Estrone in food: a factor influencing the development of obesity?

Background Estrone is a relatively abundant hormone widely distributed in t issues of animal and plant origin. It is a mild estrogen that induces incre ases in body weigt in experimental animals. The relative abundance of estro ne esters in animal tissues suggests that it may also be found in foods, fr om which it may alter the mechanisms of body weight control. Aim of the study To measure the total estrone content in food and to determ ine whether this may affect body weight. Methods In the first part of the study, a method was devised for the measur ement of total estrone content in food. This was applied to the analysis of estrone content in a variety of food. Finally, hyperlipidic diets (18.6 MJ /kg) with a total estrone content 0.89 +/- 0.21 mu mol/ kg (control group) and 1.37 +/- 0.13 mu mol/kg (laced with estrone fatty esters) were given to rats during 15 days, in order to determine the influence of dietary estron e on the body mass. Zucker lean (Fa/?) rats weighing initially 200-215 g we re used. The total estrone (essentially as fatty esters) content of food wa s investigated by combining a dried methanol extraction with saponification and measurement of the free estrone evolved through radioimmunoassay. Result The content of estrone was zero in some vegetables, but significant in fruits, meats, and especially fats, both of plant and animal origin. The application of these analyses to a standard recommended diet for humans ma y result in intakes of more than 1 mu mol of estrone per day, a figure comp arable to the estrogen production by women. When rats were exposed to a rai sed estrone content in a fat-rich diet, they significantly increased their body weights, doubling their rate of growth (1.99 g/day) compared with cont rols (0.81 g/day), but maintaining their plasma composition and the proport ions of lipid, water, and protein in their carcasses. Conclusion The widely distributed estrone esters in food and their relative ly high concentrations may result in high free hormone intakes in humans. T he continued and massive intake of estrone may enhance tissue deposition an d lead to obesity.