Dietary inflammatory index (DII) and telomere length: a systematic review

Dietary intake influences inflammation and may impact telomere length (TL), a biomarker of biological aging. However, the relationship between the inflammatory potential of the diet and TL remains unclear. This review systematically assessed whether higher Dietary Inflammatory Index (DII) scores, indicative of pro-inflammatory diets, are associated with shorter TL. Searches in PubMed, Embase, Scopus, Web of Science, and Cochrane up to October 2024 identified nine eligible studies, involving 123,923 participants (53% women), aged 9-80 years. Seven studies were cross-sectional, and two were longitudinal, with follow-ups of 5-10 years. Most studies (n = 4) examined adult and older adult populations of both sexes. DII values ranged from -6.48 (anti-inflammatory) to 3.98 (pro-inflammatory). None included all DII parameters, and three adjusted for energy intake. Four studies linked higher DII to shorter TL, focusing on European adults with and without cardiovascular risk, healthy American adults, and Chinese older adults with mild cognitive impairment. This systematic review presents limited data to provide a definitive conclusion on the association between higher DII and shorter TL. Additional studies that address the limitations identified in this review are needed.