Does p-lactate increase in patients with GSD1 after ingesting a meal with common-size sources of fructose and galactose? Observations from a prospective, non-blinded, crossover pilot study.

Ingestion of fructose and galactose may result in elevated lactate concentrations in patients with glycogen storage disease type 1 (GSD1). In this randomized cross-over pilot study, 7 patients with GSD 1a (6) and GSD1b (1) orally consumed a common-size fructose and galactose from either 200 mL of skimmed milk, 200 mL juice or 200 mL water. This was given after a night with their usual dietary treatment using either cornstarch, glycosade or continuous feed. P-lactate and -glucose were measured 2 h before dosing (T = -120 min and -60 min). At baseline (T = 0), p-lactate, p-glucose, p-triglycerides, p-uric acid and p-alanine were measured just before dosing. P-lactate and p-glucose were measured every 30 min for 4 h. Four hours after the consumption (T = 240 min, end-of-test), levels of p-lactate, p-glucose, p-triglycerides, p-uric acid and p-alanine were measured. P-lactate increased in three patients with mean of 0.3 mmol/L (range 0.2-0.6 mmol/L) after consuming milk. The highest level was seen after 60 min. A decrease was seen in three patients. P-lactate increased in four patients with a mean increase at 1.3 mmol/L (range 0.2-2.2 mmol/L) after consuming 200 mL juice. A peak increase was seen after the first 30 min in two patients whereas the peak in the remaining two patients was at 60 min; all values decreased to baseline values after further 60 min. In two patients, p-lactate was unchanged, respectively, decreased after juice ingestion. Calculation of galactose and fructose AUC percentage change after challenge did not reveal consistent increase or decreases.