ID 342 -
Magnez
PL: Magnez
EN: Magnesium
Pdf: magnesium
Oświadczenie (2)
- metabolizm węglowodanów oraz wrażliwość na insulinę
1. Charakterystyka żywności / składnika
The food constituent that is the subject of the health claims is magnesium, which is a well recognised nutrient and is measurable in foods by established methods.
Magnesium occurs naturally in foods and is authorised for addition to foods (Annex I of Regulation (EC) No 1925/20066 and Annex I of Directive 2002/46/EC7). This evaluation applies to magnesium naturally present in foods and to those forms authorised for addition to foods (Annex II of the Regulation (EC) No 1925/2006 and Annex II of Directive 2002/46/EC).
The Panel considers that the food constituent, magnesium, which is the subject of the health claims, is sufficiently characterised.
2.4. Utrzymanie prawidłowego stężenia glukozy we krwi (ID 342)
The claimed effect is “carbohydrate metabolism and insulin sensitivity”. The Panel assumes that the target population is the general population.
In the context of the proposed wording, the Panel assumes that the claimed effect refers to the maintenance or achievement of normal blood glucose concentrations.
The Panel considers that long-term maintenance of normal blood glucose concentrations is a beneficial physiological effect.
3. Naukowe uzasadnienia wpływu na zdrowie człowieka -
Magnesium is an essential nutrient and serves as a cofactor for over 300 enzymes involved in biological processes. Magnesium is part of the Mg-ATPase complex and is essential for oxidative phosphorylation; it has roles in energy metabolism, mineral homeostasis, calcium metabolism, and neuromuscular and endocrine function (IoM, 1997; SCF, 2001; Volpe, 2006).
In the human body, 50 to 60 % of magnesium is located in the bone. Part of it is readily exchangeable with serum and therefore bone represents a magnesium store. The remaining magnesium is mainly intracellular; extracellular magnesium represents only 1 % of the total magnesium content of the body.
Because magnesium is mostly within cells or in bone, assessment of magnesium status is difficult (Rude and Shils, 2006).
Manifestations of magnesium deficiency include signs related to bone and mineral metabolism, neuromuscular and psychological manifestations (e.g. positive Chvostek and Trousseau signs, spontaneous carpal-pedal spasm, seizures, vertigo, ataxia, nystagmus, athetoid and choreiform movements, muscular weakness, tremor, fasciculation, wasting, depression, psychosis, hallucinations, confusion), symptoms related to potassium homeostasis, and cardiovascular manifestations (Rude and Shils, 2006; FAO/WHO, 2001; O'Brien, 1999). Most of the early symptoms of magnesium depletion are neurological or neuromuscular; thus, a decline in magnesium status produces loss of appetite, nausea, muscular weakness, vomiting, fatigue, lethargy, staggering and, if the deficit is prolonged, weight loss (FAO/WHO, 2001; Volpe, 2006). Progressively increasing with the severity and duration of deficiency are signs such as hyperirritability, hyperexcitability, muscular spasms and tetany, leading ultimately to convulsions (FAO/WHO, 2001).
3.3. Utrzymanie prawidłowego stężenia glukozy we krwi (ID 342)
The references provided for the substantiation of the claimed effect include textbooks, one reference unrelated to the food constituent, a general narrative review on magnesium metabolism, status and deficiency, and publications on health outcomes unrelated to the claimed effect: tension headaches and muscle tension, stress and neuropsychiatric disorders, cardiovascular disorders, sports, myocardial infarction. Also, a reference reporting on intracellular changes in magnesium before and after insulin stimulation in diabetic and obese children was provided. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect.
One meta-analysis of double-blind randomised controlled trials (RCTs) (Song et al., 2006) and four intervention studies in humans (Purvis et al., 1994; Rodriguez-Moran and Guerrero-Romero, 2003; Paolisso et al., 1989b; Guerrero-Romero et al., 2004) on the effects of oral magnesium supplementation on different outcomes were provided. Seven out of the nine trials considered in the meta-analysis (Gullestad et al., 1994; Purvis et al., 1994; Eibl et al., 1995; Erikson and Kohvakka, 1995; de Lourdes et al., 1998; de Valk et al., 1998; Rodriguez-Moran and Guerrero-Romero, 2003), including two of the intervention studies (Purvis et al., 1994; Rodriguez-Moran and Guerrero- Romero, 2003) provided, were performed in diabetic subjects under antidiabetic medications. The Panel considers that the evidence provided does not establish that interactions between magnesium and antidiabetic medication can be excluded. The two remaining trials in the meta-analysis (Paolissoet al., 1989a; 1994) and the two remaining intervention studies (Paolisso et al., 1989b; Guerrero-Romero et al., 2004), which were all performed in insulin resistant subjects or type-2 diabetic subjects under dietary treatment only, did not report on outcomes related to long-term blood glucose control but rather on insulin sensitivity using the euglycaemic-hyperinsulinaemic clamp technique (Paolisso et al., 1989a, 1994) or the surrogate HOMA index (Guerrero-Romero et al., 2004), or on the secretory capacity of the pancreas after stimulation with arginine or glucose (Paolisso et al., 1989b). The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect.
Seven observational studies dealt with dietary intake, serum concentrations or urinary excretion of magnesium in very-low-birth-weight pre-term children in pre-school years (Bo et al. 2007), type 1- diabetic patients (Brown et al., 1999), obese children (Huerta et al., 2005), adults (Ma et al., 2006; Rumawas et al., 2006; Song et al., 2004) and nursing home residents (Worwag et al., 1999). Parameters such as fasting glucose or insulin, HOMA-IR, HbA1c, quantitative insulin sensitivity check index, intravenous glucose tolerance test, post-challenge plasma glucose and insulin, or risk or prevalence of diabetes were considered. The Panel notes that no conclusions can be drawn from these studies for the scientific substantiation of the claimed effect because residual confounding by other dietary and lifestyle factors inherent to the observational study design cannot be excluded.
The Panel considers that no conclusions can be drawn from the meta-analysis for the scientific substantiation of the claim owing to the inclusion of studies that cannot be used for the substantiation
of the claim, from the individual trials provided owing to inappropriate study groups or endpoints and from the observational studies provided owing to inadequate control of possible confounding factors.
The Panel concludes that a cause and effect relationship has not been established between the dietary intake of magnesium and maintenance of normal blood glucose concentrations.
5. Warunki i możliwe ograniczenia stosowania oświadczenia
The Panel considers that in order to bear the claim a food should be at least a source of magnesium as per Annex to Regulation (EC) No 1924/2006. Such amounts can be easily consumed as part of a balanced diet. The target population is the general population. No Tolerable Upper Intake Level (UL) has been established for magnesium normally present in food and beverages. An UL for older children and adults has been established for readily dissociable magnesium salts and compounds like magnesium oxide in nutritional supplements, waters or added to food and beverages (SCF, 2001).
Warunki i możliwe ograniczenia stosowania oświadczenia
Food supplement with 100-350mg of magnesium in the daily dose