Suboptimal Dietary Patterns Are Associated with Accelerated Biological Aging in Young Adulthood: a Twin Study

Background & aims Suboptimal diets increase morbidity and mortality risk. Epigenetic clocks are algorithms that can assess health and lifespan, even at a young age, before clinical manifestations of diseases. We investigated the association between dietary patterns and biological aging in young adult twins. Methods The data were drawn from the population-based FinnTwin12 study and consisted of twins aged 21-25 years (n=826). Food and beverage intakes were assessed using a food frequency questionnaire. Biological aging was estimated using the epigenetic clocks GrimAge and DunedinPACE. Latent class analysis was used to identify dietary patterns. The association between dietary patterns and biological aging was assessed using linear regression modeling at the individual level, followed by within-twin pair analyses to account for genetic liabilities and shared familial confounders. Results Six dietary patterns were identified: 1) High fast food, low fruits and vegetables (F&V), 2) Plant-based, 3) Health-conscious, 4) Western with infrequent fish, 5) Western with regular fish, and 6) Balanced average. At the individual level, GrimAge acceleration was slower in the Plant-based, Health-conscious, and Balanced-average patterns compared to the High fast food, low F&V, and faster in the Western with infrequent fish pattern compared to the Balanced average, regardless of sex, nonalcoholic energy intake, smoking, and alcohol consumption. After further adjustment for BMI and sports participation, the strengths of the associations modestly decreased; however, the difference between the Balanced-average and High fast food, low F&V patterns remained significant. The pace of aging (DunedinPACE) was slower in the Plant-based pattern compared to the High fast food, low F&V and the Western with infrequent fish patterns after adjustment for sex, nonalcoholic energy intake, smoking, and alcohol. The effect sizes were attenuated and reached a non-significant level when BMI and sports participation were added to the model. Most of the associations were replicated in the within-pair analyses among all twin pairs and among dizygotic twin pairs, but the effect sizes tended to be smaller among monozygotic twin pairs. This suggests that genetics, but not a shared environment, may partially explain the observed associations between diet and biological aging. Conclusion Diets high in fast food, processed red meat, and sugar-sweetened beverages and low in fruits and vegetables are associated with accelerated biological aging in young adulthood. The clustering effect of lifestyle factors and genetic confounders should be considered when interpreting the findings. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement SR is supported by the Juho Vainio Foundation. ES is supported by the Research Council of Finland (grant numbers 358894, 361981, 341750, 346509, 260001), the Juho Vainio Foundation, the Paivikki and Sakari Sohlberg Foundation, and the Yrjo Jahnsson Foundation (6168). MO is supported by the Research Council of Finland (grant numbers 328685, 307339, 297908 and 251316), Minerva Foundation, Liv o Halsa sr., and the Sigrid Juselius Foundation. KHP is supported by the Research Council of Finland (grant numbers 272376, 266286, 314383, 335443), Finnish Medical Foundation, Signe and Ane Gyllenberg Foundation, Novo Nordisk Foundation (NNF10OC1013354, NNF17OC0027232, NNF20OC0060547), Finnish Diabetes Research Foundation, Paulo Foundation, University of Helsinki and Helsinki University Hospital, and Government Research Funds. AH is supported by the University of Helsinki, Faculty of Medicine, Doctoral School of Population Health (DOCPOP). Phenotype and genotype data collection in the FinnTwin12 study has been supported by the Wellcome Trust Sanger Institute, the Broad Institute, ENGAGE - European Network for Genetic and Genomic Epidemiology, FP7-HEALTH-F4-2007, grant agreement number 201413, National Institute of Alcohol Abuse and Alcoholism (grants AA-12502, AA-00145, and AA-09203 to R J Rose; AA15416 and K02AA018755 to D M Dick; and AA015416 to Jessica Salvatore) and the Research Council of Finland (grants 100499, 205585, 118555, 141054, 264146 and 308248 to J Kaprio). J Kaprio acknowledges support by the Research Council of Finland (grants 265240, 263278) and by the Research Council of Finland Centre of Excellence in Complex Disease Genetics (grants 312073, 336823 and 352792). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the Institutional Review Board of Indiana University and the ethics committees of the University of Helsinki and Helsinki University Central Hospital (113/E3/2001 and 346/E0/05). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data are available for qualified researchers through a standardized application procedure (see the website (https://thl.fi/en/research-and-development/thl-biobank/for-researchers) for details.