ID 335 - Krzem

PL: Krzem
EN: Silicon
Pdf: silicon

1. Charakterystyka żywności / składnika

The food constituents that are the subjects of the health claims are “silicon”, “silicon (as stabilised oligomeric orthosilicic acid (OSA))”, “choline-stabilised orthosilicic acid (ch-OSA)”, “Mineral- wasser/Kieselsäure (Silizium)”, “silica/silicious earth”, and “monométhylsilanetriol”.
From the references and conditions of use provided in relation to the health claims considered in this opinion, the Panel assumes that the food constituent under evaluation is silicon.
Silicon 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 silicon naturally present in foods and added to foods.
Silicon occurs naturally in foods as silicon dioxide (silica, SiO2) and silicates, and may also be added to foods as an anti-caking and anti-foaming agent in the form of silica, silicates and dimethylpolysiloxane. Silicate-containing antacids have been widely used for a number of decades.
Orthosilicic acid [Si(OH)4] or mono-silicic acid is a water soluble form of silicon. A saturated solution contains 0.1 % silicic acid. Silicic acid can also exist as an oligomer and as polysilicic acid (EFSA, 2004). Oligomeric silica (oligomeric orthosilicic acid) is formed as a meta-stable intermediate in the progressive polymerisation of silicic acid in saturated solutions. Monomethylsilanetriol, also called organic silicon (CH3-Si-(OH)3), and choline-stabilised orthosilicic acid (ch-OSA) are usually added to food supplements as a source of silicon (EFSA, 2009a, 2009b).
The Panel considers that the food constituent, silicon, which is the subject of the health claims, is sufficiently characterised.

2.5. Udział w prawidłowym tworzeniu kolagenu i tkanki łącznej (ID 287, 288, 333, 334, 335, 1405, 1652, 1718, 1719, 1945)

The claimed effects are “silicon is required for normal bone and connective tissue formation”, “normal skin, hair and nails”, “maintenance and promotion of healthy connective tissue in skin by stimulating collagen synthesis in the dermis”, “helps support hair quality by helping to maintain healthy connective tissue in the dermis”, “maintenance and promotion of healthy connective tissue in bone by stimulating bone collagen synthesis”, “stability of the connective/cell tissue; strengthening the joint cartilage and the intervertebral disks, protection against”, “essential part of the connective tissues, skin and hair”, “maintenance and promotion of healthy connective tissue in bone by stimulating bone collagen synthesis, healthy women and men”, “helps support hair quality by helping to maintain healthy connective tissue in the dermis, healthy women and men”, and “bioavailable silicon form, silicon is an essential element for normal structure of connective tissues such as skin, hair, joints, bone and blood vessels”. The Panel assumes that the target population is the general population.
Collagen is a structural component of several tissues in the body including bone, cartilage, gums, skin, tendons and blood vessels.
In the context of the proposed wordings and clarifications provided by Member States, the Panel assumes that the claimed effects refer to the contribution to normal formation of collagen and connective tissue.
The Panel considers that contribution to normal formation of collagen and connective tissue is a beneficial physiological effect.

2.6. Utrzymanie prawidłowego stanu kości (ID 287, 335, 1652, 1718, 1945)

The claimed effects are “silicon is required for normal bone and connective tissue formation”, “maintenance and promotion of healthy connective tissue in bone by stimulating bone collagen synthesis”, “essential part of the connective tissues, skin and hair”, “maintenance and promotion of healthy connective tissue in bone by stimulating bone collagen synthesis, healthy women and men”, and “bioavailable silicon form, silicon is an essential element for normal structure of connective tissues such as skin, hair, joints, bone and blood vessels”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to the maintenance of normal bone.
The Panel considers that maintenance of normal bone is a beneficial physiological effect.

3. Naukowe uzasadnienia wpływu na zdrowie człowieka - 

Silicon is considered an ultra-trace element for which a functional role in humans has not been identified. As the essentiality of silicon for humans has not been established, a dietary reference value for silicon has not been set (IoM, 2000).
A number of narrative reviews on the health effects of silicon containing no original data for a scientific evaluation, post-mortem studies in humans assessing the content of silicon in various tissues (e.g. blood vessels), and human intervention studies on silicon supplementation for the treatment of acne were provided. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claims.
The vast majority of the references provided for the scientific substantiation of the claims reported on animal studies which addressed the effects of silicon-free diets and/or the effects of reintroducing silicon into the diet on the structure and morphology of various tissues and/or organs, including collagen and bone. The Panel considers that evidence provided in animal studies is not sufficient to predict the occurrence of an effect of silicon withdrawal or silicon intake in humans.

3.2. Udział w prawidłowym tworzeniu kolagenu i tkanki łącznej (ID 287, 288, 333, 334, 335, 1405, 1652, 1718, 1719, 1945)

No evidence has been provided that silicon plays a role in collagen formation in humans, and no human studies which addressed the effects of silicon intake on collagen or connective tissue formation have been provided.
The Panel concludes that a cause and effect relationship has not been established between the consumption of silicon and contribution to normal formation of collagen and connective tissue.

