Abstract
Randomized controlled trials on diet and shortening of leukocyte telomere length (LTL) mostly focus on marine-derived n-3 polyunsaturated fatty acids (PUFA). Walnuts are a sustainable source of n-3 PUFA. We investigated whether inclusion of walnuts (15% of energy) in the diet for 2 years would maintain LTL in cognitively healthy elders (63–79 years old) compared to a control group (habitual diet, abstaining from walnuts). This opportunistic sub-study was conducted within the Walnuts and Healthy Aging study, a dual-centre (Barcelona, Spain and Loma Linda University, California) parallel trial. A sub-set of the Barcelona site participants were randomly assigned to the walnut (n = 80) or control group (n = 69). We assessed LTL at baseline and at 2 years and we conducted repeated-measures ANCOVA with 2 factors: time (baseline, 2 years) and group (control, walnut) and their interaction. Adjusted means (95% confidence interval) of LTL (in kb) in controls were 7.360 (7.084,7.636) at baseline and 7.061 (6.835,7.288) after 2 years; corresponding values in the walnut group were 7.064 (6.807,7.320) and 7.074 (6.864,7.284). The time × intervention interaction was nearly significant (p = 0.079), suggestive of a trend of walnut consumption in preserving LTL. This exploratory research finding should be confirmed in trials with adequate statistical power.
Highlights
Population aging is a global trend [1]
There were 2 dropouts due to severe dyspepsia attributed to walnuts, while 6 participants had milder dyspepsia that was solved by reducing walnut doses
Complete leukocyte telomere length (LTL), dietary, anthropometric and RBC fatty acid data were available for 149 participants (80 walnuts and 69 controls) and subsequent data refer only to them
Summary
Population aging is a global trend [1]. Given the socioeconomic burden of treating age-related diseases [2], identifying simple strategies to promote healthy aging (preserved physical and cognitive function, quality of life and independence) have emerged as a major public health concern [3]. The nine tentative hallmarks of aging listed in 2013 [4] prompted many potential aging biomarkers. Telomeres are repeating DNA sequences (50 -TTAGGG-30 ) located at chromosomal ends. They allow cells to distinguish chromosome ends from double-strand breaks and protect chromosomes from end-to-end fusion, recombination and degradation. The critical accumulation of uncapped (short) telomeres triggers cellular senescence, apoptosis and/or the permanent cell cycle arrest in many body tissues. This fostered the use of shortening of leukocyte telomere length (LTL) to help explore the link between diet and aging, despite having inherent caveats [5]
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