Glutamate is a chemical messenger in the brain that plays a crucial role in learning and memory. It also helps regulate mood.
Abnormal glutamate levels
In this article, we provide a definition of glutamate and explain its function in the body and its role in neurological and psychiatric diseases. We also provide information on healthy glutamate levels, including how to raise or lower them accordingly. Finally, we answer some frequently asked questions about glutamate.
Glutamate is a type of neurotransmitter. A neurotransmitter is a chemical messenger that carries messages from nerve cells or “neurons” to cells in other bodily tissues. Glutamate is an excitatory neurotransmitter, meaning that it stimulates cells into action.
Glutamate is the primary excitatory neurotransmitter in the central nervous system (CNS). It works by binding to glutamate receptors on neurons. In the brain, this process can trigger different functions, such as cognitive, motor, and sensory functions.
As glutamate is so abundant, it contributes to many different bodily functions. Examples include:
- relaying signals between neurons
- developing memories
- increasing immunity
- improving gut function
A 2021 review notes that glutamate is important for neuroplasticity, which is the brain’s ability to adapt or change over time. According to the author, glutamate also helps with managing stressors and regulating mood.
Ongoing stress can have a negative effect on the levels of glutamate and its function. Abnormal glutamate levels may contribute to certain diseases or health conditions, including those below.
According to a 2015 review article, an excess of glutamate in the brain can lead to neuron damage. This damage may contribute to certain neurodegenerative diseases, including:
- Huntington’s disease
- Alzheimer’s disease
However, research into how excess glutamate contributes to these conditions is limited. Further studies are necessary to help scientists understand this process more fully.
Monosodium glutamate (MSG) is an artificial form of glutamate. It is a type of food additive that helps enhance the flavor of certain foods.
A 2020 review notes that too much dietary glutamate may contribute to certain psychiatric conditions, such as anxiety, depression, and psychosis.
According to the review, it is possible that reducing added glutamate in the diet may improve mental health in certain cases. However, further high quality clinical trials are necessary to determine whether this is the case.
Glutamate is present in multiple bodily tissues. Special cells in the blood-brain barrier help transport glutamate into the blood, maintaining healthy glutamate levels throughout the CNS and the rest of the body.
The level of glutamate in the blood varies widely, even among healthy individuals. In one 2017 study, the mean blood glutamate level among healthy individuals was 0.87 nanomoles per milliliter (nmol/ml).
Elevated levels of glutamate may lead to negative health outcomes. For example, the 2017 study found that individuals with multiple sclerosis (MS) tend to have higher-than-average glutamate levels, with a mean of 1.32 nmol/ml.
Added glutamate in the diet can disrupt healthy glutamate levels. This happens most often with the flavor enhancer monosodium glutamate (MSG). This additive first appeared in the United States in the 1940s. In the past few decades, it has become a popular ingredient in many food products.
A 2019 review of the toxicological effects of MSG states that excessive consumption of this additive can negatively affect health. According to the review, it can affect health by:
- increasing cholesterol levels
- increasing bleeding and clotting time
- disrupting certain hormones, including testosterone, estrogen, and progesterone
- increasing body weight and the risk of obesity
- increasing the risk of liver and kidney damage
It is important to note that glutamate is not hazardous in itself. The human body naturally produces and uses glutamate. Rather, it is the artificial version of glutamate in MSG that may prove harmful in excess.
A 2016 study found that partaking in exercise can help raise glutamate levels. In this study, a session of vigorous exercise increased glutamate by nearly 5% after about 20 minutes. Glutamate levels returned to baseline about 34 minutes after the exercise session.
This study also found that maintaining higher physical activity levels for a week can increase baseline glutamate levels the following week. The researchers suggest that this finding may be beneficial for people who have depression, as these individuals have lower glutamate levels.
Certain dietary changes may help reduce glutamate levels. Limiting the intake of foods high in glutamate can help. Examples of such foods include:
- dairy products
- meat, poultry, and fish
- some high protein vegetable sources
The authors state that intermittent fasting can help reduce the symptoms or progression of neurodegenerative diseases. However, further clinical trials are necessary to define the link between dietary changes, glutamate levels, and neurodegenerative diseases.
Below, we answer some common questions about glutamate.
How does alcohol affect glutamate levels?
Alcohol leads to the short-term
However, a 2015 review notes that long-term alcohol consumption can actually increase glutamate levels. This can worsen the effects of alcohol withdrawal, making it harder for a person to quit drinking.
What sources of glutamate are available?
A person can acquire glutamate from a range of dietary sources. Glutamate is available in many different vegetable and animal proteins. It is also present as an additive in various processed foods.
Some common food sources of glutamate include:
- ripened cheeses
- raw or sundried tomatoes
- soy sauce
- cured meats
- tree nuts
- raw watermelon
- soft white bread rolls
Glutamate is an abundant neurotransmitter that plays an important role in cognitive processes, such as learning and memory. It is also an important mood regulator.
However, abnormally high glutamate levels may increase a person’s risk of certain neurological conditions, such as Alzheimer’s disease, Huntington’s disease, and ALS. Research also highlights an association between excessive dietary glutamate in the form of MSG and mental health conditions, such as depression and anxiety.
A person may be able to restore healthy glutamate levels through certain dietary and lifestyle adjustments. A person with low levels may benefit from increasing their consumption of glutamate-rich foods and their levels of exercise. A person with high levels should avoid frequent alcohol consumption and glutamate-rich foods.
A person may wish to speak with a doctor for individual advice on how to achieve healthy glutamate levels.