HoldsUp

Elissa Epel

University of California, San Francisco

Elissa Epel, PhD, is a professor in the Department of Psychiatry at the University of California, San Francisco, where she directs the Aging, Metabolism, and Emotions Center. Her research focuses on stress biology and the mechanisms underlying healthy and cellular aging. Her published work investigates the relationships between perceived stress, telomere dynamics, eating behaviors, metabolic health, and social factors.

41 claims checked on air: 1 context 1 contradicted 2 overstated 34 supported 3 unverified 3 flagged

What they said on air

0:03:02overstatedhighDr. Elissa Epel on Telomeres and the Role of Stress Biology

Life expectancy in the United States is approximately 78 years for men and 83 years for women.

"So for men, life expectancy is around 78 years in the United States, for women it's around 83 years." (said at 0:03:02)

According to National Vital Statistics Reports from the Centers for Disease Control and Prevention (CDC), life expectancy at birth in the United States is lower than stated for both sexes. In 2023, life expectancy at birth was 75.8 years for males and 81.1 years for females (with an overall population average of 78.4 years). Pre-pandemic 2018 figures were similarly 76.2 years for males and 81.2 years for females. The speaker appears to have mistaken the overall population life expectancy (~78 years) for male life expectancy and overstated female life expectancy (~81 years vs. the claimed 83 years).

0:04:35supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

A healthy lifestyle in midlife predicts longer telomeres and increased longevity decades later.

"So like a healthy lifestyle—not extreme, but just healthy—in midlife predicts longer telomeres, predicts longevity decades later." (said at 0:04:35)

Prospective cohort data demonstrate that healthy lifestyle factors in midlife—such as moderate physical activity, maintaining a normal body mass index, not smoking, and low alcohol intake—predict longer leukocyte telomere length and lower proportions of short telomeres decades later in old age. In the Helsinki Businessmen Study cohort (followed over 29 years), moderate midlife physical activity was associated with longer late-life telomeres compared to either sedentary behavior or high-intensity activity, aligning with the observation that moderate ('not extreme') healthy habits support long-term cellular aging markers and longevity.

0:04:35supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Having positive social support and strong social connections is a significant predictor of longevity.

"And then also like the web of social connections that we have. The more positive they are and the more we feel supported, those are really important predictors of longevity, too." (said at 0:04:35)

A landmark meta-analysis of 148 prospective studies involving over 308,000 individuals found that individuals with stronger social relationships had a 50% increased likelihood of survival (OR = 1.50, 95% CI 1.42 to 1.59) across an average follow-up of 7.5 years. The association held across age, sex, initial health status, and causes of death, with complex measures of social integration showing particularly strong associations with reduced mortality.

0:08:43supportedhighDr. Elissa Epel on Telomeres and the Role of Stress Biology

Telomeres induce replicative senescence when they get too short, causing dividing cells to stop replicating.

"The pathway is this: it's called replicative senescence. And it's basically how long can that cell continue to divide and divide and replenish into new, fresh, young cells. So the telomeres, when they get too short, prevent that particular cell—whether it's an immune cell or a neuron in our hippocampus or the lining of our cardiovascular system, we need those cells to replenish throughout the decades—when the telomere gets too short, that cell stops dividing." (said at 0:08:43)

The statement accurately reflects established cellular biology. Progressive telomere attrition occurs with each round of somatic cell division due to the end-replication problem. When telomeres reach a critically short length, they trigger a persistent DNA damage response that halts the cell cycle and induces permanent replicative senescence (the Hayflick limit), preventing further replication.

0:11:48supportedhighDr. Elissa Epel on Telomeres and the Role of Stress Biology

Telomerase is an intracellular RNA reverse transcriptase that rebuilds telomeres, and knocking it down stops cell division while upregulating it immortalizes cells.

