Biological Age: Part 5 - How to Measure Biological Age: Telomere Length

Welcome to part 5 of the ODX series on "Biological Age: A True Measure of Health." In the fifth post in our series, we will discuss Telomere Length, one of the methods used to measure biological age.

The ODX Biological Age Series

Dicken Weatherby, N.D. and Beth Ellen DiLuglio, MS, RDN, LDN

1. Biological Age - Part 1: What is Biological Age?
2. Biological Age - Part 2: How to Measure Biological Age: Overview
3. Biological Age - Part 3: How to Measure Biological Age: Key Biomarkers
4. Biological Age - Part 4: How to Measure Biological Age: DNA Methylation (DNAm)
5. Biological Age - Part 5: How to Measure Biological Age: Telomere Length
6. Biological Age - Part 6: How to Improve Biological Age
7. Biological Age - Part 7: Optimal Takeaways

Telomeres are the protective “caps” located at the tail end of a chromosome that promote genomic stability and integrity. Research suggests that telomere length may reflect an individual’s risk for chronic disease, considering shorter telomeres are associated with atherosclerosis, impaired blood vessel repair, cardiovascular disease, Alzheimer’s, and mortality (Herrmann 2018). Extreme telomere shortening is associated with cellular senescence, a cellular stress response that disrupts normal cell replication (Ferrucci 2020).

Telomeres become shorter during cell division or exposure to damage or stress, and severe shortening contributes to the loss of cell and tissue integrity and cell death and may be a hallmark of aging. One study found that telomere shortening in leukocytes (WBCs) was associated with higher stress levels, including perceived stress, and was associated with an age ten years older than chronological age. However, measuring leukocyte telomere length appears to be unable to differentiate between different types of white blood cells, which may limit its use as a general marker of aging (Levine 2023).

Several research studies have demonstrated the association between shorter telomeres and malignancy. Even when measured in the same individual, telomere length was shorter in cancer cells than in healthy cells from the same organ or elsewhere in the body. Decreased telomere length observed in breast, colon, and prostate tumor tissue was associated with more advanced disease, faster progression, and poor survival (Hermann 2018).

Research reveals that the protein telomerase can restore some of the lost genetic material at the end of chromosomes. However, enhanced telomerase activity is a hallmark of cancer, and it is possible that artificially lengthening telomeres may increase cancer risk (Levine 2023).

Lifestyle may impact telomere length as well. Shorter telomeres were associated with a higher score on the Dietary Inflammatory Index in a review of NHANES data from 35,575 subjects participating from 1999 to 2018. This data may reflect a healthy versus an unhealthy diet (Xie 2023).

Longer telomere length was associated with the American Heart Association’s 2010 Life’s Simple 7 (LS7), which includes a balanced diet, smoking abstinence, healthy BMI, physical activity, desirable fasting glucose and total cholesterol, and healthy blood pressure. A higher LS7 score is associated with a more desirable biological age, as is a higher LS8 score, which incorporates restorative sleep into the score (Zhang 2023).

References

Ferrucci, Luigi et al. “Measuring biological aging in humans: A quest.” Aging cell vol. 19,2 (2020): e13080. doi:10.1111/acel.13080

Herrmann, Markus et al. “Telomere biology and age-related diseases.” Clinical chemistry and laboratory medicine vol. 56,8 (2018): 1210-1222. doi:10.1515/cclm-2017-0870

Ho, Kwok M et al. “Biological age is superior to chronological age in predicting hospital mortality of the critically ill.” Internal and emergency medicine vol. 18,7 (2023): 2019-2028. doi:10.1007/s11739-023-03397-3

Levine, Morgan E et al. “An epigenetic biomarker of aging for lifespan and healthspan.” Aging vol. 10,4 (2018): 573-591. doi:10.18632/aging.101414 This is an open-access article distributed under the terms of the Creative Commons Attribution (CC BY) 3.0 License.

Levine, Morgan. True Age: Cutting-edge Research to Help Turn Back the Clock. Penguin, 2023.

National Institutes of Health. National Institute on Aging. The epigenetics of aging: What the body’s hands of time tell us. March 26, 2021. https://www.nia.nih.gov/news/epigenetics-aging-what-bodys-hands-time-tell-us

Xie, Ruijie et al. “Dietary inflammatory potential and biological aging among US adults: a population-based study.” Aging clinical and experimental research vol. 35,6 (2023): 1273-1281. doi:10.1007/s40520-023-02410-1

Zhang, Ronghuai et al. “Association between life's essential 8 and biological ageing among US adults.” Journal of translational medicine vol. 21,1 622. 14 Sep. 2023, doi:10.1186/s12967-023-04495-8