A daily dose of 4.5 grams of CLA produced significant reduction in airway hyper-responsiveness as well as favorable effects on body weight and adipokine levels – cytokines produced in fat tissue – according to findings published in this month’s journal Clinical & Experimental Allergy.
CLA (conjugated linoleic acid) is a fatty acid naturally present in ruminant meat and dairy products. Due to changes in the Western diet, average intake of CLA has fallen; if the fat is removed from a dairy product to make a low fat version that will be acceptable to consumers, CLA is removed along with it.
The researchers used Cognis’ Tonalin branded CLA, and the study was funded by Cognis. The CLA oil used is a mixture of isomers: cis-9, trans-11 (36.4 percent) and trans-10, cis-12 (37.0 percent).
A significant body of science supports the potential of the ingredient to enhance lean body mass and aid in body sculpting. The new study, by scientists from the University of British Columbia in Vancouver, is the first to report that the ingredient may also have benefits for overweight asthmatics.
According to the European Federation of Allergy and Airway Diseases Patients Association (EFA), over 30m Europeans suffer from asthma, costing Europe €17.7bn every year. The cost due to lost productivity is estimated to be around €9.8bn.
Commenting on the potential mechanism, the researchers note two possibilities: “Whether the improvement in AHR was due to direct effects on airway inflammation (likely cis-9, trans-11 mediated) or perhaps related to altered body composition and adipocytokine levels (likely trans-10, cis-12 mediated) in our overweight population is not clear,” they stated.
Indeed, talking to NutraIngredients-USA at the IFT Annual Meeting and Expo in Chicago, David Cai, PhD, science and regulatory manager, North America and Asia for Cognis concurred that it was too early to make conclusions.
Study details
The researchers recruited 28 overweight mild asthmatics aged between 19 and 40 to participate in their prospective, randomized, double-blind, placebo-controlled study. Subjects were randomly assigned to receive either 4.5 grams per day of CLA or placebo for 12 weeks.
At the end of the study the researchers noted significant improvements in airway hyper-responsiveness (AHR) and this was accompanied by a significant improvement in their ability to tolerate strenuous exercise.
In addition, subjects in the CLA group experienced significant improvements in the BMI, with an average reduction of 0.5 kg/m2, compared to a 0.8 kg/m2 increase in the placebo group.
Potential asthma alternative
The authors stressed however that care should be taken in extending the results to other sections of the population. “However, we believe our demonstrated efficacy is such that additional studies in these groups are warranted,” they said.
“A huge number of asthma patients seek complementary therapies, and a wide array of products are marketed as ‘asthma treatments’, frequently with no evidence. CLA is safe, clinically effective and may be considered for overweight mild asthmatics seeking natural remedies as part of their asthma management plan,” wrote the researchers. “We encourage further studies to elucidate the role of CLA in a broader asthma population,” they concluded.
Source: Clinical & Experimental Allergy
July 2010, Volume 40, Pages 1071-1078
“Conjugated linoleic acid improves airway hyper-reactivity in overweight mild asthmatics”
Authors: R. MacRedmond, G. Singhera[1], S. Attridge, M. Bahzad, C. Fava, Y. Lai, T. S. Hallstrand, D. R. Dorscheid