According to Gram Research analysis of a 2026 cross-sectional study of 3,040 adults, men who ate more vitamin A, beta-carotene, vitamin K, and thiamin had significantly fewer cavities and missing teeth, while women eating more lutein and zeaxanthin showed similar benefits. The study found that vitamin A intake above the median was associated with 0.65 fewer dental problems in men, and thiamin intake showed a 0.84 reduction in tooth decay and missing teeth. However, because this study captured a single moment in time, researchers cannot prove that vitamins directly prevent tooth problems—only that people eating more vitamins tend to have healthier teeth.
A Gram Research analysis of nearly 3,000 adults in Iran found that people who ate more of certain vitamins had fewer dental problems. Men who consumed higher amounts of vitamins A, K, and B1 (thiamin) showed better tooth health, while women who ate more lutein and zeaxanthin (plant nutrients) had fewer cavities and missing teeth. The study couldn’t prove that vitamins directly cause better teeth, but it suggests that eating a vitamin-rich diet might be one way to protect your smile.
Key Statistics
A 2026 cross-sectional study of 3,040 Iranian adults published in Scientific Reports found that men consuming above-median amounts of vitamin A had 0.65 fewer decayed, missing, or filled teeth compared to those eating less.
According to the same 2026 study of 3,040 participants, men eating higher amounts of thiamin (vitamin B1) showed 0.84 fewer dental problems, while women eating more lutein and zeaxanthin had 0.92 fewer tooth issues.
Gram Research analysis of this 3,040-person study found that vitamin K intake above the median was associated with 0.72 fewer dental problems in men, suggesting a protective effect for tooth health.
In a 2026 analysis of 3,040 adults, beta-carotene intake above the median was linked to 0.82 fewer decayed, missing, or filled teeth in men, indicating a dose-dependent relationship with oral health.
The Quick Take
- What they studied: Whether eating different amounts of vitamins affects how many cavities, missing teeth, and filled teeth people have
- Who participated: 3,040 adults between ages 35-70 from Rafsanjan, Iran who were part of a larger health study that started in 2015
- Key finding: Men eating more vitamin A, beta-carotene, vitamin K, and thiamin had significantly fewer dental problems. Women eating more lutein and zeaxanthin (found in leafy greens) also had better tooth health.
- What it means for you: Eating more vitamin-rich foods might help keep your teeth healthier, though this study can’t prove vitamins directly prevent cavities. It’s one more reason to eat plenty of fruits, vegetables, and whole grains.
The Research Details
Researchers looked at information collected from 3,040 adults who were part of a large health study in Iran. They examined each person’s teeth and counted how many were decayed, missing, or filled (called the DMFT score). They also asked people what they ate using a detailed food questionnaire to figure out how many vitamins they were getting from their diet. Then they used math to see if people eating more vitamins had better or worse teeth. The researchers adjusted their results to account for other things that might affect tooth health, like age, smoking, and brushing habits.
This approach is important because it looks at real people’s actual eating habits and real tooth health, rather than just testing vitamins in a lab. However, because it’s a snapshot in time (not following people over years), we can’t be sure if vitamins actually prevent tooth problems or if people with healthier teeth just happen to eat better.
The study included a large number of people from a well-organized health study, which is good. Researchers measured actual tooth health by examining mouths directly, not just asking people. However, the study only looked at one point in time, so we can’t be completely sure about cause and effect. The results were different for men and women, which is interesting but needs more research to understand why.
What the Results Show
Among men in the study, those who ate more than the average amount of vitamin A had about 0.65 fewer dental problems on the DMFT scale. Men eating more beta-carotene (which the body converts to vitamin A) had 0.82 fewer problems, and those eating more vitamin K had 0.72 fewer problems. Thiamin (vitamin B1) showed similar benefits with 0.84 fewer dental problems for men eating higher amounts. For women, the pattern was different: those eating more lutein and zeaxanthin (nutrients found in spinach and kale) had 0.92 fewer dental problems. All of these differences were statistically significant, meaning they’re unlikely to be due to chance.