"So the telomerase enzyme is a very interesting enzyme that is intracellular, that has the ability to actually rebuild telomeres by adding back base pairs. So it's an RNA reverse transcriptase. And this was discovered by Liz Blackburn and Carol Greider and colleagues over 25 years ago, and they were showing how if you knock it down, the cells cannot divide anymore, and if you upregulate it, the cells become immortal." (said at 0:11:48)

Telomerase is an intracellular ribonucleoprotein reverse transcriptase discovered in 1985 by Carol Greider and Elizabeth Blackburn (who shared the 2009 Nobel Prize in Physiology or Medicine for the discovery). The enzyme uses an internal RNA template subunit along with its catalytic reverse transcriptase protein subunit (TERT) to synthesize and rebuild telomeric repeat sequences at chromosome ends. Experimental studies have shown that introducing or upregulating telomerase activity into normal, telomerase-negative human somatic cells elongates telomeres and bypasses replicative senescence, conferring extended cellular lifespan and immortalization, whereas telomere shortening from telomerase absence or deficiency limits cell division and induces cellular senescence.

0:11:48unverifiedvery lowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Telomerase was discovered by Elizabeth Blackburn, Carol Greider, and colleagues over 25 years ago.

"And this was discovered by Liz Blackburn and Carol Greider and colleagues over 25 years ago, and they were showing how if you knock it down, the cells cannot divide anymore, and if you upregulate it, the cells become immortal." (said at 0:11:48)

No published record matching the claim was located; this does not prove the claim false.

0:12:19supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Telomerase activity measured in normal peripheral blood cells is associated with metabolic health and socioeconomic circumstances.

"So at UCSF, my colleague Jue Lin actually has an assay that's very sensitive and can measure the level of telomerase in our normal blood cells. They're not cancerous, they're not stem cells, but you can still measure the level, and that is associated with health, with metabolic health, with socioeconomic circumstances." (said at 0:12:19)

Research co-authored by Jue Lin and colleagues at the University of California, San Francisco (UCSF) demonstrates that quantitative assays can detect low baseline levels of telomerase activity in normal, non-cancerous human peripheral blood cells (such as peripheral blood mononuclear cells, T cells, and B cells). Furthermore, observational studies show that leukocyte telomerase activity and telomere dynamics are correlated with psychosocial circumstances, chronic stress, allostatic load, and cardiometabolic health markers, including subclinical atherosclerosis.

0:12:50supportedhighDr. Elissa Epel on Telomeres and the Role of Stress Biology

Longer telomeres measured in the blood predict an increased risk of certain cancers, including glioma and melanoma.

"the genetic index, but sometimes also when you measure in the blood, long telomeres also predict greater risk of certain cancers like glioma and melanoma and several others." (said at 0:12:50)

Genetic and epidemiological evidence demonstrates that longer telomere length—whether genetically determined or evaluated in leukocyte assays—is associated with an increased risk of specific malignancies, most notably glioma and cutaneous melanoma, as well as lung adenocarcinoma, neuroblastoma, and renal cell carcinoma.

0:13:49supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

In genetic telomerase deficiency disorders, short telomeres can be transmitted epigenetically to offspring even if the offspring do not inherit the mutated gene.

"they also can transmit just the short telomeres epigenetically, like in a direct epigenetic pattern to offspring. So the offspring may, thank goodness, not get the mutated gene, but they still get short telomeres, and they might have a mild aging syndrome from that." (said at 0:13:49)

Evidence from human pedigree analyses and mouse models shows that offspring who do not inherit a familial telomerase mutation (e.g., in TERT) can still inherit abnormally short telomeres from their affected parent or grandparent. Because telomere length serves as a structural set-point rather than being determined solely by genotype, wild-type offspring do not automatically reset or elongate these short telomeres back to normal levels, potentially predisposing them to telomere-shortening-related phenotypes.

0:15:05supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Mendelian randomization studies show that genetic propensity for longer telomeres directly predicts reduced risk of heart disease and dementia.

