Dried fruit, oily fish intakes help preserve telomere length

Eating dried fruits and oily fish appear to have positive effects on telomere length (TL), suggests a study.

Specifically, dried fruit intake showed a positive causal association with granulocyte TL, lymphocyte TL, and naïve T-cell TL, while oily fish intake correlated with memory T-cell TL.

On the other hand, TL did not demonstrate a causal relationship with alcohol intake frequency, alcoholic drinks per week, average weekly beer plus cider intake, average weekly red wine intake, beef intake, bread intake, cereal intake, coffee intake, cooked vegetable intake, fresh fruit intake, lamb/mutton intake, nonoily fish intake, pork intake, processed meat intake, salad/raw vegetable intake, tea intake, and water intake. [Asia Pac J Clin Nutr 2025;34:783-795]

“These findings provide insights into how specific dietary components may help maintain TL,” the investigators said.

This study applied the inverse variance weighted, Mendelian Randomization-Egger, weighted median, simple mode, and weighted mode methods. Accuracy was ensured using heterogeneity, pleiotropy, MR-PRESSO, and leave-one-out tests.

Dried fruit intake positively correlated with granulocyte TL (odds ratio [OR], 4.31, 95 percent confidence interval [CI], 1.29‒14.4; p=0.02), lymphocyte TL (OR, 4.22, 95 percent CI, 1.21‒14.7; p=0.02), and naïve T-cell TL (OR, 5.49, 95 percent CI, 1.58‒19.0; p=0.01). Oily fish intake showed a positive association with memory T-cell TL (OR, 2.55, 95 percent CI, 1.16‒5.58; p=0.02).

No significant causal associations were observed between outcomes and other exposures.

“This study had significant potential for the field of public health,” the investigators said. “It provided valuable information for ageing prevention, which thereby promoted the overall health and well-being of the population.”

Oxidative stress

Each replication cycle, which is accelerated by oxidative stress, affects telomeres, but foods rich in antioxidants and anti-inflammatory properties help maintain TL. [J Cell Sci 2004;117:2417-2426; Clin Nutr 2015;34:694-699]

However, it remains unclear which specific types of foods affect TL. An earlier study suggested that individuals who regularly consume fruits and vegetables have longer telomeres, while another study did not find a significant association between TL and intakes of fruit and vegetable. [Mutagenesis 2012;27:49-57; Am J Clin Nutr 2010;91:1273-1280]

Fruits contain essential vitamins, minerals, and antioxidants and have positive effects on maintaining TL. In addition, their nutritional contents become concentrated during drying, which could potentially explain why a causal relationship was found between dried fruits and TL, but not fresh fruits. [J Funct 2016;21:113-132]

On the other hand, oily fish is rich in omega-3 fatty acids like DHA and EPA. Prospective studies revealed that higher blood omega-3 levels could slow telomere shortening, as well as a positive relationship between DHA/EPA and TL. [Food Chem 2006;97:674-678; JAMA 2010;303:250-257; Nutr J 2020;19:119]

“Overall, omega-3 fatty acids were beneficial for maintaining TL, and making a bold inference, oily fish rich in omega-3 fatty acids also likely benefited TL,” the investigators said.

Notably, significant tissue-specific differences existed among cell types, which helped explain why dried fruits and oily fish only affect the TL of certain cells. [Science 2020;369:eaaz6876]

“Therefore, in diets for the elderly, this study recommended moderate increases in dried fruits and oily fish,” the investigators said.