Abstract
It remains unknown how different glucose tolerance status affects the relationships between dietary intake of different tocopherol isoforms (α-, β-, γ-, and δ-tocopherol) and cellular aging, oxidative stress, and inflammatory markers. The authors conducted a cross-sectional study among 582 Chinese adults with different glucose tolerance status to explore the association between dietary intake of different tocopherol isoforms and cellular aging, oxidative stress, and inflammatory markers. The inverse correlations between non-α-tocopherols and tumor necrosis factor-alpha (TNF-α) varied substantially across different glucose tolerance status, with the strongest observed in prediabetes (r = −0.33 for β-/γ-tocopherol, r = −0.37 for δ-tocopherol, p < 0.01), followed by normal glucose tolerance (NGT). While such correlations were abolished in established diabetes. Furthermore, within prediabetes, the strongest inverse correlations between non-α-tocopherols and TNF-α were observed in impaired fasting glucose (IFG) (r = −0.42 for β-/γ-tocopherol, r = −0.55 for δ-tocopherol, p < 0.01), while such correlations were significantly attenuated in individuals with impaired glucose tolerance (IGT) and IFG+IGT. And mediation model analysis displayed that TNF-α mediated the protective effect of non-α-tocopherols on leukocyte telomere length and mitochondrial DNA copy number, which was uniquely observed in prediabetes, while such mediation effect was statistically nonsignificant in NGT and established diabetes. In conclusion, our findings indicate that dietary intake of non-α-tocopherols might protect against cellular aging markers mediated by TNF-α in prediabetes. Individuals with prediabetes, especially for IFG, might benefit from increasing dietary intake of non-α-tocopherol in alleviating inflammation and cellular aging, which might provide a new dietary avenue for delaying diabetes onset.
Highlights
Tocopherols (Toc), with four isoforms including α, β, γ, and δ-Toc in diet, are potent peroxyl radical-scavenging antioxidants and anti-inflammatory agents [1]. α-Toc was the most studied because of its abundance in the diet and circulation, followed by γ-Toc, while δ-Toc was scarcely investigated
Prediabetes is the earliest stage of diabetes (impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG)) which tends to progress to diabetes along with the loss of β-cell function, due in part to factors such as elevated glucose and lipid levels, inflammation, and oxidative stress [19]
The authors explored the associations between different Toc isoforms and cellular aging, oxidative stress, and inflammatory markers in individuals with IFG, IGT, and IFG+IGT, respectively (Table 3)
Summary
Tocopherols (Toc), with four isoforms including α-, β-, γ-, and δ-Toc in diet, are potent peroxyl radical-scavenging antioxidants and anti-inflammatory agents [1]. α-Toc was the most studied because of its abundance in the diet and circulation, followed by γ-Toc, while δ-Toc was scarcely investigated. As one of the agerelated diseases, diabetes has been indicated to be closely associated with cellular aging and oxidative stress as well as inflammation [14,15,16]. Association between dietary intake of different Toc isoforms and markers of oxidative stress, inflammation, and cellular aging in prediabetic individuals may provide new insight into dietary intervention of prediabetes. It is still unknown how different glucose tolerance status affects the relationships between dietary intake of different Toc isoforms and cellular aging, oxidative stress, and inflammatory markers
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