Immunological and metabolic effects of cis-9, trans-11-conjugated linoleic acid in subjects with birch pollen allergy

Abstract

Animal studies suggest that conjugated linoleic acid (CLA) may modulate the immune response, while studies in healthy human subjects have shown little effect and results are controversial. However, the effects of CLA may be more prominent in situations of immune imbalance, such as allergy. We studied the effects of the natural CLA isomer, cis-9, trans-11-CLA, on allergy symptoms and immunological parameters in subjects with birch pollen allergy. In a randomised, placebo-controlled study, forty subjects (20-46 years) with diagnosed birch pollen allergy received 2 g CLA/d in capsules, which contained 65·3 % cis-9, trans-11-CLA and 8·5 % trans-10, cis-12-CLA (n 20), or placebo (high-oleic acid sunflower-seed oil) (n 20) for 12 weeks. The supplementation began 8 weeks before the birch pollen season and continued throughout the season. Allergy symptoms and use of medication were recorded daily. Lymphocyte subsets, cytokine production, immunoglobulins, C-reactive protein, lipid and glucose metabolism and lipid peroxidation were assessed before and after supplementation. The CLA group reported a better overall feeling of wellbeing (P, 0·05) and less sneezing (P,0·05) during the pollen season. CLA supplementation decreased the in vitro production of TNF-a (P, 0·01), interferon-g (P, 0·05) and IL-5 (P,0·05). Total plasma IgE and birch-specific IgE concentrations did not differ between groups, whereas plasma IgA (P, 0·05), granulocyte macrophage colony-stimulating factor (P,0·05) and eosinophil-derived neurotoxin (P, 0·05) concentrations were lower after CLA supplementation. Urinary excretion of 8-iso-PGF 2a , a major F 2 -isoprostane (P, 0·01), and 15-keto-dihydro-PGF 2a , a primary PGF 2a metabolite (P,0·05), increased in the CLA group. The results suggest that cis-9, trans-11-CLA has modest anti-inflammatory effects in allergic subjects.

Effect of Conjugated Linoleic Acid Supplementation on Inflammatory Factors and Matrix Metalloproteinase Enzymes in Rectal Cancer Patients Undergoing Chemoradiotherapy

“…13 In another clinical trial, CLA (cis-9,trans-11 isomer) supplementation in those with birch pollen allergy decreased the in vitro production of TNF-α. 34 The finding of the present study is in agreement with results of the above-mentioned studies. 13,[32][33][34] Another result of this study was that IL-1β decreased slightly in the CLA group while increasing in the placebo group.…”

Mucosal IgA increase in rats by continuous CLA feeding during suckling and early infancy

“…Recent studies carried out in young animals have shown that immune function is enhanced after feeding c 9,t11 CLA isomer (18,19). The immune effects of CLA have been also seen in healthy and ill individuals (20,21). However, little work has been done on the effects of CLA during the early postnatal periods (lactation or infancy), and even less during the prenatal period (gestation).…”

Anti-allergic effect of the naturally-occurring conjugated linolenic acid isomer, jacaric acid, on the activated human mast cell line-1

“…To the best of our knowledge, this is the first study demonstrating the in vitro anti-allergic effect of CLNAs on HMC-1 cells, and this is in line with earlier findings showing that CFAs, such as CLAs, may possess anti-allergic activities. For example, Jaudszus et al (24) reported that 9Z, 11E-CLA could inhibit allergic sensitization and airway inflammation through peroxisome proliferator-activated receptor-γ dependent mechanism in mice, whereas others demonstrated that human healthy volunteers supplemented with 9Z, 11E-CLA resulted in a decreased plasma IgE level and reduced secretion of IL-5 by PBMCs (25,26). Despite these earlier findings, the underlying action mechanisms for the anti-allergic effects of CFAs, such as CLAs and CLNAs, remain poorly understood and further studies are required to elucidate the mechanisms, in vitro and in vivo, for the anti-allergic activity of CFAs.…”