ID 637 -
Kwas gamma-linolenowy
PL: Kwas gamma-linolenowy
EN: Gamma linolenic acid (GLA)
Pdf:
1. Charakterystyka żywności / składnika
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, which is the subject of the health claims is sufficiently characterised.
2.1. Utrzymanie prawidłowego stanu stawów (ID 494, 637, 1774, 2098)
The claimed effect is “joint health”. The Panel assumes that the target population is the general population.
The Panel assumes that the claimed effect relates to maintenance of normal joints.
The Panel considers that maintenance of normal joints is a beneficial physiological effect.
3.1. Utrzymanie prawidłowego stanu stawów (ID 494, 637, 1774, 2098)
The references provided consisted of one monograph on GLA, two book chapters, nine reports on intervention studies of which seven were double-blind, placebo-controlled trials, one open trial and one controlled trial in patients with rheumatoid arthritis of different severity, 15 reviews of the use of GLA in various medical conditions, and four concerned mechanistic studies of GLA effects ex vivo and in vitro or in animal models of inflammation. The intervention studies were mostly of small sample sizes and did not include healthy controls.
All (but one) human intervention studies, all reviews and the mechanistic studies presented concern therapeutic trials in patients with a clinical diagnosis of acute or chronic rheumatoid arthritis (Belch et al., 1988; Brzeski et al., 1991; Hansen et al., 1983; Jäntti et al., 1989; Leventhal et al., 1993 and 1994; Pullman-Mooar et al., 1990; Zurier et al., 1996; Watson et al., 1993).
Rheumatoid arthritis (RA) is a chronic, symmetric, inflammatory, and destructive autoimmune arthropathy affecting the synovial joints with a prevalence of 0.5 to 2.0 % in the population (Calder and Zurier, 2001). In the studies presented, GLA doses varied between <500 mg /d and 2 g/d and the duration of the intervention was from two weeks to 15 months (Furse et al., 2001; Belch and Hill, 2000; Chilton et al., 1996; Kast, 2001; Pullman-Mooar et al., 1990; Watson et al., 1993) following GLA consumption.
The Panel considers that the evidence provided does not establish that patients with the clinical diagnosis of RA are representative of the general population with regard to the status of joint tissues, or that results obtained in subjects with RA relating to the treatment of symptoms of the disease (e.g. joint pain, joint swelling, joint stiffness, erosion of joint cartilage) can be extrapolated to maintenance of structure and function of joints in the general population.
Administration of GLA-rich oils (2.4 g GLA/d) to healthy volunteers resulted in decreased production of pro-inflammatory cytokines (TNF-α, interleukin-1, interleukin-6) by monocytes (DeLuca et al., 1999), decreased lymphocyte reactivity (Rossetti et al., 1997), and decreased chemotaxis of neutrophils. GLA doses less than 1 g/d did not have an effect on lymphocyte proliferation nor on the production of TNF-α, interleukin-1β, interleukin-2 or interferon-γ (Yaqoob et al., 2000; Wu et al., 1999). These reactions are similar to those measured in patients with RA. However, their clinical significance in healthy subjects with respect to joint health is unknown.
The Panel concludes that a cause and effect relationship has not been established between the consumption of GLA and maintenance of normal joints.
Warunki i możliwe ograniczenia stosowania oświadczenia
From 450-540 mg GLA/day to 2.8 g GLA/day
