Study analysis · Clinical Epigenetics · 2025
A vegan diet might turn back your biological clock, but only if you're one of 5 people studied.
In a large Dutch study, vegans had blood markers that looked 2-3 years younger than meat eaters, but only 5 vegans were in the final analysis, so we can't be sure.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study is like taking a snapshot of people at one moment and looking at what they eat and how their bodies are aging at that time. It found that people who say they eat a vegan diet tend to have 'younger' biological age scores, but we can't tell if the diet caused that because we didn't follow them over time. It's like noticing that people who wear glasses tend to have books, but we don't know if reading causes the need for glasses.
What’s the bottom line?
Scientists looked at people's eating habits and a 'biological clock' in their blood (epigenetic age) to see if vegans age slower. They found that vegans seemed to have younger biological clocks than meat eaters, but only a few vegans were in the study, so we can't be sure.
How strong is this study?
This study had a very small number of vegans (only about 22 out of thousands), so the results might not be reliable. Also, the diet was reported by the people themselves, and the blood samples were taken years before the diet survey, so we're not sure if their diet at the time of the blood draw was the same. It's like asking people what they ate last week but measuring their health from a blood test last year.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
25 / 100
- Randomizationnot randomized
- Blindingnot blinded
- Control groupno control group
- Sample size (n=1198)+19.9/20
- Follow-upno follow-up reported
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 544 / 100
Probability of being correct
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
This design cannot establish causation — the findings describe an association, not a cause. Cross-sectional design measures exposure and outcome at the same time, so temporality cannot be established. Reverse causation is possible (people may adopt a vegan diet due to existing health conditions). Unmeasured confounders may exist, and the large time gap between dietary assessment and DNA methylation measurement precludes causal inference.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding sources declared; study appears to use public data from the Netherlands Twin Register.
The text does not include an explicit conflict of interest declaration or funding statement. The study uses previously collected data from the Netherlands Twin Register, which may reduce bias, but no specific safeguarding measures are described.
Key takeaways
- 01
In a group of about 1,200 people, vegans (only 5 of them) had blood markers that were about 2-3 years younger than meat eaters.
- 02
However, this was not found for other groups like vegetarians or pescetarians.
- 03
This is a small hint that a vegan diet might slow aging, but it's not strong enough to change health advice.
- 04
We need more research with bigger vegan groups.
Surprising findings
- The pork paradox: skipping pork is linked to slower aging, but skipping poultry is linked to faster aging.This contradicts the idea that all meat is equally bad; specific types may have different effects.
- Only vegans, not vegetarians or pescetarians, showed significant deceleration on some clocks, despite all being plant-based.You'd expect a gradient, but only the strictest group had a measurable effect, and that effect was only on two of five clocks.
- The small sample: only 5 vegans in the adjusted analysis, yet they drove the significant result.Such a tiny group can produce false positives, making the result more a curiosity than a solid finding.
Practical takeaways
If you're considering plant-based eating, note that vegans in this study also tended to have lower BMI, which is consistently linked to slower aging. However, the evidence is too weak to recommend going vegan solely for longevity.
Cross-sectional design, small vegan group, and temporal mismatch between diet and blood draw.
Low confidenceWhy this study matters
Vegan Diet and Biological Age
Using data from nearly 1,200 people, vegans showed significantly lower epigenetic age on the Hannum and Horvath clocks after adjusting for lifestyle factors. Vegans were on average 2.4 years 'younger' biologically. However, only 5 vegans had complete data, making the finding fragile.
It suggests diet might directly affect how fast we age at the cellular level, but the tiny sample size calls for caution.
Lifestyle Trumps Diet?
In the same model, higher education, physical activity, being female, and never smoking were all strongly associated with lower epigenetic age, while higher BMI accelerated it. These factors overshadowed diet in strength.
It reminds us that daily habits like exercise and not smoking might be more powerful than any specific diet.
The Pork/Poultry Paradox
People who avoided pork had slower aging according to the Dunedin Pace of Aging clock, but those who avoided poultry had faster aging on PhenoAge and DunedinPACE. This is confusing and needs more research.
It shows how specific foods might have opposite effects, and that blanket advice to cut out meat may be oversimplified.
