Glutamate - Could its Hidden Sources Be Harming Your Health?
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Beyond MSG: Could Hidden Sources of Glutamate Be Harming Your Health?

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This is a guest post written by staff clinician Amy Nett, MD.

A few weeks ago, Chris interviewed Yrmis and Bobby from Mission Heirloom on his podcast, and the topic of glutamate in our food was briefly discussed. Since then, we have had several questions from our patients about potential health concerns regarding glutamate, so I decided to take a closer look to see what role dietary glutamate plays in our health.

What Is Glutamate and Why Is It so Important?

Glutamic acid is an amino acid found in abundance in both plant and animal protein.  It is considered a non-essential amino acid, meaning that our bodies are able to generate glutamic acid even without ingesting it through food sources. (Yes, glutamic acid is just that important that we cannot risk being without.)

Is There a Link between ADHD, Autism, Migraines, and Glutamate?

Glutamate is essentially the same compound as glutamic acid and is the most common form of glutamic acid in our bodies. Glutamate is not only beneficial, but essential for life. It is the most abundant neurotransmitter in the brain. (Neurotransmitters are chemical messengers that nerve cells use to communicate.)

Glutamate thus activates—or excites—cells in the brain in order to communicate messages, and is particularly important in the growth and development of the brain, learning, and memory.  Because of the way glutamate sends these messages, by “exciting” the cells, it is called an excitatory neurotransmitter. You can think of glutamate as a stimulant. And as anyone who’s had too much coffee can tell you, too much of a stimulant is not a good thing.

What’s the Difference between Bound and Free Glutamate?

It’s important to note the distinction between bound and free glutamate since any potential health concerns are associated with the free form of glutamate. Bound glutamate refers to glutamate in a whole, unmodified protein source and is therefore generally digested and absorbed slowly. Free glutamate, by contrast, is no longer bound to other amino acids, and may therefore be absorbed much more rapidly, causing spikes in the concentration of glutamate in the blood. Free glutamate is found in natural food sources, with particularly high sources listed at the end of this article.  But of more concern is the abundance of free glutamate in nearly all processed and packaged foods, also described in more detail below. 

All Glutamates Are Not Created Equal

MSG, or monosodium glutamate, is a synthetic chemical that is added to manufactured and processed foods to make them more palatable. This form of free glutamate is present in almost all processed foods and is valued by manufacturers for imparting a pleasing, savory taste. Though MSG contains glutamic acid, due to the manufacturing process it is also almost always accompanied by unwanted by-products or contaminants. Searching the scientific literature regarding the health effects of MSG indicates controversy over the potential of MSG to cause various adverse reactions—from headaches and migraines to endocrine disruption. However, careful attention to the source of funding from these studies often reveals that many confirming the safety of MSG are in fact supported by food manufacturers. The Truth in Labeling Campaign has extensively studied the role of MSG and found that some people are clearly sensitive, with the most common sensitivity likely being intolerance to one or more of the contaminants produced through the manufacturing process (1).   

Even those of us without an identifiable reaction to MSG should aim to avoid this additive due to the lack of reliable safety data.

So let’s get back to natural glutamate…

How Does Glutamate Affect the Brain?

Glutamate and glutamate receptors are well established as playing critical roles in normal and abnormal brain development and function (2, 3, 4, 5, 6).  

In particular, abnormal concentrations of glutamate are associated with migraines (7, 8, 9), and hypersensitivity to glutamate is proposed in several other diseases, including Huntington’s Disease (10) and autism (11). Genes that predispose patients to glutamate sensitivity are being investigated.

An imbalance in glutamate and GABA (another neurotransmitter that counters the effects of glutamate) is increasingly implicated in many conditions involving the brain. This imbalance likely disrupts the brain’s ability to efficiently process information, and gradually leads to lasting injury to the brain.

Can lowering dietary glutamate help treat autism and ADHD?

Because of this genetic sensitivity to glutamate seen in children with autism spectrum disorder and ADHD, some clinicians recommend lowering glutamate intake in the diet (12). Decreasing glutamate intake intuitively seems like a potentially effective approach to decreasing the amount of glutamate exposure to our brain. However, this strategy is not as straightforward when we consider the role of the blood-brain barrier (BBB).

