Bound Glutamate vs Free Glutamate
Proteins contain the amino acid, glutamate. When glutamate is “bound” to the protein or in whole form, it is rarely problematic, even for those highly sensitive to glutamate. However, glutamate often becomes problematic when the proteins are degraded and glutamate is “freed” from the protein chain. MSG is the most common form of free glutamate in our food, and the terms, free glutamate and MSG, are frequently used interchangeably. Historically, MSG and its various names have been added to our food to provide a competitive edge over other manufacturers by making food taste better and more addictive. Due to the public backlash against MSG in the 1980’s, many food manufacters started to utalize different food processing techniques that would increase the amount of free glutamate in processed foods, while avoid having to add MSG as an additive to the ingredint list. Additionally, the FDA only requires ingredients over 99% free glutamate to be listed as MSG. Therefore, anything under 99% free glutamate doesn’t have to be identified as MSG and can be hidden or disguised in well over 50 different names. These names can be as innocuous and deceptive as “natural flavors” or “spices”, leaving the consumer completely unaware of their neurotoxic properties.
Commercial processing techniques like acid hydrolysis, fermentation, high heat extraction, lysing, pasteurization, etc. can substantially degrade proteins and will ultimately result in free glutamate. This processing makes certain foods problematic for those more sensitive to glutamate and/or those with already high intrinsic glutamate levels (high levels of glutamate produced by the body in response to immune activation, infection, etc). Because glutamate is also a neurotransmitter, consumption of a large amount of free glutamate alters glutamate-mediated metabolic functions, triggering a cascade of dysfunction- including immune dysfunction
The Real Problem With Glutamate
The real problem with glutamate comes when it is in excess, especially when you have high levels of intrinsic glutamate produced by the body. However, determining what “excess” means for an individual can be challenging as underlying factors such as inflammation, infection, and age all need to be considered. Excess glutamate poses risk to everyone, but especially children as their brains are about 4xs more sensitive to it than an adult brain.
Glutamate Levels in Whole Food
By strictly eating a whole food diet, glutamate levels would not be in excess, but when one already has high glutamate levels and whole foods naturally containing some amount of free glutamate are altered or processed, it will result in excess free glutamate. “For example, the amount of free glutamate naturally found in a tomato is reported to be 0.1%, but the tomato isn’t the issue. If you only ate tomatoes, you might accumulate a bit of excess glutamate; however, if you’re eating tomato and cheese on a big thick yeast-risen pizza dough loaded with salami and pepperoni, you now have a pizza laden with MSG.”- Dr. Reid
Gluten, casein, and to a lesser extent, soy and corn, contain roughly 25% glutamic acid as part of their protein structure. In the bound protein, raw and unprocessed form, this amount of glutamate should rarely cause an issue. The issues arise when these proteins are degraded (pasteurization, fat removal, fermentation, acid hydrolysis, etc). The protein degradation breaks down the amino acids, freeing up glutamate, leading to a high amount of free glutamate. Because of this, these foods in the processed form should be avoided.
So How Do We Navigate This?
We have personally had to rely heavily on symptoms and behavioral reactions as an indication of overall glutamate/inflammation and exposure to dietary sources of glutamate. Without a lab, it is hard to know exactly how much free glutamate will be found in a particular product due to different types of processing and/or how much of the individual ingredient is added to the packaged food. The way that we have found to balance this, is by consuming a variety of whole real foods and strictly avoiding gluten, dairy, soy and to a lesser extent, corn, and working to lower overall glutamate and inflammation. For us, the “bucket” concept can be applied to our glutamate levels. We may be able to tolerate small amounts (maybe a surge as a result of yeast or a surge from a loose tooth, etc) but we will see a behavioral reaction when the “bucket” tips or overflows (maybe from consuming a portion of food with free glutamate, or an active infection, etc.).
There is very little scientific evidence to back my chart below, but this is closely how we have personally viewed glutamate levels based on behavioral reactions with our son. Disclaimer*** reactions will very much be based on individual sensitivity. Not all sources are listed below but I will work to make it as comprehensive as possible.