"even more so now we know that if you have a genetic propensity for long telomeres, it directly predicts less heart disease and dementia. So those kind of Mendelian randomization studies are one of the best ways that we can say there's a direct physiological connection here." (said at 0:15:05)

Mendelian randomization (MR) studies and systematic reviews consistently demonstrate that genetically predicted longer leukocyte telomere length is associated with a reduced risk of coronary heart disease and Alzheimer's disease/dementia. Systematic reviews of MR studies confirm robust causal inverse associations between genetically determined telomere length and coronary artery disease, myocardial infarction, and ischemic heart disease. Multiple MR investigations also report that genetic instruments associated with longer telomeres significantly reduce the risk of Alzheimer's disease (and conversely, genetically predicted shorter telomeres increase dementia risk), though findings across some individual cohort subsets show varying effect sizes.

0:16:11supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Environmental chemicals in plastics such as BPA mimic estrogen in the human body.

"a lot of these chemicals in plastics, etc., are mimicking estrogen. They're linked to greater risk sometimes of cancer or other diseases like diabetes, metabolic disease, and we can see when we look at these aging biomarkers, we can see they're impacting them—inflammation and telomere shortening." (said at 0:16:11)

The speaker's claims are supported by published literature. Plastic-associated environmental chemicals, such as bisphenol A (BPA) and phthalates, act as endocrine disruptors that mimic natural estrogen by binding to estrogen receptors and altering endocrine signaling pathways. Epidemiological and mechanistic studies link exposure to these chemicals with increased risks of cancer (such as breast cancer), insulin resistance, and metabolic disorders like type 2 diabetes. Additionally, clinical research indicates that elevated exposure to plasticizers like BPA correlates with heightened markers of systemic proinflammation and accelerated telomere shortening.

0:17:00overstatedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Heavy metal exposure to cadmium and lead is associated with shorter telomeres in a dose-response manner.

"So heavy metals, cadmium, lead, those are directly in a dose-response way related to our telomere shortness." (said at 0:17:00)

Epidemiological studies, notably large NHANES analyses, demonstrate a clear, statistically significant dose-response association between cadmium exposure (measured in blood and urine) and shorter leukocyte telomere length. However, the evidence for lead exposure is mixed and inconsistent: major population-level analyses found no significant association between blood lead concentration and telomere length, though some subgroup models observed modest inverse associations. Stating that both cadmium and lead are definitively linked to telomere shortening in a direct dose-response manner overstates the evidence regarding lead.

0:17:34supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Traumatic experiences, especially during youth and early childhood, leave an imprint associated with shorter telomeres.

"traumatic experiences leave an imprint on telomeres, particularly when they're in youth and early in life." (said at 0:17:34)

Multiple systematic reviews and meta-analyses support the claim that traumatic experiences and early life adversity, particularly during childhood and youth, are associated with accelerated cellular aging and shorter telomere length. A meta-analysis of 41 studies (N = 30,773) found a significant inverse association between early adversity and telomere length (Cohen's d = -0.35), with timing and type of adversity significantly moderating the effect. A subsequent meta-analysis of 54 studies (N = 116,010) similarly found that early adversity, particularly threat-related trauma (e.g., violence exposure), was significantly associated with accelerated cellular aging (d = -0.43). Because these findings are derived from observational and retrospective cohort designs, certainty is moderate.

0:18:32supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Consumption of pro-inflammatory foods such as red meat, processed meat, and sugary drinks is associated with shorter telomeres.

"So what do I mean by, like, the pro-inflammatory foods? So red meat, particularly processed meat, sugar drinks, particularly sugared soda, high-sugar foods. So those are pretty much the culprits that stand out mostly." (said at 0:18:32)

Observational research supports the association between diets high in pro-inflammatory potential, processed meats, and sugar-sweetened sodas with shorter leukocyte telomere length (LTL). In cross-sectional analyses of NHANES data (Leung et al., 2014; Shivappa et al., 2017), higher Dietary Inflammatory Index (DII) scores and regular sugar-sweetened soda consumption were independently associated with significantly shorter telomeres. Similarly, cohort analyses (such as the Strong Heart Family Study, Fretts et al., 2016) found that processed meat intake was inversely associated with LTL, although unprocessed red meat alone often shows weaker or non-significant associations. Because the available evidence is predominantly observational and cross-sectional, certainty is rated as low.

0:19:08supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Drinking three cups of caffeinated coffee is associated with longer telomeres.

