Causal association of dietary intake habits and telomere lengths: A Mendelian randomization study.

Background and objectives: Healthy diets are crucial in disease prevention and balanced diets can slow te-lomere shortening. Currently, it is still unclear which dietary factors are causally related to telomere length.

Methods and study design: The inverse variance weighted, Mendelian Randomization-Egger, weighted median, simple mode, and weighted mode methods were used. Additionally, heterogeneity, pleiotropy, MR-PRESSO and leave-one-out tests were conducted to ensure accuracy. Outcomes included granulocyte, lym-phocyte, naive T-cell, memory T-cell, B-cell, and natural killer-cell telomere lengths. Exposures included alcohol intake frequency, alcoholic drinks per week, average weekly beer plus cider intake, average weekly red wine intake, intake of beef, bread, cereal, coffee, cooked vegetable, dried fruit, fresh fruit, lamb/mutton, non-oily fish, oily fish, pork, processed meat, salad/raw vegetable, tea and water.

Results: The positive causal relationships were found between dried fruit intake and granulocyte telomere length (OR: 4.31; 95% CI: 1.29 to 14.4; p = 0.02), lymphocyte telomere length (OR: 4.22; 95% CI: 1.21 to 14.7; p = 0.02), naive T-cell telomere length (OR: 5.49; 95% CI: 1.58 to 19.0; p = 0.01). Oily fish intake was positively associated with memory T-cell telomere length (OR: 2.55; 95% CI: 1.16 to 5.58; p = 0.02). No significant causal relationships were found between other exposures and outcomes.

Conclusions: This study found positive causal associations between telomere length and the intake of dried fruit and oily fish. No significant causal relationships were observed with other dietary factors. These findings provide insights into how specific dietary components may help maintain telomere length.