ID 321 -
Potas
PL: Potas
EN: Potassium
Pdf: potassium
1. Charakterystyka żywności / składnika
The food constituent that is the subject of the health claim is potassium, which is a well recognised nutrient and can be measured by established methods. Potassium occurs naturally in foods in several forms, mainly as organic salts.
Different forms of potassium are authorised for addition to foods and for use in food supplements (Annex II of the Regulation (EC) No 1925/20065 and Annex I of Directive 2002/46/EC6). This evaluation applies to potassium naturally present in foods and those forms authorised for addition to foods and for use in food supplements (Annex II of the Regulation (EC) No 1925/2006 and Annex I of Directive 2002/46/EC).
Potassium is naturally present in unprocessed foods mainly in association with bicarbonate-generating precursors such us citrate, and to lesser extent phosphate. Potassium is authorised for addition to foods for technological purposes (Regulation (EC) No 1333/20087) and for addition to foods for nutritional purposes (Annex I of the Regulation (EC) No 1925/2006). Potassium is also authorised for use in food supplements (Annex II of the Directive 2002/46/EC). This evaluation applies to potassium naturally present in foods and those forms authorised for addition to foods (Annex II of the Regulation (EC) No 1925/2006).
The Panel considers that the food constituent, potassium, which is the subject of the health claims is sufficiently characterised.
2.2. Utrzymanie prawidłowego ciśnienia tętniczego (ID 321)
The claimed effect is “blood pressure”. The Panel assumes the target population is the general population.
In the context of the proposed wording, the Panel notes that the claimed effect relates to the maintenance of a normal blood pressure.
Blood pressure (BP) is the pressure (force per unit area) exerted by circulating blood on the walls of blood vessels. Elevated BP, by convention above 140 mmHg (systolic) and/or 90 mmHg (diastolic), may compromise the normal arterial and cardiac function.
The Panel considers that maintenance of normal blood pressure is a beneficial physiological effect.
3. Naukowe uzasadnienia wpływu na zdrowie człowieka -
Potassium is the major intracellular cation and plays a significant role in several physiological processes. Potassium has a crucial role in energy metabolism and membrane transport. A major function of potassium is membrane polarisation, which depends on the extra- and intra-cellular concentrations of potassium (gradient trans-membrane). Relatively small changes in the concentration of extracellular potassium greatly affect the gradient trans-membrane and thereby neural transmission, muscle contraction, and vascular tone (IoM, 2005; Preuss, 2006).
3.2. Utrzymanie prawidłowego ciśnienia tętniczego (ID 321)
Twenty three references have been provided, all pertinent for the assessment of the claimed effect, including statements from authoritative bodies (IoM, 2005; Lichtenstein et al., 2006, FDA, 2000; Appel et al., 2006), meta-analysis of randomised controlled trials (Capuccio and MacGregor, 1991; Whelton et al., 1997; Geleijnse et al., 2003), large observational studies (Dyer et al., 1994), as well as single studies on the effects of different potassium salts (He et al., 2005; Braschi and Naismith, 2008) or low doses of potassium (Naismith and Braschi, 2003) on BP.
The American Heart Association recommends increasing dietary potassium intakes to 4.7 g/d as a diet-related modification that effectively lowers BP (Appel et al., 2006; Lichtenstein et al., 2006) preferably by increasing consumption of potassium-rich foods (e.g. fruits and vegetables) instead of
supplements. This recommendation is in line with the recommendations from the US Food and Nutrition Board, which has set an intake of 4.7 g potassium per day from food as an adequate intake, mainly based on its blood pressure-lowering effects (IoM, 2005). In this report, data from a large number of observational studies reporting potassium intake (or urinary excretion of potassium as a proxy of intake) from foods were reviewed. Whereas potassium intake generally showed an inverse (and sodium intake a direct) association with BP values and/or the risk of hypertension, the sodium/potassium ratio was a stronger predictor than the intake of either electrolyte alone. Owing to the high colinearity between sodium and potassium intakes, the effects of either one on BP were difficult to estimate.
