Photos by Leigh Beisch

By choosing organic versions of the foods you eat most often, you're not only reducing your own pesticide exposure, you're also voting with more of your food dollars.

In an ideal world, we'd always eat fresh, healthy, organic food. All things being equal, I know I'd choose certified organic for my family every time. But sometimes I find myself waffling before a splashy display of conventionally grown strawberries on sale and a bin of picked-over organic ones. How do I weigh the healthiest choices for my family—and the planet? Because ultimately we can't very well protect the former without the latter.

To help make choices while shopping, I carry along a printout of the Environmental Working Group's (EWG) "Dirty Dozen", the 12 fruits and vegetables with the highest levels of pesticide residue, and a list of the cleanest 12—generally the healthiest conventional choices to make when necessary (see "Is Your Produce Packing Pesticides?").

Avoiding pesticide residues is a great place to start. But it seems like the big picture keeps getting bigger. What about growth hormones and antibiotics? Or genetically modified foods? (None are allowed in certified-organic foods; see "Organic Labels, Decoded") And are organic foods actually more nutritious? Which crops are most harmful to our planet? To get some answers—and the latest research—I called on experts. Here's what I learned.

Whenever you buy organic milk, you're casting a powerful vote to help transform an entire agricultural system. Organic cows eat organic feed and graze on pasture during the growing season. Voilá, you just reduced the use of pesticides and chemical fertilizers on millions of acres of worldwide farmland dedicated to growing livestock feed.

At home, you're avoiding pesticide residues. This is especially important for young children, who generally drink a lot more milk in relation to their body weight, and whose developing bodies are particularly vulnerable to toxins. In 2004, when the USDA's Pesticide Data Program began testing milk with more sensitive equipment, it found worriesome pesticide residues in all 739 samples.

With organic milk, you're also saying no to bovine growth hormone, rBST or rBGH, the effects of which have not been adequately studied. Ditto for the routine use of antibiotics, which scientists warn will lead to treatment-resistant bacteria.

Some initial research also has found that on average, organic milk contains more omega-3 fatty acids (essential for heart, brain, and cardiovascular health) when compared with conventional milk (Journal of Dairy Science, 2006, vol. 89, no. 6). However, the body of research on whether, overall, organic foods are more nutritious remains small; many more studies are needed to confirm these and other early positive outcomes.

Ask for organic milk at your kids' schools and favorite restaurants.

Like organic dairy, buying organic beef helps change a whole system and an inefficient one at that. To add just 1 pound of cattle weight, it takes about 7 pounds of corn (according to the late food geographer Georg Borgstrom) and nearly 2,500 gallons of water, per a widely cited report from Sacramento's Water Education Foundation. Eliminating pesticides—as well as overused antibiotics—from that equation is a smart beginning.

At the 2005 international congress on Organic Farming, Food Quality, and Human Health, Newcastle University agriculture professor Carlo Leifert, PhD, testified that grass-based organic cattle diets reduce the risk of E. coli contamination, whereas grain-based conventional diets increase the risk. Some initial research also suggests that eating grass-fed beef may be healthier than conventional beef because it's generally leaner and is a richer source of omega-3 fatty acids (Journal of Animal Science, 2002, vol. 80, no. 5).

To learn about sustainable ranches near you, log on to and search according to your ZIP code.

If you can pick only one organic fruit, apples may be your best choice. They're Americans' second-most loved fresh fruit (after bananas). Unfortunately, they also rank the second highest on pesticide-contamination lists, after peaches.

Apple orchards commonly are sprayed with organophosphate pesticides, nerve agents that studies link to decreased intelligence and increased attention problems in children (Pediatrics, 2006, vol. 118, no. 6). "Apples appear regularly in the cafeteria of every North American school," says Ronnie Cummins, national director of the Organic Consumers Association." It's unbelievable they haven't made the switch." According to EWG analysis of USDA and FDA data from 2000 and 2004, more than 93 percent of conventional apples tested positive for pesticide residues. One out of every eight times a child under age 6 eats an apple, the group estimates, he exceeds the Environmental Protection Agency's reference dose for organophosphates.

In taste tests, organic apples score higher—and preliminary findings, such as those presented by Warsaw Agricultural University researchers at a food and farming conference in Germany last spring, indicate they may be higher in phenols, flavonoids, and vitamin C.

Although conventional apples rank high in pesticide residues, apple juices tend to rank lower, according to a 2000 Consumers Union report.

Potatoes are truly an all-American staple. Not only do white potatoes account for almost a third of all vegetables consumed by adults, they also are the top vegetable eaten by children. And most often, these beauties are enjoyed as—you guessed it—french fries.

Although they're sprayed above ground, potatoes growing underground absorb the toxins. To avoid mold growth during storage, they're often sprayed again with fungicides, which can disrupt endocrine systems. "White potatoes have the highest average pesticide load after washing and peeling than any other fruit or vegetable," says Alan Greene, MD, of Stanford's Lucile Packard Children's Hospital, noting they are the only peeled item to make the EWG's Dirty Dozen list. A recently published review also found" moderately strong and consistent data" supporting that organic potatoes are richer sources of vitamin C than conventionally grown potatoes (Nutrition Journal, 2007, vol. 32, no. 2).