The Cross-Sectional Limitation
Diet was surveyed in 2014-2016, but DNA methylation was from blood drawn in 2004-2011, so we don't know if people ate the same diet years earlier. Plus, causality can't be proven because of the observational design.
It explains why we shouldn't jump to conclusions—correlation isn't causation, and timing matters.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists looked at people's eating habits and a 'biological clock' in their blood (epigenetic age) to see if vegans age slower. They found that vegans seemed to have younger biological clocks than meat eaters, but only a few vegans were in the study, so we can't be sure.
Research results
In a group of about 1,200 people, vegans (only 5 of them) had blood markers that were about 2-3 years younger than meat eaters. However, this was not found for other groups like vegetarians or pescetarians.
What this means - more context
This is a small hint that a vegan diet might slow aging, but it's not strong enough to change health advice. We need more research with bigger vegan groups.
This study investigates whether plant-based diets, particularly veganism, are associated with decelerated biological aging as measured by epigenetic clocks in a Dutch population.
Using data from the Netherlands Twin Register, the study compared epigenetic age acceleration across dietary groups (meat eaters, pescetarians, vegetarians, vegans). After adjusting for confounders, veganism was significantly associated with lower epigenetic age on the Hannum and Horvath clocks. Lifestyle factors such as higher education, physical activity, being female, and never smoking were also associated with lower epigenetic age, while higher BMI was linked to higher epigenetic age. The study acknowledges small vegan sample sizes and the need for larger cohorts.
Methods Used
Cross-sectional analysis of 22,124 participants with dietary data, and DNA methylation data for 3,049 individuals. Epigenetic age was calculated using five clocks (Hannum, Horvath, PhenoAge, GrimAge, DunedinPACE). Generalized estimating equations (GEE) adjusted for age, sex, smoking, education, physical activity, BMI, and alcohol.
Main Finding
A vegan diet was significantly associated with reduced epigenetic age acceleration on the Hannum and Horvath clocks after adjustment. For example, vegans had a median deltaAge of -2.4 years on the Hannum clock compared to meat eaters. No other dietary group showed significant associations, and the vegan sample was very small (n=5 in adjusted analysis).
Confidence Level
Low to moderate. The cross-sectional design and very small vegan sample size limit causal inference. Results are suggestive but need replication in larger, prospective studies.
Study Flags
Red Flags
- •Very small vegan sample size (only 5 in adjusted analyses)
- •Cross-sectional design cannot establish causality
- •Time gap between dietary survey (2014-2016) and DNA methylation data (2004-2011)
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
The pork paradox: skipping pork is linked to slower aging, but skipping poultry is linked to faster aging.
This contradicts the idea that all meat is equally bad; specific types may have different effects.
Practical Takeaways
If you're considering plant-based eating, note that vegans in this study also tended to have lower BMI, which is consistently linked to slower aging. However, the evidence is too weak to recommend going vegan solely for longevity.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 544 / 100
Probability of being correct
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Human Cross-Sectional
Subject
Moderate probability
on the GRADE evidence scale
This study is like taking a snapshot of people at one moment and looking at what they eat and how their bodies are aging at that time. It found that people who say they eat a vegan diet tend to have 'younger' biological age scores, but we can't tell if the diet caused that because we didn't follow them over time. It's like noticing that people who wear glasses tend to have books, but we don't know if reading causes the need for glasses.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Used multiple epigenetic aging clocks (Hannum, Horvath, PhenoAge, GrimAge, DunedinPACE)
- Adjusted for important confounders including age, sex, smoking, education, physical activity, BMI, and alcohol
- Utilized family-relatedness in GEE models to account for clustering
Weaknesses
- Cross-sectional design does not allow for temporal assessment
- Very small number of vegan participants (n=22 overall, only 5 with complete data)
- Dietary data collected after DNA methylation samples (time gap of 3-12 years)
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists looked at people's eating habits and a 'biological clock' in their blood (epigenetic age) to see if vegans age slower. They found that vegans seemed to have younger biological clocks than meat eaters, but only a few vegans were in the study, so we can't be sure.
Research results
In a group of about 1,200 people, vegans (only 5 of them) had blood markers that were about 2-3 years younger than meat eaters. However, this was not found for other groups like vegetarians or pescetarians.
