Unexpected immunoregulation effects of D-lactate, different from L-lactate

ABSTRACT With advances in the study of the human microbiome, the fact that lactate is the smallest chiral molecule in nature has drawn attention. However, there have been few comparative studies on the classification of L-lactate and D-lactate. In this study, we investigated the safety and efficacy of D-lactate as an immunomodulator of food origin. In terms of safety evaluation, both lactates were found to promote cell proliferation and repair. D-lactate was well tolerated for 30 d at doses up to 2000 mg/kg in mice. In terms of immune function evaluation, unexpectedly, D-lactate was found to enhance immunity by increasing the immune organ index, ear swelling index, lymphocyte conversion rate, haemolysis rate and macrophage phagocytosis rate and had a dose-dependent effect. D-lactate showed stronger immune regulation effects than L-lactate. This study proves the safety and the immunoregulation capacity of D-lactate and provides a mechanistic basis for the bioactivity of fermented foods.