A supplement could ease brain fog and cognitive symptoms for patients who have undergone treatment for breast cancer, a new study has found.
Researchers at the University of California, Los Angeles, found that the naturally occurring compound oxaloacetate could alleviate some of the side effects of chemotherapy, which includes brain fog and fatigue. Oxaloacetate is known for being essential for human energy production and is involved in many fundamental metabolic reactions.
The study was published in the journal JCO Oncology Advances on October 20.
Studies have previously found that fatigue and cognitive impairment are "frequently" reported among survivors of breast cancer, and that these symptoms may persist for several years after the end of primary treatment, negatively impacting quality of life.
The authors of this recent study noted that this cancer-related cognitive impairment has "emerged as one of the most concerning potential complications of cancer treatment."
"These are exciting early results from clinical trial that may lead to improved memory and thinking, or cognitive, issues often experienced by breast cancer patients on chemotherapy, sometimes called 'chemo brain,'" Mauricio Reginato, a professor of biochemistry and molecular biology at Drexel University who was not involved in the study, told Newsweek.
"Many types of chemotherapy used to treat breast cancer patients have an unintended effect of reaching the brain," he said. "These drugs can often cause side effects associated with 'brain fog' especially as drug doses are increased during treatment."
Breast cancer is the most common cancer in women in the U.S. after skin cancer, and accounts for around one in three new cancers each year, according to the American Cancer Society. Around one in eight American women will develop breast cancer.
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Cognitive Impairment Scores Improved After Eight Weeks
The study included 18 women who had received a diagnosis of early-stage breast cancer, who were at least 12 months after primary treatment (which included surgery, chemotherapy, and radiotherapy) and who had no evidence of active or recurrent breast cancer.
The participants had a mean age of 49.6 years. Most had received chemotherapy and 89 percent were currently receiving endocrine therapy. On average, they were around two years past their initial cancer diagnosis.
The participants were given 500 mg anhydrous enol-oxaloacetate capsules by mouth twice a day for eight weeks.
By the end of the eight weeks, all of the participants that continued the supplementation experienced a notable improvement of their cognitive impairment scores.
The mean cognitive score of the group had been 29.1, signaling impairment (any scores below 54 indicate impairment) and by the end of the eight weeks the group's mean score was 55.5.
Cognitive impairment was measured using the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) Perceived Cognitive Impairment (PCI) subscale, a self-report scale used to assess perceived cognitive difficulties in cancer survivors.
Cancer Survivors See Other Symptom Improvements
The 16 participants who continued oxaloacetate supplementation for the eight weeks also experienced a "significant improvement" in fatigue related symptoms, which the researchers noted could have supported the notable change in cognitive impairment scores.
Physical functioning also showed "dramatic improvement" over the course of the eight weeks, the researchers said.
There were also slight positive changes in other symptoms like insomnia, anxiety and depression, but these were not significant.
Were There Any Side Effects?
Across the course of the eight weeks, two women discontinued the treatment because of adverse effects. One experienced severe diarrhea in the first week, and the second also experienced gastrointestinal (GI) issues, including diarrhea.
Other participants did also report experiencing GI related symptoms including dyspepsia (indigestion), bloating, constipation, diarrhea, and nausea, though the researchers said that these were "mild" and that the supplement was largely "well-tolerated."
Reginato said that the causes of cancer-related cognitive impairment are "not entirely clear, but one possibility is that certain chemotherapy drugs that reach the brain trigger inflammation and increase glutamate release, contributing to cognitive problems."
"Excessive glutamate levels are known to cause damage in the brain," he said, adding that the study authors suggested the supplement may be "working as a glutamate 'sponge' and reduce the damage caused by chemotherapeutic drugs."
Given the small sample size, the researchers now need to see how the findings play out in a larger population. They are planning on doing a larger phase two placebo-controlled trial, plus an animal study to better understand the impact and function of oxaloacetate.
"More studies are needed to fully understand specific mechanisms of oxaloacetate in cancer-related cognitive impairment," Reginato said. "Although this study is still in its early stages, the findings offer hope for improving the quality of life of breast cancer patients by reducing the cognitive side effects associated with certain chemotherapy treatments."
Reference
Patricia A. Ganz et al. (2026) Results From a Phase II Single-Arm Trial Evaluating the Safety and Efficacy of Anhydrous Enol-Oxaloacetate on Improving Cognitive Complaints in Breast Cancer Survivors. JCO Oncology Advances. https://ascopubs.org/doi/10.1200/OA-26-00063
Contact Newsweek editors on this story: Marc Vargas and Paul Donnelley.