What this means - more context
This is a small hint that a vegan diet might slow aging, but it's not strong enough to change health advice. We need more research with bigger vegan groups.
This study investigates whether plant-based diets, particularly veganism, are associated with decelerated biological aging as measured by epigenetic clocks in a Dutch population.
Using data from the Netherlands Twin Register, the study compared epigenetic age acceleration across dietary groups (meat eaters, pescetarians, vegetarians, vegans). After adjusting for confounders, veganism was significantly associated with lower epigenetic age on the Hannum and Horvath clocks. Lifestyle factors such as higher education, physical activity, being female, and never smoking were also associated with lower epigenetic age, while higher BMI was linked to higher epigenetic age. The study acknowledges small vegan sample sizes and the need for larger cohorts.
Methods Used
Cross-sectional analysis of 22,124 participants with dietary data, and DNA methylation data for 3,049 individuals. Epigenetic age was calculated using five clocks (Hannum, Horvath, PhenoAge, GrimAge, DunedinPACE). Generalized estimating equations (GEE) adjusted for age, sex, smoking, education, physical activity, BMI, and alcohol.
Main Finding
A vegan diet was significantly associated with reduced epigenetic age acceleration on the Hannum and Horvath clocks after adjustment. For example, vegans had a median deltaAge of -2.4 years on the Hannum clock compared to meat eaters. No other dietary group showed significant associations, and the vegan sample was very small (n=5 in adjusted analysis).
Confidence Level
Low to moderate. The cross-sectional design and very small vegan sample size limit causal inference. Results are suggestive but need replication in larger, prospective studies.
Study Flags
Red Flags
- •Very small vegan sample size (only 5 in adjusted analyses)
- •Cross-sectional design cannot establish causality
- •Time gap between dietary survey (2014-2016) and DNA methylation data (2004-2011)
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
The pork paradox: skipping pork is linked to slower aging, but skipping poultry is linked to faster aging.
This contradicts the idea that all meat is equally bad; specific types may have different effects.
Practical Takeaways
If you're considering plant-based eating, note that vegans in this study also tended to have lower BMI, which is consistently linked to slower aging. However, the evidence is too weak to recommend going vegan solely for longevity.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 544 / 100
Probability of being correct
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Human Cross-Sectional
Subject
Moderate probability
on the GRADE evidence scale
This study is like taking a snapshot of people at one moment and looking at what they eat and how their bodies are aging at that time. It found that people who say they eat a vegan diet tend to have 'younger' biological age scores, but we can't tell if the diet caused that because we didn't follow them over time. It's like noticing that people who wear glasses tend to have books, but we don't know if reading causes the need for glasses.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Used multiple epigenetic aging clocks (Hannum, Horvath, PhenoAge, GrimAge, DunedinPACE)
- Adjusted for important confounders including age, sex, smoking, education, physical activity, BMI, and alcohol
- Utilized family-relatedness in GEE models to account for clustering
Weaknesses
- Cross-sectional design does not allow for temporal assessment
- Very small number of vegan participants (n=22 overall, only 5 with complete data)
- Dietary data collected after DNA methylation samples (time gap of 3-12 years)
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
This study had a very small number of vegans (only about 22 out of thousands), so the results might not be reliable. Also, the diet was reported by the people themselves, and the blood samples were taken years before the diet survey, so we're not sure if their diet at the time of the blood draw was the same. It's like asking people what they ate last week but measuring their health from a blood test last year.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
25 / 100
- Randomizationnot randomized
- Blindingnot blinded
- Control groupno control group
- Sample size (n=1198)+19.9/20
- Follow-upno follow-up reported
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 544 / 100
Probability of being correct
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
This design cannot establish causation — the findings describe an association, not a cause. Cross-sectional design measures exposure and outcome at the same time, so temporality cannot be established. Reverse causation is possible (people may adopt a vegan diet due to existing health conditions). Unmeasured confounders may exist, and the large time gap between dietary assessment and DNA methylation measurement precludes causal inference.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding sources declared; study appears to use public data from the Netherlands Twin Register.
The text does not include an explicit conflict of interest declaration or funding statement. The study uses previously collected data from the Netherlands Twin Register, which may reduce bias, but no specific safeguarding measures are described.