| Nettleton et al. 2008 (56) | Cross-sectional | 840 white, black, and Hispanic US adults from the MESA, 45–84 y | PBL/qPCR | Food groups and dietary patterns derived from principal component analysis | Processed meat intake was inversely associated with TLNeither the derived dietary pattern for fats and processed meat nor the dietary pattern for whole grains and fruit were significantly associated with telomere length after adjustment for demographic and lifestyle factors |
| Sun et al. 2012 (73) | Cross-sectional | 5862 US women from the NHS aged 30–55 y | PBL/qPCR | AHEI | No association between the AHEI score and TL was observed |
| Boccardi et al. 2013 (74) | Cross-sectional | 217 elderly Italian subjects (102 females and 115 males) | PBL/qPCR | MedDiet | High adherence to MedDiet showed longer leukocyte TL (P = 0.003) and higher telomerase activity (P = 0.013) compared with the group with lower adherence to MedDiet |
| Crous-Bou et al. 2014 (58) | Cross-sectional | 4676 healthy American women within the NHS, 35–55 y | PBL/qPCR | MedDiet | Greater adherence to the MedDiet was associated with longer telomeres after adjustment for potential confounders |
| Gu et al. 2015 (60) | Cross-sectional | 1743 US multiethnic individuals (WHICAP), >65 y | PBL/qPCR | MedDiet | MedDiet score was not associated with LTL in the overall study population after adjusting for age, sex, education, ethnicity, caloric intake, smoking, and physical and leisure activities. A significant association between MedDiet and LTL among non-Hispanic whites was reported |
| García-Calzón et al. 2015 (75) | Cross-sectional | 520 Spanish individuals at high cardiovascular disease risk- PREDIMED-NAVARRA, 55– 80 y | Buffy coat/qPCR | DII | Longer telomeres at baseline were found in participants who had a more anti-inflammatory diet (lowest DII score) |
| García-Calzón et al. 2016 (76) | Cross-sectional | 520 females and males at high cardiovascular disease risk from the PREDIMED-NAVARRA center, 55–80 y | Buffy coat/qPCR | MedDiet | A greater baseline adherence to a MedDiet pattern was associated with longer telomeres only in women in a cross-sectional setting |
| Mazidi et al. 2017 (77) | Cross-sectional | 10,568 participants from NHANES, USA, 48% (n = 5020 were men). Mean age was 44.1 y | PBL/qPCR | Dietary patterns determined by principal component analysis and food components “a posteriori” | Three food patterns together explaining 56.8% of the variance of the dietary nutrient consumption were identified. A food pattern, which was a representative of minerals and vitamins, increased across TL quarters and had a positive association with TL. Mean (adjusted for sex, age, and race) dietary intakes of carbohydrate, dietary fiber, total folate, vitamin B-6, magnesium, iron, copper, PUFAs 22:5, and vitamin C increased across TL quarters whereas total fat and caffeine decreased across TL quarters |
| Shivappa et al. 2017 (78) | Cross-sectional | 7215 adults aged >19 y in the NHANES program, USA | Whole blood/qPCR | DII | After multivariable adjustment, higher DII scores (i.e., relatively more proinflammatory) were associated with shorter LTL |
| Leung et al. 2018 (79) | Cross-sectional | 4758 healthy US adults, NHANES, 20–65 y | Whole blood/qPCR | HEIAHEIMedDietDASH | HEI-2010, AHEI-2010, MedDiet, and DASH scores were each positively associated with longer LTL |
| De Meyer et al. 2018 (66) | Cross-sectional | 2509 Belgian males and females aged 35–55 y (Asklepios population) | Whole blood/SB | Dietary patterns and individual food components (DII) | Upon adjustment for confounders, no significant associations could be identified between LTL and holistic dietary patterns, i.e., overall dietary score, dietary quality, dietary diversity, and dietary equilibrium. Additionally, the association between LTL and other general dietary characteristics, i.e., total daily energy, fiber intake, as well as the DII were evaluated, without significant results. A higher daily intake of deep-fried potato, sweets, and meat was associated with shorter telomeres in both sexes |
| Karimi et al. 2018 (67) | Cross-sectional | 300 healthy Iranian men 25–40 y | Whole blood/qPCR | Healthy dietary pattern; Western dietary pattern; traditional dietary pattern “a posteriori” | A positive relation was reported between the healthy dietary pattern (with consumption of whole grains, refined grains, dairy, and cereals) and traditional dietary pattern (with increased consumption of fruit, vegetables, and whole grains, fish and dairy products) with TLNegative association was identified with the Western pattern and TL |
| Milte et al. 2018 (80) | Cross-sectional | 679 (females and males) participants at WELL study in Victoria, Australia, 57–68 y | Whole blood/qPCR | Dietary Guideline IndexRecommended food scoreMedDiet score | After adjustment for age, sex, education, smoking, physical activity, and BMI, there were no significant associations between diet quality and relative telomere length |
| Meinilä et al. 2019 (81) | Cross-sectional | 1046 females and males from the HBCS, Helsinki, Finland, 56–70 y | Whole blood/qPCR | BSDSModified MedDiet scoreDII | BSDS, mMED, and DII were not associated with TL in the cross-sectional analysis in men or women |
| Gong et al. 2018 (82) | Cross-sectional | 553 Chinese adults (50.8% men), 25–65 y | Whole blood/TRF; SB | Dietary pattern determined by principal component analysis “a posteriori” | Vegetable-rich pattern characterized by higher intake of fruit, whole grains, various vegetable groups, dairy products, nuts, eggs, and tea, was positively related to TL in women |
| Meinilä et al. 2019 (81) | Prospective cohort | 1046 females and males from the HBCS, Helsinky, Finland, 56–70 y | Whole blood/qPCR | BSDSModified MedDiet score, DII | No association between mMED and LTL change was found in men. In women, mMED was associated with faster LTL shorteningAdherence to BSDS and DII did not associate with LTL change in men or women |
| García-Calzón et al. 2015 (75) | Prospective cohort | 520 Spanish individuals at high cardiovascular disease risk- PREDIMED-NAVARRA, 55–80 y | Buffy coat/qPCR | DII | A greater anti-inflammatory potential of the diet (i.e., a decrease in the DII) could significantly slow down the rate of telomere shortening |
| Lee et al. 2015 (45) | Prospective cohort | 1958 Korean adults, 40–69 y, 10-y follow-up | PBL/qPCR | Dietary patterns determined by factor analysis “a posteriori” | The first factor labeled “prudent dietary pattern” characterized by high intake of whole grains, seafood, legumes, vegetables, and seaweed was positively associated with leukocyte TL. In the analysis of particular food items, higher consumption of legumes, nuts, seaweed, fruit, and dairy products and lower consumption of red meat or processed meat and sweetened carbonated beverages were associated with longer leukocyte TL |
| García-Calzón et al. 2016 (76) | RCT | 520 Spanish individuals at high cardiovascular disease risk from the PREDIMED-NAVARRA center, 55–80 y | Buffy coat/qPCR | Two MedDiets, 1 supplemented with extra-virgin olive oil and the other with mixed nuts compared with a low-fat diet | No beneficial effect of the intervention with the MedDiet for the prevention of telomere shortening in comparison with a low-fat diet was observed after 5 y of intervention |