Safer Food For a Healthier You

Medically Reviewed by Michael W. Smith, MD on December 18, 2008
7 min read

Pesticides in produce, hormones in milk, antibiotics in meat -- what are all these extra ingredients doing in our food?

Improved testing methods now allow researchers to detect and monitor a strange brew of unpleasant chemicals in our food and bodies. Although the amounts are small and there’s controversy about whether or not they’re harmful, their presence alone is disturbing to many --especially parents of small children.

“Modern production of foods incorporates a wide range of synthetic chemicals,” says Jeff Gillman, PhD, associate professor of horticulture at the University of Minnesota and author of The Truth About Organic Gardening. “Many of these chemicals have the potential to be very damaging to humans if they are exposed to high concentrations, or to low concentrations over an extended period of time.”

“More people are realizing there’s a myriad of chemicals in conventionally produced food,” says Craig Minowa, environmental scientist with the Organic Consumers Association, a nonprofit advocacy group. Although each has passed its own safety review, Minowa points out that “most of the studies on safety are done or supported by the companies themselves.”

So what are the health effects of these unwanted ingredients?

Injecting hormones into young livestock can make them gain weight faster. More weight means more meat, which means more profit for the producer. Hormones also increase the production of milk by dairy cows.

Hormones have been used for decades in the meat and dairy industries. Synthetic estrogens and testosterone are the most common. Typically, farmers implant a pellet in a cow’s ear at an early age; it releases hormones throughout the animal’s life.

Initial concerns about estrogen-injected cows centered on a compound called diethylstilbestrol (DES). Nearly all beef cattle were treated with DES in the 1950s and 1960s. DES was also used as medicine, given to pregnant women to prevent miscarriages.

However, it was also discovered that DES caused a higher risk of vaginal cancer in the daughters of women who received the medicine. By the 1970s, over the protests of ranchers, diethylstilbestrol was phased out from use in medicine and agriculture.

It’s also long been known that breast cancer risk increases with higher lifetime exposure to estrogen. These facts have led many to question whether the continued use of synthetic estrogens in livestock is safe.

Recombinant bovine growth hormone (rBGH) is a different class of hormone that increases the amount of milk dairy cows produce. Some suggest that although rBGH itself appears safe, it increases the amount of other chemicals in the body that might cause cancer. So far, there’s no definitive proof one way or the other.

How much hormone is in a hamburger, and could it hurt you? The answer is, no one really knows. Studies show the added hormones do show up in beef and milk, pushing their estrogen and testosterone content to the high end of normal for cows. Whether that translates to increased risk for humans is the question.

“It really depends on how you look at the science,” Minowa tells WebMD. “Many industry-funded studies show no risk, but there are independent studies that suggest” a potential cancer risk from hormones in milk.

Hormone-treated meat has long been suspected of contributing to early puberty in children, although the link has not been proven. There’s no question that the age of puberty has been decreasing in the U.S. But some suggest that’s due to improved nutrition and health, not to second helpings of hormones in children’s diets.

The effects are very hard to study, experts say, because hormones are naturally present in both food and our bodies. Plus, the effects could be subtle and take years to show up.

The amount of hormone that enters a person’s bloodstream after eating hormone-treated meat is small compared with the amount of estrogen a person produces daily. However, even low levels of hormones can have strong effects on some body processes.

Responding to the lack of certainty, the European Union has banned all hormones in beef, and Japan, Canada, Australia, New Zealand, and the EU have banned rBGH. No major studies are under way in the U.S. to evaluate the safety of hormones in meat and milk.

Farmers use pesticides on many conventionally grown fruits and vegetables. The EPA sets limits on how much pesticide residue can remain on food. It’s a complex process that’s not easy to understand, incorporating variables such as the toxicity of the pesticide and how much of the food people generally eat. At the end, each of the 9,700 pesticides (at last count, in 1996) receives a number called a “tolerance.”

The EPA, FDA, and USDA all play a role in ensuring pesticides on our food don’t exceed the tolerances. In 1999, 40% of U.S. produce tested by the government contained pesticide residue. About 1% of domestically produced and 3% of the imported food had levels that violated standards.

