Is a Vegetarian Diet Bad for Your Brain?

If creatine is important for brain functioning and vegetarians have lower creatine levels, could a vegetarian or vegan diet have a negative impact on cognitive function?

Monica Reinagel, MS, LD/N, CNS
4-minute read
Episode #524

Bea writes: "Can you comment on research showing that creatine supplements can improve cognitive function in vegetarians? Do I need to worry about my vegan diet hurting my brain?”

If you've heard much about creatine, you’ve probably heard it in the context of enhancing athletic performance. My colleague, Brock Armstrong, recently devoted an episode of the Get-Fit Guy podcast to the potential uses of creatine to build muscle.

But creatine has also been investigated as potential a nootropic. A nootropic is a substance that enhances brain function or cognition.

Creatine is a non-essential amino acid, which means that our bodies have the ability to manufacture it from other amino acids. However, we can also get creatine from our diets. Meat, poultry and fish are the primary sources of creatine. Not surprisingly, vegetarians and vegans have lower levels of creatine in their blood and muscle tissue than meat eaters.

Is a Vegetarian Diet Bad for Your Brain?

If creatine is important for brain functioning and vegetarians have lower creatine levels, could a vegetarian or vegan diet have a negative impact on cognitive function?

Observational data suggest that lifelong vegetarians and vegans actually have a lower risk of dementia than meat eaters. Now, this may not have to do directly with the amount of animal products they do or don’t consume. It could be due to a higher intake of vegetables or legumes, for example. Or it could have to do with the fact that vegetarians are statistically more likely to exercise and less likely to smoke or any number of other lifestyle factors. That’s the difficulty with observational data; it’s impossible to prove cause and effect.

There’s little evidence to suggest that a vegetarian or vegan diet impairs brain function or increases the risk of cognitive decline.

Should Vegetarians Take Creatine?

Since vegetarians have lower creatine levels, would there be any benefit to taking creatine supplements? 

One study compared the effects of creatine supplementation on healthy young women who were either vegetarians or meat eaters.This was a short study, lasting just five days, and the subjects took 20 grams of creatine per day or a placebo. The good news is that the omnivores and vegetarians performed about the same on the initial tests, which again suggests that a vegetarian diet was not negatively affecting their brain function. The bad news is the the supplement didn’t seem to do a whole lot for either group.

Another smaller but longer study involving only vegetarians found that 5 grams of creatine a day for six weeks led to some improvements in performance on standardized tests of cognitive function in healthy young subjects. They tested things like reaction time, short term recall, and vigilance. It's not clear that the improvements measured by the scientists would be significant enough to translate into any meaningful impact on daily life, such as making them safer drivers or helping them remember their gym locker combination.

At this point, it's still unclear whether taking a creatine supplement would produce any meaningful benefits for vegetarians. 

Can Creatine Improve Cognitive Function in the Elderly? 

But what about older individuals, who are more likely to suffer from cognitive decline?

One small study of about 30 elderly individuals found that taking 20 grams of creatine per day led to statistically significant improvements in performance on cognitive tasks after five days. But again, did this translate into noticeable effects in the subjects’ daily life? Did they find it easier to finish the crossword puzzle or remember where they left their glasses? We don't know. But even if it did, a single pilot study isn't enough to provide a definitive answer regarding the benefits of creatine supplementation for older people. 

My Take on Creatine as a Brain Booster

I think we need to know more before we start recommending creatine as a cognitive enhancer—for vegetarians or anyone else. You'd be amazed at how many pilot studies produce promising results that are not borne out by further research. So, the first step is to see whether larger studies can confirm any of these preliminary findings. 

The next step would be to establish the optimal regimen. Is 5 grams per day just as effective as 20? Can benefits be measured after just five days or does it take several weeks to see results? I'd also like to learn more about the effects of long term use. Might the benefits increase with longer use? Or might the supplement actually become less effective over time?

What about safety? Although the research on creatine as a cognitive enhancer is still in the early stages, there's been much more research on creatine to build muscle and enhance performance. It's been evaluated at various doses, durations, and in a variety of populations. The good news is that creatine is pretty safe. But keep in mind that the supplement can have some unpleasant side effects such as stomach cramping or diarrhea as well as weight gain due to water retention.  

Other Considerations for Vegetarians

Although I don’t think there's enough evidence to justify creatine supplements for vegetarians, there are a few important nutrients that are quite limited or missing entirely from a vegan diet. Strict vegans need to be sure to have a source of B12, whether that’s in the form of a supplement or fortified foods. Although not strictly essential, vegans may also want to consider an algae-based DHA supplement, and should take care to get enough calcium, iron, vitamin D and zinc from their diets.

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About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.