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Hey toxicologists, is organic food safer to eat?

By Michael L. Dourson, PhD., DABT, FATS, FSRA

Pick just about any newspaper or journal and during the course of a year, one or more articles will be devoted to the benefits (or not) of organic foods and the downsides (or not) of conventionally grown food with pesticides and herbicides. These articles are often confusing. 

So how does one sort them out?

Food, whether organically or conventionally grown, is a combination of chemicals, many of which our bodies need in order to function well. Organic food comes from plants grown without added antibiotics or growth hormones, pesticides, herbicides or genetic modification , whereas conventionally grown food may use one or more of these products.

However, not all chemicals in food are useful to our body, and some of them are harmful at a certain level, like too much aflatoxin—a natural fungal product—in peanut butter. And did you know the plants we grow for food naturally produce pesticides and herbicides to protect themselves from insects and weeds? Any gardener who has tried to grow tomatoes near a walnut tree can tell you this is true—the walnut tree’s roots produce a herbicide that is poisonous to tomato plants. The use of pesticides and herbicides, whether human-made or natural, often results in small levels of these chemicals in our food.

Genetic modification (GM) of a food crop, whether done in the lab or through traditional crossbreeding, is often one way to get the crop to develop a new pesticide or herbicide, or to increase the level of an already existing natural one. Such modification may also give the crop a way to resist damage by a human-made herbicide. So corn can be genetically modified in the lab to make a protein to protect it against insect damage and at the same time to resist damage by human-made herbicides used to kill weeds. The use of GM corn with both of these traits is popular because it not only increases yields, but also reduces plowing, soil erosion, and use of conventional pesticides and herbicides. Of course, corn has been genetically modified through traditional crossbreeding for years to increase yields and resist pests.

So now to the question! Is organic food safer to eat? Or perhaps, are the small levels of pesticides, herbicides and genetic modifications in our food, whether human-made or natural, harmful? 

Many organizations work on a daily basis to answer this latter question. In fact, tens of millions of dollars are spent by competing industries on appropriate experimental animal and exposure studies. These studies then are reviewed by toxicologists to establish safe levels. These levels are then compared with the anticipated exposures when the pesticide, herbicide or genetic modification is used according to its label. If the anticipated exposures are below the safe levels, then the uses are permitted and the small levels of these chemicals in our food are not harmful. Although such testing is generally not done on naturally occurring plant chemicals, human experience would suggest that exposures to many of these naturally occurring pesticides, herbicides or genetic modifications are also below safe levels, and thus, are also not harmful.

When comparing organic versus conventional methods of growing food, other issues may be important. For example, organically grown foods may better maintain a sustainable farm practice, may reduce unanticipated environmental impacts of a human-made pesticides, herbicides or genetically modified plants, and would reduce accidental and often demonstrated harm to workers from over exposure to these chemicals. However, organic farming generally needs extra plowing so soil erosion is increased when compared with conventional farming. And while eating organic foods has been demonstrated to lower consumer exposure to some human-made pesticides and herbicides, insect damage from unprotected plants can cause natural pesticides and herbicides to increase. Additionally, there is no strong evidence that organic foods are significantly more nutritious than conventional foods.

A Google query entitled “organic and conventionally grown foods, including GM foods” will yield many websites, many of which were judged by the scientific staff of Toxicology Excellence for Risk Assessment (TERA) as too biased, not credible, or non-related. However, some sources appear to of unbiased, credible and related. For example, nutritional content of food grown by either method does not appear to differ. Other sources can be accessed to answer numerous other questions.

Forman J. and J. Silverstein. 2012. Organic Foods: health and environmental advantages and disadvantages. Pediatrics: 2012-2579. October 22.

Jason J. Hlywka , Gerald R. Stephenson , Mark K. Sears , Rickey Y. Yada. 1994. 
Effects of insect damage on glycoalkaloid content in potatoes (Solanum tuberosum). J. Agric. Food Chem., 42 (11), pp 2545–2550.

WEEL OEL

Occupational Exposure Limits (OELs) are designed to safeguard the health of healthy workers during their careers. These limits are based on the assumption of repeated daily exposure throughout a working lifetime, typically averaged over an 8-hour workday. Their purpose is to prevent both immediate (acute) and long-term (chronic) health issues arising from workplace exposures. It’s important to note that OELs are not intended for the general public, which includes vulnerable groups like infants, the elderly, and those with pre-existing health conditions.

Workplace Environmental Exposure Levels (WEELs) are health-based guidelines for chemical hazards in the workplace. These values represent air concentrations believed to protect the majority of workers from negative health effects resulting from occupational chemical exposure.

The WEEL Process
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The development of new or revision of existing WEELs is typically assigned to voluntarily designated subcommittees. A subcommittee usually comprises 3 – 4 members from the WEEL Committee. New WEELs are developed using the OARS-WEEL administrative standard operating procedure (SOP), while existing WEELs are usually revised every 10 years, unless the availability of significant new data which may impact the existing WEEL value compels the committee to make a revision sooner. The OARS-WEEL SOP contains procedures and guidelines governing conflicts of interest, draft document preparation, literature searches, draft document review, balloting process, post-ballot WEEL documentation quality assurance scientific review, and publication.

Once a subcommittee has prepared a draft WEEL document, a review of the draft is scheduled for the next available Committee meeting. The WEEL Committee members are expected to have reviewed all such drafts prior to the meeting. If no major changes are necessary to a draft, the attending Committee membership may, by a simple majority, approve the WEEL for balloting. Alternatively, the Committee may direct the subcommittee to revise the WEEL and present it for further discussion at a future meeting. If a ballot is not approved by a two-thirds majority of non-abstaining Committee members, it is discussed at the next Committee meeting to determine the appropriate course of action. Once the WEEL is approved by a two-thirds majority of non-abstaining Committee members, copies of ballot comments are forwarded to the designated subcommittee and all substantive comments must be addressed in the final draft. If resolution of a substantive comment results in a change to the WEEL value or a change in the basis for the value, the draft must be re-balloted.

Once all comments have been addressed on a successfully balloted draft, document formatting and editorial review are performed by TERA, before the draft WEEL document is made available for public comment (usually for a period of 30 days but may be extended if the need arises). After the public comment period has elapsed, comments are addressed by the subcommittee responsible for that specific draft, after which the WEEL documentation is submitted to Toxicology and Industrial Health (TIH), a peer-reviewed medical journal that covers research in the fields of occupational health and toxicology, for publication. A thorough review of the galley proof by the scientific content quality coordinator at TERA, and proofreaders and editors at TIH is the penultimate step before eventual publication of the WEEL documentation.

The WEEL Committee

The OARS-WEEL Committee is composed of volunteer experts specializing in the scientific determination of occupational exposure levels. This committee actively seeks a balanced representation of professionals from toxicology and industrial hygiene, drawing upon a diverse range of experience from industry, government, academia, and consulting. Importantly, each member contributes to the Committee based on their individual expertise and not as an official representative of their respective employer, organization, or agency.