How the blood-brain barrier protects your brain

The BBB is a layer of cells surrounding most of the brain, that acts to limit the compounds entering the brain. Under normal circumstances, there is careful regulation of the types and amounts of compounds that enter the brain.  This means that normally, glutamate can only enter the brain through specific receptors that regulate the amount allowed in. (This is analogous to a bouncer letting only a limited number of people through the door.) One study, notably funded in part by the International Glutamate Technical Committee (a nongovernmental organization funded by industrial producers and users of glutamate in food), perhaps not surprisingly demonstrated that glutamate, even at high concentrations, does not readily cross the BBB.  

Even if glutamate does not cross the healthy BBB, there are many factors which may contribute to a leaky BBB, potentially allowing too much glutamate to enter the brain. In his podcast on the “gut-brain axis,” Chris explained that having a leaky gut (which itself can be due to a number of underlying causes, including food intolerances, dysbiosis, or small intestinal bacterial overgrowth) can contribute to a state of chronic low grade inflammation. This low grade inflammation then also makes the BBB leaky, which essentially loosens the control over what enters the brain. More recent research has identified a specific molecule that damages the cells to create microscopic gaps allowing material through, bypassing the normal regulatory pathways, and explaining how general inflammation within the body can cause a leaky BBB.

Thus, it may be that in the setting of inflammation, we have a leaky BBB, which allows more glutamate to enter the brain than normal.  Moreover, since some people have a genetic predisposition to glutamate sensitivity,  it may be that a combination of excess glutamate in the diet, combined with chronic low grade inflammation, and an associated leaky BBB, contribute to symptoms.

It seems less clear if people without an underlying genetic predisposition to glutamate sensitivity experience any adverse effects from excess dietary glutamate. Further research is clearly needed to elucidate the contribution of dietary glutamate to symptoms.

How to Lower Glutamate in Your Diet

What we can take from all of this is that some individuals do have a particular sensitivity to glutamate.  Understanding the different sources and types of food that contain glutamate can help you make the best food choices for you and your family, and avoid symptoms of sensitivity. If you suspect that glutamate may be playing a role in your symptoms, you can try to eliminate any sources with added free glutamate (specifically in processed and packaged foods) and monitor your symptoms. If symptoms persist, then try eliminating sources of natural free glutamate as well. Once your symptoms have subsided or resolved, gradually introduce some natural sources of free glutamate back into your diet as tolerated over a period of weeks to learn which foods may trigger a reaction.

Additionally, given that glutamate excess may be associated with symptoms only in the setting of chronic inflammation, consider adding turmeric or ginger to some of your meals for their potent anti-inflammatory properties while you investigate potential causes of inflammation.

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Free glutamate may be listed as any one of a number of ingredients:  

Monosodium glutamate, monopotassium glutamate, yeast extract, anything “hydrolyzed” such as hydrolyzed protein, calcium caseinate, autolyzed yeast, textured protein, gelatin, soy protein (including isolate and concentrate), whey protein (including isolate and concentrate), carrageenan, bouillon and broth, stock, and “flavors” or “flavoring” (i.e. natural vanilla flavor), maltodextrin, citric acid, pectin, milk powder, soy sauce, anything “protein fortified,” corn starch, corn syrup and modified food starch.

Here are links to more inclusive lists of hidden free glutamate, including a link to unblindmymind.org, which is a nonprofit working to raise awareness of the link between autism and MSG (13, 14).

Natural sources of free glutamate:

  • Foods matured, cured, or preserved, such as matured cheeses (Parmesan and Roquefort) and cured meats
  • Fish sauce
  • Soy sauce and soy protein
  • Mushrooms
  • Ripe tomatoes
  • Broccoli
  • Peas
  • Walnuts
  • Grape juice
  • Bone broths and meats cooked for long times (generally using moist cooking methods such as braising)
  • Malted barley used in breads and beer
  • Wheat gluten
  • Dairy casein

Please share your experiences and post a comment below to let us know if you notice any symptoms after eating foods containing free glutamate.

