Keeping more of your natural teeth is linked to a lower risk of developing memory and thinking problems as you age, according to a 10-year study of 4,364 older Chinese adults. Gram Research analysis found that people with the most natural teeth had a 19% lower risk of cognitive impairment compared to those with the fewest teeth, with the protective effect strongest in adults over 70 years old. The connection may partly work through diet, since natural teeth allow people to eat more varied and nutritious foods.
A major study following over 4,000 older Chinese adults for 10 years found that people who kept more of their natural teeth were less likely to develop memory and thinking problems as they aged. Gram Research analysis shows that for every 20 additional natural teeth someone had, their risk of cognitive decline dropped by 14%. The connection appeared strongest in people over 70 years old. Researchers also discovered that eating a more varied diet might explain part of this link, suggesting that natural teeth help people eat better foods, which in turn supports brain health.
Key Statistics
A 10-year cohort study of 4,364 older Chinese adults published in 2026 found that each additional 20 natural teeth reduced the risk of cognitive impairment by 14%, with the strongest protection observed in participants aged 70 and older.
Over a median follow-up of 6 years in the Chinese Longitudinal Healthy Longevity Survey, 42% of participants developed cognitive impairment, but those in the highest tooth-count quartile had a 19% lower risk compared to those in the lowest quartile.
Dietary diversity accounted for approximately 10% of the protective association between natural tooth count and cognitive health in older adults, suggesting that the ability to eat varied foods partially explains the tooth-cognition link.
The Quick Take
- What they studied: Whether the number of natural teeth a person has affects their chances of developing memory problems and cognitive decline later in life.
- Who participated: 4,364 older Chinese adults who started the study in 2008 with normal thinking and memory skills. Researchers checked on them regularly through 2018, tracking how many natural teeth they had and testing their mental abilities over time.
- Key finding: People with more natural teeth had significantly lower risk of developing cognitive impairment. Those with the most teeth had a 19% lower risk compared to those with the fewest teeth. This protective effect was especially strong in adults aged 70 and older.
- What it means for you: Keeping your natural teeth as you age may help protect your brain function. This gives you another important reason to maintain good dental health throughout your life. However, this study shows an association, not proof that teeth directly prevent cognitive decline, so more research is needed.
The Research Details
This was a long-term follow-up study, meaning researchers tracked the same group of people over many years to see what happened to them. In 2008, they enrolled 4,364 older Chinese adults who had normal memory and thinking abilities. Every few years through 2018, researchers counted how many natural teeth each person still had and gave them memory tests to check if they had developed cognitive impairment, which they defined as scoring below 24 on a standard memory test.
The researchers used a statistical method called Cox proportional hazards models to figure out whether people with more teeth were less likely to develop memory problems. They looked at tooth count in two ways: as a continuous number (comparing people with 20 more teeth) and by dividing people into four groups based on how many teeth they had. They also tested whether the relationship was straight or curved, and whether age changed how strong the connection was.
This research approach is powerful because it follows real people over a long time period, which helps establish whether tooth loss happens before cognitive decline or if they occur together. By measuring tooth count at the start and then tracking cognitive changes for up to 10 years, researchers could determine the timing of events. The study also explored whether diet quality might explain the connection, which helps us understand the mechanism behind the association.
This study has several strengths: it included a large number of participants (4,364), followed them for a substantial period (median 6 years, up to 10 years), and used standardized tests to measure cognitive function. The researchers adjusted their analysis for many other factors that could affect brain health, including age, sex, education, physical activity, and health conditions. However, this is an observational study, meaning researchers watched what happened naturally rather than randomly assigning people to different tooth-loss conditions. Therefore, we cannot be certain that tooth loss directly causes cognitive decline, as other unmeasured factors could explain the connection.
What the Results Show
Over the 10-year study period, 1,835 participants (42%) developed cognitive impairment. People with more natural teeth had significantly lower risk. For every 20 additional natural teeth someone had at the start of the study, their risk of developing cognitive impairment dropped by 14% (hazard ratio 0.86). When researchers divided people into four groups by tooth count, those in the highest group (most teeth) had a 19% lower risk compared to those in the lowest group (fewest teeth).
The protective effect of having more teeth was strongest in adults aged 70 and older. In this older group, each additional 20 teeth reduced cognitive impairment risk by 27%. However, in younger participants (under 70), the tooth-teeth connection was much weaker and not statistically significant. This suggests that tooth preservation becomes increasingly important for brain health as people age.
