Isoflavones and Functional Foods Alter the Dominant Intestinal Microbiota in Postmenopausal Women.Author: Thomas Clavel, Matteo Fallani, Patricia Lepage, Florence Levenez, Jacinthe Mathey, Violaine Rochet, Michèle Sérézat, Malène Sutren, Gemma Henderson, Catherine Bennetau-Pelissero, Françoise Tondu, Michael Blaut, Joël Doré and Véronique Coxam.
Publication: Journal of Nutrition 135:2786-2792, December 2005.
Isoflavones are often used to by women to ease menopause symptoms and can reduce hormone related diseases such as osteoporosis and prostate cancer.The bioavailability of isoflavones depends on the activity of the intestinal flora. During digestion of isoflavones they undergo different chemical reactions including deglycosylations (removal of sugar part), demethylation, reduction and ring fusion. The isoflavone daidzein is for example converted to equol which has other biological activities than daidzein. The production of equol differs strongly from individual to individual and might be influenced by the intestinal flora. The composition of the intestinal flora is relatively stable in healthy adults but the composition can change depending on the consumed food. Many functional foods have been developed that contain probiotics or prebiotics. Probiotics are life bacteria which improve improve the gut health. Prebiotics are indigestible food components that stimulate the growth of good bacteria in the colon.
The purpose of this study was to investigate the change in intestinal flora after intake of isoflavones, with and without probiotics or prebiotics. The experiment was carried out on 39 postmenopausal women who consumed daily 100 mg isoflavones. After a period of 30 days the women were divided in three groups: control group (100 mg isoflavones), probiotics group (100 mg isoflavones and Bifidobacterium animalis) and prebiotics (100 mg isoflavones and oligofructose). The composition of the intestinal flora was determined gel electrophoresis and fluorescent in situ hybridization.
The researchers found that isoflavones stimulated certain group of bacteria. After 1 month of treatment with 100 mg isoflavones per day, the numbers of Clostridium coccoides, Eubacterium rectale, Lactobacillus, Enterococcus, Faecalibacterium prausnitzii and Bifidobacterium. After a treatment of 2 months the levels of bifidobacteria increased. The stimulation of Clostridium coccoides and Eubacterium rectale was related to the equol excretion. Isoflavones caused a prolonged bifidogenic effect and lasting changes in the composition of the intestinal flora. The prebiotics and probiotics caused a more dynamic changes in the intestinal flora that isoflavones alone.
The study concluded that the simultaneous consumption of isoflavones and probiotics or prebiotics caused a marked change in the composition of the intestinal flora of postmenopausal women.