A couple of recent news stories are causing concern about chemical exposure from foods that we would normally consider healthy. How does this affect your food choices?
A couple of recent news stories are causing concern about chemical exposure from foods that we would normally consider healthy. How does this affect your food choices?
Related listening:
What’s the Difference between hazard and risk? (Nutrition Diva #355)
Mentioned in this episode:
Produce Without Pesticides. (Consumer Reports)
Patterns of Seafood Consumption Among New Hampshire Residents Suggest Potential Exposure to Per- and Polyfluoroalkyl Substances. (Exposure and Health)
Public Perceptions of Pesticides & Produce Consumption. (IFIC)
Preventable Cancer Burden Associated With Poor Diet in the United States (JNCI)
Hello and welcome to the Nutrition Diva podcast, a show where we take a closer look at nutrition news, research, and trends so that you can make more informed decisions about what you eat. I’m your host, Monica Reinagel.
In the past couple of weeks, two well-publicized studies are causing some concern about chemical exposure from foods that we would normally consider healthy. But I think the media coverage may have created a somewhat distorted impression. In both cases, the risks are presented without important context that allows you to weigh the comparative risks and benefits.
The first was a Consumer Reports study on pesticide residues in commonly eaten produce. Approximately 20% of the 59 types of commonly eaten fruits and vegetables analyzed were found to pose a risk of exposure to potentially unsafe levels of pesticide residues. Organic produce generally showed significantly lower levels of pesticide residue. However, even some organic items were found to contain residues of pesticides not approved for organic farming. Imported produce, particularly from Mexico, posed higher risks compared to U.S.-grown produce.
However, it should be noted that the Consumer Reports investigators set their own standards for safety and, as a result, exposure levels that the Environmental Protection Agency considers to be safe were categorized as risky. Furthermore, a vegetable was deemed to be high risk even if only a tiny proportion of samples were found to have what CR deemed to be unsafe levels.
The other study was much more narrow, both in its scope and in its findings. Investigators were looking at levels of PFAs (popularly known as “forever chemicals”) in seafood available for purchase in the state of New Hampshire . Based on their samples and analysis, the researchers concluded that residents of the Granite State who eat shrimp and/or lobster several times a week could potentially be exposed to concerning levels of PFAs.
On the one hand, I think both of these studies demonstrate the need for ongoing monitoring and action to ensure a safe food supply. And, hey, if you live in New Hampshire and you’re cracking lobster claws Monday through Friday, week after week, you might want to mix it up a bit.
But, what do these findings really mean for the rest of us? Should be we altering our food choices to reduce our risks? And here’s where I think the media did not do a great job in putting these findings into context (probably because that wouldn’t have been quite as click-worthy).
First, we need to understand the differences between hazards, risks, and adverse outcomes.
A hazard is simply the presence of an element that in the right conditions and circumstances could cause harm. A sharp knife is a cutting hazard, for example.
When we talk about risk, we start to take into account the conditions and circumstances in which this hazard exists, in order to estimate the chances that it might actually cause harm. A sharp knife balanced point up in the dish drain poses a much bigger risk than a sharp knife resting in a knife block inside of a closed drawer. But in both cases, the knife presents the same hazard.
Hazards and risks are not the same as adverse outcomes. An adverse outcome would be that I actually slice my finger on the knife sticking out of the dish drain. This outcome is not guaranteed to happen. I could walk by that dish drain without cutting my finger. But the position of the knife, point up in the dish drain, increases the likelihood (or, risk) of that adverse outcome occurring.
Other unrelated factors could further increase the risk of that adverse outcome occurring. If the lights are out in the kitchen, for example, that might increase the chances that I cut myself on a knife that is sticking out of the dish drain. I can reduce my risk by turning on the lights before I enter the kitchen…but not to zero. The knife still poses a hazard and its position in the dish drain still presents an elevated risk. But risk is just a statistical likelihood. It does not predict the future.
OK, with that somewhat silly illustration of hazard, risk, and outcomes in mind, let’s go back to these two studies.
Both of these studies started by detecting the presence of a hazard–a compound that could pose a health threat if you were exposed to sufficient amounts of it. They then went on to use different types of statistical modeling to try to calculate the actual risk involved for people who ate various amounts of the foods in question.
In both cases, risks for the most typical eating patterns were minimal. It was only those who might consume large amounts of a small number of specific foods who might have a substantial risk. However, no adverse outcomes were observed–because these studies weren’t looking at outcomes, they were simply detecting hazards and calculating risks.
I’m not aware of any studies showing adverse outcomes as a result of consuming produce that might have contained pesticide residues, or fish that might have contained PFAs. Quite the opposite.
Fruits, vegetables, and seafood are are foods that we would normally consider to be healthy choices and would encourage you to eat. And reports like this can have a chilling effect on people’s willingness to eat these foods.
For example, in a recent nation-wide consumer survey conducted by the International Food Information Council, 4 out of 10 people said they avoiding eating certain fruits or vegetables due to fears of pesticide residues.
Before we decide that produce or fish are just too risky to eat, I think we need to look at the potential risks of not eating them. In general, consumers who worry about pesticide residues are afraid that exposure to these chemicals increases their risk of cancer. However, not eating these fruits and vegetables might pose a greater cancer risk.
Researchers writing in the Journal of the National Cancer Institute specifically looked at the impact of consuming produce on cancer risk, assessing both the risks associated with pesticide exposure and the cancer-protective effects of eating more produce. Here’s the bottom line: If you want to reduce your cancer risk you want to eat more produce–even though that produce may contain pesticide residues.
Similarly, while the risks of PFA exposure from high intake of shrimp and lobster affect a tiny slice of the population, the benefits of seafood consumption are far more universal--and available at much lower levels of consumption. People eating just one to two servings of fish per week can cut their risk of heart disease, stroke and all-cause mortality.
The safest level of PFAs or pesticides in the food supply would obviously be zero. And if there are steps that we can take, either individually or as a society, to reduce the amount of these chemicals in our food supply, that’s worth pursuing. Furthermore, I want to acknowledge that everyone’s tolerance for risk is different. Which means that people may come to different conclusions about how or whether they want to change their behavior based on a given risk assessment.
Here’s the point I want to make: When you assess your risk of an adverse outcome due to exposure to a hazard, such as pesticide residues, remember to balance that potential harm against the well-documented benefits that you get from those foods, and the increased health risks that you incur by avoiding them.
If you have a comment on today’s episode or a question you'd like me to answer, you can email me at nutrition@quickanddirtytips.com You can also leave me a message at 443-961-6206.
I’d also like to invite you to check out my other podcast. It’s called the Change Academy, where we explore the art and science of creating positive behavior change, both in our own lives, and in our workplaces and communities. You can find it on all the major podcast platforms. Just search for Change Academy.
Nutrition Diva is a Quick and Dirty Tips podcast and is supported by a fantastic team, which includes Brannan Goetschius, Nathan Semes, Davina Tomlin, Holly Hutchings, Morgan Christianson, and Kamryn Lacy.