Amy NettAbout Amy:  Amy Nett, MD, graduated from Georgetown University School of Medicine in 2007.  She subsequently completed a year of internal medicine training at Santa Barbara Cottage Hospital, followed by five years of specialty training in radiology at Stanford University Hospital, with additional subspecialty training in pediatric radiology.

Along the course of her medical training and working through her own personal health issues, she found her passion for functional medicine, and began training with Chris in June of 2014. She has recently joined his clinical practice to work with patients through a functional medicine approach, working to identify and treat the root causes of illness. Similar to Chris, she uses nutritional therapy, herbal medicine, supplements, stress management, detoxification and lifestyle changes to restore proper function and improve health.

All of our clinicians are accepting new patients at this time. Find out more about becoming a patient at the California Center for Functional Medicine.

249 Comments

Join the conversation

  1. It’s easy to just whitewash all the studies against MSG by saying “they were funded by XYZ organization”, but the Weston A. Price article does just that and then skips to citing a bunch of animal studies that have already been disproven for humans. I don’t care if a rat got lesions if that dose isn’t even near human equivalent doses.

    Anecdotal evidence is great and all, but I highly doubt that it’s the glutamate causing these issues – where is the citation for glutamate sensitivity via food? Glutamate neurotransmitter signaling problems for neurological diseases/disorders is a very different thing.

    Also, this is the same argument people make against dietary cholesterol, but forget that there are downregulation systems – why do we assume that an overstimulated synapse would downregulate receptors and thus re-establish balance? That is, if an appreciable amount of glutamate is even crossing the BBB.

    If chronic low-grade inflammation is actually a problem, oats (as an anti-inflammatory) would help: http://www.ncbi.nlm.nih.gov/pubmed/23072529

    • Hi,

      found your comment a bit provocative because you’re kind of saying that all the people making comments about how sick they get when ingesting dietary glutamate are probably imagining things!

      Maybe you didn’t mean to offend anyone, but you sure did offend me!

      Here’s a research article on the topic:

      The effect of dietary glutamate on fibromyalgia and irritable bowel symptoms
      http://www.ncbi.nlm.nih.gov/pubmed/22766026

  2. Yes! Thank you for bringing awareness to this topic! Most of my clients are quite sensitive to glutamate, even in foods such as bone broths and peas. This is often related to functional enzyme deficiencies due to toxins such as lead, in addition to actual genetic mutations. We also find glutamate issues increase during a detoxification protocol. Highly intelligent people do tend to be more susceptible because they have higher glutamate receptor activity. http://peelingbacktheonionlayers.com/excitotoxicity-when-nourishing-foods-do-harm/

  3. Despite permeable BBB, Hashi-hypoT, tTG2 Ab (celiac), many genetic markers for autism, COMT homozygous variant, I don’t seem to be negatively affected by the high glutamic acid foods. But cysteine levels are naturally high-end with normal glutathione, so this may have something to do with not being bothered by glutamic acid.

    I have some powdered glutamic acid (Vitamin Shoppe, 1 level teaspoon = ~3000 mg = ~3 mg) that I take sublingually occasionally, about every 1-4 weeks, for a mild jolt of extra energy and mental clarity, and to shake up the system a bit.

    Concord grape juice has always acted like a re-set button for me since I was a toddler. In my 60’s now. I had attributed it to the resveratrol, but maybe also to glutamic acid?

  4. I was finally able to pinpoint the cause of my ocular and acne rosacea as being glutamates. As long as I avoid them, and limit the amount of natural glutamates in my diet, my skin remains clear. I don’t have to avoid all of them, but I do have to be careful about the amount.

