Phytoestrogen Content of Cereals and Cereal-Based Foods Consumed in the UK

Abstract

Dietary phytoestrogens may be involved in the occurrence of chronic diseases. Reliable information on the phytoestrogen content in foods is required to assess dietary exposure and disease risk in epidemiological studies. However, there is little information on isoflavone, lignan, and coumestrol content of cereals and cereal-based foods, leading to an underestimation of intake. This is the first study of phytoestrogens (isoflavones: biochanin A, daidzein, formononetin, genistein, glycitein; lignans: matairesinol, secoisplariciresinol; coumestrol) in a comprehensive selection of 101 cereals and cereal-based foods-including breads, breakfast cereals, biscuits, pasta and rice-consumed in the UK using a sensitive LCMS technique with 13C-labelled internal standards. Phytoestrogens were detected in all foods analyzed; bread contained the highest amount of phytoestrogens-many as isoflavones-with an average content of 375 +/- 67 microg/100 g wet weight (excluding soya-linseed bread with 12,000 microg/100 g). Most other foods contained less than 100 microg/100 g, many as lignans. Our study shows that all foods analyzed contained phytoestrogens, with the highest amount found in breads, making them one of the main sources of dietary phytoestrogens in the UK. These results will allow a more accurate estimation of exposure to dietary phytoestrogens.

Dietary intakes and food sources of phytoestrogens in the European Prospective Investigation into Cancer and Nutrition (EPIC) 24-hour dietary recall cohort

“…37,44 In the UK general population, the isoflavone intake was also higher (2.34 mg/day) compared with other European countries because of the addition of soy flour to regular flour used in baking. 32 Therefore, cereals and cereals products, sugar and confectionary, cakes and biscuits contributed 69.1% of the total isoflavone intake. Isoflavone intake in vegetarians is higher than in non-vegetarians, as was observed in the health-conscious cohort in the present study (19.4 mg/day) and in a former UK study (10.1 mg/day), which includes a subset of participants from the current study.…”

“…We used these four European regions because in the UK, regular flour is supplemented with soy flour (one of the richest sources of isoflavones) in the elaboration of breads, cakes and biscuits. 32 Moreover, the UK healthconscious group form a distinct subgroup with higher consumptions of fruit, vegetables, legumes, nuts and seeds, cereals and soy products compared with the other EPIC centres. 33 These models were adjusted for sex, age, centre, BMI and energy intake.…”

The DietCompLyf study: A prospective cohort study of breast cancer survival and phytoestrogen consumption

“…It was expected that bread and soya milk consumption would provide the majority of isoflavones consumed in a UK diet [3], yet only 1% of the patients in this subset reportedly drank soya milk. The heterogeneity (bread containing soy and linseed for example being contained in the same group as standard brown bread; genistein contents of 6,807 and 246 µg/100g respectively) was not controlled for [26].…”

Phytoestrogens in foods on the Nordic market

“…The most commonly reported phytoestrogens in food are the isoflavones: daidzein, genistein, glycitein, and the lignan secoisolariciresinol (Milder et al, 2005;Thompson et al, 2006;Kuhnle et al, 2007Kuhnle et al, , 2008aKuhnle et al, , 2008bKuhnle et al, , 2009aKuhnle et al, , 2009b.…”