Researchers explored whether dietary diversity might explain part of the tooth-cognition connection. They found that eating a wider variety of foods accounted for approximately 10% of the protective effect of having more teeth. This makes biological sense: people with more natural teeth can chew a greater variety of foods, including harder fruits, vegetables, and proteins, which may provide better nutrition for brain health. The relationship between tooth count and cognitive decline appeared to be linear, meaning there was no threshold effect where a certain number of teeth suddenly became protective.
This study adds important evidence to a growing body of research linking oral health to brain function. Previous studies have suggested connections between tooth loss and cognitive decline, but most were conducted in Western populations. This research extends those findings to older Chinese adults, suggesting the association may be universal across different populations. The finding that dietary diversity partially explains the connection provides a new mechanistic insight that earlier studies had not thoroughly explored.
This study cannot prove that having more teeth directly prevents cognitive decline. Other factors not measured in the study could explain both tooth loss and cognitive problems, such as systemic inflammation, genetic factors, or socioeconomic factors affecting both dental care and healthcare access. The study included only Chinese adults, so findings may not apply equally to other populations. Additionally, cognitive impairment was defined by a single test score rather than a clinical diagnosis, which could misclassify some participants. The mediation analysis exploring dietary diversity was exploratory and should be interpreted cautiously.
The Bottom Line
Maintain good dental hygiene and seek regular dental care to preserve your natural teeth as you age. This is especially important if you are over 70 years old. While this study does not prove that keeping your teeth prevents cognitive decline, it provides strong evidence that tooth preservation is associated with better brain health outcomes. Eating a varied diet rich in different foods may also support both dental and cognitive health. Moderate confidence: the evidence is observational, but the association is consistent and biologically plausible.
This finding is most relevant to adults over 70 who are concerned about maintaining cognitive health as they age. It applies to anyone considering tooth extraction or dental implants, as preserving natural teeth appears beneficial. People with family histories of cognitive decline or dementia should pay particular attention to dental health. The findings may be less directly applicable to younger adults, as the protective effect was not evident in those under 70.
Cognitive decline typically develops gradually over years. This study followed people for a median of 6 years, with some followed for up to 10 years. You should not expect immediate cognitive benefits from improved dental health, but maintaining natural teeth throughout your life may reduce your long-term risk of memory problems and cognitive impairment in your 70s and beyond.
Frequently Asked Questions
Does losing teeth cause memory problems and cognitive decline?
Research shows an association between tooth loss and cognitive impairment, but this study cannot prove tooth loss directly causes memory problems. The connection may work through diet quality or other factors. More research is needed to establish causality.
At what age does keeping natural teeth become important for brain health?
The protective effect of natural teeth on cognitive health was strongest in adults aged 70 and older. People under 70 did not show a significant association, suggesting tooth preservation becomes increasingly important for brain protection in your 70s and beyond.
How does eating different foods help protect your brain?
Natural teeth allow you to chew a wider variety of foods, including harder fruits, vegetables, and proteins. This dietary diversity provides different nutrients that support brain function. The study found diet quality explained about 10% of the tooth-cognition connection.
Can dental implants provide the same brain protection as natural teeth?
This study measured only natural teeth, not implants or dentures. While implants may help with eating varied foods, they may not provide identical benefits to natural teeth. More research comparing natural teeth to dental replacements is needed.
What should I do to protect my teeth and brain health?
Maintain good dental hygiene with twice-daily brushing and daily flossing, visit your dentist regularly, and eat a varied diet with different food groups. These habits support both dental health and cognitive function, especially as you age.
Want to Apply This Research?
- Track your dental health maintenance by logging dental visits, cleanings, and any tooth loss or dental procedures. Record the date and number of natural teeth remaining at each dental checkup. Correlate this with periodic cognitive self-assessments or memory tests to monitor any changes over time.
- Set reminders for twice-daily tooth brushing, daily flossing, and regular dental checkups every 6 months. Log these activities in the app to build consistency. Also track dietary diversity by recording the number of different food groups consumed each day, aiming for variety across fruits, vegetables, proteins, grains, and dairy.
- Create a long-term dashboard showing dental health status (number of natural teeth, dental visit frequency) alongside cognitive wellness indicators (memory self-tests, mental clarity ratings). Review this dashboard quarterly to identify any correlations between changes in dental status and cognitive function. Set annual goals for maintaining or improving both dental and cognitive health.
This research shows an association between natural tooth count and cognitive health in older adults but does not establish that tooth loss causes cognitive decline. Individual results vary based on genetics, overall health, and lifestyle factors. This information is not a substitute for professional medical or dental advice. Consult your doctor or dentist before making decisions about dental treatment or cognitive health management. People concerned about memory problems should seek evaluation from a healthcare provider for proper diagnosis and treatment.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.