Could folate and B12 affect cellular ageing?
Nutrients such as folate and vitamin B12 are essential for healthy metabolic processes and well known for reducing oxidative stress.  New research however, is targeting these nutrients for their role in the prevention of cellular ageing by influencing telomere length.
 
Telomeres cap the ends of chromosomes, preserving genome stability and making sure healthy cellular replication occurs. Telomeres naturally shorten during each cell division until they become too short to replicate causing accelerated cellular ageing and associated age-related diseases.
 
Telomere shortening can be partially rescued by telomerase, as enzyme which adds nucleotides to the ends of the chromosomes preserving their integrity.  Research also points to specific nutrients promoting telomere optimisation, by reducing oxidative stress and ‘wear and tear’. Folate and vitamin B12 are of particular interest because they influence nucleotide synthesis and DNA stability.
 
According to a recent 2019 study on 5581 adults, folate and vitamin B12 improved telomere structure and function and therefore biologic ageing.

Several other studies have concluded that diet and lifestyle strongly influence cellular ageing. Specifically, more alkaline diets higher in vegetables, fruits and lower consumption of red meat or processed meat and sweetened soft drinks were associated with telomere length.

References:
Lee, J. Y., Jun, N. R., Yoon, D., Shin, C., & Baik, I. (2015). Association between dietary patterns in the remote past and telomere length. European journal of clinical nutrition, 69(9), 1048-1052.
Boccardi, V., Paolisso, G., and Mecocci, P. (2016). Nutrition and lifestyle in healthy ageing: the telomerase challenge. Ageing, 8(1), 12–15. doi:10.18632/ageing.100886
Tucker, L. A. (2019). Serum and Dietary Folate and Vitamin B12 Levels Account for Differences in Cellular Aging: Evidence Based on Telomere Findings in 5581 U.S. Adults. Oxidative Medicine and Cellular Longevity, 2019, 1–10. doi:10.1155/2019/4358717 

​Recent media attention has uncovered a smoldering divide between the general public and health practitioners alike. The topic of plant-based diets vs the meat-eating population and the question of protein. How much do we actually need?
High protein foods and beverages are arguably the fastest growing sectors in the health food market both locally and globally. However critical discourses on protein, suggest there is has been a mythologization of protein perpetuated by the food industry, which according to the Chen (2019) paper, is a myth.
‘Research shows that consumers (and practitioners) believe high protein food has a positive impact on physical performance and body composition, despite the lack of evidence.’

Robust epidemiological studies indicate that a high intake of animal protein, particularly red meat, may increase the risk of age-related diseases. Protein intake is associated with increased IGF-1 and mTOR, substances known to block intrinsic longevity promoting processes in the body.2-4 In fact, research suggests a reduced protein intake may play a critical role in extending longevity and metabolic health.2
On the other hand, research clearly indicates that insufficient protein may be associated with sarcopenia and frailty in elderly populations which is harmful to longevity, suggesting that the time of life may require individualised protein consumption.

How much protein do we need?
Looking at the longest-lived populations and what they ate, may provide valuable insights into understanding our healthspan. The Mediterranean and traditional Okinawan diets for example, ate approx. 9-13% protein, not entirely but largely from plant sources. They also ate a diet very high in alkaline vegetables and fruits.
There is still hot debate and emerging research about the ideal balance of macronutrients, which is only part of the equation when it comes to healthy aging. 

• Chen, A., & Eriksson, G. (2019). The mythologization of protein: a Multimodal Critical Discourse Analysis of snacks packaging. Food, Culture & Society, 1-23.
• Kitada, M., Ogura, Y., Monno, I., & Koya, D. (2019). The impact of dietary protein intake on longevity and metabolic health. EBioMedicine.
• Fung, et al. (2016). Association of animal and plant protein intake with all-cause and cause-specific mortality. JAMA internal medicine, 176(10), 1453-1463
• Levine, M. E., et al. (2014). Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population. Cell Metabolism, 19(3), 407–417.Song, M.,
• Buettner, D., & Skemp, S. (2016). Blue Zones. American Journal of Lifestyle Medicine, 10(5), 318–321.
• Willcox, D. C., Scapagnini, G., & Willcox, B. J. (2014). Healthy aging diets other than the Mediterranean: A focus on the Okinawan diet. Mechanisms of Ageing and Development, 136-137, 148–162.