Oral sodium lactate ingestion does not increase blood lactate concentrations and is accompanied by moderate to severe gastrointestinal side effects

Lactate has diverse roles in biology and has been implicated in the control of energy intake. A variety of methods (i.e., exercise, ingestion, infusion) have been used to study its effects on different metabolic outcomes and the original intent of this project was to explore the effect of oral sodium lactate (Na-Lactate) ingestion on appetite regulation. During piloting we were unable to show that Na-Lactate could increase blood lactate concentrations, thus the purpose of the brief manuscript is to highlight that oral Na-Lactate ingestion is not an effective method to study lactate metabolism. Five male participants (26 ± 3 y, 82.4 ± 3.8 kg, 25.4 ± 1.6 kg∙m -2 ) completed 15 experimental sessions where Na-Lactate solutions were consumed with assessment of blood lactate pre-ingestion, 30 min, 45 min, and 60 min post-ingestion. Oral Na-Lactate ingestion did not increase blood lactate concentrations (Pre: 0.9±0.2; 30 min: 1.2±0.7; 45 min: 1.0±0.5; 60 min: 0.9±0.4 mmol∙L -1 ). Additionally, there were moderate-severe gastrointestinal (GI) side effects (e.g., vomiting, diarrhea) following ingestion. Taken together our data suggest that oral ingestion of Na-Lactate is not an effective method to study lactate's role on metabolism as it did not increase blood lactate concentrations and was accompanied by problematic GI side effects.