"caffeinated coffee is associated with longer telomeres. HOST: Yeah, and it was quite a bit of coffee, right? GUEST1: Yeah, three cups." (said at 0:19:08)

Cross-sectional cohort studies support an association between coffee intake and longer leukocyte telomere length. In the Nurses' Health Study (n = 4,780), women consuming three or more cups of coffee per day had significantly greater odds of having longer telomeres compared with non-drinkers (multivariable OR 1.36, 95% CI: 1.04–1.78). Similarly, in NHANES (n = 5,826), coffee consumption was positively associated with telomere length, although isolated caffeine intake from non-coffee sources was inversely related. Because the available evidence is entirely cross-sectional and observational, certainty is low and cannot establish causality.

0:20:10supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

A workplace ban on sugar-sweetened beverages at UCSF significantly reduced sugary drink consumption and waist circumference.

"So we just completed a study at our university where this university banned all sugared beverages... And so bottom line is that it reduced drinking dramatically, and it reduced waist size just getting rid of it at work." (said at 0:20:10)

A study conducted at the University of California, San Francisco (UCSF) evaluated the effects of an institutional workplace sales ban on sugar-sweetened beverages (SSBs) among 214 frequent SSB-consuming employees over 10 months. The study found that total daily SSB intake decreased significantly by 48.6% (from 1,050 mL to 540 mL per day; P < .001), and participants experienced a statistically significant average reduction in waist circumference of 2.1 cm (P < .001).

0:25:25supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Ordinary work stress is not associated with telomere shortening, whereas clinical burnout is.

"Like work stress is not related to telomere shortening— HOST: Oh, really? GUEST1: Burnout is, when you really, you know, it's gone on long enough that you've gotten this kind of profile of demoralisation from it, but not the typical adrenaline-type stress that we deal with a lot." (said at 0:25:25)

Cross-sectional observational studies indicate that routine occupational stress and job strain categories are generally not associated with leukocyte telomere shortening, whereas severe work-related exhaustion and burnout (characterized by prolonged emotional exhaustion and demoralization) show a significant association with shorter telomere length. In a large population-based cohort of 2,911 Finnish working-age adults, severe work-related exhaustion assessed by the Maslach Burnout Inventory was significantly linked to shorter relative leukocyte telomere length after adjusting for sociodemographic, lifestyle, and health covariates. Conversely, epidemiological analyses assessing general occupational stress and job strain (such as in the Multiethnic Study of Atherosclerosis) found no significant differences in telomere length across job strain or occupational demand categories.

0:26:44unverifiedvery lowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Perseverative cognition and waking stress in caregivers correlate with elevated cortisol and accelerated aging biomarkers like inflammation and shorter telomere length.

"And we are looking at daily stress in our current studies and seeing that people who have this profile of more elevated—we call it perseverative cognition or thought processes—they have accelerated biomarkers of aging: telomere length and inflammation... We find that our caregivers do that a lot more. They wake up, they are already in a stressed state, their cortisol is higher." (said at 0:26:44)

No published record matching the claim that perseverative cognition and waking stress in caregivers correlate with elevated cortisol and accelerated aging biomarkers such as inflammation and shorter telomere length was located; this does not prove the claim false.

0:27:57supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

High trait pessimism is associated with shorter telomeres.

"So if you're high in pessimism, you just expect bad things to happen. Pessimism is related to shorter telomeres." (said at 0:27:57)

Observational studies have found that higher trait or dispositional pessimism is significantly associated with shorter leukocyte telomere length. An initial study in post-menopausal women found dispositional pessimism was independently associated with shorter telomeres (beta = -0.68, p = 0.001), while optimism was not. A larger longitudinal cohort of 490 older men in the VA Normative Aging Study similarly found that higher pessimism scores were associated with shorter average telomere length (-3.08% per 1-SD increase in pessimism), although pessimism was not significantly associated with the rate of telomere attrition over time.

0:29:06contradictedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Studies by Eli Puterman show that exercise reduces ruminative thought processes.