  5. What’s the difference between glutamine and glutamate? Does one preclude the other?

    What about supplementing with NAC to bind with excess glutamic acid and glycine to form glutathione-which cleans the liver etc…

    My understanding is the NAC pulls put the excitatory transmitter glutamine reducing adhd, OCD, and drug addiction withdraw… (Controversial research). Is this glutamate unrelated? Glutamate converts to glutamine

  6. Not only did lowering glutatmate intake reduce the frequency of my then 9yr old daughter’s seizures, she noticed improved ability to focus within 5 days and was asking for subsitute foods, rather than go back to the higher glutamate foods. The worst offenders for her, besides gluten, casein, and soy, were peanuts, yeast, and gelatin (those pesky supplement capsules!).

  7. Do you recommend avoiding all foods on the list at the end of the article? I have a hard time believing that mushrooms, tomatoes, and broccoli are bad for one’s health.

    • Hi Michael,

      I agree, most of the foods listed as containing fairly high amounts of free glutamate are very nutritious, and should be part of a healthy diet for the majority of us who tolerate them well. The only people who may want to consider decreasing some of these foods, are those who notice symptoms, such as headache, migraine, depressed mood, etc. after eating foods with high amounts of free glutamate.

      • Great article.

        “Amy Nett” MD does not show up as a licensed medical doctor in California when checking on the DCA (.gov) (BreEZe) website. Are you practicing in California?

        Thank you

        Paul

    • no! unless you do have a severe sensitivity, which is RARE to this ingredients you are listing. these are very specific cases.
      What we are avoiding and have lead to amazing results in our cases are the listed in unblindmimind.org
      Ingredients like these:
      Barley malt, Bouillon and commercially processed broth, Brown rice syrup, Calcium glutamate (E 623) Carrageenan (E 407) Citric acid, Dextrose Enriched (anything)
      Enzyme modified (anything) Fermented protein (any) specially sauces with fermented anchovies. Flavors or flavoring [i.e. natural flavors, raspberry flavor, vanilla flavor, etc..] Gelatin (yes. sorry, but we have to find a better way to consume gelatine than in powder form) Glutamic acid (E 620), Glutamate (E 620) Hydrolyzed (anything) Hydrolyzed protein (any) Lipolyzed butter fat
      Maltodextrin Milk powder, reduced fat milk (skim; 1%; 2%), most things low fat or no fat
      Modified food starch, Pectin (E 440)
      Protease, Protein fortified (anything)
      Rice syrup, Soy protein isolate
      Soy protein, soy protein concentrate
      Stock (comercial) Textured protein
      Ultra-pasteurized any protein, Whey protein isolate
      Whey protein, whey protein concentrate
      Xanthan gum , Yeast (almost any)

      To name the most common ones.

    • Sharon Campbell. Well mushrooms give me raging migraines. In fact since going Paleo my migraines have been constant. I am so sensitive to glutamate that I do have to avoid all natural forms. As I am still trying to eliminate the migraines and I am worried what this will mean for my Paleo diet. I suspect my home made stocks n casseroles…even aged meat…(which we can’t avoid in the UAE) are contributing. Unless I can become more resilient somehow Amytriptaline may have to go back on the menu.

  8. I’ve been told and read a lot of the great health benefits of taking powdered grass-fed gelatin. I take the Great Lakes hydrolyzed gelatin due to its versatility. Is taking the gelatin a bad idea then? I also mix in a little to my infant’s formula.

    • Hi Angela,

      Grass-fed gelatin offers many nutritional benefits. Unless you notice symptoms after eating gelatin, there is no reason to exclude this from your diet.

      • i bought the Knox gelatin because it was cheaper. Any opinions on non grassfed gelatin? it was half the price (per lb) but i’m not sure i see much difference.

  9. I am confused. The author implies that bone broths may be harmful. A number of us are wondering under what circumstances that could be true. Long cooking, e.g. 3 days?
    Individual sensitivity, but which types?

    • Hi Grace,

      For most people bone broths are incredibly nutritious and healing for the gut. However, all bone broths contain free glutamate — the amount will vary, and may be more if cooked for longer periods, such as two or three days. This free glutamate does not adversely affect most people, and the benefits of bone broth far outweigh any potential concerns for this majority. However, when some people eat foods that are high in free glutamate, they may notice symptoms like depressed mood, difficulty concentrating, headache, migraine, or even heart palpitations. And, as mentioned in the article, this may apply particularly for children with autism spectrum disorder, though more research is needed. For these people, it is best to be aware of foods that contain high levels of free glutamate, since they may do better without them. So, individual sensitivity specifically means that some individuals notice symptoms when eating foods that contain moderate or high levels of free glutamate. In the absence of these symptoms, there is little evidence to suggest you should have any concern about eating these otherwise highly nutritious foods, such as bone broth or gelatin.

