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10-06-2010 | Respiratory | Article

Conjugated linoleic acid benefits overweight mild asthmatics

Abstract

Free abstract

MedWire News: Dietary supplementation with conjugated linoleic acid (CLA) is associated with reductions in airway hyper-responsiveness (AHR) and body mass index (BMI) in patients with mild asthma who are overweight, results from a Canadian study suggest.

Writing in the journal Clinical and Experimental Allergy, Ruth MacRedmond (University of British Columbia, Vancouver) and team explain: “CLAs are lipids derived from fatty tissues of ruminant animals that have gained attention because of effects on obesity, body composition and insulin sensitivity. Additional biological properties of CLA include effects on carcinogenesis, atherosclerosis, and immune modulation.”

As obesity has previously been associated with asthma and may affect AHR and inflammation, the researchers investigated the effects of CLA supplementation in overweight adults with mild asthma.

In total, 28 asthmatic patients, aged 19–40 years, with a FEV1 of more than 70% of the predicted value and a mean BMI of 27.9 kg/m2 were randomly assigned to CLA 4.5 g/day or placebo for 12 weeks.

All the participants underwent methacholine challenge at baseline and after 12 weeks to assess AHR.

The researchers found that the concentration of methacholine needed to provoke a 20% fall in FEV1 (PC20) increased significantly from a mean of 2.4 mg/ml at baseline to 7.5 mg/ml at week 12 in the CLA-treated group. In contrast, mean PC20 increased from 1.4 mg/ml at baseline to just 2.6 mg/ml at 12 weeks among the placebo-treated group.

Furthermore, BMI decreased from a mean of 27.8 kg/m2 at baseline to 27.1 kg/m2 at week 12 in the CLA-treated group, compared with a respective increase from 27.3 to 28.1 kg/m2 among placebo-treated patients.

The researchers note that BMI reductions in CLA-treated patients were accompanied by reductions in the leptin/adiponectin ratio.

MacRedmond and team conclude: “This study demonstrates that dietary supplementation with CLA 4.5 g/day for 12 weeks in mild asthmatics was safe and well tolerated and resulted in a significant reduction in AHR. In addition, CLA had favorable effects on body weight and adipokine concentrations in our young overweight cohort.”

They add: “We encourage further studies to elucidate the role of CLA in a broader asthma population.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Mark Cowen

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