"Your n of 1 has also been shown up in, you know, studies of exercise and studies by Eli Puterman showing that exercise actually does reduce ruminative processes." (said at 0:29:06)

The speaker mischaracterizes the findings of research led by Eli Puterman. In the primary published study on this topic by Puterman and colleagues (2011), physical activity was examined as a moderator of the physiological stress response, not as an intervention that reduced rumination itself. The study found that being physically active buffered the body against the adverse effects of stressor-induced rumination on cortisol reactivity and recovery (i.e., active individuals did not show the elevated and prolonged cortisol output seen in sedentary individuals who ruminated), but it did not show that exercise reduced ruminative thought processes.

0:30:19supportedhighDr. Elissa Epel on Telomeres and the Role of Stress Biology

The sex gap in human longevity, with women living longer than men, is consistent across different cultures and countries.

"And so this sex gap in longevity is robust across cultures, across countries. I mean, this is a fundamental thing about human biology species. Women live longer." (said at 0:30:19)

Demographic evidence demonstrates that the female survival advantage is remarkably consistent across human populations, countries, and historical periods, including during extreme mortality crisis events such as severe famines and epidemics. An analysis by Zarulli et al. (2018) examining historical demographic datasets under extreme hardship found that women lived longer than men in almost all populations, with females exhibiting lower mortality rates across nearly all ages—including infant ages where behavioral and social differences are minimal. This strong consistency across varied environments and historical contexts supports the view that the female longevity advantage has deep biological foundations.

0:30:55needs contextmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Women have leukocyte telomeres that are hundreds of base pairs longer than men's, a difference present at birth.

"For example, women have much longer telomeres, like hundreds of base pairs longer, and that starts at birth, and that's probably related to sex hormones." (said at 0:30:55)

Systematic reviews and meta-analyses confirm that females, on average, have longer leukocyte telomeres than males across the lifespan. However, the claim requires nuance: the effect size is small (standardized difference of approximately 0.09 SDs, typically translating to tens to a few hundred base pairs depending on measurement method and age), and whether this difference is definitively present at birth or arises and widens early in life remains debated in the literature (with some neonatal studies finding significant differences at birth while others find comparable terminal restriction fragment lengths at birth).

0:31:05supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Opposite-sex twins do not show the typical sex difference in telomere length at birth.

"So twins, where there's a female and a male, don't have different telomere lengths, so there's probably a masculinization in the womb." (said at 0:31:05)

A study evaluating adult twin cohorts found that while same-sex female twins display the typical pattern of longer leukocyte telomere length (LTL) compared to male twins, opposite-sex female co-twins have LTL indistinguishable from their male co-twins. The study authors concluded that these findings are compatible with intrauterine masculinization of the female fetus sharing a uterine environment with a male fetus. Because this finding is based on observational data in adult twins rather than direct longitudinal measurement from birth, certainty is low.

0:31:12unverifiedvery lowDr. Elissa Epel on Telomeres and the Role of Stress Biology

In cellular and mouse models, estrogen upregulates telomerase, enhances mitochondrial ATP production, and reduces oxidative stress leakage.

"estrogen, when we look at these experimental models and in vitro and in mice, estrogen is protective and anti-aging in a sense in that it upregulates telomerase, it improves mitochondrial health. Those energy stores in our cells, those batteries, are more robust, they create more ATP, they leak less oxidative stress." (said at 0:31:12)

No published record matching the claim that estrogen upregulates telomerase, enhances mitochondrial ATP production, and reduces oxidative stress leakage in cellular and mouse models was located; this does not prove the claim false.

0:31:35supportedvery lowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Inducing menopause in rats causes brain mitochondrial dysregulation and cognitive deficits that are reversed by estrogen replacement.

"So if you like cause menopause in a rat, you're going to create more mitochondrial dysregulation in the brain and cognitive problems, and then if you replace estrogen, you fix it." (said at 0:31:35)

Preclinical animal evidence supports the claim that surgical menopause (ovariectomy) in rats causes mitochondrial dysregulation and loss of synaptic integrity in the brain, and that estradiol replacement prevents or reverses these bioenergetic impairments. Because the underlying evidence relies entirely on animal models, certainty for human translational equivalence is very low.

