Ten chronic diseases are the leading causes of human deaths in industrialized countries. Five of these diseases—cardiovascular disease, stroke, cancer, type 2 diabetes, and hypertension—are associated with poor dietary choices and excess weight. The World Health Organization, the European Public Health and Agriculture Consortium, the U.S. Dept. of Agriculture, and other governing bodies and health organizations regularly publicize the health benefits of vegetables and fruits and the link between poor diets and poor health. As a consequence, consumers are well aware that daily meals consisting mainly of plant-based foods reduce or eliminate risk factors for chronic diseases. However, many consumers also are under the impression that organic vegetables and fruits are safer, more nutritious, and healthier for the prevention of chronic diseases. These notions are promoted by the organic food industry, its advocates, food marketers and writers, and even some physicians and scientists.
For example, a webpage for Rodale Inc.—publisher of Prevention magazine—declares, “The most harmful and deadly diseases plaguing America today are caused by food … and pesticides. But when you reach for whole, nutrient-dense, organic foods, you get a food-remedy tool kit that not only will ward off cancer and heart disease but also colds, flu, allergies, and a host of other ailments” (Rodale, 2011). The “All about Organics” section of the Organic Consumers Association’s website proclaims, “Organic foods ... contain higher levels of … health-promoting polyphenols, cancer-fighting antioxidants, flavonoids that help ward off heart disease, essential fatty acids, and essential minerals. Organic food doesn’t contain pesticides” (OCA, 2012). And the website for Organic Valley food products asserts, “Organic food and farming can help slow and potentially reverse the rising incidence of overweight, obesity, and diabetes through mechanisms that include … promoting healthy cell division and laying the groundwork for healthy endocrine, immune system and other metabolic development” (Organic Valley, 2012).
The biological, chemical, and physical reasons behind these claims seem logical and straightforward: Excess weight causes cells and tissues in the body to be in a perpetual state of inflammation, which is triggered by oxidative stress precipitated by free radicals. Studies have implicated oxidative stress and inflammation as contributing factors for many ailments, including cancer, atherosclerosis, hypertension, cardiovascular disease, and lung disease. This stress interferes with the body’s normal ability to deter cellular damage that causes chronic diseases. Also interfering with the body’s regular functioning are endocrine disrupting compounds (EDCs) such as synthetic pesticides and fertilizers. EDCs disturb normal functioning of glands and hormones and may have adverse effects during gestational development and on successive generations (PCP, 2010).
According to a comprehensive analysis of scientific studies by the American Institute for Cancer Research, a plant-based diet combined with physical activity and weight management could eliminate instances of cancer in the United States by one third (AICR, 2012). Besides determining that vegetables, fruits, and whole grains can reduce the risk of certain cancers, research also indicates that these foods diminish the risk of hypertension, type 2 diabetes, heart disease, and other chronic diseases linked to persistent inflammation resulting from excess weight and poor diets. Likewise, cultural studies indicate that societies such as Okinawans in Japan and Sardinians in Italy that consume diets consisting predominantly of fresh produce have very low incidences of chronic diseases (Willet et al., 2006; Iqbal et al., 2008). The protective benefit of vegetables and fruits is largely attributed to the micronutrients that are found exclusively in plants—although the high fiber content and low calorie density of plant foods receive some credit.
Vegetables, fruits, and grains are sources of phenolic phytochemicals, many of which are plant-based antioxidants that are perceived to combat inflammation and oxidative stress—the mechanisms that lead to numerous chronic ailments. Plants produce phenolic phytochemicals to protect themselves against the daily stressors they encounter during cultivation. Hence, antioxidants are essentially plants’ natural defenses against weeds, insects, pathogens, poor soil quality, and oxidative stress from photosynthesis. It thus seems logical to deduce that plants cultivated without the assistance of synthetic pesticides and fertilizers—such as organic vegetables and fruits—would naturally produce and retain higher contents of antioxidants and other nutrients than plants grown conventionally with the use of synthetic chemicals. Of course, for this argument to appear valid, proponents of organic food either ignore or minimize the fact that organic farmers can and do use natural pesticides to control crop diseases, weeds, and other pests.
