ID 4245 - Izoflawony sojowe

PL: Izoflawony sojowe
EN: Soy Isoflavones
Pdf: soy isoflavones

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the health claims is soy isoflavones.
Soy isoflavones constitute a wide range of compounds of plant origin, which mainly comprise genistein, daidzein and glycitein, among others (Ma et al., 2008a, 2008b). Soy isoflavones can be consumed as isolated soybean protein (ISP), as whole-soybean foods or extracts, as supplements or as pure compounds (Cassidy et al., 2006).
The Panel considers that the food constituent, soy isoflavones, which is the subject of the health claims, is sufficiently characterised.

2.1. Ochrona DNA, białek i lipidów przed uszkodzeniem oksydacyjnym (ID 1286, 4245)

The claimed effects are “vascular effects including protection from oxidative damage” and “antioxidant status”. The Panel assumes that the target population is the general population.
The Panel considers that claims made on the antioxidant capacity/content or properties of foods/food constituents based on their capability to scavenge free radicals in vitro refer to a property of the foods/food constituents measured in model systems, and that the information provided does not establish that this capability exerts a beneficial physiological effect in humans as required by Regulation (EC) No 1924/2006.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to the protection of body cells and molecules from oxidative damage caused by free radicals.
Reactive oxygen species (ROS) including several kinds of radicals are generated in biochemical processes (e.g. respiratory chain) and as a consequence of exposure to exogenous factors (e.g. radiation and pollutants). These reactive intermediates can damage molecules such as DNA,
proteins and lipids if they are not intercepted by the antioxidant network which includes free radical scavengers such as antioxidant nutrients.
The Panel considers that protection of DNA, proteins and lipids from oxidative damage may be a beneficial physiological effect.

3.1. Ochrona DNA, białek i lipidów przed uszkodzeniem oksydacyjnym (ID 1286, 4245)

Among the references provided were a number of narrative reviews and textbooks which were either not related to the claimed effect or did not provide any original data which could be used for the scientific substantiation of the claim. A number of human, animal and in vitro studies were not related to the claimed effect; these included references on endothelial function, antioxidant gene expression, metabolic syndrome, blood pressure, cholesterol concentrations, subarachnoid haemorrhage,
cardiovascular disease, atherosclerosis and symptoms associated with menopause. Some of the references provided did not address the food constituent which is the subject of the claim, but rather soy foods in general, or soy foods in combination with other foods. These studies did not control for other components besides isoflavones in these soy foods, which could have an effect on the protection of DNA, proteins and lipids from oxidative damage. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
Human intervention studies which assessed the effects of soy isoflavones on plasma total antioxidant status (DiSilvestro et al., 2006) and on ex vivo resistance of LDL to peroxidation (Jenkins et al., 2002; Nestel et al., 1997; Steinberg et al., 2003), and in vitro studies which assessed the effect of soy isoflavones on the oxidation lag time of LDL particles (Hwang et al., 2000) and on the resistance of HDL to copper-ion-induced peroxidation by measuring conjugated dienes (Ferretti et al., 2004) were provided. The Panel notes that the evidence provided does not establish that these markers predict peroxidation of LDL or HDL particles in vivo (Griffiths et al., 2002; Lapointe et al., 2006; Verhoye and Langlois, 2009). The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
A randomised, double-blind, cross-over study by Wiseman et al. (2000) investigated the effects of diets low or high in soy isoflavones on lipid peroxidation in 24 healthy subjects aged 19-40 years. The subjects consumed textured soy protein as vegetarian burgers high (21.2 mg daidzein and 34.8 mg genistein) or low (0.9 mg daidzein and 1.0 mg genistein) in isoflavones for 17 consecutive days each, separated by a 25-day wash-out period. Two subjects did not complete the low-isoflavone intervention. Blood plasma concentrations of 8-epiprostaglandin F2α (8-epi-PGF2α), and malondialdehyde (MDA) measured by the HPLC-based thiobarbituric acid test, and resistance of LDL to copper-ion-induced peroxidation were assessed in 18 samples for each intervention period. The statistical analysis, which was corrected for multiple comparisons, was based on these samples only. The Panel notes the use of a valid biomarker to assess lipid peroxidation (8-epi-PGF2α determined by gas chromatography–mass spectrometry) and the inclusion of a marker which could be used as supportive (MDA measured by HPLC). The Panel notes that resistance of LDL to copper-ion-induced peroxidation is not a reliable marker to assess lipid peroxidation in vivo. The Panel also notes that 25 % of the samples were not available for analysis, and that missing data were not taken into account in data analysis, and considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
The Panel notes that no human studies from which conclusions could be drawn for the scientific substantiation of the claim were provided.
The Panel concludes that a cause and effect relationship has not been established between the consumption of soy isoflavones and protection of DNA, proteins and lipids from oxidative damage.

Warunki i możliwe ograniczenia stosowania oświadczenia

Intake of 45 mg isoflavones (aglycone equivalent) per day