    • i think bone broths are great when done correctly. as far as our research and testing this is what seems to work better… btw we are looking for a plate reader spectrophotometer because we want to work with Dr. Katie Reid and have her run the standard curve with each test sample so this can be labeled in food!
      So back to how to do lower risk bone broths: do not add acidity, no vinegar, no citrus. Add antioxidants like rosemary or turmeric. only simmer, do not boil. cook for less than 6 hours. you will get all the amazing nutrition it has to offer with lower risk of unbonding the glutamic acid.
      Each person needs to determine its own threshold. hope it helps.

  10. Thanks for the great post. My 4 year old son has a sensitivity to glutamates and has had so all of his life (or as soon as he was on solids at least). We noticed some nights he would whimper and cry and bunch himself up into a ball. It was quiet distinct and different to his normal presentation and it caused him obvious stomach distress. We were keeping a goo diary as we thought he might be sensitive to fructose but it was glutamates in soy sauce, tomatoes and Parmesan cheese. We avoided any added MSG but on odd occasions he would ingest he would be extremely uncomfortable. He seems better able to tolerate the naturally occurring glutamates as he gets older and as we eat clean foods we don’t know if the same is for added MSG products.

  11. It’s funny how MSG makes food more palatable now and the ancient form was garum sauce. The romans put it on everything. I bought some and it’s repulsive. It does not make anything more palatable. I’ll stick to better, natural forms.

  12. I take L-glutamine from when I did The Clean Gut cleanse. I have continued taking it due to the fact it was described to work at healing the gut. The cleanse did wonders for me but know am concerned that this supplement is harmful or not something I should be taking. This is very confusing considering it was on the list of supplements to take in gut healing.

    • Hi Peggy,

      Glutamate and glutamine are different amino acids. The information in this article is about glutamate, and does not apply to glutamine.

      • Supplementation with any free amino acid outside the balance of natural proteins is a problem. Since glutamine metabolism can result in glutamate under certain conditions, I recommend avoiding glutamine supplements. Consuming natural intact proteins provides all the glutamine necessary for a healthy gut.

  13. Whey protein, which is generally considered an extremely nutritious substance and health food, actually contains more glutamate than any other amino acid. Since glutamate is the major excitatory neurotransmitter found in the brain, I don’t see how very much of it could be making its way past the blood-brain barrier, because if it did, it would probably cause a seizure. I think the glutamate content of natural foods is just not something we have to worry about.

    • Problem is, a lot of peoples blood brain barriers don’t work very well. If a person with epilepsy has poor blood brain barrier function, then glutamate often causes seizures. Though, when I had epilepsy, I never reacted to totally natural foods like tomato. I did react to bone broth and stock. Similar with narcolepsy, depression and other things sometimes triggered or exacerbated by an increase in exitotoxicity. Cold processed non denatured whey protein concentrate is ok, but whey protein isolate can be exitotoxic.

      • Gh.I wonder if youll see this now but I love your sentence “when I had epilepsy…..”
        I’m currently
        trying to help my adult daughter To elimnate seizures . . Can we talk ? [email protected].

    • You are right and it does! As Amy’s article stresses, some people are more vulnerable than others. Celiac’s for instance are highly prone to a leaky gut, which is the catalyst to a compromised BBB. As Chris points out in his e-book 9 Steps To Perfect Health, 2.3% of people with Celiac Disease have epilepsy and “…17% of people with CD have an “undefined neurological disorder.”” Further more, it’s not uncommon at all to reduce or even eliminate seizures in humans and pets by eliminating gluten and healing their gut.

      http://dogtorj.com/main-course/epilepsy-and-diet/the-epilepsy-diet-made-simple/

  14. MSG and related compounds are a definite trigger for my restless legs symptoms. Ordinarily if I avoid specific foods the symptoms are not present, but they flare up if I eat synthetic versions of glutamate. Cheese and soy sauce don’t bother me, but the processed versions of glutamate definitely does.