The study found that the benefits of vitamins appeared stronger in men than women for most nutrients tested. This gender difference is interesting but wasn’t fully explained by the researchers. Other B vitamins and vitamin C didn’t show the same clear connection to tooth health in this analysis, though this doesn’t mean they’re unimportant for teeth.
Previous research has suggested that vitamins play a role in tooth and gum health, but most studies focused on vitamin D or calcium. This study is broader, looking at many different vitamins at once. The findings support the idea that overall nutrition matters for teeth, not just one or two specific nutrients. However, most previous studies were also unable to prove that vitamins directly prevent tooth problems.
The biggest limitation is that this study is like taking a photograph at one moment in time—it shows what’s true right now but can’t prove that vitamins caused the better teeth. People who eat more vitamins might also brush their teeth better or visit the dentist more often. The study only included people from one region of Iran, so results might be different in other countries. Also, people had to remember what they ate, which isn’t always accurate.
The Bottom Line
Eat plenty of foods rich in vitamins A, K, and B vitamins (like leafy greens, carrots, whole grains, and eggs) as part of a healthy diet. For women, make sure to include foods with lutein and zeaxanthin like spinach, kale, and broccoli. These recommendations have moderate confidence because the study shows an association but can’t prove cause and effect. Continue regular brushing, flossing, and dental checkups—these remain the most proven ways to prevent tooth problems.
Anyone concerned about keeping their teeth healthy should pay attention to this research. It’s especially relevant for people who already have cavities or missing teeth and want to improve their oral health. People with vitamin deficiencies might particularly benefit from eating more vitamin-rich foods. However, this study doesn’t replace professional dental care or treatment for existing problems.
You won’t see results overnight. If vitamins do help protect teeth, the benefits likely build up over months and years of eating well. The best approach is to think of vitamin-rich eating as long-term tooth protection, not a quick fix.
Frequently Asked Questions
Do vitamins actually prevent cavities and tooth decay?
This study shows an association between higher vitamin intake and fewer cavities, but can’t prove vitamins directly prevent decay. People eating more vitamins may also have better overall health habits. More research is needed to confirm a direct cause-and-effect relationship.
Which vitamins are best for teeth health?
According to this 2026 study of 3,040 adults, vitamin A, beta-carotene, vitamin K, and thiamin showed the strongest associations with fewer dental problems in men. For women, lutein and zeaxanthin were most protective. These nutrients are found in leafy greens, carrots, and whole grains.
Can I take vitamin supplements instead of eating healthy foods?
This study measured vitamins from food, not supplements, so we don’t know if pills work the same way. Whole foods contain many nutrients beyond just vitamins that may benefit teeth. Eating actual foods is likely better than relying on supplements alone.
How long does it take for vitamins to improve tooth health?
This study was a snapshot in time, so it doesn’t show how quickly vitamins work. Tooth health improvements from better nutrition likely take months to years to develop, since teeth are constantly changing throughout life.
Are the results the same for men and women?
No. The 2026 study found different vitamins helped men versus women. Men benefited most from vitamins A, K, and B1, while women showed the strongest benefits from lutein and zeaxanthin. Researchers aren’t sure why these differences exist.
Want to Apply This Research?
- Track daily servings of vitamin A sources (carrots, sweet potatoes, spinach), vitamin K sources (leafy greens, broccoli), and B vitamin sources (whole grains, eggs, legumes). Aim for at least 3 servings daily and log them in your nutrition app.
- Add one vitamin-rich food to each meal this week: a handful of spinach in breakfast eggs, carrot sticks as a snack, or broccoli with dinner. Use the app to set daily reminders to include these foods.
- Track your vitamin intake weekly and correlate it with your dental health notes (any new sensitivity, gum changes, or dental visit results). Over 6-12 months, you may notice patterns between better nutrition and improved oral health.
This research shows an association between vitamin intake and tooth health but cannot prove that vitamins directly prevent cavities or tooth decay. The study was conducted in Iran and results may not apply to all populations. This information is not a substitute for professional dental care. Always consult your dentist about tooth problems and your doctor before making major dietary changes or starting supplements. If you have existing dental issues, seek professional treatment rather than relying on diet alone.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.