Sweet potatoes are more nutritious than white potatoes—and generally have fewer pesticide residues. Try slicing them and tossing in olive oil, salt, and pepper, and baking at 400 degrees until crispy—yum!

It's hard to mention french fries without ketchup—and why not, when organic ketchup is such an easy, healthy switch? (Yes, it still contains sugar but generally in smaller amounts.) A 2004 USDA study found that on average, organic brands packed in as much as 57 percent more lycopene (a potent antioxidant) than conventional brands (Journal of Agriculture and Food Chemistry, vol. 52, no. 26). Just eyeballing the two bottles gives you a visual clue: Organic varieties tend to be a deeper red color, indicating higher lycopene levels.

This is a high-impact choice because ketchup is America's most used condiment, especially by kids. (Remember Ronald Reagan's bid to get the stuff categorized as a vegetable on school menus?)

While you're at it, consider switching to organic pasta and pizza sauces.

At the time you bite into a fresh ear of conventional corn, it has one of the lowest levels of pesticide residues. Unfortunately, it left plenty of chemicals in its wake. Because the United States grows so much of it, corn is our top polluting crop and the biggest user of pesticides and chemical fertilizers, the runoff of which contaminates rivers and streams. Corn also is one of the most genetically modified U.S. crops: More than half the corn planted in 2006 was genetically engineered (see "Why worry about GMOs?").

Most often, we eat corn not fresh from the cob but as an incognito ingredient in sodas, baked goods, and snack foods.

Avoid GMOs by opting for an organic product when you see the following terms on an ingredient list: corn syrup, high-fructose corn syrup, corn sweetener, dextrose, glucose, cornstarch, modified cornstarch, vegetable starch, corn solids, or corn oil.

Behind corn, soy is the biggest source of pesticide contamination in our countryside. According to USDA data, it's the domestic crop most contaminated with controversial organophosphate pesticides. Soy also leads the pack in genetic modification: 89 percent of the U.S. crop, and growing.

"A lot of people don't think they eat soy, or eat very little soy," says Greene. "But the great majority of soy consumption in the United States is not in what would be identified as a soy product." Most of the U.S. soy crop is crushed into soybean oil—some of which is partially hydrogenated (think trans fat)—that makes its way into chips, cookies, crackers, and even infant rice cereal.

Look for organic soy products, such as soy milk and veggie burgers, made from organic whole soybeans.

"This one surprises people," Greene says. "Most of us don't realize that about two-thirds of the cotton crop actually goes into the food supply in the form of cottonseeds that are made into oil. "

Often listed as vegetable oil, cottonseed oil is used in salad dressings, peanut butter, and many snack foods. A cheap protein source, the leftover cottonseed meal is fed to dairy cows and is even starting to make its way into the human food supply.

Unfortunately, cotton is by far our most chemically intensive crop. According to the Pesticide Action Network, cotton accounts for less than 2.5 percent of the world's agricultural land—but an astounding 25 percent of all insecticide use. Along with corn and soy, cotton also ranks in the top three genetically modified crops.

Check ingredient lists on packaged foods. If you see cottonseed oil—or an unidentified vegetable oil—make sure the product is organic. And try to buy organic-cotton clothing and linens—even Levi's. You'll pay a bit more, but it's a choice that makes a big impact.

These fragile wonders are perhaps the most intuitive of fruits to buy organic. You can't peel them, and they are best washed only gently just before eating. For me, berries are the ultimate midsummer treat, and I don't want a nagging worry about pesticides sliding down my throat along with all that delectable juice.

You may want to be especially wary of imported produce, including grapes, strawberries, tomatoes, and sweet bell peppers, which average nearly three times higher organophosphate pesticide residues than domestic varieties.

According to the EWG, strawberries rank sixth highest for pesticide residues. Tests done by the USDA and FDA between 2000 and 2005 detected combinations of up to 38 different pesticides in samples of conventionally grown strawberries; 92 percent tested positive for pesticide residues.

Organic strawberries may be as much as 19 percent higher in antioxidants than conventionally grown (Journal of Agriculture and Food Chemistry, 2003, vol. 51, no. 5). Because plants naturally produce phenolics—the family of molecular compounds that includes antioxidants— to help defend against nibbling pests, researchers theorize that chemical pesticides may lessen the need to generate these powerful compounds.

During nonpeak berry season, stock up on frozen organic berries. Toss in smoothies; on top of cereal, yogurt, or oatmeal (still-frozen wild blueberries are the best); and serve alongside simple desserts (thaw and serve whole, or blend with agave nectar to make a delicious coulis).

In life, and in the grocery store, perfect choices are hard to come by—and sometimes budget or convenience take precedence over the best of intentions. Rather than feeling badly about some choices, it's more important to feel good about every organic choice we can make. The next time I'm waffling in front of a produce display, I'm going to follow the pragmatic advice given by Organic Trade Association spokeswoman Holly Givens: "Choose what you use most. It's where your dollar will make the most impact." Consumer demand for organics sends a powerful message. And it's probably the quickest way to an agricultural revolution that will benefit our families and our planet.

Delicious Living senior editor Susan Enfield Esrey just bought her first pair of organic jeans.