by Lewis Chang, PhD
A century ago, the global average life expectancy of humans was around 32 years. Today, it is 73. Because we live much longer, aging is now a major risk factor for a myriad of modern-day chronic illnesses. For scientists to study aging-related health issues, one must find a scientific way to measure aging, a quantifiable biochemical marker that reflects our biological age, so to speak. Having the ability to detect changes in such a biomarker will allow researchers to study whether certain factors cause acceleration in aging and, as important, whether specific interventions can slow it (and by how much).
Enter epigenetic age, a futuristic-sounding biomarker whose concept was elegantly described in a journal editorial by Dr. Michael M. Mendelson (of Department of Cardiology from Boston Children’s Hospital) as “where a drop of blood is fed into a machine, in which an algorithm churns through an accumulation of chemical groups coating a strand of DNA and spits out an individual’s true age reflecting a lifetime of experiences and exposure.”1 Encouragingly, human studies are finding that this aging biomarker—based on DNA methylation patterns—correlates well with our chronological age.
For example, in a large cohort study called Atherosclerosis Risk in Communities (ARIC study), the investigators reported that classic cardiovascular disease risk factors such as smoking or type 2 diabetes were associated with acceleration of epigenetic age. Even after statistically adjusting for chronological age, sex, education, health behaviors, body weight, diabetes status, blood lipid panels, and more, epigenetic age acceleration remained associated with increased carotid intima-media thickness.2
Which brings us to the subject of this write-up: the first exploratory clinical trial to investigate whether nutrition and lifestyle intervention might affect epigenetic age.3 Forty-three healthy adult males between the ages of 50 and 72 were randomized to control group (receiving no intervention) or treatment group. The treatment comprised an 8-week multimodal intervention:
- Diet: plant-centered diet (e.g. 2 cups of dark leafy greens, 2 cups of cruciferous vegetables, and 3 cups of colorful vegetables per day), with limited nutrient-dense animal protein (e.g. up to 10 eggs per week), excluding sugar, candy, dairy, grains, and legumes. Eating window was set between 7 AM and 7 PM each day
- Sleep: a minimum of 7 hours per night
- Exercise: a minimum of 30 minutes per day for at least 5 days per week at an intensity of 60-80% of maximum perceived exertion
- Stress management: via breathing exercise twice daily
- Daily probiotic supplement containing the strain Lactobacillus plantarum 299v
- Daily phytonutrient supplement containing powder of organic vegetables, fruits, seeds, herbs, plant enzymes, prebiotics, and probiotics
And the results? The investigators found the intervention was associated with 3.23 years’ decrease in the biomarker of epigenetic age compared with control.3 Meaning: Reengaging in healthy nutrition and lifestyle for 8 weeks may improve your epigenetic age by roughly 3 years.
We all know good nutrition and lifestyle can promote health. Data from this study help us see the effect in a quantifiable manner. However, there is still much for scientists to learn. First, although there is scientific rationale behind the mathematical algorithm with which the epigenetic age is calculated, it is still a biomarker in development. What age-related biological processes have been captured by the algorithm are yet to be fully explained. Second, the clinical trial described here is limited to a small group of middle-aged men who were relatively healthy. Larger scale trials with robust statistical power and diverse participant characteristics are definitely needed. Last, but certainly not least, it is still yet to be determined whether reversing or slowing epigenetic age translates to reductions in age-related chronic illnesses and improvements in life expectancy and quality of life. Nevertheless, the research is heading toward a promising direction.
Why is this clinically relevant?
- Epigenetic age is a promising biomarker that correlates well with chronological age
- The clinical study demonstrates in a quantifiable way how healthy nutrition and lifestyle can potentially slow aging by improving epigenetic age
- Mendelson MM. Epigenetic age acceleration: a biological doomsday clock for cardiovascular disease? Circ Genom Precis Med. 2018;11:e002089.
- Roetker NS et al. Prospective study of epigenetic age acceleration and incidence of cardiovascular disease outcomes in the ARIC study (Atherosclerosis Risk in Communities). Circ Genom Precis Med. 2018;11:e001937.
- Fitzgerald KN et al. Potential reversal of epigenetic age using a diet and lifestyle intervention: a pilot randomized clinical trial. Aging (Albany NY). 2021;13:9419-9432.
Lewis Chang, PhD is Scientific Editorial Manager of R&D at Metagenics. Dr. Chang received his PhD in Nutritional Sciences at University of Washington, along with his MS in Nutrition and Public Health from Teachers College, Columbia University and BS in Pharmacy from National Taiwan University. Prior to joining Metagenics, he conducted dissertation research and completed a research assistantship and postdoctoral fellowship at the Fred Hutchinson Cancer Research Center in Seattle, WA. Dr. Chang has authored or co-authored and managed the publication of over 30 peer-reviewed journal articles and numerous scientific abstracts and posters. He has quite a green thumb, enjoys opera, theater and jazz, and loves cooking, collecting art, and learning to play gypsy jazz guitar.