Phthalates—a worrisome endocrine-disrupting group of chemicals that shows up in food—may put adults at risk for obesity, diabetes, and the metabolic syndrome.

Phthalates can also affect fertility

Some of the strongest evidence that phthalates cause harm: “Higher levels in mothers during pregnancy are linked to anatomical changes in infant boys that may affect their ability to father children later in life,” says Ami Zota, a professor of environmental and occupational health at George Washington University.1

What’s more, “phthalate exposure during adulthood is linked to decreased fertility, alterations in sperm, and decreased testosterone levels,” notes Sheela Sathyanarayana, an associate professor of pediatrics at the University of Washington.2

Females may be at risk, too.

“We now have enough evidence from animal studies to show that exposure to phthalates during pregnancy harms the later reproductive health of the female offspring,” says Jodi Flaws, a professor of comparative biosciences at the University of Illinois.

Those studies used phthalate levels comparable to what humans are routinely exposed to.

“When the offspring are sexually mature, they have abnormal levels of sex steroid hormones, it will take them longer to get pregnant, they’re more likely to have complications during the pregnancy, and they produce smaller litters,” Flaws explains.3

Several studies suggest that phthalates can also affect fertility in women.

Harvard researchers measured the levels of 11 phthalates in the urine of 256 women undergoing in vitro fertilization. Those with the highest levels of six of the phthalates produced fewer eggs than those with the lowest levels. And women with the highest levels of one of the 11 phthalates were half as likely to become pregnant as those with the lowest levels.4

Other researchers analyzed 111 endocrine-disrupting chemicals in 31,575 women who were participating in the National Health and Nutrition Examination Survey from 1999 to 2008.

Those with the highest levels of one particular phthalate reached menopause about four years earlier than the other women.5

An earlier menopause “could increase rates of infertility and lead to earlier development of cardiovascular disease, osteoporosis, and other medical problems,” the researchers noted.

How to avoid phthalates in food

Phthalates are hard to dodge because they increase the flexibility of plastics in everything from vinyl flooring and shower curtains to IV tubes, food processing equipment, and food packaging.

Phthalates are also common in many foods. But some—such as poultry, red meat, butter, margarine, cooking oil, cream, and cheese—are more likely to contain phthalates. 


1Hum. Reprod. 30: 963, 2015.

2 Hum. Reprod. 30: 2645, 2015.

3 Toxicol. Appl. Pharmacol. 318: 49, 2017.

4Environ. Health Perspect. 124: 831, 2016.

5PLoS One 10: e0116057, 2015.

Photos: © Zffoto/ (baby), © Yeko Photo Studio/ (cheese).