Changes in serum enterolactone, genistein, and daidzein in a dietary intervention study in Finland

Phytoestrogens are plant-derived compounds that may have cancer-protective properties. The purpose of the study was to see how enterolactone, daidzein , and genistein serum concentrations reflect major changes in the diet of F innish subjects. Phytoestrogen concentrations were measured by time-resolve d fluoroimmunoassay after hydrolysis and extraction in samples from 85 midd le-aged subjects who were part of a 12-week dietary intervention study carr ied out in North Karelia, Finland. In the baseline and the switchback perio ds, the subjects consumed their habitual Finnish diet, which is high in sat urated fat and low in polyunsaturated fat and vegetables. During the 12-wee k intervention period, the proportion of dietary energy derived from fat wa s reduced from similar to 39% to 23%, and the consumption of vegetables, fr uit, and berries was markedly increased. Enterolactone concentrations were measured during the baseline, intervention, and switchback periods. The med ian concentration of enterolactone rose from 12.2 to 19.5 mmol/l (P = 0.002 ) during the few-fat, high-vegetable diet. Daidzein and genistein concentra tions were very low and did not change during the intervention. At baseline , 65% of the population had a low serum enterolactone concentration of <15 mmol/l. During the intervention period, this proportion fell to 34%, These major differences in serum enterolactone concentrations suggest that entero lactone may be used as a biomarker of a healthy diet containing plenty of v egetables, fruit, and berries.