The Worst Offenders:

The statement addresses 2 broad categories of additives: direct and indirect. Indirect additives refers to substances in “food contact materials,” such as “adhesives, dyes, coatings, paper, paperboard, plastic, and other polymers,” the authors of the policy statement explain. Direct food additives include chemicals such as colorings, flavorings, and preservatives added to food during processing. Within those two categories the authors identified six types of additives of most concern, based on accumulating evidence summarized in the report and in an accompanying press release:

Bisphenols: Used to manufacture plastic containers and food and beverage cans, these compounds have been associated with endocrine and neurodevelopmental disruption and obesogenic activity, with alterations in the timing of puberty, reduced fertility, and impaired neurological and immunological development. One bisphenol, bisphenol A, has already been banned from baby bottles and sippy cups.

Phthalates: As components of plastic wrap and plastic tubing and containers, phthalates similarly have been implicated in endocrine disruption and obesogenic activity. "A robust literature" shows that these chemicals adversely affect male sexual development, may contribute to childhood obesity and insulin resistance, and may also contribute to cardiovascular disease.

Perfluoroalkyl chemicals: These chemicals are used in the manufacture of greaseproof paper and cardboard packaging. They have been associated with immunosuppression, endocrine disruption such as impaired thyroid function, and decreased birth weight.

Perchlorate: Often added to plastic packaging for dry foods to control static electricity, perchlorate has been shown to disrupt production of thyroid hormone, with implications for subsequent cognitive function. Of particular concern is exposure among pregnant women, "given that the developing fetus is entirely reliant on the maternal thyroid hormone during the first trimester of pregnancy," the authors write in the technical report. They suggest that perchlorate "may be contributing to the increase in neonatal hypothyroidism and other thyroid system perturbations that have been documented in the United States."

Nitrates and nitrites: As direct food additives, these compounds are used as preservatives and color enhancers in cured and processed meats, fish, and cheese. There has been "longstanding concern" over their use, the authors write, because of an association with cancers of the nervous and gastrointestinal systems, and methemoglobinemia in infants. They were classified as "probable human carcinogens" in 2006 by the International Agency for Research on Cancer.

Artificial food colors: Often added to products that appeal to children, such as juice drinks, artificial food colors have been associated in some studies with an increased risk for attention-deficit hyperactivity disorder. Although their mechanisms of action are not yet completely understood, and the research "should be interpreted with caution," the authors recommend "a thorough reassessment" of artificial food colors to ensure they are safe.