EPIGENETIC BENEFITS OF PLANT BASED DIET

UNVEILING THE EPIGENETIC IMPACT OF VEGAN VS. OMNIVOROUS DIETS ON AGING: INSIGHTS FROM THE TWINS NUTRITION STUDY (TWINS)

Varun B. Dwaraka^1*†, Lucia Aronica^2†, Natalia Carreras‑Gallo¹, Jennifer L. Robinson², Tayler Hennings³, Matthew M. Carter⁴, Michael J. Corley⁵, Aaron Lin¹, Logan Turner¹, Ryan Smith¹, Tavis L. Mendez¹, Hannah Went¹, Emily R. Ebel⁴, Erica D. Sonnenburg⁴, Justin L. Sonnenburg^4,6,7 and Christopher D. Gardner^2*

BMC Medicine   (2024) 22:301 An open access, transparent peer-reviewed general medical journal,

ABSTRACT

 Background

 Geroscience focuses on interventions to mitigate molecular changes associated with aging. Lifestyle modifications, medications, and social factors influence the aging process, yet the complex molecular mechanisms require an in‑depth exploration of the epigenetic landscape. The specific epigenetic clock and predictor effects of a vegan diet, compared to an omnivorous diet, remain underexplored despite potential impacts on aging‑related outcomes.

Methods

This study examined the impact of an entirely plant‑based or healthy omnivorous diet over 8 weeks on blood DNA methylation in paired twins. Various measures of epigenetic age acceleration (PC GrimAge, PC Pheno‑ Age, Dunedin PACE) were assessed, along with system‑specific effects (Inflammation, Heart, Hormone, Liver, and Metabolic). Methylation surrogates of clinical, metabolite, and protein markers were analyzed to observe diet‑specific shifts.

Results

Distinct responses were observed, with the vegan cohort exhibiting significant decreases in overall epigenetic age acceleration, aligning with anti‑aging effects of plant‑based diets. Diet‑specific shifts were noted in the analysis of methylation surrogates, demonstrating the influence of diet on complex trait prediction through DNA methylation markers. An epigenome‑wide analysis revealed differentially methylated loci specific to each diet, providing insights into the affected pathways.

Conclusions  

This study suggests that a short‑term vegan diet is associated with epigenetic age benefits and reduced calorie intake. The use of epigenetic biomarker proxies (EBPs) highlights their potential for assessing dietary impacts and facilitating personalized nutrition strategies for healthy aging. Future research should explore the long‑term effects of vegan diets on epigenetic health and overall wellbeing, considering the importance of proper nutrient supplementation.

BACKGROUND

While advances in technology and medicine have allowed the average person to live longer, age-related disease and impairment remain an issue that greatly impacts individuals and healthcare systems. Aging is associated with increases in health care costs and financial stress on social insurance systems [1]. In light of these challenges, the field of geroscience has emerged, proposing interventions aimed at slowing down or reversing the molecular changes that occur with aging. These interventions encompass a wide range of factors, including lifestyle modifications, nutrition, medications, sleep, and social factors, all of which can influence the aging process and potentially delay or prevent the onset of multiple chronic diseases, ultimately extending healthy lifespan [2–4]. Consequently, the exploration of nutritional and dietary recommendations has become an increasingly significant area of research within the broader field of aging, pro- viding insights into how dietary choices can impact the aging process and overall health outcomes.

However, unraveling the intricate molecular mechanisms through which diets influence aging necessitates a deeper understanding of the epigenetic landscape [5]. Epigenetic modifications, such as DNA methylation, have emerged as pivotal regulators of gene expression and provide a promising avenue for investigating the effects of vegan diets on the aging process [6]. The epigenetic effects of a vegan diet, in comparison to an omnivore diet, remain largely unexplored, with limited available evidence. Although certain studies have indicated potential positive impacts of specific components of a vegan diet, such as heightened intake of vegetables and fruits, on epigenetic aging, concerns have been raised regarding potential deficiencies in essential “epi-nutrients” necessary for effective epigenetic regulation [7]. Notably, vitamins and nutrients, including vitamin B12, vitamin B+, choline, vitamin D, omega-3 fatty acids, and zinc, are among the concerns associated with a vegan diet, as their availability may be compromised. Furthermore, other work on diets has aimed to discover the association between diets and longevity [8, 9]. For instance, the Mediterranean diet has been documented to slow the progression of frailty with aging [10]. Dietary protein intake is another important factor considered in aging and frailty, with many studies showing beneficial impacts of protein regardless of animal or plant origin [11]. These and other studies have provided mixed notions of a healthy vegan diet, necessitating additional interrogation of its impact on aging and disease outcomes, as measured by aging markers.

Epigenetic clocks, derived from DNA methylation pat- terns, have emerged as powerful tools for estimating bio- logical age and predicting age-related outcomes. These clocks have also been refined over time to incorporate known clinical factors, making them sensitive and reliable indicators of aging-related changes [12]. Additionally, epigenetic interpretation algorithms have proven valuable in predicting relative immune cell levels and protein expressions, providing insights into immune system functionality through immune deconvolution [13–15]. Moreover, these clocks can estimate the number of cell cycle divisions, reflecting cellular senescence and potential disease susceptibility [16].

While aging intervention studies face the challenge of requiring sufficiently long periods to show statistically significant effect, advancements in DNA based analysis, such as phenotypically and clinically trained DNAm clocks, have allowed for changes in the pace of aging and risk factors related to aging to be studied [17]. Epigenetic age trials using these epigenetic clocks have found that different diets such as a Mediterranean diet and DASH diet have shown improvements of aging pathways and markers, including protective effects of immunosenescence markers, activation of mTOR pathway, and epigenetic aging [18, 19]. In particular, a Mediterranean diet has been shown to both slow aging and delay the onset of frailty [20].

Given the discussion on which diets are most beneficial to longevity, this study aims to identify the effect of an 8-week plant-based or healthy omnivorous diet on blood DNA methylation in twins and evaluate age-related risk factors and health biomarkers. The novelty of this study includes the twin-pair study design which controls for genetic, age, and sex differences, while highlighting the methylation changes based on diet. Furthermore, this is the first study assessing the impact of epigenetic measures on twin-pair study design, and specifically addressed whether diet impacts such measures. Finally, we con- ducted a differential methylation analysis using the twin-pair design to identify potential DNAm markers which are related to the application of a healthy vegan or omnivorous diet, while also identifying DNAm markers which differentiate between diets. This comprehensive approach will provide insights into how diet type influences epigenetic dynamics and contribute to our understanding of potential interventions in the process of nutrition.

METHODS

Ethical approval and study design

Procedures adhered to the ethical standards of the Helsinki Declaration, approved by the Stanford University Human Subjects Committee (IRB protocol 63955, approved March 9, 2022). Written informed consent was obtained from all participants. The study, a single-site, parallel-group  dietary  intervention  trial,  randomized generally healthy adult twins to either a healthy vegan or omnivorous diet for 8 weeks. Enrollment commenced in March 2022, concluding in May 2022, with the final follow-up in July 2022. The trial employed the CONSORT reporting guideline for randomized clinical trials, focusing on the primary outcome: the 8-week change in DNA methylation profiles from baseline. Secondary outcomes encompassed triglycerides, HDL-C, glucose, insulin, TMAO, vitamin B12, and body weight, serving as controls for relevant methylation risk scores and were published previously [21]. Diet quality, adherence, and study design are illustrated in Fig. 1.

READ ENTIRE ARTICLE