MSG
What is it?: a food additive derived from glutamate, an amino acid
Where is it?: packaged foods, Asian dishes
Is it a common trigger?: probably not (hear me out!)
The Basics
MSG, or monosodium glutamate, is a food additive commonly found in Asian dishes and prepackaged foods. It's known for its distinctive umami flavor and has long been thought of as a headache trigger, even in non-migraineurs.
MSG is derived from glutamate, a naturally-occurring amino acid found in your body and in foods. Glutamate is a neurotransmitter that allows your nervous system to communicate with the rest of your body and is an important part of normal brain functioning.
For decades people have linked MSG with headaches and migraine, but science is telling a different story.
Do we need to avoid MSG for migraine? Let's take a look at what it does in your body and how it impacts the brain.
The Science
Migraine triggers are hard to study due to the numerous factors involved in an episode occurring (you can read more about this here). As such, we'll focus more on how MSG behaves in your body rather than clinical trials attempting to prove that MSG acts as a trigger.
When you eat a food containing MSG, your body processes it and breaks it down into glutamate, that amino acid that also acts as a neurotransmitter. Glutamate is a normal, natural substance found in the body and in foods that has excitatory effects on the nervous system. Some of these "excitatory effects" include forming and retrieving memories, experiencing emotion, and coordinating movement. Glutamate is important!
There have been some concerns that getting too much glutamate from food can cause "excitotoxicity" - aka over-stimulation, damage, or death of nerve cells. While this is true, it's pretty unlikely that you would experience these effects from eating MSG.
MSG and the glutamate that comes from it cannot cause the shield surrounding and protecting your brain called the Blood Brain Barrier. This means that even if you ate high levels of MSG, it shouldn't cause any negative side effects in your brain.
What happens to glutamate that comes from the MSG you eat, then? Your intestines either:
- use it to create other amino acids
- use it to create important molecules like glutathione, one of the major antioxidants in your body
In higher amounts, it seems that dietary glutamate does have excitatory effects - however, they are likely limited to your gut's own nervous system, known as the enteric nervous system or ENS.
So what does all this mean?? MSG is likely not triggering migraine symptoms, at least not with what we currently know about how it interacts with the body. Could there be something we haven't discovered yet? Of course. The gut-brain connection is an extremely complicated area of research, and there is always more to be learned.
One thing to remember is the sodium part of monosodium glutamate. Eating a food high in MSG means you are also eating a food high in sodium, which can elevate your blood pressure and potentially contribute to migraine symptoms. This is something to keep in mind when consuming the foods listed below - if you know you are sensitive to changes in blood pressure it may be a good idea to stick to smaller amounts of these foods.
Food Sources
***In the US, the FDA requires companies to disclose when they use MSG on the ingredients list. However, MSG does occur naturally in some foods like soy sauce and tempeh, and labeling is not required for these foods.
To Avoid or Not to Avoid?
MSG is likely not a universal migraine trigger. The current science shows us that the MSG we eat probably doesn't have direct effects on the brain, but despite this many people are avoid this additive out of fear that it may trigger an episode.
There is the possibility that you may have a sensitivity to MSG (read more about the difference between triggers and sensitivities here), which could explain an increase in symptoms following a meal containing the additive.
If you think you react to MSG, having food sensitivity testing done or trying an elimination/reintroduction diet could be a great place to start.
Bottom Line
MSG does not appear to be a migraine trigger in its own right, but you could experience symptoms if you have developed a sensitivity to it. You likely do not need to completely avoid MSG unless you have an obvious reaction after eating foods that contain it.
References
Glutamate as a neurotransmitter in the healthy brain
Does monosodium glutamate really cause headache? : a systematic review of human studies
The blood-brain barrier and glutamate
Metabolic fate and function of dietary glutamate in the gut
