TemaNord 2017:541 Phytoestrogens in foods on the Nordic market the Nordic on foods in 2017:541 Phytoestrogens TemaNord Nordic Council of Ministers Nordens Hus Ved Stranden 18 DK-1061 Copenhagen K www.norden.org Phytoestrogens in foods on the Nordic market Phytoestrogens are plant-derived compounds that may bind to estrogen receptors, but with less affinity than the natural ligand estradiol. They may be biologically active as such or after metabolization in our body. To investigate the occurrence and level of phytoestrogens, scientific literature was screened for data on isoflavones, lignans, stilbenes and coumestans in raw and processed foods of plant origin. The review presents data based both on analytical methods hydrolysing glucosides and non-destructive methods. Many phytoestrogens are phytoalexins. Their production is induced when plants are exposed to abiotic and/or biotic stress. This could explain the rather different levels reported in plants by various investigators, and indicates that many samples are required to describe the levels generally occurring in foodstuffs. The influence of food processing was also considered. Phytoestrogens in foods on the Nordic market A literature review on occurrence and levels Phytoestrogens in foods on the Nordic market A literature review on occurrence and levels Linus Carlsson Forslund and Hans Christer Andersson TemaNord 2017:541 Phytoestrogens in foods on the Nordic market A literature review on occurrence and levels Linus Carlsson Forslund and Hans Christer Andersson ISBN 978-92-893-5046-4 (PRINT) ISBN 978-92-893-5047-1 (PDF) ISBN 978-92-893-5048-8 (EPUB) http://dx.doi.org/10.6027/TN2017-541 TemaNord 2017:541 ISSN 0908-6692 Standard: PDF/UA-1 ISO 14289-1 © Nordic Council of Ministers 2017 Cover photo: Unsplash.com Print: Rosendahls Printed in Denmark Although the Nordic Council of Ministers funded this publication, the contents do not necessarily reflect its views, policies or recommendations. Nordic co-operation Nordic co-operation is one of the world’s most extensive forms of regional collaboration, involving Denmark, Finland, Iceland, Norway, Sweden, the Faroe Islands, Greenland, and Åland. Nordic co-operation has firm traditions in politics, the economy, and culture. It plays an important role in European and international collaboration, and aims at creating a strong Nordic community in a strong Europe. Nordic co-operation seeks to safeguard Nordic and regional interests and principles in the global community. Shared Nordic values help the region solidify its position as one of the world’s most innovative and competitive. Contents Preface ..................................................................................................................................... 5 Summary .................................................................................................................................. 7 1. Introduction ...................................................................................................................... 11 1.1 Oestrogens ............................................................................................................. 11 1.2 Phytoestrogens ...................................................................................................... 12 1.2.1 Identification of phytoestrogens ................................................................... 14 1.2.2 Relevant phytoestrogens in a food and feed context ..................................... 17 1.2.3 Food plants containing relevant phytoestrogens ..........................................19 2. Chemical analysis of phytoestrogens ................................................................................. 21 2.1 Analysis of endogenous phytoestrogens in plants ................................................... 21 2.1.1 Extraction of isoflavones, lignans, and coumestrol ........................................ 21 2.1.2 Summary of analytical methods ................................................................... 21 3. Phytoestrogen content in food plants ................................................................................ 23 3.1 Isoflavone levels in foods......................................................................................... 23 3.1.1 Occurrence of isoflavones ............................................................................ 23 3.1.2 Chemical analytical methodology ................................................................. 32 3.1.3 Studies on isoflavone contents in foodstuffs .................................................34 3.1.4 Isoflavones in products of animal origin ........................................................36 3.1.5 Isoflavones in beverages ...............................................................................39 3.1.6 Isoflavones in fruits and berries ..................................................................... 41 3.1.7 Isoflavones in legumes ................................................................................ 44 3.1.8 Isoflavones in vegetables and root vegetables ............................................. 64 3.1.9 Isoflavones in nuts ........................................................................................ 67 3.1.10 Isoflavones in oilseed crops .......................................................................... 67 3.1.11 Isoflavones in cereals .................................................................................... 67 3.1.12 Isoflavones in other foodstuffs ..................................................................... 69 3.1.13 Isoflavones in dietary supplements ............................................................... 73 3.1.14 Influence of storage and processing on isoflavone content............................ 74 3.2 Lignan levels in foods .............................................................................................. 76 3.2.1 Lignans in animal products ........................................................................... 79 3.2.2 Lignans in beverages ................................................................................... 80 3.2.3 Lignans in fruits and berries ......................................................................... 82 3.2.4 Lignans in legumes ...................................................................................... 84 3.2.5 Lignans in vegetables .................................................................................. 86 3.2.6 Lignans in nuts ............................................................................................ 86 3.2.7 Lignans in oil seeds ...................................................................................... 89 3.2.8 Lignans in cereals ........................................................................................ 89 3.2.9 Lignans in other foodstuffs .......................................................................... 90 3.2.10 Lignans in dietary supplements ....................................................................93 3.2.11 Influence of storage and processing on lignant content .................................93 3.3 Stilbene levels in foods ........................................................................................... 95 3.3.1 Stilbene production in plants........................................................................ 95 3.3.2 Chemical analytical methodology ................................................................ 97 3.3.3 Stilbenes in nuts and almonds .................................................................... 100 3.3.4 Stilbenes in hops and beer ......................................................................... 102 3.3.5 Stilbenes in fruits and berries ..................................................................... 104 3.3.6 Stilbenes in grape ...................................................................................... 106 3.3.7 Stilbenes in grape juice .............................................................................. 120 3.3.8 Stilbenes in wine ........................................................................................ 121 3.3.9 Stilbenes in legumes ...................................................................................133 3.3.10 Stilbenes in solanaceous food plants ...........................................................133 3.3.11 Stilbenes in mulberry ................................................................................. 134 3.3.12 Stilbenes in sugarcane ............................................................................... 135 3.3.13 Stilbenes in rhubarb ................................................................................... 135 3.3.14 Other products containing stilbenes ........................................................... 135 3.4 Coumestan levels in food ...................................................................................... 136 3.4.1 Legumes ..................................................................................................... 137 3.4.2 Occurrence in other foods than legumes .................................................... 139 References ............................................................................................................................ 141 Sammanfattning .................................................................................................................... 177 Preface In many countries, there is a vivid discussion on compounds called endocrine disruptors.