Robert Paarlberg is the B. F. Johnson Professor of Political Science at Wellesley College and Associate at the Weatherhead Center for International Affairs, Harvard University. His new book, Food Politics: What Everyone Needs To Know, carefully examines and explains the most important issues on today’s global food landscape. Politics in this area have become polarized and Paarlberg helps us map this contested terrain, challenging myths and critiquing more than a few of today’s fashionable beliefs about farming and food. In the excerpt below we learn about the organic food.
Many who buy organic goods believe such foods are healthier than conventional foods because they contain more nutrients. Others believe organic foods are safer to eat because they carry no pesticide residues. Nutritionists and health professionals from outside the organic community tend to question both of these beliefs.
The strongest claim of superior nutrient content has been made by the Organic Center, an institution founded in 2002 to demonstrate the benefits of organic products. In 2008, the Organic Center published a review “confirming” the nutrient superiority of plant-based organic foods, showing they contained more vitamin C and vitamin E and a higher concentration of polyphenols, such a flavonoids. This review was rebutted, however, by conventional nutritionists who showed that the Organic Center had used statistical results that were either not peer reviewed or not significant in terms of human health. Organic milk from cows raised on grass may indeed contain 50 percent more beta-carotene, but there is so little beta-carotene in milk to being with that the resulting gain is only an extra 112 micrograms of beta-carotene per quart of milk, or less that 1 percent the quantity of beta-carotene found in a single medium-size baked sweet potato.
Most certified health professionals find no evidence that organic foods are healthier to eat. According to the Mayo Clinic, “No conclusive evidence shows that organic food is more nutritious than is conventionally grown food.” European experts agree. Claire Williamson from the British Nutrition Foundation says, “From a nutritional perspective, there is currently not enough evidence to recommend organic foods over conventionally produced foods.” In 2009, the American Journal of Clinical Nutrition published a study, commissioned by the British Food Standards Agency, of 162 scientific papers published in the past 50 years on the health and diet benefits of organically grown foods and found no evidence of benefit. The director of the study concluded, “Our review indicates that there is currently no evidence to support the selection of organically over conventionally-produced on the basis of nutritional superiority.” The acidity of organic produce was found to be higher, which enhanced taste and sensory perception, but there was no difference for health.
The claim that organic food is safer due to lower pesticide residues is also suspect in the eyes of most health professionals. The Mayo Clinic says, “Some people buy organic food to limit their exposure to [pesticide] residues. Most experts agree, however, that the amount of pesticides found on fruits and vegetables poses a very small health risk.” Residues on food can be a significant problem in many developing countries, where the spraying of pesticides is poorly regulated and where fruits and vegetables are often sold unwashed, straight from the field. Yet in advanced industrial countries, such as the United States, this risk is seldom encountered. In 2003, the Food and Drug Administration analyzed several thousand samples of domestic and imported foods in the U.S. market-place and found that only 0.4 percent of the domestic samples and only 0.5 percent of the imported samples had detectable chemical residues that exceeded regulatory tolerance levels.
What are the tolerance levels? The United Nations, through the Food and Agriculture Organization (FAO) and the World Health Organization (WHO), has established acceptable daily intake (ADI) levels for each separate pesticide. The ADI level is set conservatively at 1/100 of an exposure level that still does not cause toxicity in laboratory animals. Moreover, actual residue levels in the United States on conventional foods are well below the ADI level. For example, when FDA surveyed the highest exposures to 38 chemicals in the diets of various population subgroups, it found that for 4 of these 38 chemicals estimated exposures were less than 5 percent of the ADI level. For the other 34 chemicals, estimated exposures were even lower, at less than 1 percent of the ADI level. Carl K. Winter and Sarah F. Davis, food scientists at the University of California-Davis and the Institute of Food Technologies, conclude from these data, “[T]he marginal benefits of reducing human exposure to pesticides in the diet through increased consumption of organic produce appear to be insignificant.”
It is true that conventional foods are sometimes not safe to consume, but organically grown foods can also carry risks. In 2006, bagged fresh spinach from a California farm in its final year of converting to organic certification was the source of E. coli infections in the United States that killed at least three and sickened hundreds. In 2009, there were nine documented fatal episodes of salmonella poisoning from peanut butter and ground peanut products traced to peanut plants in Texas and Georgia, both of which had organic certification.