    Other things that set off my restless legs are corn syrup, gluten, sugar, and other refined grains (even gluten-free flours). Probably other artificial chemicals would too, although I don’t eat anything artificial anymore.

    • According to the Gut and Psychology Syndrome Diet, bone broth can help heal a leaky gut, thus reducing depression and other mental disorders.
      Chris, can you please explain??

      • I think Nils comments above makes a great point about the benefits of bone broth. Unless you are extremely sensitive to glutamate and have determined you react to natural sources like bone broth, then i wouldn’t worry about bone broth. The pros far outweigh the cons and for majority of people the cons may not be an issue at all. Individuality is seems to be the big challenge.

        • This is true. Bone broth is an extremely nutritious and beneficial food for the vast majority of people. As Amy mentioned in the article, however, for a select minority with a leaky BBB and glutamate sensitivity, bone broth may exacerbate their symptoms. I have seen this in my work with patients, particularly children on the autism spectrum. But that doesn’t mean it applies to everyone.

    • Histamine can also be an issue in bone broths depending on how they are produced. Histamine has many roles in the body and some with histamine intolerance are affected in terms of mood.

    • I totally understand as I’ve had similar reactions myself. When I was drinking Shakeology (loaded with Amino Acids, therefore full of free glutamates) I got so miserable I thought I had a brain tumor and was going to die. I had horrible headaches, TERRIBLE, evil moods – including rages, brain fog that was ridiculous, and exhaustion. It took me the longest time to realize what was causing it. Since then I have experienced similar (though more short-lived due to the fact that I recognize the reaction now, and am more likely to determine the cause) reactions to bone broth, gelatin, and amino acid supplements. For people sensitive to these foods it is so important to figure it out and eliminate the cause because the reaction is awful. Thank you for getting the word out and helping to educate people!! This is so important.

  15. What about Glycine though. One of its functions is being a powerful inhibitory neurotransmitter. So while gelatin and bone broth might be relatively high in Glutamate, they are far better sources of Glycine. This makes these food sources very suitable in PREVENTING Glutamate (and tryptophan and methionine) overloads. Gelatin also happens to be very low in methionine and deficient in tryptophan as a bonus!

    While I liked the post, I don’t think talking about a single amino acid makes sense without discussing its interactions with other amino acids.

    • if cook correctly (low heat and about 6 hours – no more) you should not be unbonding the glutamic acid. Which makes it ok.
      Again, the problem comes when you add acidity, sugars or pass 300 degrees and cook over longer periods of time which unbounds the glutamic acid, becoming an unstable molecule that will look to bind with sodium or potassium now becoming Monosodium glutamate, monopotassium glutamate which are the problem when consume in large amounts and pass your threshold.

    • I have to agree – it becomes unnecessarily alarmist, since you will never be able to tell if you are sensitive. Elimination/reduction is next to impossible, it makes you fear foods, even whole good foods. I can see people avoiding gelatin and bone broths as a result of reading this!

      • When you are sensitive, you will have no trouble telling. At least for me, it is one of the strongest reactions I have ever experienced. I am learning which foods affect me by paying attention to my reactions – the lists are not alarmist; they are simply guidelines to help people like me suffer a little less as I learn what I can tollerate.

    • Hi!
      Bonded glutamate is great! We need it, that is why is so common in nature. Free glutamate above your personal threshold is the problem! To learn more about this also take a look at https://unblindmymind.org/ Dr. Katie Read is leading this subject, I can’t wait for her book coming soon. Hope this helps.

  16. Chris,
    I would love to hear more of your opinion on this and how common is this in your experience with patients? Its seems very similar to the diet component (fodmaps) with treating SIBO that Kelsey and Laura discussed on their podcast. The individuality seems to be a challenge.

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