Onion and Leek Consumption, Garlic Supplement Use and the Incidence of Cancer
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Onion and leek consumption, garlic supplement use and the incidence of cancer Citation for published version (APA): Dorant, E. (1994). Onion and leek consumption, garlic supplement use and the incidence of cancer. Maastricht: Datawyse / Universitaire Pers Maastricht. Document status and date: Published: 01/01/1994 Document Version: Publisher's PDF, also known as Version of record Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. 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If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, please follow below link for the End User Agreement: www.umlib.nl/taverne-license Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim. Download date: 04 Dec. 2019 Onion and Leek consumption Garlic supplement use and the Incidence of Cancer CIP-DATA KONINKLIJKE BIBLIOTHEEK, DEN HAAG Dorant. Elisabeth Onion and leek consumption, garlic supplement use and the incidence of cancer / Elisabeth Dorant Maastricht: Universitaire Pers Maastricht. - III. Thesis Maastricht. With ref. - With summary in Dutch. ISBN 90 5278-156-7 Subject headings: Allium vegetables / garlic supplements / cancer. Het onderzoek beschreven in dit proefschrift werd verricht vanuit de vakgroep Epidemiologie van de Rijksuniversiteit Limburg en de afdeling Epidemiologie van TNO-Voeding te Zeist, met financiële steun van de Nederlandse Kankerbestrijding. In de drukkosten van dit proefschrift werd bijgedragen door de Nederlandse Kankerbestrijding, Kneipp Nederland BV, Bloem Natuurprodukten BV, Arizona knoflook - Nutrivital BV, Parmalux Voedingssupplementen Amsterdam, Orthica BV, AGB Fresh Foods, Kyolic/Wakunaga, Pharmafood BV, Nutramin BV, NL Pharma BV Onion and leek consumption. Garlic supplement use and the Incidence of Cancer Proefschrift ter verkrijging van de graad van doctor aan de Rijksuniversiteit Limburg te Maastricht, op gezag van de Rector Magnificus, Prof. Dr. H. Philipsen, volgens het besluit van het College van Dekanen, in het openbaar te verdedigen op vrijdag 28 oktober 1994 om 14.00 uur door Elisabeth Dorant Promotores: Prof.dr. F. Sturmans Prof.dr.ir. R.J.J. Hermus Co-promotores: Dr.ir. P.A. van den Brandt Dr.ir. R.A. Bausch-Goldbohm Beoordelingscommissie: Prof.dr. W.H.M. Saris, voorzitter Prof.dr. G.H. Blijham, Universiteit Utrecht Prof.dr. J.A. Knottnerus Prof.dr. W.A. van Staveren, Landbouwuniversiteit Wageningen Prof.dr. Sj.Sc. Wagenaar Contents page 1 Introduction 1 2 Garlic and its significance for the prevention of cancer in humans: 7 a critical view 3 The use of vitamins, minerals and other dietary supplements in The 23 Netherlands 4 Agreement between interview data and a self-administered questionnaire 33 on dietary supplement use 5 A prospective cohort study on Allium vegetable consumption, garlic 45 supplement use and the risk of lung carcinoma in The Netherlands 6 Allium vegetable consumption, garlic supplement intake and female 61 breast carcinoma incidence 7 A prospective cohort study on the relation between onion and leek 71 consumption, garlic supplement use and the risk of colon and rectum carcinoma in The Netherlands 8 Consumption of onions and a reduced risk of stomach carcinoma 87 9 Epilogue 103 Summary 113 Samenvatting 116 Dankwoord 119 Curriculum vitae 121 Chapter 1 Introduction Background Onions, leeks, and garlic are vegetables belonging to the Allium genus (a genus with more than 500 different species). The majority of the Allium plants, which can be found in all parts of the world, have merely decorative value, although most of them are edible. At present, only a few are produced as food '•*. Originally, Allium vegetables were cultivated in China, the Middle East and Egypt. These vegetables were subsequently introduced in Greece and from there in other countries in Europe by the Romans. Until the introduction of onions, leeks and garlic from Europe in the US and Canada, the Indian population occasionally consumed wild species'. Names of important Allium plants cultivated for food production are listed in the table below. Table. Cultivated species of Allium. Species Common name Allium cepa L. var. cepa common onion Allium cepa L. var. ascalonicum scallion, shallot Allium fistulosum L. Japanese bunching onion Allium schoenoprasum L. chives Allium chinense (bakeri) rakkyo Allium sativum L. garlic Allium ampeloprasum L. var. porrum leek Allium tuberosum Chinese chives The Netherlands is one of the most important onion-producing countries in the world '. In the last two decades the yield of onions and shallots has nearly doubled in terms of absolute levels: from 284 million kg in 1 970 to almost 500 million kg in 1 991 '•*, with approximately 80% being exported *. The present production of onions and shallots represents approxi- Chapter 1 mately 14% of the total vegetable production in The Netherlands*. Production of leeks was nearly 100 million kg in 1991, about twice as high as in 1980^*. Consumption of Allium vegetables, particularly of onions, is also very high in The Netherlands. According to the 1992 Dutch national Food Consumption Survey onions were ranked number one in the vegetable top ten, with more than 20% of the Dutch population consuming onions every day *. Earlier, in the 1987-1988 Dutch national Food Consumption Survey more than 30% of the total population reported the consumption of onions on at least one of the two days of the survey '. In another large household survey carried out in 1987 in The Netherlands, West-Germany, Great-Britain and France, nearly all respondents reported that they had been using onions during the 3-month period before completion of the questionnaire (ranging from 92% of the population in West-Germany to 96% in France). In all four countries, onion consumption was highest among elderly persons, among those living in small households and in larger cities. The consumption decreased with increasing income and social class. Nearly two-thirds of the onions in The Netherlands were consumed cooked or baked and one third was consumed raw, while in France and great-Britain onions are most often consumed stewed or cooked*. More detailed information, especially on temporal trends in consumption of Allium vegetables in the Dutch population, is currently not available. One of the striking features of Allium plants is the large amount of organic bound sulfur. Numerous different so-called organosulfur compounds have been isolated from Alliums, both from intact as well as from crushed plants. These organosulfur compounds, responsible for the typical odour and flavour of Alliums, are suggested to be accountable for the medicinal effects'*. Allium vegetables have been used for medical purposes for centuries to treat or prevent many different diseases, such as headache, worm infections and 'body weakness', but also haemorrhoids, ulcers, pneumonia, suppurative wounds, dog and snake bites, baldness, eczema and other skin disorders, leprosy, cholera, influenza and chronic bronchitis. Onions and garlic were also claimed to possess diuretic, antidiabetic and antirheumatic properties, to be good for the eyes and act as heart stimulant *-'°"'*. Some of the edible Alliums are still being used in some cultures as natural remedy "•"•'*•'*. For instance, garlic extract has recently been used in China as adjuvant therapy to prevent fungal infection in patients with leukaemia treated with bone marrow transplantation '*. Experimental research into the prophylactic and therapeutic properties of Allium vegetables and Allium compounds has been conducted since the 1 9th century *. However, most of the scientific research was initiated after the detection of important chemical components by Cavallito and Bailey in 1944 ", and by Stoll and Seebeck in 1947 '*. In many in vitro studies that were published since then, fresh Allium vegetables and preparations have been demonstrated to possess antibacterial and fungicidal activity^. However, there might be considerable variation in activity depending on type, variety or production method. For instance, it has been shown that fresh garlic and garlic compounds exhibit greater antibacterial activity than several onion types ". Another in vitro experiment showed that garlic supplements varied greatly in