0:32:55supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Women with a longer reproductive lifespan (later menopause) have longer telomeres.

"we know that if you have a longer reproductive lifespan, meaning your menopause is a lot later, you likely have longer telomeres." (said at 0:32:55)

Large-scale epidemiological studies consistently show a positive association between a longer reproductive lifespan (and older age at natural menopause) and longer leukocyte telomere length (LTL). In a UK Biobank cohort of over 220,000 women, shorter reproductive lifespan and early menopause were significantly associated with shorter LTL. Similarly, combined data from the UK Biobank and the Women's Health Initiative (over 130,000 postmenopausal women) found that earlier menopause was associated with shorter LTL, a relationship further supported by Mendelian randomization analyses.

0:33:05supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Women whose last childbirth occurs later in life, such as in their 30s rather than their 20s, have longer telomeres.

"If you give birth later, like in your 30s instead of your 20s, I'm sorry, your last birth, you have longer telomeres." (said at 0:33:05)

Observational research supports the association between older maternal age at last birth and longer leukocyte telomere length later in life. In a cross-sectional study of 1,232 perimenopausal and postmenopausal women from the National Health and Nutrition Examination Survey (NHANES), maternal age at last live birth was positively associated with leukocyte telomere length after multivariable adjustment for age, race/ethnicity, parity, and other covariates. Adjusted geometric mean telomere-to-single-copy-gene ratios increased across age-at-last-birth categories (<25, 25–29, 30–34, 35–39, and ≥40 years: 0.90, 0.93, 0.93, 0.95, and 0.96, respectively; p for trend = 0.04). Because these findings are derived from cross-sectional observational data, certainty is graded as low.

0:35:20supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Severe maternal life events and stress during pregnancy and the year prior to birth predict shorter telomere length in newborn cord blood.

"So bad things that happen: job loss, mourning, difficult financial events. So when you add those up during pregnancy, they predict shorter telomeres. But also in the... it's been studied in the year before birth, and that predicts shorter telomeres in cord blood." (said at 0:35:20)

Observational cohort studies have found that maternal exposure to severe psychosocial stress and cumulative negative life events (such as financial strain, bereavement, or job loss) during pregnancy is significantly associated with shorter telomere length in newborn umbilical cord blood. Because this body of evidence consists of prospective observational cohort studies, the certainty is graded as low.

0:39:45supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Unlike other cell types, sperm telomeres lengthen as men age, and older fathers pass on longer telomeres to their offspring.

"So older fathers have sperm with longer telomeres, and there is an effect in the offspring. So when we do studies, when we have the data to know how old was your father when you were born, that's a covariate, that's something that shapes telomere length." (said at 0:39:45)

Published human studies consistently show that while telomeres in somatic cells (such as leukocytes) shorten with age, telomere length in sperm increases with paternal age. Consequently, older paternal age at conception is reliably associated with longer telomere length in offspring, and paternal age at birth is widely recognized and used as an important covariate in epidemiological studies of human telomere biology.

0:42:42supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Higher educational attainment is positively correlated with longer leukocyte telomere length.

"What shows up the most is education, and I think that we see— [0:43:12] HOST: More educated, the longer the telomeres? [0:43:13] GUEST1: Yes, exactly. A positive correlation." (said at 0:42:42)

Observational studies, systematic reviews, and Mendelian randomization analyses consistently demonstrate a positive correlation between higher educational attainment and longer leukocyte telomere length, although the effect size is generally modest.

0:43:13supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

Among low-income Hispanic pregnant women, having graduated high school was associated with longer cord blood telomeres in their newborns compared to not graduating.

"My colleague Janet Wojcicki found that in a low-income sample of Hispanic women—they're all pregnant—those who graduated high school had babies with longer telomeres in their cord blood. Those who did not graduate high school had babies with shorter telomeres." (said at 0:43:13)

A 2016 observational study by Janet Wojcicki and colleagues evaluated determinants of cord blood leukocyte telomere length in a cohort of Latino newborns (n = 54). In multivariate analysis, maternal educational attainment of a high school diploma or greater was independently associated with significantly longer infant cord blood telomeres (~500 base pairs longer, adjusted β = 505.68, 95% CI 151.69 to 859.68, p < 0.01) compared to mothers with less than a high school education. The certainty of evidence is low due to the observational design and small sample size.