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In concert with organic farming’s nonuse of synthetic compounds known to disrupt endocrine functions and cause tumors in rodents, the theoretical higher content of antioxidants of organic vegetables, fruits, and grains should therefore make them superior to conventionally grown produce in the battle against chronic diseases. Several research teams have investigated this theory. For example, researchers at the University of California at Davis ascertained that organic marionberries and corn contained 58% more antioxidants than their conventional counterparts (UC Davis, 2003). Similarly, the “Qualified Low Input Food” project coordinated by scientist Carlo Leifert and funded by the European Union determined that vegetables and fruits produced through organic methods had up to 40% higher levels of antioxidants due to the nonuse of synthetic fertilizers and pesticides (2009). And during a two-year study, researcher John Reganold and his colleagues at Washington State University found that organically grown strawberries had higher levels of antioxidants than conventionally grown strawberries (2010).
On the other hand, an abundance of research contradicts those findings; of this volume of studies, three are perhaps the most prominent. Six years ago, researcher Faidon Magkos and his Colleagues at Harokopio University determined that although organic vegetables and fruits contained fewer pesticide residues than conventional ones, the difference was statistically insignificant “as actual levels of contamination in both types of food are generally well below acceptable limits” (2006). A few years later, public health nutritionist Alan Dangour and his colleagues at the London School of Hygiene & Tropical Medicine reviewed 50 years of studies on the nutrition differences between organic and conventional crops and concluded that the nutritional contents of organic and conventional produce were essentially the same (2009). Shortly thereafter, Dangour and his colleagues completed a review of 98,727 studies comparing the health effects of organic and conventional foodstuffs; they subsequently determined that there was no clear and compelling evidence that organic food generated better health outcomes (2010).
Consequently, the widely held notion that organic produce contains higher levels of nutrients and antioxidants is either invalid or, at best, uncertain. Even if there were unequivocal evidence that organic foods really did have higher contents of antioxidants, the point would be irrelevant as it has become increasingly clear that antioxidants by themselves are not necessarily responsible for improved human health (Melton, 2006; Rosen, 2010). “A lot of what organic proponents call antioxidants plant physiologists call secondary metabolites,” says Alex Avery, a plant physiologist with the Hudson Institute and author of the book The Truth about Organic Foods. “Whether these compounds are actually beneficial to human health is still unclear. These ‘antioxidants’ could actually be harmful to our health,” he cautions. While many epidemiological studies have consistently associated high intakes of antioxidant-rich plant foods—organic and conventional—with decreased incidence of chronic diseases, other studies have concluded that supplements of individual antioxidants such as beta carotene, vitamins C and E, selenium, and lycopene offer no protective benefits against disease and, in some cases, may even have deleterious effects on health (Halliwell, 2007; Bjelakovic et al., 2007, 2008; Briançon, 2011). “Study participants actually fared worse than those taking placebo—enough worse that [researchers] halted the studies immediately to protect the health of the participants,” Avery points out. (Nevertheless, this fact has deterred neither food manufacturers from fortifying foods with antioxidants nor food marketers from touting the benefits of such products.)
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The alleged health hazards of all synthetic pesticides used to cultivate conventional crops are also unlikely. Research performed by scientists at the University of California at Berkeley (UC Berkeley) indicates that humans consume far more natural pesticides and chemicals—such as those intrinsic to vegetables, fruits, and alcoholic beverages as well as those produced by cooking French fries and meat—than synthetic pesticides. According to their findings, less than 1% of the dietary chemicals humans consume are synthetic pesticides (Gold et al., 2001; Ames and Gold, 2003; CPDB, 2008). Even more surprising is the fact that more than half of naturally occurring pesticides and chemicals qualify as carcinogens when subjected to the same testing standards as synthetic pesticides (Gold et al., 2005; CPDB, 2008). After all, if plants naturally produce phytochemicals that are toxic to insects and other pests, then it stands to reason that these natural compounds could be toxic to larger animals such as laboratory rodents and humans.
