Monosodium glutamate (MSG) is a popular food additive used to enhance flavor in processed foods.
But some evidence suggests MSG may have negative health effects, particularly on the brain.
Natural products like herbs and vitamins may help counteract MSG’s toxic effects.
Key Facts:
- MSG is a sodium salt added to foods to improve taste. It’s found in many processed and restaurant foods.
- Average intake ranges from 0.3-2.3 grams per day, with higher amounts in Asian countries.
- MSG may increase risk of obesity, liver toxicity, headaches, and reproductive issues. The greatest concern is neurotoxicity.
- Natural compounds like curcumin, gingerols, lycopene, and vitamins C, D, and E show protective effects against MSG in studies.
- Limiting MSG intake and eating more antioxidant-rich foods may reduce potential toxic effects. More research is still needed.
Source: Iran J Basic Med Sci
The Wide Use and Potential Risks of MSG
MSG, short for monosodium glutamate, is a common food additive used to enhance flavor.
First extracted from seaweed in 1908, it’s now made synthetically and added to a wide array of processed, canned, and fast foods.
MSG imparts a savory umami taste by exciting glutamate receptors in the mouth.
Average intake ranges from 0.3-1.0 grams per day in most Western nations.
But levels are higher in Asian countries at 1-2+ grams per day.
Some people appear sensitive to even small amounts of MSG and report adverse reactions like headaches, flushing, and heart palpitations after consuming MSG-laden foods.
A number of animal and cell studies indicate MSG may have toxic effects at high doses or long-term exposure:
- Obesity & Metabolic Issues: Rodent studies link high MSG doses to weight gain, fatty liver disease, insulin resistance, and elevated cholesterol and triglycerides. The effects may stem from MSG-induced leptin resistance.
- Liver Toxicity: MSG generates reactive oxygen species (ROS) and oxidative stress markers like lipid peroxides in the liver. This can impair liver function.
- Headaches & Neurotoxicity: MSG can overexcite neurons leading to oxidative damage, impaired signaling, and cell death in the brain. High glutamate levels are implicated in neurodegenerative disorders like Alzheimer’s.
- Reproductive Toxicity: Studies show MSG impairs sperm parameters and testosterone in male rodents. It may also impact ovulation and estrogen in females.
Other possible effects include mutagenicity and kidney toxicity.
While human data is limited, some epidemiological studies do link greater MSG consumption to weight gain and metabolic syndrome.
More research is still needed given MSG’s widespread use.
Antioxidant-Rich Foods May Counteract MSG’s Effects
A number of natural compounds show protective benefits against MSG toxicity in animal and cell studies.
Adding more of these antioxidant-rich foods to your diet may help mitigate MSG’s negative effects.
Key antioxidant and anti-inflammatory compounds include:
- Curcumin from turmeric
- Gingerols from ginger
- Lycopene from tomatoes
- Piperine from black pepper
- Rosmarinic acid from rosemary
- Vitamins C, D, and E
These compounds appear to combat MSG toxicity through different mechanisms:
- Neutralizing reactive oxygen species
- Suppressing inflammatory cytokines
- Inhibiting lipid peroxidation
- Boosting glutathione and antioxidant enzymes
- Reducing excitotoxic neuron death
- Lowering cholesterol, triglycerides, and glucose
Specific examples of foods and compounds that may counteract MSG include:
Turmeric: Curcumin prevented brain oxidative damage, improved cognition, and increased testosterone in MSG-treated rodents. It protects neurons by reducing inflammation and apoptosis.
Tomatoes: Lycopene lowered oxidative stress, prevented neuron death, and protected the kidneys in MSG models. It may suppress glutamate receptor overactivation.
Ginger: Gingerols inhibited MSG-induced lipid peroxidation in the brain and increased neurotransmitters. Anti-inflammatory effects likely contribute to neuroprotection.
Green Tea: Epigallocatechin gallate (EGCG) in green tea reduced weight gain, insulin, leptin, cholesterol, and liver enzymes in MSG rodent studies. Powerful antioxidant effects are responsible.
Vitamin C: Co-administration of vitamin C minimized MSG’s toxic effects in the liver, testes, thymus, and ovaries in animal studies. It reduces oxidative stress and inhibits proliferation.
