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03/05/2013 10:07

Why fish is so good for you

Dr. Ute Schönfelder Stabsstelle Kommunikation/Pressestelle
Friedrich-Schiller-Universität Jena

    Scientists of Friedrich Schiller University Jena and Jena University Hospital decode the antihypertensive impact of omega-3 fatty acids

    Fish is healthy: easy to digest and with a high level of precious proteins, fish is considered an important part of a healthy diet. And with the so-called omega-3 fatty acids fish contains real ‘fountains of youth‘. These fatty acids – like docosahexaeonic acid (DHA) occur mostly in fatty fish like herring, salmon and mackerel. They are thought to lower the blood pressure, to strengthen the immune system and to have positive effects on the development on the nervous system and the cardiovascular system.

    “Clinical studies about the intake of nutritional supplements containing omega-3 fatty acids haven’t provided complete clarity so far,“ Prof. Dr. Stefan H. Heinemann from Friedrich Schiller University Jena (Germany) says. “The molecular impact of the omega-3 fatty acids isn’t fully understood yet,” the biophysicist continues. But now scientists of the DFG research group FOR 1738 based at Jena University are able to bring new facts to light: in two newly published articles for the well-known science magazine ‘Proceedings of the National Academy of Sciences, USA’ they describe how they analyzed the impact of omega-3 fatty acids on a systemic level and they also described the underlying molecular mechanisms for the first time.

    The teams around Prof. Heinemann (Jena University), Prof. Dr. Michael Bauer (Jena University Hospital) and Prof. Dr. Toshinori Hoshi (University of Pennsylvania) were able to show that the so-called ‘SLO1’ potassium channel is an important component in the effectiveness of omega-3 fatty acids. “These ionic channels act like very specific receptors for DHA and are opened by the binding of the omega-3 fatty acids,” Biophysicist Heinemann explains. In the case of other omega-3 fatty acids – like the shorter eicosapentaenoic acid (EPA) or the alpha-linolenic acid (ALA) extracted from plants – the impact is much weaker.

    Prof. Bauer and his colleagues examined the effects of omega-3 fatty acids on SLO1 channels of the cardiovascular system by experimenting with mice. “Administration of DHA should result in an expansion of the blood vessels and consequently a drop in blood pressure,” the physician says. The laboratory experiments confirmed exactly that. In genetically modified mice however, which were not able to produce the SLO1 channel, the antihypertensive impact of DHA failed to appear. ”Thus we were able to show for the first time that DHA directly influences the blood pressure, which is being mediated through SLO1 channels,” Bauer summarizes.

    Beyond that, the scientists made another surprising discovery: a variant of DHA, which can often be found in nutritional supplements containing omega-3 fatty acids, doesn’t show an antihypertensive effect. Moreover, it suppresses and even diminishes the effect of the natural DHA from fish oil. “The intake of non-natural omega-3 fatty acids can therefore also have counter-productive effects,” Prof. Bauer stresses. This is of particular importance for the nutritional supplements of patients in intensive care who are being drip-fed: their supplements of omega-3 fatty acids should be specifically aimed at and adapted to the patients’ clinical requirements.

    Original Publications:
    Hoshi, T., B. Wissuwa, T. Tian, N. Tajima, R. Xu, M. Bauer, S.H. Heinemann, S. Hou (2013) Omega-3 fatty acids lower blood pressure by directly activating large-conductance Ca2+-dependent K+ channels. Proceedings of the National Academy of Sciences USA (DOI: 10.1073/pnas.1221997110)
    Hoshi, T., T. Tian, R. Xu, S.H. Heinemann, S. Hou (2013) Mechanism of the modulation of BK potassium channel complexes with different auxiliary subunit compositions by the omega-3 fatty acid DHA. Proceedings of the National Academy of Sciences USA (DOI: 10.1073/pnas.1222003110)

    Contact:
    Prof. Dr. Stefan H. Heinemann
    Institute for Biochemistry and Biophysics
    Center for Molecular Biomedicine (CMB)
    Friedrich Schiller University Jena and Jena University Hospital
    Hans-Knöll-Str. 2
    D-07745 Jena
    Germany
    Phone: ++49 3641 / 9395650
    Email: stefan.h.heinemann[at]uni-jena.de

    Prof. Dr. Michael Bauer
    Department of Anesthesiology and Intensive Care Medicine
    Center for Sepsis Control and Care (CSCC), Jena University Hospital
    Erlanger Allee 101
    D-07747 Jena
    Germany
    Phone: ++49 3641 / 9323110
    Email: michael.bauer[at]med.uni-jena.de


    More information:

    http://www.uni-jena.de


    Images

    Fish is healthy. Scientists of Jena University and Jena University Hospital now analyzed the impact of omega-3 fatty acids and described the underlying molecular mechanisms for the first time.
    Fish is healthy. Scientists of Jena University and Jena University Hospital now analyzed the impact ...
    Photo: Jan-Peter Kasper/FSU
    None


    Criteria of this press release:
    Journalists, Scientists and scholars, all interested persons
    Biology, Medicine, Nutrition / healthcare / nursing
    transregional, national
    Research results, Scientific Publications
    English


     

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