Yogurt and Streptococcus thermophilus metabolites ameliorated telomere attrition in D‐galactose‐induced ageing mice and t‐BHP‐challenged HepG2 cells

Summary Antioxidant‐rich diets affect telomere length, an integrative marker associated with age‐related diseases. Yogurt exerts antioxidative capacity and is speculated to support healthy ageing. However, direct experimental evidence is missing. Here, the effects of yogurt and dairy‐fermenting bacteria on D‐galactose‐induced ageing mice and chemically challenged HepG2 cells were evaluated. Relative telomere length (RTL) in leucocyte and liver were significantly longer in yogurt (1.21 ± 0.07; 1.23 ± 0.11) and Streptococcus thermophilus group (1.18 ± 0.15; 1.13 ± 0.12). When t ‐BHP‐challenged HepG2 cells were treated with digested yogurt and S. thermophilus , the senescence index (13.67 ± 3.30; 19.67 ± 2.87) were lower and RTL (1.25 ± 0.11; 1.18 ± 0.10) were longer than the model. Antioxidative effects were observed for yogurt and S. thermophilus metabolites, whereas milk and Lactobacillus rhamnosus metabolites showed minimal influence on RTL and oxidative stress. In conclusion, this study showed that yogurt and S. thermophilus metabolites ameliorated telomere attrition in ageing mice and t ‐BHP‐challenged HepG2 cells, possibly by reducing oxidative stress.