ID 699 - Glutamina

PL: Glutamina
EN: Glutamine
Pdf: L-glutamine

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the health claims is L-glutamine.
Glutamine is a conditionally indispensable amino acid provided by mixed dietary protein intakes from different sources. It can also be consumed as a food supplement. The content of L-glutamine in foods can be measured by established methods.
The Panel considers that the food constituent, L-glutamine, which is the subject of the health claims, is sufficiently characterised.

2.2. Szybsze regenerowanie mięśniowych zapasów glikogenu po intensywnych ćwiczeniach (ID 434, 699, 701, 723, 1569)

The claimed effects are “supporting glycogen replenishment”, “muscle function”, “metabolic stress, protein synthesis, gut permeability, carbohydrate metabolism” and “supporting glucose homeostasis”. The Panel assumes that the target population is adults performing strenuous exercise.
In the context of the proposed wordings, clarifications from Member States and references provided, the Panel assumes that the claimed effects refer to the faster restoration of glycogen stores in skeletal muscle after strenuous exercise.
The Panel considers that faster restoration of muscle glycogen stores after strenuous exercise might be a beneficial physiological effect.

3. Naukowe uzasadnienia wpływu na zdrowie człowieka - 

The references provided for the scientific substantiation of these claims included textbooks and narrative reviews which did not provide original data for the scientific substantiation of the claim. Human, animal and in vitro studies on food constituents other than L-glutamine alone (e.g. branched- chain aminoacids (BCAA); N-acetyl-cysteine; mixtures of whey protein plus BCAA or arginine plus L-glutamine; mixtures of soy lecithin, sodium dihydrogen phosphate, thiamin, pyridoxine and L- glutamine; mixtures of glycine, niacin, and glutamine), on glutamine given intravenously, on health outcomes (e.g. treatment of chronic disease or pathological conditions, morbidity and mortality in pre- term infants, use in enteral nutrition) unrelated to the claimed effects, or on the effects of intense training on plasma and tissue concentrations of L-glutamine, were also provided. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claims.

3.2. Szybsze regenerowanie mięśniowych zapasów glikogenu po intensywnych ćwiczeniach (ID 434, 699, 701, 723, 1569)

Two references which assessed the effects of L-glutamine consumption on muscle glycogen stores after exercise were provided.
In the study by Bowtell et al. (1999) seven male subjects participated in three trials, in each of which they received one of three different drinks by systematic rotation: 18.5 % (wt/vol) glucose polymer solution (containing glucose, maltose, maltotriose, tetrasaccharide, pentasaccharide and “higher sugars”), a solution containing 8 g glutamine, or 18.5 % glucose polymers containing 8 g glutamine. Tests were undertaken one month apart. On each test day, subjects followed a validated standard exercise protocol designed to deplete of glycogen both type I and type II muscle fibres. A muscle biopsy was taken from the quadriceps femoris muscle within 15 min of the end of exercise. Within 20 min, a 2 h constant [1-13C]glucose intravenous infusion started at a rate of 8.5 mg/kg/h for the first 30 min after a 9 mg/kg bolus of [1-13C]glucose. Subjects then consumed the test drinks (330 mL) within 2 min of the start of the infusion. Second and third quadriceps femoris muscle biopsies were taken after 1 and 2 h of recovery. No significant differences with respect to the average rate of net muscle glycogen storage during the 2 h of recovery after exercise were observed between the test drinks. The Panel notes that this study does not show an effect of L-glutamine on the restoration of muscle glycogen stores after strenuous exercise.
In the study by Van Hall et al. (2000) eight trained subjects were studied during 3 h of recovery while consuming one of four drinks in random order. Drinks were ingested in three 500 mL boluses. Each bolus of the control drink contained 0.8 g/kg body weight of glucose. The other drinks contained the same amount of glucose and either 0.3 g/kg body weight of glutamine, or a wheat hydrolysate (26 % glutamine), or a whey hydrolysate (6.6 % glutamine). On each test day (7 days apart), subjects followed a validated standard exercise protocol for glycogen depletion. A biopsy was taken from the quadriceps muscle 15 min after the end of exercise, and the first bolus was taken immediately thereafter. The other boluses followed after 1 and 2 h of recovery. A second muscle biopsy was taken after 3 h of recovery. The rate of glycogen re-synthesis in skeletal muscle was not significantly different between the four test drinks. The Panel notes that this study does not show an effect of L-glutamine on the restoration of muscle glycogen stores after strenuous exercise.
In weighing the evidence, the Panel took into account that the two studies from which conclusions could be drawn for the scientific substantiation of the claim did not show an effect of L-glutamine consumption on the restoration of muscle glycogen stores after strenuous exercise.
The Panel concludes that a cause and effect relationship has not been established between the consumption of L-glutamine and faster restoration of muscle glycogen stores after strenuous exercise.

Warunki i możliwe ograniczenia stosowania oświadczenia

50 - 900 mg/kg per day