Association of healthy and unhealthy plant-based diets with telomere length

Previous studies have shown that plant-rich dietary patterns, such as the Mediterranean diet, are associated with longer telomeres. However, no association has been found between vegetarian diet and telomere length. We hypothesized that the quality of plant-based diets plays an important role in telomere length.

Data were obtained from the National Health and Nutrition Examination Survey 1999-2002. Diet was assessed using a 24-h recall method. Plant-based diet quality was assessed using the overall plant-based diet index (PDI), healthy PDI (hPDI), and unhealthy PDI (uPDI). Telomere length was measured using quantitative PCR. Linear and ordinal logistic regression models were used to assess the association of PDIs with log-transformed telomere length and ordinal quintiles of telomere length in descending order, respectively.

In both regression models, the overall PDI was not associated with telomere length. The hPDI was associated with longer telomere length [percentage change = 2.34%, 95% confidence interval (CI): 0.42%, 4.31%, P_trend = 0.016; odds ratio (OR) = 0.81, 95% CI: 0.69, 0.95, P_trend = 0.013]. However, uPDI was associated with shorter telomere length (percentage change = -3.17%, 95% CI: -5.65%, -0.62%, P_trend = 0.017; OR = 1.25, 95% CI:1.03, 1.53, P_trend = 0.014) and this inverse association was stronger in the non-Hispanic white population (P_interaction = 0.001 in both regression models).

A plant-based dietary pattern rich in healthy plant foods is associated with longer telomeres. However, plant-based dietary patterns rich in unhealthy plant-based foods are associated with shorter telomere lengths, especially in non-Hispanic white populations.