Vogt, R, D Bennett, D Cassady, J Frost, B Ritz and Irva Hertz-Picciotto. 2012. Cancer and non-cancer health effects from food contaminant exposures for children and adults in California: a risk assessment. Environmental Health http://dx.doi.org/10.1186/1476-069X-11-83.
According to the results from a recent California study published in 2012, pre-schoolers come in contact with more food contaminants than older children and adults. This is the first research to evaluate multiple contaminants, mostly pesticides and metals, in children’s diets and then compare the estimated exposures with the U.S. Environmental Protection Agency’s guidelines. Chemicals included in this study have previously been linked to cancer, liver toxicity, reproductive effects or neurological damage at the levels estimated in the children, based on their diets.
Most people are typically exposed to multiple contaminants at the same time, yet studies usually investigate one chemical at a time. The one-at-a-time approach typically ignores the ways chemicals can act together or in opposition to affect health. It is also important to identify exposure routes since simple lifestyle changes can reduce them.
It is interesting to note that, prior to this study, the amount of chemical exposures adults and children receive every day through food is not well studied because of the many factors that complicate the issue. These include the variety of foods – how they’re grown, cooked, processed and packaged – as well as personal differences, such as what kinds, how often and how much is eaten. Many of the pesticides, metals or persistent compounds assessed in this particular study are banned, are considered carcinogens or can interfere with the endocrine system.
The University of California, Davis, and UCLA researchers report that the youngest children had higher exposures than school-aged children, parents or older adults when comparing by body weight. To find specific the exposure levels, they asked participants how much and how often they ate certain foods then used national databases to estimate the amount of toxic chemicals they had eaten.
Children are particularly vulnerable to chemicals because their brain and organ systems are developing. Any disruption to developing organs can lead to disorders and health risks later in life. In addition, children eat more per body weight than adults, exposing them to higher levels of chemicals.
The research is part of the U.S. Environmental Protection Agency (EPA) Study of Use of Products and Exposure-Related Behavior (SUPERB) that examines how food, personal or home care products, and timing of exposures can affect exposure to environmental chemicals. The participants were from 21 counties in California. Adults answered telephone survey questions for themselves and their children about how often and how much of 44 key foods and food groups they had typically eaten in the past year.
Data from government agencies and nonprofit organizations were used to estimate the levels of 11 pollutants from four major contaminant groups that represent different chemical classes, food groups and health effects. These were: metals (arsenic, lead, mercury), pesticides (chlorpyrifos, permethrin, endosulfan), persistent organic pollutants (POPs) (dioxin, DDT, dieldrin, chlordane), and processing byproducts (acrylamide).
Acrylamide occurs naturally when carbohydrate-rich foods are cooked at high temperatures. It is commonly found in crackers, cookies and french fries.
The researchers calculated the participants’ chemical exposures based on their reported diet and the amount of chemicals estimated to be in each food. The data were grouped by age and adjusted for body weight: preschoolers (2-4 years), school-age children (5-7 years), parents of young children and older adults.
Contaminants that were higher than EPA’s daily oral intake dose were identified as posing cancer or non-cancer health risks because they exceeded the agency’s benchmarks based on known risks for these types of exposures.
Preschoolers and School-aged Children Were By Far the Most Exposed Groups
Both age groups ate contaminants at levels with known health effects, including cancer, liver toxicity, and damage to the neurological and reproductive systems.
Preschoolers exceeded the cancer benchmarks for arsenic and the pesticides dieldrin, DDE and PCDD/Fs. When compared to school-aged children, preschoolers were more likely to consume higher levels of acrylamide, lead, chlordane, dieldrin, DDE and PCDD/Fs. When compared to adults, preschoolers were more likely to be exposed to acrylamide, arsenic, lead, mercury, dioxins/furans (PCDD/Fs), and the pesticides chlorpyrifos, endosulfan, chlordane, dieldrin, and DDE.
For non-cancer effects, more than 95 percent of preschool and school-aged children exceeded the benchmark for acrylamide, while all of them exceeded non-cancer benchmarks for lead and DDE, a metabolite of DDT. EPA’s daily intake levels for no risk of effect for both lead and DDE are zero.
Based on body weight, the younger age groups were more likely to have higher exposures than the older age groups.
It is not surprising to note that the primary sources of the exposures were traced to expected food culprits such as:
- Processed foods – such as crackers, chips and french fries – were the primary source of acrylamide.
- Fish was the primary source of arsenic and mercury exposures.
- Pesticide exposure was particularly high in fruits and vegetables, including tomatoes, peaches, apples, peppers, grapes, lettuce, broccoli, strawberries, spinach, pears, green beans and celery.
- Dairy and meat products contained other pesticides such as chlordane, DDE and PCDD/Fs.
Results from the study showed that milk was the leading dietary contributor of exposure to POPs (persistent organic pollutants) for all age groups with animal foods and produce items making up the next four leading contributors.
Although the study did not focus on health effects, health effects from these chemicals could be significant. For instance, exposure to acrylamide may induce neuromuscular effects. Lead exposure can damage the nervous and reproductive systems and is thought to be harmful at any level. Pesticides have known cancer risks, neurotoxicity and reproductive effects.
Researchers Suggest Ways to Lower Exposure
- Reduce acrylamide exposure by avoiding or limiting highly processed foods – such as cereals, crackers, cookies, potato chips and French fries.
- Eat organic produce and drink organic milk when possible to reduce pesticide exposures.
- Thoroughly wash non-organic fruits and vegetables to reduce pesticide exposure.
- Decrease meat and dairy products to reduce exposures to persistent organic pollutants, since these chemicals accumulate in fats and can biomagnify in the food chain.
- When selecting fish, choose varieties low in methyl mercury – such as catfish, salmon and scallops – in place of varieties with high levels – including shark and swordfish.
Contaminants in the participants’ blood or urine were not measured. Instead, the exposure estimates were based on self-reports and national databases for chemical exposures. The study did not measure health-related effects in the participants. Instead, health risks were evaluated based on known effects and their estimated exposure levels through food.
The authors suggest “further studies are needed to understand the synergistic effects of exposure to multiple dietary toxins, the variability of cumulative dietary toxic exposure – particularly among young children – and the best approaches to limiting exposure to multiple compounds and from multiple routes.”