For millions of years plants have been quietly producing chemicals. Through countless generations they have been perfecting a potpourri of chemicals, some benign some deadly. As the ability to detect, isolate, measure and test chemicals found in nature has progressed a starling fact has emerged: hundreds of plants appear to produce endocrine disrupters.
Many of the plants that produce phytoestrogens and other endocrine disrupters are edible. In laboratory test more than 43 plants and foods found in the human diet have been shown to be estrogenically active. Many phytoestrogen containing plants are common elements of our diet. Such grains as corn and wheat form a significant part of the human diet. Many legumes have also shown a surprising capacity for phytoestrogen production.
Although much more work has been done on phytoestrogens, some work has been done on plant chemicals which are known to effect the production of sperm. Only a handful have been discovered in the human diet. Of these the most common is cottonseed oil. Although cottonseed oil is rarely sold as a vegetable oil, it is commonly used in manufactured snack foods.
A great deal of attention has recently been given to the fact that synthetic chemicals have exhibited estrogenic effects in laboratory studies. The chemicals most prominently cited are PCBs and DDT, both of which have been banned in the United States. Compared with phytoestrogens, the concern over synthetic estrogens may be somewhat overstated. The estrogenic effects from the phytoestrogens in our diet are an estimated 40 million times greater than those from synthetic chemicals. To date, however, there is no concrete evidence that either pose a risk to human health.