Most of the intervention studies on the effects of potassium on BP have been conducted with supplements of potassium chloride and have been reviewed in four meta-analysis of randomised controlled trials (RCTs) (Capuccio and MacGregor, 1991; Whelton et al., 1997; Geleijnse et al., 2003; Dickinson et al., 2006), three of them included in the US Food and Nutrition Board report (Capuccio and MacGregor, 1991; Whelton et al., 1997; Geleijnse et al., 2003). Three of the meta-analysis included exclusively trials where the only difference between the intervention and control groups was potassium intake (Whelton et al., 1997; Geleijnse et al., 2003; Dickinson et al., 2006).
The meta-analysis by Whelton et al. (1997) included 33 RCTs (2,609 subjects 18-79 years old), from which 12 trials were on normotensives (1,005 subjects) and 21 in hypertensives (1,560 subjects). Only in four trials subjects received concurrent antihypertensive medications. All but six trials provided potassium chloride as supplements. Systolic and diastolic BP significantly decreased with potassium supplementation as compared to placebo after adjustment for confounders, i.e., the effect size estimates were higher when only trials in non-pharmacologically treated subjects were considered (n=29). The effects were also more pronounced at higher urinary sodium excretions.
In the meta-analysis by Geleijnse et al. (2003), 27 RCTs with a mean duration of six weeks (range 2 to 114 weeks) were included. A significant reduction in systolic and diastolic BP was observed after adjustment for confounders with potassium supplementation as compared to placebo. Age, gender, and initial sodium and potassium excretion did not change the effect size estimates, but the effects were higher in hypertensive subjects.
The meta-analysis by Dickinson et al. (2006) included six RCTs (483 subjects older than 18 years) and observed large (but not significant) reductions in BP following potassium supplementation (8-16 weeks follow-up). The authors concluded that the evidence on the effects of potassium supplementation on BP is inconclusive owing to the large heterogeneity between trials.
The BP-lowering effect of potassium could be mediated by direct vasodilatation, by suppression of the sympathetic nervous system and the renin-angiotensin-aldosterone axis (COMA, 1991), and/or by its natriuretic effects (i.e. it increases urinary excretion of sodium chloride), which is independent of the accompanying ion (EFSA, 2005). This is supported by the observation that moderate potassium deficiency (without hypokalaemia) is characterised by increased BP and salt sensitivity, and that potassium lowers BP more in subjects with high sodium intakes. Potassium intake can also attenuate and even revert the hypertensive effects of sodium chloride in salt-sensitive individuals in a dose- dependent manner (IoM, 2005). Since data from observational studies has been obtained with potassium intakes from foods (as organic acids such as citrate) whereas intervention studies have been mostly conducted with potassium chloride, the effects on BP can likely be attributed to potassium itself independent on the accompanying ion (IoM, 2005).
In weighing the evidence, the Panel took into account that, even if one meta-analysis of RCTs did not observe an effect on BP following potassium supplementation (Dickinson et al., 2006), most observational and most of the RCTs reviewed in three meta-analyses (Whelton et al., 1997; Geleijnse et al., 2003; Dickinson et al., 2006), two of them including well controlled trials and adjustment for confounders, reported a significant association between potassium intake and lower BP. Although not
all bodies agree on this association (JHCI, 2003), European and American professional associations recommend increasing dietary potassium intakes for the prevention and management of human hypertension (Appel et al., 2006; Lichtenstein et al., 2006; Mancia, 2007) and biologically plausible mechanisms for these effects have been proposed.
The Panel concludes that a cause and effect relationship has been established between the dietary intake of potassium and the maintenance of a normal blood pressure.
4.2. Utrzymanie prawidłowego ciśnienia tętniczego (ID 321)
The Panel considers that the following wording reflects the scientific evidence: “Potassium helps maintain normal blood pressure.”.
5. Warunki i możliwe ograniczenia stosowania oświadczenia
The Panel considers that in order to bear the claims a food should be at least a source of potassium as per Annex to Regulation 1924/2006. Tolerable Upper Intake Levels (UL) have not been established for potassium in children, adolescents and adults (EFSA, 2006).
Warunki i możliwe ograniczenia stosowania oświadczenia
Appropriate warning needed for K to be determined (to be determined) Must at least be a source of mineral/s as per annex to regulation 1924/2006
