Researchers studied 2,760 older adults to understand if a substance called methylmalonic acid (MMA) in the blood affects thinking and memory skills. They found that people with higher levels of this chemical performed worse on tests of memory, language, and attention. Those with the highest MMA levels were about 50% more likely to have poor overall thinking skills compared to those with lower levels. While this discovery is interesting, scientists still need to figure out exactly why this happens and whether lowering MMA could actually improve brain health in older people.

The Quick Take

  • What they studied: Whether a chemical in the blood called methylmalonic acid (MMA) is connected to problems with memory, thinking, language, and attention in older people
  • Who participated: 2,760 older adults with an average age of 69 years old, about half men and half women, from a large national health survey in the United States
  • Key finding: People with higher blood levels of MMA had worse performance on thinking tests, especially for language and attention. Those with the highest MMA levels were 53% more likely to have poor overall thinking skills compared to those with the lowest levels
  • What it means for you: This research suggests that MMA might be a warning sign for thinking problems in older age, but it doesn’t prove that MMA causes these problems. More research is needed before doctors can use this information to prevent memory loss or dementia

The Research Details

This was a cross-sectional study, which means researchers looked at a large group of people at one point in time rather than following them over years. The scientists measured the amount of MMA in participants’ blood using a laboratory technique called gas chromatography/mass spectrometry, which is very accurate at detecting small amounts of chemicals. They then gave all participants a series of thinking and memory tests to evaluate four different brain skills: immediate memory (remembering something just told to you), delayed memory (remembering something from earlier), language ability (understanding and using words), and attention (focusing on tasks).

The researchers also created an overall thinking score by combining results from all the tests. Additionally, participants answered questions about whether they felt their own memory and thinking had gotten worse. The scientists used statistical methods to look for connections between MMA levels and thinking performance, while accounting for other factors that might affect brain health like age, education, and overall health conditions.

This research approach is important because it uses real-world data from thousands of people rather than just a small group in a lab. By measuring actual blood levels of MMA and giving standardized thinking tests, the researchers could see if there’s a real connection between this chemical and brain function. However, because this is a snapshot in time rather than following people over years, it can show a connection but not prove that one thing causes the other.

This study has several strengths: it included a large, diverse group of older adults from across the United States, used precise laboratory methods to measure MMA, and gave standardized thinking tests to everyone. The researchers also adjusted their analysis to account for other factors that could affect thinking skills. However, the study is limited because it only shows a connection at one point in time, not whether changes in MMA actually cause thinking problems. The study also relied on self-reported information about cognitive decline, which may not be as accurate as objective testing.

What the Results Show

The main finding was that older adults with higher blood levels of MMA performed worse on thinking and memory tests. Specifically, people with MMA levels of 250 or higher (compared to those below 170) were about 53% more likely to have poor overall thinking skills. They were also 56% more likely to have language problems and 48% more likely to have attention difficulties.

When researchers looked at the actual test scores rather than just comparing high and low groups, they found that each increase in MMA was associated with lower scores on overall thinking tests and attention tests. The connection was strongest for language ability and attention, while the link to memory was less clear.

Interestingly, the study also found that people with higher MMA reported feeling like their thinking had gotten worse, though this self-reported decline wasn’t as strongly connected to MMA levels as the actual test results were.

The study found that the connection between MMA and poor thinking was consistent across different age groups and between men and women. The relationship held true even after accounting for other health conditions and factors that typically affect brain health in older adults. This suggests that MMA might be an independent marker of thinking problems, separate from other known risk factors.

This is one of the first studies to look at MMA and thinking problems in older adults. Previous research had shown that MMA accumulates with age and is linked to cancer risk, but little was known about its connection to brain health. This study adds a new piece to the puzzle of what causes memory and thinking problems as we age, though it doesn’t contradict or strongly support any previous findings since this connection hadn’t been well studied before.

The biggest limitation is that this study only looked at people at one point in time, so it can’t prove that MMA actually causes thinking problems—only that they’re connected. It’s possible that something else causes both high MMA and poor thinking. The study also couldn’t explain why this connection exists or what biological processes might be involved. Additionally, the thinking tests were relatively brief, and the study relied partly on people’s own reports about their memory problems, which may not be completely accurate. Finally, the study included mostly older adults from the United States, so results might not apply to younger people or other populations.

The Bottom Line

Based on this research, there is currently no specific recommendation to test for or treat MMA levels to prevent thinking problems. The evidence suggests a connection but doesn’t prove cause and effect. If you’re concerned about memory or thinking changes, talk to your doctor about standard approaches like staying mentally active, exercising, eating a healthy diet, and managing conditions like high blood pressure and diabetes. Future research may lead to new recommendations about MMA testing and treatment.

This research is most relevant to older adults concerned about memory loss and their doctors. It may be of particular interest to people with family histories of dementia or those experiencing thinking changes. However, this is early-stage research, and people shouldn’t change their health habits based solely on this study. People with vitamin B12 deficiency (which can raise MMA levels) should continue working with their doctors on this known issue.

This study doesn’t tell us how quickly changes in MMA might affect thinking or how long it would take to see improvements if MMA levels were lowered. More research following people over months and years would be needed to understand the timeline for any effects.

Want to Apply This Research?

  • Track cognitive performance monthly using simple self-assessments: note any changes in memory recall (remembering names, appointments), language use (finding words, understanding conversations), and attention span (ability to focus on tasks). Rate each area on a scale of 1-10 to spot trends over time
  • Use the app to set reminders for brain-healthy habits that may support cognitive function: daily mental exercises (puzzles, reading), physical activity (30 minutes most days), and tracking B12-rich foods (meat, fish, eggs, fortified cereals) since B12 deficiency raises MMA levels
  • Create a quarterly cognitive check-in where you review your self-assessment scores and note any patterns. Share this information with your doctor during annual visits to catch any concerning changes early and discuss whether MMA testing might be appropriate for your situation

This research shows a connection between methylmalonic acid levels and thinking problems in older adults, but it does not prove that MMA causes cognitive decline. This study should not be used to self-diagnose or self-treat any condition. If you’re experiencing memory loss, confusion, or other thinking changes, consult with a healthcare provider for proper evaluation and diagnosis. Do not request MMA testing or make changes to your health regimen based solely on this research. Always discuss any concerns about cognitive health with your doctor, who can evaluate your individual situation and recommend appropriate screening or treatment options.