While those numbers might seem reassuring, skeptics point out that no one could possibly test all the food grown or imported into the U.S. Even 1% of the total produce in the U.S. is a huge amount, Gillman points out.

And although pesticide tolerances are assumed to be safe, these chemicals are by their very nature toxic, and haven’t been studied directly in people.

According to Minowa, the individual safety profiles of pesticides don’t take into consideration any hazard from their combined effects. “Take a box of [cereal] off the shelf, and you can find residues from 32 pesticides,” Minowa says. “Each one is within its tolerance, but what’s the effect of those chemicals acting in combination in our bodies?”

According to FDA data analyzed by the nonprofit Environmental Working Group, the following fruits and vegetables tend to contain the highest levels of pesticide residue:

  • Peaches
  • Apples
  • Sweet bell peppers
  • Celery
  • Nectarines
  • Strawberries
  • Cherries
  • Pears
  • Imported grapes
  • Spinach
  • Lettuce
  • Potatoes

The foods with the least pesticide residues were:

  • Avocados
  • Frozen sweet corn
  • Pineapples
  • Mangos
  • Asparagus
  • Frozen peas
  • Bananas
  • Cabbage
  • Broccoli
  • Papayas

You can reduce your exposure to pesticides by buying organic for the high-pesticide items. Conventionally grown produce should be fine for those on the low-residue list, according to EWG.

Whether it’s organic or conventional, you should take steps to reduce contamination of fresh food by pesticide or bacteria:

  • Always wash fresh produce thoroughly.
  • Peeling produce reduces pesticide residue and bacteria, although it also can remove valuable nutrients.

Ranchers and farmers feed antibiotics in a daily low dose to their livestock. It’s not to stop them from getting sick, but to make them gain weight.

But many doctors and researchers suspect that this practice is contributing to the rise of antibiotic-resistant bacteria, posing a serious danger to our health:

  • A 2001 study in the New England Journal of Medicine showed that 84% of the Salmonella bacteria in supermarket ground beef were resistant to some antibiotics.
  • Another study in 2002 suggested that some people caught resistant strains of Salmonella from eating pork that had been fed the antibiotic ciprofloxacin.
  • The FDA estimates that use of antibiotics in chickens directly led to 11,000 people catching intestinal illnesses from antibiotic-resistant bacteria in 1999.

Partly because of these findings, several major fast food chains have refused to buy chicken treated with ciprofloxacin or similar antibiotics. Other companies continue to buy and sell antibiotic-treated meat, though.

There’s no easy way to know if the meat you buy was raised with antibiotic feed. Companies aren’t obligated to label their meat, or to provide consumers with the information.

“The best way to do that is to look for organic products, or to buy locally,” says Minowa. “If you have a direct relationship with the farmer raising your food, you can just ask them.”

Buying from local farmers’ markets gets you the freshest produce possible. It also makes your food “greener” by reducing the wasted fuel, pollution, and greenhouse gases created by long-haul shipping.

“By buying local, you also have the ability to ask the farmer which pesticides he or she used on the crop as it was grown,” says Gillman.

“Organic” is a term that’s regulated by the USDA. Organic produce can’t be treated with conventional pesticides, and must be grown in nearly pesticide-free soil. For these reasons, organic fruits and vegetables have much lower pesticide residues.

To be sold as organic, livestock must meet several criteria:

  • They are fed only organic, vegetarian feed. They may not be fed meat from other slaughtered animals (a common component of conventional livestock feed).
  • They are not treated with any antibiotics or hormones.
  • The meat is not treated with radiation.
  • They are raised under conditions that allow exercise and access to the outdoors.

The USDA can inspect farms for compliance. It’s believed that the vast majority of organic farmers follow these practices.

The main drawback to organic food is expense. As you’ve noticed in the checkout lane, organic food nearly always costs more than conventionally produced food.

Is buying organic money well spent? Limited research suggests that some organic foods have more nutrients than conventional food. And then there’s the issue of the environment. Gillman cautions that “organic practices aren’t always 100% sustainable and green either,” but they are usually “greener” than modern industrial farming.

To Minowa and many others in the organic food movement, “it’s a matter of responsibility. Each bite that you consume, each dollar that you spend provides an opportunity to make positive change for a sustainable future.”