Bruce N. Ames, a biochemist with Children’s Hospital Oakland Research Institute and co-founder of the Carcinogenic Potency Database at UC Berkeley, reasons that greater emphasis should be placed on consuming more vegetables and fruits regardless of how they were cultivated. “People think cancer is due to some external toxin. The focus on synthetic pesticides diverts people from the real problems,” he says. “The really important [risks] are smoking and poor diets. Obesity is a complete disaster in terms of health; every possible disease is linked to it. As a source of what causes poor health, pesticides would be way down at the bottom of the list. Why worry about a part per billion of pesticide? It’s just way too small to worry about. If we spend all our time chasing after a thousand minor hypothetical risks, we’re lost.”
Carl Winter, a food toxicologist and professor at the University of California at Davis, has a similar perspective. “The first principle of toxicology is that everything is toxic at a high enough dose.In other words, the dose makes the poison. Those consuming organic produce may lower their exposure to pesticide residues but not by much,” he says. “[U.S.] organic farmers are allowed to use pesticides as long as the chemicals are approved by the National Organic Standards Board. In most cases, [biopesticides] are naturally occurring chemicals,” Winter says, “but they still follow the basic principle of toxicology: the dose makes the poison.” Avery points out that biopesticides must be applied to organic crops much more frequently than synthetic pesticides. For example, “The natural pesticide pyrethrin breaks down so quickly in the environment that it loses its effectiveness; organic farmers thus have to apply it far more frequently than conventional farmers using synthetic pyrethroids,” he says.
Turning conventional wisdom on its head, Ames strongly believes that eliminating synthetic pesticides from agriculture and relying solely on organic farming techniques would be counterproductive. “There are no reliable epidemiological studies linking synthetic pesticides to higher rates of cancer. And if [farmers] stop using pesticides, vegetables and fruits will become much more expensive. That will cause people to eat even less [fresh produce], and rates of cancer would likely soar—especially among poor people,” he says. “I’ve come to the conclusion that it’s not what we’re adding to food that’s problematic but what we’re leaving out or removing from food that’s leading to problems. So you can buy organic food if you want to pay 50% more, but it’s not going to be better for your health.”
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Taste and Sustainability
Avery dispenses comparable advice: “Consumers should just buy the best cost-effective produce. They don’t need to buy only local or organic produce because sometimes the conventional items
may be fresher. Instead of shopping out of fear, they can purchase vegetables and fruits based on the quality of produce [as determined by] appearance and smell.” Even writer and food industry critic Michael Pollan doesn’t eat organic produce exclusively. “[T]here are exceptional farmers and ranchers in America who for one reason or another are not certified organic and the food they grow should not be overlooked,” he states on his website. “Organic is important, but it’s not the last word on how to grow food well. I think eating vegetables and fruit is so important that I buy them even when they’re not organic—and even when they’re not fresh” (Pollan, 2010).
“The health risks are much more pronounced from not consuming enough fruits and vegetables,” Winter adds. “On the whole, food tends to taste better if it is grown locally, ripe, and eaten as soon as possible after harvesting. I haven’t seen any real good data that organic produce tastes better than conventionally grown produce.” And while the taste of organic produce is subjective, its potential for global sustainability is not. “Organic farming is sustainable for a population of about 2 to 3 billion people. It is not sustainable for a world of nearly 7 billion people, which is where we are now,” Avery says. “We don’t have enough land for organic crop rotation that could feed the world. We could possibly do it if we drastically cut our consumption of poultry and meat because there would be land available from not raising food animals.”
Therefore, it seems that organic produce is not more nutritious or otherwise healthier than conventional produce—it’s just more expensive. The alleged superior health-engendering effects of organic vegetables and fruits cannot be claimed on the basis of dubious higher levels of antioxidants or the nonuse of synthetic chemicals. In fact, antioxidants themselves may not be solely responsible for improved health outcomes, and numerous natural compounds can be as toxic as man-made chemicals. The blueprint for good health lies in the combined effect of all the known and unknown phytochemicals present in plant foods regardless of whether they are organic or conventional. So those who buy and consume conventional produce can take comfort in knowing that the main factors affecting the nutritional content and health-engendering effects of vegetables and fruits are freshness and degree of processing, not farming techniques and pesticides. And those who buy and consume organic produce should use other justifications such as environmental concerns (e.g., water quality issues), support of local farmers, safety of farm workers, and uncertainties about genetically modified foods.
Toni Tarver is Senior Writer/Editor for Food Technology magazine ([email protected]).
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