| Boccardi et al. 2019 (89) | Cross-sectional | 68 subjects from the Geriatric Unit of Ospedale Maggiore Policlinico of Milan (2009–2016) | PCR-ELISA and qPCR | Plasma β-carotene | In all populations, β-carotene was significantly and positively correlated with telomerase activity, independent of gender. Subjects affected by AD had significantly lower concentrations of β-carotene and LTL compared with healthy controls |
| Julin et al. 2017 (90) | Cross-sectional | 2483 men from a multiple nested case-control subcohort of the HPFS | PCR | Plasma vitamin D | Neither plasma 25(OH)D3 or 1,25(OH)2D3 were associated with LTL |
| Min and Min, 2016 (91) | Cross-sectional | 3660 healthy subjects from the NHANES study (1999–2002) | PCR | Serum carotenoids | A doubling of blood α-carotene, β-carotene (trans + cis), and β-cryptoxanthin was associated with ∼2% longer telomeres. Compared with the lowest carotenoid quartile of α-carotene, β-carotene (trans + cis), and β-cryptoxanthin, telomere length for adults with the highest quartiles was significantly increased by 5–8% |
| Pusceddu et al. 2017 (92) | Cross-sectional | 65 healthy subjects | PCR | Serum vitamin B-12, total serum folate | Age and gender-adjusted RTL correlated with total serum folate and 5-methyltetrahydrofolate |
| Richards et al. 2007 (93) | Cross-sectional | 2160 healthy women | PCR | Serum vitamin D | Serum vitamin D concentrations were positively associated with LTL, and this relation persisted after adjustment for age and other covariates (age, season of vitamin D measurement, menopausal status, use of hormone replacement therapy, and physical activity). The difference in LTL between the highest and lowest tertiles of vitamin D was 107 bp, which is equivalent to 5.0 y of telomeric aging. This difference was further accentuated by increased concentrations of CRP |
| O'Callaghan et al. 2014 (30) | Cross-sectional | 89 healthy South Australian adults | PCR | Plasma magnesium and calcium | A negative association between telomere length and both plasma calcium and magnesium concentrations were reported in older females. These relations were not observed in the younger adults, nor in the older males |
| Sen et al. 2014 (94) | Cross-sectional | 786 healthy subjects from the Austrian Stroke Prevention Study, a population-based cohort study on brain aging | PCR | Plasma lutein, zeaxanthin, and vitamin C concentrations | Of all micronutrients, the combination of lutein and zeaxanthin (Lu∼Zx) and vitamin C remained significantly and independently associated with LTL when adjusted for age and sex. After additional adjustment the relation between Lu and Zx and LTL became stronger, whereas the association between vitamin C and LTL remained virtually unchanged |
| Paul et al. 2015 (95) | Cross-sectional | 1044 healthy subjects from the Framingham Offspring Study | PCR | Plasma folate | There was no significant positive association between plasma folate and leukocyte telomere length |
| Liu et al. 2016 (96) | Cross-sectional | 1154 healthy subjects from the USRT study | PCR | Plasma 25(OH)D3 | No significant association between continuous 25(OH)D3 and long LTL in all participants, nor in white females, white males, black females, or black males were reported. Vitamin D deficiency (defined as 25(OH)D3 <30 nmol/L), was significantly associated with shorter telomeres in whites, but not in other groups |
| Shin and Baik, 2016 (97) | Cross-sectional | 798 healthy subjects | PCR | Serum vitamin B-12 and folate | In multiple adjusted models, no association was observed between LTL and serum folate and vitamin B-12 |
| Williams et al. 2016 (98) | Cross-sectional | 5096 healthy subjects from the Northern Finland Birth Cohort 1966 | PCR | Plasma 25(OH)D3 | No evident association between plasma 25(OH)D3 and telomere length was observed |
| Nomura et al. 2017 (99) | Cross-sectional | 7826 healthy subjects from NHANES cohort data (1999–2002) | PCR | Serum folate, vitamin B-12, vitamin A, γ-tocopherol, α-tocopherol, and carotenoids | Serum vitamin A was positively associated and γ-tocopherol was inversely associated with LTL. Serum folate and α-tocopherol were marginally positively associated with LTL, whereas vitamin B-12 was not associated with LTL. Serum carotenoids were generally positively associated with LTL |
| Tucker 2017 (100) | Cross-sectional | 5768 healthy subjects from NHANES cohort data (1999–2002) | PCR | Blood γ-tocopherol, blood α-tocopherol, dietary vitamin E, dietary supplements | An inverse association between serum concentrations of γ-tocopherol and TL was observed. Telomeres were approximately 1 y shorter (15.6 bp) for each increment of 47.3 to 55.7 g/dL of γ-tocopherol in the blood, depending on the variables controlled |
| Liu et al. 2019 (101) | Cross-sectional | 7336 healthy subjects from NHANES cohort data (1999–2002) | PCR | Serum ferritin | Low ferritin concentrations (iron deficiency) were not significantly associated with telomere length compared with normal ferritin concentrations |
| Mazidi et al. 2018 (102) | Cross-sectional | 5446 healthy subjects from NHANES cohort data (1999–2000) | PCR | Plasma trans-fatty acids like palmitelaidic acid, elaidic acid, vaccenic acid, and linolelaidic acid | After adjusting for age, sex, ethnicity, education, marital status, subclinical inflammation, BMI, and smoking, only palmitelaidic acid and linolelaidic acid were negatively associated with TL |
| Farzaneh-Far et al. 2010 (14) | Prospective cohort | 608 patients from the Heart and Soul Study | PCR | Serum marine ω-3 fatty acids | Those participants in the highest quartile of DHA3EPA experienced the slowest rate of telomere shortening |