Questions are based on the following passage.
Is It Worth Eating an Organic Diet?
[A] Sales of organic food have been rising steadily over the past decade, reaching almost $30billion in 2011, or 4.2% of all U.S. food and beverage (饮料) sales, according to the OrganicTrade Association. Many of the consumers who purchase these products say paying morefor organic produce, milk and meat is a trade-off(权衡) they are willing to make in order toavoid exposure to chemical pesticides and fertilizers and milk from cows given bovine growthhormone (牛生长激素). Some experts say common sense should tell us that food grownwithout the help of synthetic chemicals is probably safer and healthier to consume than foodcontaining those substances, even in trace amounts. They believe Americans should try tosubstitute organic products for conventional ones whenever possible.
[B] However, other families, especially those whose food budgets may be more limited wonder iforganic food is really worth its hefty (异常大的) price tag. Other experts point out that thereisn't enough scientific evidence to say for sure that eating organic food leads to better health.As such, they say the most important dietary advice they can give Americans is to eat morefresh fruit and vegetables and less processed food.
[C] Alex Leo, associate professor of environmental exposure biology at the Harvard School of PublicHealth, argues for eating more organic food. Janet H. Silverstein, a professor of endocrinology (内分泌学) at the University of Florida and a co-author of an American Association of Pediatrics (儿科学) study on the health benefits of an organic diet, takes the skeptic's (怀疑者的) view. So far,researchers haven't been able to provide them with a definitive answer.
[D] Is there definitive scientific proof that an organic diet is healthier? "Not yet," said Leo. Robustscientific studies comparing food grown organically and food grown conventionally don'texist, thanks to a lack of funding for this kind of research. "The lack of definitive evidencecombined with the higher price of organic food has given skeptics a golden opportunity toargue that organic isn't worth the cost and effort," he added.
[E] While studies in recent years have delivered a decidedly mixed message about thehealthfulness of organic food, those on both sides of the debate generally agree that organicproduce typically contains fewer pesticides than conventional produce, and that people maybe able to reduce or eliminate agricultural chemicals from their bodies by adopting an organicdiet. This was illustrated in a study published in the journal Environmental Health Perspectivesin 2006. That study, which was led by Leo, showed that within five days of substituting mostlyorganic produce for conventional produce in children's diets, pesticides disappeared from thechildren's urine ( 尿液).
[F] Many say the pesticides found in our food are nothing to fear because the levels fall well belowfederal safety guidelines and thus aren't dangerous. Similarly, they say the bovine growthhormone used to increase cows' milk yield is perfectly safe. But federal guidelines don't take intoaccount what effect repeated exposure to low levels of chemicals might have on humans overtime. And many pesticides were eventually banned or restricted by the federal government afteryears of use when they were discovered to be harmful to the environment or human health.
[G] Pesticides, in particular, are made to kill organisms, and the President's Cancer Panel in 2010made clear that it sees them as a threat, advising Americans to "reduce their cancer risks bychoosing, to the extent possible, food grown without pesticides or chemical fertilizers."
[H] Recent field studies showed that organic produce, such as strawberries, leafy vegetables andwheat, not only tastes better but contains much higher levels of phenolic acids (酚酸) thanconventional produce. Phenolic acids can prevent cellular damage, and offer some protectionagainst oxidative stress ( 氧化应激), inflammation (炎症) and cancer.
[I] Yes, organic food typically costs more and can be harder to find than traditional food, but onecould argue that the price of conventional food is artificially low because of all the subsidiesthat organic farmers don't get and that the government could do more to help organic farmerslower their costs. Nevertheless, when bought in season, organic produce is often comparable inprice to conventional produce.
[J] A good strategy for consumers on limited budgets is to buy the organic versions of foods on theEnvironmental Working Group's "Dirty Dozen" list, as they typically contain the most pesticides.Or, consumers could focus on buying the organic versions of the foods they eat most. Knowingthat we could reduce our exposure to pesticides and increase our exposure to antioxidants ( 抗氧化剂 ) by eating organic food, it makes great common sense to consume more of it.
[K] Organic food is more expensive than conventional offerings, which could make it costprohibitive for families on limited food budgets. Given the lack of data showing that organicfood leads to better health, it would be counterproductive to encourage people to adopt anorganic diet if they end up buying less produce as a result. If families can afford to buyorganic and still put a good amount of healthy food on the table, then the decision aboutwhether to spend the extra money on organic produce, milk and meat should be based on asolid understanding of what we do and don't know about the benefits.
[L] It is difficult to compare the nutritional value of organic versus conventional food because thesoil, climate, timing of harvest, and storage conditions all affect the composition of produce.Still, published studies have found no significant differences in nutritional quality betweenorganic and nonorganic produce or milk. Similarly, there is no evidence that giving bovinegrowth hormone (BGH. to cows changes the composition of milk or affects human health.BGH is inactive in humans and degrades in the acidic environment of the stomach. As forpesticide exposure, the U.S. in 1996 established maximum permissible levels for pesticideresidues (残留) in food to ensure food safety. Many studies have shown that pesticides levels in conventional produce fall well below those guidelines.
[M] While it's true that organic fruits and vegetables in general contain fewer traces of these chemicals,we can't draw conclusions about what that means for health as there haven't been any long-termstudies comparing the relationship between exposure to pesticides from organic versus nonorganicfoods and adverse health outcomes. It may seem like "common sense" to reduce exposure to thesechemicals, but there are currently no good evidence-based studies to answer the question.
[N] While awaiting definitive studies, families on limited budgets who are concerned aboutpesticide exposure can refer to the Environmental Working Group's list of the "Dirty Dozen,"those foods with the highest pesticide residues, and the "Clean 15", the foods with the lowestpesticide concentrations. A good strategy would be to focus on buying organic versions of thefoods on the "Dirty Dozen" listing.
[O] We would like to think that organic food is grown locally, put in a wheelbarrow (独轮手推车) and brought directly to our homes. However, much of it comes from countries whereregulations might not be as tightly enforced as in the U.S., and labeling of the foods mightbe misleading. And just because food is labeled organic doesn't mean it is completely free ofpesticides. Contamination can occur from soil and ground water containing previously usedchemicals, or during transport, processing and storage. Organochlorine insecticides (有机氯杀虫剂) were recently found in organically grown root crops and tomatoes even though thesepesticides haven't been used for 20 years.
Food marked organic may contain pesticides as well.