it affects later development. If it's an effect of just the glycemic index of something, it's possible it changes with every meal and thus may not really be heavily impacting adulthood. OTOH, the grades you get DO affect how well you subsequently do in school and beyond, because they not only impact what colleges you get into, but also your self esteem, etc. So, how does this work over the long term?

As far as this particular study, I'm not convinced. That doesn't mean I'm giving up on breakfast, but I'm not going to start angsting over whether I'm buying rice crispies or mini wheats any time soon.

Taki, Y., Hashizume, H., Sassa, Y., Takeuchi, H., Asano, M., Asano, K., & Kawashima, R. (2010). Breakfast Staple Types Affect Brain Gray Matter Volume and Cognitive Function in Healthy Children PLoS ONE, 5 (12) DOI: 10.1371/journal.pone.0015213

7 responses so far

  • bsci says:

    One small correction to your post. This paper uses MRI, not fMRI. MRI refers to an anatomical image. functional MRI collects many images across time to see how the regional signal changes.

    As for the actual paper, I'm not sure what the MRI data even shows. The rice group has significantly higher socioeconomic status & ate more side dishes with the meal. The dot plot you show doesn't adjust for this. When they do adjust for this, there are some random areas that have more gray matter in the rice group and others in the bread group. They try to explain this a bit in the discussion, but a model where GI selectively alters regional brain volume goes against their original hypotheses.

    It's also no clear how they could properly adjust for age since 5-18 is quite a wide age range with very complex changes in brain structure. Even a slight difference in age distribution across populations could cause headaches.

    I'd love to see them simply to the same analysis with volume vs age or volume vs economic status to simply see the results. I suspect they'd both be more interesting & show larger effects than breakfast content.

    • Scicurious says:

      Oh thanks, for that. I'll edit it in. I automatically assumed fMRI, but you're very right.

      And yeah, I only listed the most glaring problems to me. They state they controlled for socio-economic status, but quite clearly they did not.

  • Alchemystress says:

    Well i agree I think breakfast is important but should only be eaten when you feel hungry. I think what our society forgets as a whole that really best rule of thumb is you should eat when and if you are hungry. Some days I am hungry right out of bed, some days it takes me a few hours. I do not eat at set times just because that is when we are "supposed" to eat. I try to listen to my body and this takes me far. People find it strange I eat lunch sometimes at 2 or 3 in the afternoon but some days I want it a 11am. I eat when I need to ... no more no less. My food intake goes up and down, some days I eat lots and others I don't. I am also a healthy weight and quite in shape so its coming from my experience on how I maintain my health. It wasn't always this way.

    Also there is something to eating so many carbs. If i have toast or something from breakfast guaranteed I will be hungry faster but if I eat an egg with same amount of calories, it will take longer. I don't know but i think most people fall in this category, i most definitely cannot think straight when I am hungry. So i think there is something to it, you need fuel to go. Watch out for letting yourself get too hungry because then you will eat much more than intended. Just my two cents.

  • hod says:

    Love the sarcastic but sharp criticism of this paper! As well as the problems you mentioned, it's also more than a bit dodgy that the authors of the paper consider white rice a low GI food. By most standards it's a high GI one, and while the value given for Japanese-style white rice is lower than those for some other white rices, there's no data for the type of white bread consumed by the children, which also might vary from the standard. There are also other types of rices labeled as Japanese in that chart that have much higher GI index than bread. Anyway, even if there weren't these problems, GI values are for test subjects consuming a standardized portion of the food alone - eating the 'staple' with butter, nut spread, eggs, soups of various kinds, etc., etc. - will change the GI index /load of the meal significantly.

  • The authors of the study related this to cognitive performance, and said that the rice group had higher IQ scores and POI scores compared to the bread group. The authors believe this to be because rise has a lower glycemic index score than white bread.

    ... Because there are no other nutritional differences between rice and bread? Or the things people tend to eat with rice and bread?

  • "Did you know that after reading this blog post, you will show increased grey matter in the cynicus nucleus of the sarcastic complex? It CHANGES YOUR BRAIN, people."

    😀 Love it!

    And thanks for sharing the paper, even with all its flaws it is interesting. As a diabetic I'm used to measuring my blood sugar levels regularly and realised that a) keeping the sugar levels stable is good for energy/concentration/cognitive ability, and b) that is easiest done by leaving out or limiting the amount of carbs consumed, and avoiding especially the "fast ones", i.e. the ones with high GI.

    Thus I think the link between cognitive functioning and GI is not surprising, and I'm glad this has been shown in a number of studies recently. Kids (and also adults) are drinking energy drinks and eating candy to "refuel" which is clearly a wrong strategy, they are just amplifying the ups and downs of their blood sugar rollercoaster while ingesting far too many calories.

    BTW (re peanut butter), I have been told that it is especially fat that slows down the sugars, but I suppose proteins would have a similar effect?

  • Nicole Achter says:

    I think the blood sugar level affects diff. people differently. I remember my friend at school who never got dizzy even without breakfast, while I had to eat or would faint (teenage hormonal chaos causing diabetic effects). I also remember, though it's been a while, that, depending on which teacher was there trying to get our attention, the attention span and thus our collective classroom intelligence differed, regardless if one had breakfast or not.
    So from a scientific study one should be able to expect study participants with comparable age, weight, gender, hormon status, metabolism, living pattern, social environment, attention span and a similar diet to compare to logical, social ... intelligent output.
    Also very important is, did the kids sleep well the night before testing?

    So in a nutshell: go take twins, with alike performance, as well as health, personality, environment and feed them differently for a couple of weeks. Will you see a change?
    Curious, Nicole

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