Vitamin D: Vitamin D supplements mitigated weight gain, insulin resistance, and liver oxidative damage from MSG in rodents. It may suppress food intake and fat accumulation.
Vitamin E: α-Tocopherol reversed declines in glutathione and antioxidant enzymes while lowering liver enzymes and lipid peroxidation induced by MSG.
While more clinical studies are needed, current evidence suggests a diet high in antioxidant foods like turmeric, ginger, tomatoes, green tea, and vitamins C, D, and E may reduce some of MSG’s potential toxicity.
MSG’s Effects On The Brain: Excitotoxicity & Neurodegeneration
The greatest health concern with MSG revolves around its effects on the brain.
How exactly does MSG impact the brain and what natural compounds counteract its neurotoxicity?
MSG and Glutamate Excitotoxicity
Glutamate is the main excitatory neurotransmitter in the brain.
It plays key roles in cognition, learning, and memory.
MSG contains glutamate, and its effects in the brain largely stem from overactivating glutamate receptors.
In particular, MSG can overstimulate NMDA receptors.
Excess calcium then enters neurons leading to oxidative stress, protein misfolding, cell death pathways, and ultimately neuron damage or loss.
This “excitotoxicity” is implicated in neurodegenerative diseases like Alzheimer’s.
Animal studies show MSG can destroy hypothalamic neurons and alter neurotransmitters.
Neonatal MSG exposure caused neuroendocrine disorders linked to anxiety, depression, obesity, and pain perception changes.
High glutamate levels may also contribute to cognitive decline.
Antioxidant Foods Protect Neurons
Fortunately, many natural antioxidants can reduce MSG’s neurotoxic effects.
Curcumin, gingerols, lycopene, piperine, and rosemary extract lowered oxidative damage, prevented neuron loss, and improved cognition in MSG-treated animals.
Specific neuroprotective mechanisms include:
- Scavenging reactive oxygen species
- Suppressing microglia activation
- Reducing lipid peroxidation
- Increasing glutathione, SOD, and catalase
- Stabilizing neuron calcium levels
- Blocking apoptotic pathways
- Inhibiting inflammatory cytokines like NF-kB
Through these effects, antioxidants defend neurons from hyperexcitability, oxidative injury, and cell death induced by high MSG levels.
A diet rich in antioxidant foods may therefore protect the brain against MSG’s neurotoxic assault.
Key Takeaways: MSG’s Brain Effects and Natural Safeguards
In summary, key points to remember about MSG’s effects on the brain include:
- MSG overstimulates glutamate receptors leading to neuron hyperexcitability and oxidative damage – a process called excitotoxicity.
- Animal studies show it can destroy hypothalamus neurons, alter neurotransmitters, and impair cognition and mood.
- Curcumin, lycopene, gingerols, and other antioxidants reduce MSG’s neurotoxic effects by suppressing oxidative stress, inflammation, and apoptosis.
- Eating more antioxidant-rich foods like turmeric, ginger, and tomatoes may protect the brain against MSG’s effects. But more clinical studies are still needed.
Conclusion: MSG’s Safety is Controversial, so Limit Intake and Eat More Antioxidants
MSG is a popular flavor enhancer added to many processed foods, particularly in Asian cuisine.
But extensive use of MSG may not be entirely safe – animal and cell studies link high or chronic MSG intake to obesity, liver toxicity, headaches, neuron damage, and other effects.
Exact mechanisms involve overactivating glutamate receptors, inducing oxidative stress, and disrupting cell signaling and metabolism.
On the plus side, several natural antioxidants like curcumin, lycopene, gingerols, and vitamins C, D, and E show protective effects against MSG toxicity in animal models.
Adding more antioxidant-rich foods to your diet, like tomatoes, green tea, rosemary, and turmeric, can help counterbalance MSG’s negative effects.
Until more definitive human data is available, the prudent course is to limit processed foods with added MSG.
Cooking more meals at home with fresh, whole ingredients is a healthier approach.
Eating a diet high in colorful fruits, vegetables, teas, herbs, and spices may also confer protection against MSG’s potential health risks thanks to their high antioxidant content.
While MSG’s safety remains controversial, a little culinary wisdom and nutrition know-how can go a long way in promoting wellness.
References
- Study: Natural products as safeguards against MSG-induced toxicity
- Authors: Mohammad Mahdi Hajihasani et al. (2020)
