“There are a lot of compounds that give quite strong responses in a culture dish that really don’t produce any effects on lab rats,” said Foster, who is deputy director of the National Toxicology Program's Center for the Evaluation of Risks to Human Reproduction, which is part of the National Institutes of Health.
The major concern, Foster said, is what happens when people are exposed to mixtures of these estrogenic compounds.
“There are examples where you can take dose levels of compounds on their own that won’t produce an effect, but when you put these compounds together, you may get something different,” he said.
However, Foster said people should keep in mind that they already ingest significant numbers of fairly potent estrogens in their diets by consuming foods like tofu and milk, so findings like these shouldn’t necessarily scare people until more research has been conducted.
“It’s clear that humans are exposed to a mixture of these estrogenic compounds,” Foster said. “But you have to try to balance out what might already be present in your diet or your lifestyle with these things that might be coming from some other sources,” such as food additives.
Systems like the one used by the Italian researchers are useful for screening potentially estrogenic additives, Foster said, adding that it’s a “good first step” towards identifying these compounds.
Of the estimated 3,000 additives used in the United States to preserve foods or improve their taste and appearance, only about 2,000 have detailed toxicological information available, according to the FDA.
"Our results are part of a bigger, more important problem, which is that there could be other additives used in foods that could have estrogenic activity," Cozzini said.
Globally, the market for additives is expected to reach more than $33 billion by 2012. There are five main reasons that companies add compounds to food: to emulsify, to preserve, to add nutritional content, to add flavor or color and to balance alkalinity and acids.
"With some 3,000 compounds being used in food formulations there may be other additives with estrogenic properties that come to light with these types of studies," Hicks said.
Using the traditional animal testing system, “it would be impossible to test all of the additives in a short time,” Cozzini said. “Every day we discover new molecules, and we must continue to identify new ways to study them.”
Propyl gallate is considered “Generally Recognized As Safe” (GRAS) by the FDA, a title given to food additives that don’t require approval because they have a proven track record based on either a history of use before 1958 or on published scientific evidence. Examples of other GRAS substances include salt, sugar, spices and vitamins.
The other estrogenic one, 4-hexyl resorcinol, which is used on raw shelled seafood to inhibit melanosis, or black spots, was petitioned in 1990 for GRAS status. Its status is still pending, according to Michael Herndon, an FDA press officer.
The FDA’s lack of testing for estrogenic compounds doesn’t stop at additives. In 2008, an independent advisory board said the FDA ignored critical evidence concerning another estrogenic compound, bisphenol A, a plasticizing chemical found in polycarbonate baby bottles and the linings of metal foods cans.
“What we’ve seen with the FDA’s handling of BPA is that it’s had its head in the sand,” said Renee Sharp, director of the Environmental Working Group’s California office. “If you look at its assessments, what you see is that it has consistently ignored independent science and consistently used outdated methods in its assessments.”