Is MSG dangerous? Does it affect sleep? According to the FDA, that’s a no.
According to decades of anecdotal evidence and scientific studies, however, that’s a resounding YES.
MSG has been around for decades, and so have its so-called “non-existent” side effects. Even among increasing evidence that MSG does indeed trigger adverse symptoms, the compound is still allowed – even encouraged – in many of the foods you eat on a daily basis.
What is MSG, and what sort of terrible things can it do to your body? Here’s a rundown:
What is MSG?
MSG – short for monosodium glutamate – is a potent flavor enhancer added to a wide assortment of processed foods. The compound also exists naturally, albeit in smaller quantities, in whole, unprocessed foods.
Artificially formed by combining sodium and glutamic acid, manufactured MSG resembles a white powder, not unlike many other seasonings you might find in your local supermarket.
The glutamate portion of the compound is responsible for imparting an umami, savory flavor to foods, while the sodium is, of course, responsible for delivering the salty taste we all know and love.
Unlike other common seasonings, however, this crystalline powder can carry serious negative consequences.
Glutamate, or glutamic acid, is a non-essential amino acid, meaning your body create it naturally. When created by your own body, glutamate is essentially harmless. When artificially manufactured, though, it can overstimulate your central nervous system, resulting in seriously unpleasant side effects.
This is why MSG is commonly referred to as an excitotoxin – it overexcites your neurons to the point of toxicity.
How MSG Can Cause Fatigue
While glutamate does occur naturally in your body, it is often bound to other compounds that mitigate its effects. Free glutamate also occurs in natural foods, but typically in very small quantities.
In its manufactured, free form – which is what you’ll find in MSG – the amino acid can trigger allergic reactions, including mild to severe fatigue.
How does that happen?
MSG acts on your brain by exciting neurons that are sensitive to glutamate, stimulating an inflammatory response. With continual exposure, your body ramps up production of the neurons that are most sensitive to the amino acid.
With more of those highly sensitive neurons present, when you ingest MSG, your nervous system overexcites very quickly. Known as excitotoxicity, this phenomenon also causes neurogenic inflammation, which is one of the hallmark symptoms of brain trauma.
This series of events is believed to be one culprit behind MSG’s role in fatigue.
When glutamate receptors on these highly sensitive neurons are continually activated, they become hypersensitive, causing them to fire with even the slightest stimulation.
Although glutamate excites these receptors, it is precisely that overexcitement that leads to a significant nervous system “crash.”
Just as consuming too much caffeine eventually leads to a pronounced “crash,” consuming MSG has a very similar effect – just far more damaging to your brain.
No big deal, right?
Furthermore, when you have excess glutamate floating around in your system, your body converts it to the neurotransmitter, Gamma-aminobutyric Acid. Under normal circumstances, naturally occurring glutamate stimulates the nervous system, while GABA works to calm it down.
However, when you ingest artificial glutamate – the kind present in MSG – you flood your body with too much of the amino acid. Since you have an excess of the compound, your body converts it to GABA.
Now, not only do you have excess glutamate and an overexcited nervous system, but you also have excess GABA. Since GABA has a sedative effect on the brain, too much of it can result in pronounced fatigue.
MSG and Nightmares: What’s the Link?
With an abundance of GABA floating around in your system, you’ll likely feel quite sedated. GABA is often used as a supplement to help encourage deeper, more restful sleep – but in conjunction with glutamate, it comes with some side effects.
Because GABA promotes relaxation and sedation, it helps your body slip into REM sleep and prolongs the dreaming phase.
Since nightmares typically occur during the stretch of sleep when REM cycles are lengthened, GABA gives your brain extra time to surface those frightening dreams.
GABA is also known for promoting vivid, lucid dreaming. In a lucid dream, you are completely aware of the fact you are dreaming, but cannot seem to wake from your subconscious reality.
The phenomenon can be quite alarming, and if you’re lucid dreaming during a nightmare, it can be particularly terrifying.
While GABA promotes sleep and lucid dreaming, glutamate is the compound thought to trigger intense nightmares. When ingested, glutamate binds to specific receptor sites in the brain.
One of these sites, the NMDA receptor, is thought to stimulate unpleasant dreams when activated. Because glutamate is an NMDA receptor agonist, it can have similar subconscious effects to those of hallucinogenic drugs that fall into the same classification.
Essentially, glutamate activates receptors in your brain that promote nightmares, while GABA stimulates lengthened periods of lucid dreaming.
Together, they can trigger some very disturbing subconscious visuals.
Other MSG Intolerance Symptoms
Fatigue and crazy dreams aren’t the only side effects of MSG consumption; the substance has a long history of eliciting mild to severe physical and cognitive reactions. While not everyone will experience pronounced symptoms after ingesting MSG, that doesn’t mean it isn’t silently affecting the nervous system in the background.
The most commonly reported symptoms of MSG intolerance include:
- Chest pain
- Rapid heartbeat or heart palpitations
- Numbness, tingling or burning of the face and mouth
- Facial swelling or pressure
- Runny nose or congestion
- Cognitive dysfunction
- Bowel or digestive disturbances
You’ve no doubt heard that MSG is no worse for you than the naturally occurring glutamate in your body.
But double-blind studies would have to argue.
Even in controlled studies where neither administrators nor participants knew who was consuming MSG, sensitive individuals still reported the above symptoms.
MSG may be considered “Generally Recognized as Safe” by the FDA, but it’s not safe for everyone.
It’s important to keep in mind that GRAS labeling was established in 1958, and most of the GRAS additives in use today were grandfathered in without extensive FDA testing. MSG just so happens to be one of those additives.
How to Avoid MSG + Common Foods That Contain It
Despite what the FDA says, there is a subset of people – and it’s quite large – who should absolutely avoid MSG. So what’s the best way to do that?
Avoid processed foods like the plague.
And if you just can’t give up processed foods, watch those labels like a hawk!
No, not every single processed food contains MSG, but a large majority of them do – especially foods with salty, savory and umami flavors.
And here’s the real kicker:
Food manufacturers have wised up; today, they’re labeling MSG and free glutamate in a much more sneaky manner.
Manufactured free glutamate is the compound in MSG that triggers negative reactions in sensitive individuals. Anytime you see a food label with any of the following words, stay away from it
- Hydrolyzed protein
- Yeast extract
- Whey protein
- Soy protein, isolate, extract or sauce
- Enzyme modified
Keep in mind that this is not an exhaustive list. For a full list of ingredients that always contain manufactured free glutamate and ingredients that often contain it, check out this campaign.
Other foods you should avoid are natural but still contain substantial amounts of free glutamate, which may trigger symptom onset. These foods include:
- Parmesan cheese
- Roquefort cheese
Frequently Asked Questions
Does MSG keep you awake?
That depends on the individual. In some people, MSG has been found to cause sleep-disordered breathing, which can certainly interrupt normal sleep cycles and promote wakefulness. If you are very sensitive to artificial MSG, the substance may prevent you from getting a full night’s rest.
How long does it take for the effects of MSG to go away?
If you are very sensitive to added MSG, symptoms of intolerance may take several days to dissipate. However, most individuals find their symptoms gradually disappear over a period of 48 to 72 hours.