0:44:58supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Following subjects on a telomerase-activating supplement for one year resulted in improved telomere length.

"They followed people on one of those telomerase-activating supplements, and one year later telomeres look better." (said at 0:44:58)

Published randomized clinical trials evaluating the telomerase-activating supplement TA-65 (derived from Astragalus membranaceus) support the claim. In a 1-year randomized, double-blind, placebo-controlled trial of 117 CMV-positive adults aged 53-87, low-dose TA-65 significantly increased leukocyte telomere length over 12 months (by 530 ± 180 bp, p = 0.005) compared to significant shortening in the placebo group (-290 ± 100 bp, p = 0.01). A 2025 systematic review and meta-analysis of 8 randomized controlled trials (n = 750) confirmed that TA-65 supplementation produced statistically significant telomere elongation (SMD = 0.47, 95% CI: 0.31-0.62), though this elongation did not translate into improvements in clinical frailty or inflammatory markers.

0:45:15supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

In a trial by Janice Kiecolt-Glaser, cellular blood levels of omega-3 fatty acids predicted leukocyte telomere lengthening over four months.

"So a colleague, Janice Kiecolt-Glaser, did a study on high-dose and low-dose omegas, and it wasn't the dose, it was how much omegas people actually had in their blood cells that predicted telomere lengthening over four months." (said at 0:45:15)

A 4-month randomized controlled trial led by Janice Kiecolt-Glaser evaluated high-dose (2.5 g/day) and low-dose (1.25 g/day) omega-3 PUFA supplementation versus placebo in 106 middle-aged and older adults. While randomized group assignments (dosage categories) did not yield statistically significant differences in leukocyte telomere length, individual changes in circulating fatty acid levels did: leukocyte telomere length increased significantly with decreasing omega-6 to omega-3 ratios (p = 0.02).

0:46:40supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

A six-month exercise intervention in sedentary, stressed dementia caregivers lowered stress and increased immune cell telomere length compared to controls.

"So one study that I believe you just read, maybe just came out, was a study by Eli Puterman, who took sedentary high-stress caregivers—so men and women caring for a partner with dementia—and he had them exercise for six months. At the end of six months, their stress was lower, their telomeres were longer compared to the control group." (said at 0:46:40)

The speaker accurately describes a 2018 randomized controlled trial led by Eli Puterman (PMID 30266522). In this trial, 68 physically inactive, highly stressed dementia caregivers were randomized to either a 24-week (~6 months) supervised aerobic exercise program or a waitlist control group. At the end of the intervention, participants in the exercise group showed significant reductions in perceived stress and an increase in leukocyte telomere length compared to the control group (mean difference of 67.3 base pairs).

0:47:28supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

In a weight loss study by Ashley Mason, participants who maintained at least 10% weight loss at one year showed telomere lengthening.

"So another study, Ashley Mason just published this, we did a weight loss trial, and we found that first of all, no one really keeps off a lot of weight a year or two later, right? But the handful of people who kept off 10% of their weight a year later had telomere lengthening." (said at 0:47:28)

In a 2018 randomized trial analysis led by Ashley E. Mason evaluating 194 adults with obesity, intervention type alone did not predict telomere length change, but participants who achieved and maintained at least a 10% weight loss at 12 months showed statistically significant telomere lengthening in peripheral blood mononuclear cells and CD8+ T lymphocytes after adjusting for baseline telomere length.

0:48:03supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Multiple meta-analyses show an inverse association between body mass index (BMI) and telomere length.

"So that was pretty exciting because there's many meta-analyses showing higher BMI, shorter telomeres." (said at 0:48:03)

Multiple systematic reviews and meta-analyses of observational studies demonstrate a statistically significant inverse association between body mass index (BMI) and leukocyte telomere length. A 2014 meta-analysis found an overall inverse correlation between BMI and telomere length, and a comprehensive 2018 collaborative meta-analysis of 87 observational cohorts (n = 146,114) confirmed that each unit increase in BMI is associated with shorter telomere length (-3.99 base pairs per kg/m²), an association that was especially pronounced in young adults.