3.3. Utrzymanie prawidłowego stanu kości (ID 287, 335, 1652, 1718, 1945)

One human retrospective study on intramuscular administration of silicon on bone mineral density (BMD) was provided (Eisinger and Clairet, 1993). The Panel notes that the intra-muscular route is not relevant to human nutrition. One abstract reporting on a human intervention study on the effects of oral consumption of silicon on bone turnover and BMD, and one abstract reporting on a human observational study on the association between dietary silicon consumption and BMD, which included insufficient data for a full scientific evaluation were also provided (Jugdaohsingh et al., 2003; Spector et al., 2005). The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
One human intervention study on the effects of silicon consumed orally at doses of 5.5 g/day for 20 days per month for three months (n=14) vs. no intervention (n=15) on trabecular bone volume measured by bone biopsy was provided (Schiano et al., 1979). The Panel notes that the study was not placebo-controlled, that it is unclear whether the subjects were randomly assigned to the intervention and control groups, and that no information was provided about blinding or the statistical analyses performed. The Panel notes the poor methodological reporting and considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
One randomised, double-blind, placebo-controlled human intervention study investigated the effects of silicon as choline-stabilised orthosilicic acid (ch-OSA) in association with calcium (1,000 mg/day)
and cholecalciferol (20 g/day), administered for 12 months, on BMD and markers of bone turnover in 184 osteopenic post-menopausal women (Spector et al., 2008). Women were randomly assigned to consume ch-OSA at doses of 3, 6 and 12 mg silicon/day (3, 6 and 12 drops) or placebo (3, 6 or 12 drops to mimic the intervention) plus calcium and cholecalciferol. BMD was measured by dual- energy x-ray absorptiometry (DXA) at the beginning and end of the study, whereas markers of bone formation (osteocalcin (OC), bone specific alkaline phosphatase (BAP) and procollagen type I N- terminal propeptide (PINP)) and of bone resorption (deoxypyridoline (DPD) and C-terminal telopeptide of type I collagen (CTX-I)) were assessed at baseline and at 6 and 12 months of the study. It was estimated that 175 subjects needed to be recruited to observe a 25 % difference between ch- OSA and placebo groups on markers of bone turnover with an α<0.05 and a power of 85 %, taking into account a drop-out rate of 20 %. Statistical analysis and baseline characteristics of subjects were provided for the population of completers only (n=136, n=37 in the placebo group and n=33 in each ch-OSA group). Post-hoc sub-group analyses were carried out for changes in femoral BMD in women with a femoral BMD T-score <-1. The Panel notes that these post-hoc comparisons were not pre-planned, and that no adjustments for multiple testing were performed. Intervention and placebo groups were not comparable at baseline for markers of bone turnover or BMD. No significant differences in BMD changes between the intervention and placebo groups were observed during the 12-month intervention. Changes in markers of bone turnover were not significantly different between groups (OC, BAP, DPD), except for PINP, which at 12 months was significantly lower in the 6 and 12 mg ch-OSA groups than in the placebo group. The Panel notes that this study does not show an effect of ch-OSA on BMD in post-menopausal women.
One cross-sectional, population-based study including 2,847 subjects (306 pre-menopausal women, 1,325 post-menopausal women, 1,295 men) from the Framingham Offspring Cohort assessed the association between dietary silicon intake and BMD at the hip and lumbar spine (Jugdaohsingh et al., 2004). Dietary intake of silicon was assessed using a food frequency questionnaire and BMD was investigated by DXA. After adjustment for confounders known to affect BMD (age, height, body mass index, physical activity, calcium and vitamin D intakes, and certain medications), silicon intakes correlated positively with BMD at four hip sites in men and pre-menopausal women, but not in post-menopausal women, whereas no significant association was found between silicon intake and BMD in the lumbar spine for any group. The Panel notes that the findings of this cross-sectional study on the association between silicon intakes and BMD were inconsistent, and that no suitable explanation for a differential effect of silicon in different population sub-groups and in different bone sites has been provided.
The Panel notes that no human intervention studies addressing the effects of silicon intakes on BMD in men or pre-menopausal women have been submitted, and that no evidence for a mechanism by which silicon could exert an effect on bone has been provided.
In weighing the evidence, the Panel took into account that a randomised, double-blind, placebo-controlled human intervention study did not show an effect of silicon administration (as ch-OSA) on BMD at any site in post-menopausal women, that the findings of a cross-sectional study on the association between silicon intakes and BMD were inconsistent, and that no evidence for a mechanism by which silicon could exert the claimed effect has been provided.
The Panel concludes that a cause and effect relationship has not been established between the consumption of silicon and maintenance of normal bone.

Warunki i możliwe ograniczenia stosowania oświadczenia

Daily intake of 10 mg silicon (Si) in the form of cholinestabilized orthosilicic acid (ch- OSA); 5 mg Si in the morning and 5 mg Si in the evening Must meet minimum requirements for use of the claim "source of [name of vitamin/s] and/or [name of mineral/s]" as per Annex to Regulation 1924/2006.