Scientists find hidden brain nutrient drop that may fuel anxiety

Researchers reported the results in the journal Molecular Psychiatry, part of the Nature publishing group. The team reviewed 25 previous studies and compared neurometabolite levels, which are chemicals created during brain metabolism, in 370 individuals with anxiety disorders and 342 people without anxiety.

The analysis showed that choline, an essential nutrient, was about 8% lower in those with anxiety disorders. This reduction was most clearly seen in the prefrontal cortex, a region involved in thinking, emotional regulation and decision-making.

"This is the first meta-analysis to show a chemical pattern in the brain in anxiety disorders," said Jason Smucny, co-author and assistant professor in the Department of Psychiatry and Behavioral Sciences. "It suggests nutritional approaches -- like appropriate choline supplementation -- may help restore brain chemistry and improve outcomes for patients."

Choline (pronounced KOE lean) supports cell membranes and key brain functions, including memory, mood and muscle control. The body produces only a small amount, so most choline must be obtained through food.

Anxiety Disorders Are Common and Often Undertreated

Anxiety disorders affect about 30% of adults.

Richard Maddock, the study's senior author, is a psychiatrist and research professor in the Department of Psychiatry and Behavioral Sciences. He also works with the UC Davis Imaging Research Center, which uses magnetic resonance imaging (MRI) to investigate brain health.

Maddock has spent decades treating patients with anxiety disorders and studying the biological factors that contribute to these conditions.

"Anxiety disorders are the most common mental illness in the United States, affecting about 30% of adults. They can be debilitating for people, and many people do not receive adequate treatment," Maddock said.

Anxiety disorders include:

• Generalized anxiety disorder
• Panic disorder
• Social anxiety disorders
• Phobias

How Brain Circuits and Chemicals Shape Anxiety

Anxiety disorders involve changes in how different parts of the brain process stress and potential threats. The amygdala, which helps determine whether situations feel safe or dangerous, and the prefrontal cortex, which plays a role in planning and decision-making, both respond differently in people with anxiety.

Chemical imbalances also contribute. For example, norepinephrine, a chemical involved in the body's "fight-or-flight" response, is often higher than normal in anxiety disorders.

Typically, the brain can distinguish between everyday challenges and genuinely harmful situations. In anxiety disorders, even manageable stressors can feel overwhelming. In generalized anxiety disorder, for instance, people may experience persistent worry about routine events and struggle to control their concerns.

MRI-Based Technique Reveals Brain Chemical Differences

Maddock and Smucny have long studied brain chemistry and its role in mental health using a non-invasive imaging method known as proton magnetic resonance spectroscopy, or 1H-MRS.

This approach uses an MRI machine to measure the chemicals present in brain tissue. Although it relies on the same magnetic fields and radio waves as standard MRI, 1H-MRS focuses on chemical composition rather than producing images.

Earlier work by Maddock showed reduced choline levels in patients with panic disorder. This prompted the decision to conduct a larger meta-analysis with Smucny. Even though they expected to see lower choline levels, Maddock was still struck by the size and consistency of the difference.

"An 8% lower amount doesn't sound like that much, but in the brain it's significant," Maddock said.

Diet May Influence Brain Choline Levels

The researchers believe that the heightened fight-or-flight activity common in anxiety disorders may increase the brain's demand for choline, which could lower its available levels.

"We don't know yet if increasing choline in the diet will help reduce anxiety. More research will be needed," Maddock said. He cautioned that people should not attempt to manage anxiety by taking large amounts of choline supplements.

He emphasized that a well-balanced diet supports both physical and mental health.

"Someone with an anxiety disorder might want to look at their diet and see whether they are getting the recommended daily amount of choline. Previous research has shown that most people in the U.S., including children, don't get the recommended daily amount," Maddock said. "Some forms of omega-3 fatty acids, like those found in salmon, may be especially good sources for supplying choline to the brain."

Foods that provide choline include beef liver, egg yolks, beef, chicken, fish, soybeans and milk, among others.