ID 2887 - Fosforan sodu

PL: Fosforan sodu
EN: Sodium phosphate
Pdf: sodium phosphate

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the health claims is sodium phosphate.
Sodium phosphate is the generic name denoting the salts of sodium and phosphoric acid, which for the purpose of this opinion include sodium dihydrogen phosphate (also known as monobasic sodium phosphate), disodium hydrogen phosphate (also known as dibasic sodium phosphate), and sodium phosphate (also known as tribasic sodium phosphate).
Sodium phosphates can be measured in foods by established methods.
The Panel considers that the food constituent, sodium phosphate, which is the subject of the health claims, is sufficiently characterised.

2.1. Zwiększenie wydolności fizycznej (ID 318, 2887)

The claimed effects are “supports an increase in performance during maximal aerobic exercise lasting 10 minutes or longer” and “supports an increase in VO2 max”. The Panel assumes that the target population is adults performing endurance exercise.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to increase in endurance performance. Endurance performance relates to the ability to complete certain tasks with higher intensity, faster, or with a higher power output when performing long-term exercise.
The Panel considers that an increase in endurance performance is a beneficial physiological effect.

2.2. Wzrost wytrzymałości (ID 318, 2887)

The claimed effects are “supports an increase in performance during maximal aerobic exercise lasting 10 minutes or longer” and “supports an increase in VO2 max”. The Panel assumes that the target population is adults performing endurance exercise.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to increase in endurance capacity. Endurance capacity refers to the exercise time to self-reported fatigue when exercising at a constant workload or speed.
The Panel considers that an increase in endurance capacity is a beneficial physiological effect.

3. Naukowe uzasadnienia wpływu na zdrowie człowieka

The four references provided for the scientific substantiation of the claims reported on human intervention studies on the effects of (tribasic) sodium phosphate consumption in athletes performing endurance exercise (Cade et al., 1984; Kreider et al., 1990; Kreider et al., 1992; Stewart et al., 1990). While all four of these studies assessed the effects of the intervention on maximal oxygen uptake (VO2 max), only three were considered pertinent for the respective claims considered in this opinion; these were the two which assessed changes in endurance performance (Kreider et al., 1990; Kreider et al., 1992), and the one which assessed changes in endurance capacity (Stewart et al., 1990).

3.1. Zwiększenie wydolności fizycznej (ID 318, 2887)

In a randomised, cross-over, double-blind, placebo controlled, five-week intervention study (Kreider
et al., 1990), seven male competitive distance runners (VO2 max 73.9 6.3 mL/kg/min) received 1 g of tribasic sodium phosphate or 1 g placebo (unspecified) four times daily for six days each, with a two-week wash-out period in between. On days 3 and 6 of supplementation, either a maximal running stress test or a 5-mile performance run test on a treadmill (one on each day) were conducted, the order of which was randomised. Perception of work effort was monitored by Borg’s 10 point rating of perceived exertion scale. Ventilatory anaerobic thresholds were determined subjectively by visual inspection of respiratory data. Other outcomes measured were biochemical variables (phosphate, lactate, haemoglobin, haematocrit, 2,3-diphosphoglycerate), heart rate, oxygen uptake, maximal ventilation, and respiratory quotient both during the maximal running stress test and during the 5-mile performance run test, as well as performance time during the 5-mile performance run test. No power calculations were performed and no adjustment for multiple comparisons was made. Performance time during the 5-mile run was assessed as a measure of endurance performance. No significant differences between the sodium phosphate and placebo groups were observed with respect to performance time during the 5-mile run. The Panel notes that this study does not show an effect of sodium phosphate consumption on endurance performance.
In a randomised, cross-over, double-blind, placebo-controlled intervention study (Kreider et al., 1992), six trained male cyclists and triathletes participated in assessing the effects of phosphate loading on maximal and endurance exercise performance. Subjects consumed either 1 g of tribasic sodium phosphate or placebo (glucose) four times daily for three days prior to performing either an incremental maximal cycling test or a simulated 40 km time trial on a computerised race simulator. They continued the supplementation protocol for an additional day and then performed the remaining maximal or performance exercise test. Subjects observed a 17-day wash-out period between testing sessions and repeated the experiment with the alternate supplement (tribasic sodium phosphate or placebo) in identical fashion. Outcomes measured were biochemical variables, echocardiographic and haemodynamic variables, and anaerobic thresholds during the maximal and during the 40 km performance time trial. No power calculations were performed and the primary outcome of the study is unclear. Final performance time during the 40-km race was assessed as a measure of endurance
performance. The Panel notes that it is unclear whether comparisons between groups were performed, and whether these were statistically significant. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
In weighing the evidence, the Panel took into account that the one human intervention study provided from which conclusions could be drawn for the scientific substantiation of the claim did not show an effect of sodium phosphate on endurance performance.
The Panel concludes that a cause and effect relationship has not been established between the consumption of sodium phosphate and increase in endurance performance.

3.2. Wzrost wytrzymałości (ID 318, 2887)

In a randomised, cross-over, double-blind, placebo-controlled intervention study (Stewart et al.,
1990), eight well-trained male cyclists (VO2 max 48.5 8.3 mL/kg/min) received 600 mg of sodium phosphate or 600 mg placebo (white flour) in capsules six times daily for three days prior to a cycling test, with a one-week wash-out period in between treatments. All subjects had a control cycling test first. Cycling tests consisted of a 5-min warm-up pedalling at a workload of 3 kp/min with a pedalling frequency of 60 rpm and a power output of 180 watts. After this warm-up, the workload increased by 60 watts every 2 min each time until the subjects could no longer maintain the pedalling frequency. Outcome variables were VO2 max, biochemical variables (phosphate, lactate, 2,3-diphosphoglycerate), and endurance capacity (i.e. duration of performance on the bicycle ergometer). The Panel notes the small number of subjects recruited, that no power calculations were performed, that no adjustment for multiple comparisons was made, and that the primary outcome of the study is unclear. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
The Panel concludes that a cause and effect relationship has not been established between the consumption of sodium phosphate and increase in endurance capacity.

Warunki i możliwe ograniczenia stosowania oświadczenia

3.6 grams per day for 3 days prior to the exercise test