Authors
Shaw, I. and McCully, S.

Title
A review of the potential impact of dietary endocrine disruptors on the consumer.

Journal
International Journal of Food Science and Technology 37:471-476, 2002

Summary
Humans are exposed to endocrine active compounds (EAC) via food, water, air, soil, and household products. Some synthetic chemicals accumulate in the adipose tissue of animals and humans and are often passed along to offspring and predators. At high doses, some EACs can affect an animals' endocrine system, especially during critical stages of development. Phytoestrogens and synthetic chemicals have been associated with a number of adverse health effects in animals, including reproductive and developmental problems.

The authors of the present investigation sought to evaluate the dietary intakes of EACs in order to assess their relative risks to humans. Daily intakes of phytoestrogens (e.g. genistein from soya), plasticizers, and pesticides were calculated by using food intake data and known levels of these "xenoestrogens" in food. An exogenous estrogen was determined to have a significant pharmacological impact if its plasma concentration was a significant proportion of, or greater than, the endogenous estrogen concentration in human males. Based on the authors' calculations, dietary intakes of estrogenic pesticides and plasticizers were too low to produce physiological effects compared to the dose and potency of endogenous estradiol. However, blood concentrations of phytoestrogens (coumestrol, genistein, and genistin) were approximately eight-fold greater than the normal endogenous estrogen levels in human males, suggesting that dietary intake of phytoestrogens could have a physiological effect.

It is important to consider that certain assumptions were made in manipulating the data; therefore, the calculations presented in this paper represent a worst case scenario. For example, it was assumed that all food eaten contained residues of the highest level, that the average dietary intake consisted of all types of foods, and that the xenoestrogens were completely absorbed. The data presented here indicate that that phytoestrogen consumption results in increased endogenous estrogen concentration in human males. The authors propose that the declining human sperm count over the past five decades might be associated with the increased popularity of vegetarianism and consumption of soy products as phytoestrogens are contained in grains (i.e. soybeans), vegetables, and fruits. However, there is little more than anecdotal evidence to support the hypothesized association in the case of declining sperm counts, which itself remains a controversial issue.