Evaporative dry eye is associated with meibomian gland dysfunction and abnormalities of the tear film lipids. Dry eye is known to be affected positively by intake of linoleic and γ-linolenic acids and n-3 fatty acids. Oral sea buckthorn (Hippophaë rhamnoides) (SB) oil, which contains linoleic and α-linolenic acids and antioxidants, has shown beneficial effects on dry eye. The objective was to investigate whether supplementation with SB oil affects the composition of the tear film fatty acids in individuals reporting dry eye.
One hundred participants were randomized to this parallel, double-blind, placebo-controlled study, which 86 of them completed. The participants daily consumed 2 g of SB or placebo oil for 3 months. Tear film samples were collected at the beginning, during, and at the end of the intervention and 1 to 2 months later. Tear film fatty acids were analyzed as methyl esters by gas chromatography.
There were no group differences in the changes in fatty acid proportions during the intervention (branched-chain fatty acids: P = 0.49, saturated fatty acids: P = 0.59, monounsaturated fatty acids: P = 0.53, and polyunsaturated fatty acids: P = 0.16).
The results indicate that the positive effects of SB oil on dry eye are not mediated through direct effects on the tear film fatty acids. Carotenoids and tocopherols in the oil or eicosanoids produced from the fatty acids of the oil may have a positive effect on inflammation and differentiation of the meibomian gland cells.
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From the Department of *Biochemistry and Food Chemistry and †Department of Ophthalmology, University of Turku, Turku, Finland; ‡Turku School of Economics, University of Turku, Turku, Finland; §Turku City Hospital, Turku, Finland; and ¶Karolinska Institutet, Stockholm, Sweden.
Received for publication June 29, 2010; revision received September 27, 2010; accepted October 25, 2010.
Supported by the Applied Bioscience-Bioengineering, Food & Nutrition Environment (ABS), Graduate School; Aromtech, Ltd; Finnsusp, Ltd; Erikoisvaltionosuus (EVO) research funds of the Turku City Hospital; Niemi Foundation; Shinyhorse, Ltd; and Valioravinto, Ltd.
Conflicts of interest: J. Riikka is an employee of Finnsusp, Ltd; during the trial, B. Yang was an employee of Aromtech, Ltd. Other authors have no conflicts of interest.
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Reprints: Petra Susanna Larmo, Department of Biochemistry and Food Chemistry, FI-20014 University of Turku, Finland (e-mail: email@example.com).