ID 639 - Kwas gamma-linolenowy

PL: Kwas gamma-linolenowy
EN: Gamma linolenic acid (GLA)
Pdf:

Oświadczenie (2)

1. Charakterystyka żywności / składnika

The food constituents that are the subject of the health claims are "gamma-linolenic acid (GLA; C18: 3n-6) provided by evening primrose oil and/or borage (starflower) oil", "gamma-linolenic acid", "evening primrose oil (Oenothera biennis) contains gamma-linolenic acid", "borage oil (GLA= gamma linolenic acid)", "oenothera biennis-evening primrose-seeds oil", "long chain omega 6 polyunsaturated fatty acid GLA (gamma-linolenic acid)", "Borago officinalis", and "GLA (example from Borago officinalis, primrose oil, black currant seed oil)".
In the context of the proposed health relationships, wordings, conditions of use, and the clarifications provided by Member States, the Panel assumes that the food constituent that is the subject of the health claims is gamma-linolenic acid (GLA).
GLA is a n-6 long-chain polyunsaturated fatty acid which is present in small amounts in a variety of foods of both plant and animal origin and which can also be synthesised in the human body from its precursor linoleic acid (LA). GLA is a well recognised nutrient and can be measured in foods by established methods. This evaluation applies to GLA from all sources.
The Panel considers that the food constituent, gamma-linolenic acid (GLA), which is the subject of the health claims, is sufficiently characterised.

2.5. Utrzymanie prawidłowych funkcji ochronnych skóry (ID 499, 591, 639, 676, 1554, 2003, 2065)

The claimed effect is "skin health", "epidermic and connective tissue", and "essential fatty acid of importance for a healthy skin". The Panel assumes that the target population is the general population.
In the context of the proposed wordings and clarifications provided by Member States, the Panel assumes that the claimed effects refer to the maintenance of the barrier function of the skin by contributing to the maintenance of skin hydration.
The Panel considers that maintenance of the barrier function of the skin is a beneficial physiological effect.

3.4. Utrzymanie prawidłowych funkcji ochronnych skóry (ID 499, 591, 639, 676, 1554, 2003, 2065)

The references provided in relation to this claim were narrative reviews that did not provide original data which could be used for the scientific substantiation of the claimed effect. Some of the references addressed the effects of GLA in combination with other food constituents (e.g. green tea polyphenols and vitamin E) on different health outcomes, including the stratum corneum barrier function, or the effects of GLA and GLA-containing oils on health outcomes unrelated to the claimed effect (e.g. nerve transmission, inflammatory diseases, premenstrual syndrome). The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
The references provided also reported on human intervention studies using evening primrose oil, borage oil and other GLA-containing oils for the prevention of atopic dermatitis/eczema in high risk subjects and/or for the treatment of symptoms in subjects with diagnosed atopic dermatitis/eczema. The Panel notes that these references relate to the treatment of symptoms of a human disease and considers that patients with atopic dermatitis/eczema are not representative of the general population with respect to the status of the skin. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect.
One open-label, uncontrolled intervention study, which investigated the effects of consuming either 1.5 g or 3 g of borage oil daily (360 or 720 mg GLA, respectively) in 29 elderly subjects for two months on various skin parameters including transepidermal water loss (TEWL) and skin hydration, was provided (Brosche and Platt, 2000). The Panel considers that no conclusions can be drawn from this uncontrolled study for the scientific substantiation of the claimed effect.
One randomised, double-blind, placebo-controlled study in healthy adults investigated the effect of evening primrose oil on skin moisture, TEWL, redness, firmness, elasticity, fatigue resistance and roughness (Muggli, 2005). Subjects were randomised to consume evening primrose oil in capsules (3x2 daily) containing 57.5 mg GLA per capsule or placebo capsules (containing medium-chain triglycerides) for 12 months. Skin parameters were assessed at baseline, and at 4 and 12 weeks of the intervention. Differences between groups at each time point for each parameter were assessed. The Panel notes that the fatty acid composition of the test and placebo oils was not reported, and it is not possible, therefore, to assess whether appropriate control for fatty acids other than GLA in evening primrose oil was undertaken. Moreover, the primary outcome of the study was not identified, and there was no correction for multiple comparisons. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claimed effect.
A second randomised, double-blind, placebo-controlled study in healthy adults investigated the effect of evening primrose oil on skin moisture, TEWL, redness, firmness, elasticity, fatigue resistance and roughness in healthy adults in an experimental model (i.e. topical application of a 2 % solution of sodium dodecyl sulphate in distilled water for 24 hours) of skin irritation (Muggli, 2007). Subjects were randomised to consume evening primrose oil in capsules (3x2 daily) containing 57.5 mg GLA
per capsule, or oil-containing placebo capsules (composition not reported) for 84 days. Skin parameters were assessed at baseline, and at 28 and 84 days of the intervention. Differences between groups at each time point for each parameter were assessed. The Panel notes that the fatty acid composition of the test and placebo oils was not reported, and it is not possible, therefore, to assess whether appropriate control for fatty acids other than GLA in evening primrose oil was undertaken. Moreover, the primary outcome of the study was not identified and there was no correction for multiple comparisons. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claimed effect.
The Panel concludes that a cause and effect relationship has not been established between the consumption of gamma-linolenic acid and maintenance of the barrier function of the skin.

Warunki i możliwe ograniczenia stosowania oświadczenia

90-720 mg GLA/day