Print
Labeled “Safe” But Linked to Harm
Monosodium glutamate (MSG) has long been dismissed as a benign flavor enhancer by the food industry and regulatory bodies alike. But mounting evidence—from behavioral studies to cutting-edge cancer metabolism research—suggests that MSG may not be as harmless as advertised.
Far from being limited to Chinese takeout, MSG and its derivatives are hiding in everything from snack foods to organic broths, often under names like “yeast extract” or “hydrolyzed protein.”
At the core of MSG is glutamic acid, a naturally occurring amino acid. But when chemically isolated and concentrated in food additives, glutamic acid behaves differently in the body, triggering overstimulation in the brain and potentially contributing to systemic disorders.
And now, groundbreaking research shows that glutamine, a close metabolic cousin of glutamate and often present in foods that also contain MSG, plays a powerful and previously misunderstood role in cancer growth.
MSG, Excitotoxicity, and Brain Damage
MSG is the sodium salt of glutamic acid and has been used to amplify umami flavors in processed foods for over a century. But researchers like Dr. Russell Blaylock have warned that concentrated glutamate in the bloodstream can overstimulate neurons and cause cell death—a phenomenon called excitotoxicity.
Dr. John Olney’s research in the late 20th century showed that newborn rodents exposed to MSG developed brain lesions, particularly in the hypothalamus. These structural brain changes have been linked to hormonal imbalances, obesity, stunted growth, and reproductive dysfunction.
Even at doses considered safe by regulators, MSG has been shown to damage retinal and hypothalamic neurons. These changes are more pronounced during early developmental stages, but they can occur at any age—especially in individuals who are sensitive to glutamate.
A Deeper Metabolic Link to Disease
More recently, the spotlight has turned to glutamine, the amino acid that gives rise to glutamate in the body. Research published in ASN Neuro has revealed a striking new pathway: glutamine is not just used for respiration in tumor cells—it is fermented to fuel cancer. This fermentation occurs in both human and mouse glioblastoma cells, even in the absence of glucose and oxygen.
Traditionally, cancer was thought to rely primarily on glucose for energy. That view, rooted in Warburg’s early 20th-century theories, is now being expanded. This new research shows that cancer cells can generate ATP through mitochondrial substrate-level phosphorylation using glutamine alone.
Even when oxidative phosphorylation is blocked with cyanide or oxygen is removed entirely, ATP production continues—as long as glutamine is present. This fermentation process, distinct from the better-known glycolysis pathway, produces succinic acid as a waste product and reveals a second, powerful source of energy for cancer growth.
How MSG and Glutamine Fermentation May Feed Disease
Though glutamine and glutamate are not identical, they are metabolically interlinked. Glutamine is rapidly converted into glutamate inside the body, and both feed into similar metabolic cycles. This raises an important question: could chronic exposure to MSG—essentially dietary glutamate—impact the same cellular pathways now implicated in tumor metabolism?
While MSG does not directly cause cancer, its effects on glutamate signaling, oxidative stress, and metabolic function could, over time, support the kind of biochemical environment that allows malignancy to flourish. This is especially true for individuals with existing inflammation, metabolic syndrome, or mitochondrial dysfunction.
Systemic Organ Damage in Animal Studies
Beyond the brain, animal studies show that MSG can damage the liver, kidneys, and reproductive organs. Chronic MSG exposure has been linked to oxidative stress, cellular degeneration, and hormonal abnormalities—factors that can contribute to a wide range of chronic diseases. In rodent models, MSG disrupts insulin and leptin sensitivity, leading to obesity and reproductive failure even without increased caloric intake.
Human studies remain more limited, but many people report symptoms of MSG sensitivity, including migraines, flushing, asthma attacks, and blood pressure spikes. Up to 30% of people may be vulnerable to these effects, yet they often have no idea they’re consuming MSG due to deceptive food labeling.
How the Food Industry Hides MSG
Manufacturers frequently use alternative names for MSG and its analogues to avoid public backlash.
Ingredients like “yeast extract,” “autolyzed yeast,” “hydrolyzed protein,” and “natural flavors” can all contain free glutamate—the very compound responsible for MSG’s physiological impact.
Even “organic” and “natural” labels are not exempt from these additives, making it difficult for consumers to avoid exposure.
Glutamine Fermentation: A Cancer Breakthrough
The implications of the new glutamine fermentation research are far-reaching. Not only does this research reveal a second major fermentable fuel in cancer, but it also offers a potential path for non-toxic cancer therapies.
When both glucose and glutamine are restricted—using dietary strategies like nutritional ketosis combined with drug interventions—tumor growth is drastically reduced in vivo. This dual-fuel targeting deprives cancer cells of the very energy sources they rely on, without harming healthy tissue.
This finding resolves a longstanding gap in Warburg’s theory. While he correctly identified cancer as a disease of mitochondrial dysfunction and fermentation, he did not recognize glutamine as a fermentable fuel. Today’s research shows that glutamine, not just glucose, is driving the fermentation-based energy production that sustains tumor growth.
A Call for Caution and Reform
MSG continues to be labeled as “generally recognized as safe” by the FDA, despite decades of evidence linking it to neurological, metabolic, and organ damage. The newest findings on glutamine fermentation add even more urgency to reevaluate this stance.
If tumor cells are addicted to glutamine and glutamate, then dietary exposure to excessive free glutamate—especially from hidden sources—should be viewed with increased caution.
Consumers, especially those with chronic health conditions or a family history of cancer, should take steps to reduce their exposure to glutamate-rich additives. Meanwhile, researchers and clinicians are now rethinking cancer treatment through the lens of metabolic management, aiming to cut off the fermentable fuels that tumors depend on.
This is not just a food safety issue—it’s a public health imperative.