0:51:52supportedhighDr. Elissa Epel on Telomeres and the Role of Stress Biology

Higher dietary fiber content consistently reduces the postprandial blood glucose spike from meals.

"And the one thing that was consistent for the blood glucose response was fiber. The more fiber, the lower the glucose response, because it slows the metabolism and everything." (said at 0:51:52)

Systematic reviews and meta-analyses of randomized controlled trials confirm that higher dietary and supplemental fiber intake (particularly soluble and viscous fibers) consistently attenuates postprandial glucose excursions, lowering peak blood glucose and incremental area under the curve. Mechanistically, fiber increases chyme viscosity, delaying gastric emptying and slowing carbohydrate digestion and absorption.

0:56:00supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

High-stress caregivers who engage in approximately 10 minutes of daily vigorous walking do not show the shorter telomeres seen in sedentary high-stress caregivers.

"Yeah, so I think one of the studies that we did showed that high-stress caregivers have shorter telomeres if they're sedentary, but not if they're active. And by active, that was around 10 minutes a day of kind of vigorous walking." (said at 0:56:00)

In an observational study of 63 post-menopausal women undergoing high perceived stress, researchers found that high stress was significantly associated with shorter leukocyte telomeres among sedentary individuals, whereas among those meeting physical activity guidelines (~10–15 minutes per day of vigorous activity, as recommended by the CDC), stress was not significantly related to telomere length. Because the initial study supporting this stress-buffering effect was small (n = 63) and cross-sectional in design, the body of evidence is graded as low certainty.

0:56:30supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

The relationship between exercise volume/intensity and telomere length is non-linear, with marathon runners exhibiting only slightly longer telomeres than moderate regular runners.

"Oh, yes, there is, but it's not linear. So when you get up to extreme sports and marathon runners, yeah, they're a little bit longer in their telomeres, but not much longer than someone who's like running three times a week." (said at 0:56:30)

Observational studies and systematic reviews indicate that the relationship between physical activity volume/intensity and leukocyte telomere length is non-linear. While regular moderate physical activity is associated with preserved telomere length compared to inactivity, extreme endurance athletes and marathon runners show modest, plateaued, or inconsistent additional telomere preservation rather than a continuous linear increase, with some literature describing an inverted U-shaped dose-response pattern.

0:58:15supportedlowDr. Elissa Epel on Telomeres and the Role of Stress Biology

A three-week residential meditation retreat led to telomere lengthening, with the greatest improvements observed in individuals high in neuroticism.

"and it has one of our studies, this meditation retreat study, where it looks like people's telomeres really benefited from a three-week residential retreat... And especially benefited if they were people who are particularly neurotic, if they kind of have a lot of tendency for negative emotions." (said at 0:58:15)

A controlled study evaluating participants in an intensive 1-month residential Insight meditation retreat found an apparent increase in telomere length (TL) compared to non-retreat experienced meditators. Baseline personality traits moderated these changes: participants with higher baseline neuroticism (and lower agreeableness) exhibited the greatest increases in telomere length over the course of the retreat. The evidence certainty is rated low due to the small sample size, non-randomized design, and short observation window for telomere dynamics.

1:02:26supportedmoderateDr. Elissa Epel on Telomeres and the Role of Stress Biology

Longer telomeres experience faster rates of shortening over time, whereas shorter telomeres are more stable in length.

"Long telomeres shorten faster; short telomeres are really stable." (said at 1:02:26)

Multiple longitudinal human cohort studies demonstrate that the rate of leukocyte telomere length attrition over time is proportional to baseline telomere length. Individuals with longer baseline telomeres show faster rates of shortening, whereas individuals with shorter baseline telomeres show greater length stability and slower loss. While statistical artifacts such as regression to the mean account for part of this observed relationship, re-analyses confirming and correcting for regression to the mean show that a statistically significant biological effect persists.

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