Key Points
New research suggests a nutritional supplement may help relieve brain fog associated with cancer treatment for some patients.A recent small study found that oxaloacetate supplementation was associated with reduced cognitive symptoms for breast cancer survivors.Experts say more research is needed.
Cancer treatments like chemotherapy can come with a lot of intense side effects, making an already difficult diagnosis even harder on your body. But a recent small study published in JCO Oncology Advances suggests that a nutritional supplement may help keep treatment side effects at bay.
Meet the experts: Patricia A. Ganz, M.D., study author, director of cancer prevention and control research of the Jonsson Comprehensive Cancer Center at UCLA Health, and Breast Cancer Research Foundation scientist; Larry Norton, M.D., breast medical oncologist and medical director of the Evelyn Lauder Breast Center at Memorial Sloan Kettering.
The researchers set out to test whether the nutritional supplement oxaloacetate may help combat symptoms of cognitive impairment—like brain fog—that commonly arise during and after cancer treatment. Among the 18 early-stage breast cancer survivors with cognitive complaints who were enrolled in the study, 16 reported noticing significant improvements in their cognition. And the researchers also noted improvements in their self-reported overall fatigue, mental fatigue, and physical function with oxaloacetate supplementation.
The findings are promising, but because the study was so small, it’s still too early to draw sweeping conclusions. Here’s what experts want you to know.
Why are the findings significant?
When someone gets a cancer diagnosis, their medical care becomes focused on treating the cancer. But the side effects that come with those treatments, like cognitive complaints, often aren’t addressed.
And these side effects aren’t uncommon, either—they affect “20 to 25% of breast cancer survivors,” according to Patricia A. Ganz, M.D., study author, director of cancer prevention and control research of the Jonsson Comprehensive Cancer Center at UCLA Health, yet we don’t currently have medications designed to treat them. That’s what she says makes this study promising. Along with helping cognitive complaints, the oxaloacetate also improved fatigue, insomnia, and physical functioning, she says.
As for how it works? While more research is needed to confirm an exact mechanism, researchers suspect that oxaloacetate, a naturally occurring compound, may help boost cognition in two ways: by reducing excess levels of glutamate (a neurotransmitter involved in learning and memory) that can build up in response to inflammation, and supporting energy production in the body’s cells. Both processes may be affected by cancer and its treatments. These potential effects have also drawn interest as potential avenues of treatment for conditions that cause similar symptoms, like the fatigue involved in long COVID.
The results may be encouraging, but that doesn’t mean oxaloacetate supplements are ready for widespread use among cancer patients. Again, only 18 people participated in the study, so more research needs to be done. There may also be side effects of oxaloacetate that haven’t yet been explored. “All medicines have good and not-so-good effects,” explains Larry Norton, M.D., breast medical oncologist and medical director of the Evelyn Lauder Breast Center at Memorial Sloan Kettering. “For this reason, it is important to follow the well-established processes that determine if the balance of good outweighs the downsides. This has not yet been accomplished with this compound.”
Dr. Ganz agrees. “Right now, we cannot recommend this supplement without future testing, but it is very encouraging to know that there is a medication that can reverse these bothersome post-treatment symptoms,” she says.
What does this mean for cancer patients?
The results of the study are an encouraging sign that common side effects of cancer treatments may soon have medications available to treat them. But there’s still a lot we don’t know about the cognitive effects many cancer patients experience and what actually causes them.
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“Cancer doctors and nurses are aware of these effects. We do discuss them with patients. And it is not just cancer treatments that can cause mental changes; many medicines and procedures (like anesthesia) can cause some mental ‘fogging,’” Dr. Norton explains. “We are also aware that there are correctable changes that can occur in anybody—anemia, sleep problems, depression, thyroid function, for example—that could be mistaken for drug-induced mental changes. So, the evaluation of ‘fog’ needs to be comprehensive.”
There are a lot of factors that may play a role in worsening cognitive impairment beyond the cancer treatments themselves, including stress and natural aging, according to Dr. Norton. “But it is now clear that some anticancer drugs are more likely than others to cause changes in brain functioning. Sometimes we can see changes on brain imaging, like an MRI,” he says.
What’s more, side effects—including but not limited to brain fog—are by no means a universal experience, according to Dr. Norton. “Many receive cancer treatment with no negative effects. And most drug-induced changes in mental functioning—when they occur—are mild and transient,” he says. “So, fear of these effects is not a good reason to avoid potentially lifesaving medicines.” The potentially lifesaving capabilities of cancer treatment drugs continue to outweigh other negative side effects, based on what we know now.
And remember that the same strategies we already use to treat brain fog caused by other things, like natural aging or menopause, can still apply to cancer patients. “The use of lists, prompts on smartphones, stickers on objects, and reinforcement (like saying things like ‘I am now putting my keys on the piano’ and ‘I am now locking the door’ out loud) can help,” Dr. Norton says. “But an overlooked aid is exercise; both structured—like yoga—and outdoor walking or using an exercise bicycle really do help.”
The bottom line
While we’re not yet ready to approve the use of oxaloacetate supplements for treating cognitive symptoms in cancer patients, this small study is an important first step in the right direction toward helping manage these types of issues.
Still, there’s more to consider, which Dr. Ganz hopes to address in future research. “We did not have a comparison group that was given a placebo, so the true amount of improvement may be more modest,” Dr. Ganz points out. “However, we plan to do that testing in a future study.”
In the meantime, the most important thing is to speak up about any cognitive symptoms you may be experiencing, because even if there aren’t yet approved medications to treat them, there are other things that can help. “Patients need to be reassured that their symptoms are real, that we want to take care of them in total, not just treat the cancer, and that there are ways to help them,” Dr. Norton stresses.
Dr. Ganz agrees. “Definitely let [your] doctors know that [you’re] having difficulty, as many things can cause these problems, such as having poor sleep or depressive symptoms,” she points out. “Both of these can be treated and help with the cognitive symptoms.”
Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.