Prescriptions: Beware the Seductive Strawberry

The Clinic is an ongoing collaboration between the Program on Reproductive Health and the Environment at UCSF, Mission Loc@l and UC Berkeley’s Graduate School of Journalism. Prescriptions is a blog about health written by scientists at the Program on Reproductive Health and the Environment at UCSF.

As a child growing up in the 1960s, even middle-class families considered strawberries a pricey, seasonal luxury. In fact, I was happy to have strawberry jam with my peanut butter sandwiches. When I was lucky enough to taste a fresh strawberry, my tastebuds contracted with intense ecstasy and wanted more. Nowadays, super-sized strawberries are practically year-round and plentiful. No longer modest and consumed in one bite, they are garish and grandiose, even tawdry and tarnished. Beautiful to behold and giving the illusion of wealth, modern-day strawberries may promise more risk than taste, research shows.

Just to set the record straight, I am not against progress.

But as a physician, I have been trained to consider and weigh the risks and benefits of decisions. How do we balance the economic viability of the $2 billion strawberry industry with the potential health risks to our children of the chemicals used to grow conventional strawberries? Are strawberries the poster child for what may be wrong with our current industrialized food system?

The answers lie in examining the extensive use of especially dangerous and numerous pesticides to produce the majority of strawberries in the marketplace. More than 2.1 million acres of California strawberry fields were treated with more than 9.8 million pounds of pesticides in 2008. Pesticides’ adverse effects are not limited to the pests they target. Even low levels of some pesticides have been shown to disrupt human hormonal, neurological and immune functioning. Because of their underdeveloped detoxifying mechanisms and other factors, the most vulnerable humans are the developing fetus, babies and children.

Early development and life exposures to certain pesticides have been linked to birth defects, childhood leukemia, neurodevelopmental problems such as ADHD, adult cancers and Parkinson’s disease. Serious human health effects are very real for those whose lives are affected and forever changed. What makes conventionally grown strawberries sold in the Mission and elsewhere cheap comes at a cost for the people who work in the fields, live or attend school nearby, breathe the local air or drink the water from affected aquifers, and for consumers who eat these favored but fouled fruit.

Fumigants, designed to sterilize the soil before planting, are the most common class of pesticides used with strawberry production.  The fumigant methyl bromide is being phased out because it harms the ozone layer. Incidentally, agricultural health studies have found an association between methyl bromide exposure and risk of prostate cancer, so it is a good thing to have it retired. However, the decisionmakers of the California Department of Pesticide Regulation have decided to replace it with methyl iodide, a known carcinogen, and thyroid and nervous system disruptor, as well as a chemical that causes mammalian miscarriage. They say it will be safe to apply under stringent usage protocols. This decision, however, flies in the face of the agency’s own scientific advisory committee that considered health risks of methyl iodide.

Six Nobel scientists also consider methyl iodide to be an extremely dangerous chemical and opposed its registration by the Bush administration’s U.S. Environmental Protection Agency. High-level industrial exposures have caused brain and nervous system dysfunction. Recent groundwater and air testing one year after methyl iodide was applied to fields in Sarasota, Florida, revealed that groundwater had over twice the level of iodine found in seawater, six times the level found in average freshwater, and 150 times the level normally found in that area of Florida. The same Florida studies show that methyl iodide is not fully contained by the tarps that cover the fields, and that air levels of the chemical exceeded those deemed safe by scientists advising the California Department of Pesticide Regulation.

There are colossal public health downsides to reliance on the present system of intensive use of pesticides, including methyl iodide, for strawberry production. However, right now the public policies that drive what ends up in the stores along Mission Street and elsewhere across the state fail to favor the less toxic methods that don’t poison the air, contaminate the water table or deplete the soil. The farmers markets and stores in the Mission that carry organic fruits and vegetables are helping consumers vote for their health with their hard-earned dollars. Organic strawberries have been shown to be tastier, more nutritious, and have a longer shelf life. But in the short term, organic produce is a more costly option, and public policy needs to make food grown without toxic chemicals available at a price everyone can afford. In the end, buying cheaper, non-organic strawberries is not a good deal for us now or a good investment for future generations.