Rethinking Organics

Few things make you feel better about your health than eating organic fruits and veggies. A diet high in produce is commendable enough, but organic produce? That's a double dose of virtue. What's less clear is how much good that virtue does you. Are there real benefits to going organic? If so, are some organic fruits and vegetables better than others? And how do you choose?

One thing is certain: it's easier than ever to find organic produce. As demand for pesticide- and chemical-free foods has grown, the onetime niche product has gone mass market. Sometimes organic produce simply looks or tastes better, which for me is often reason enough to pay the higher price it may sell for. And sure, it makes sense to avoid pesticides as much as possible. At the same time, scientists have yet to document a definite, long-term negative effect of modern pesticides on our bodies, meaning that while organic foods do you no harm, they may not turn out to be as beneficial as you think.

The evidence of nutritional advantages is almost as thin. Never mind the idea that organically grown foods fairly burst with vitamins that modern farming techniques drain out of crops. To date most studies have either shown no difference between organic and conventional produce or found very small pluses in the organic column, such as slightly higher levels of vitamin C or other antioxidants.

Researchers at the University of California at Davis, however, have recently added to our understanding of hidden benefits in organic foods. In a 10-year study, the longest of its type so far, food chemist Alyson Mitchell and her team compared levels of two antioxidants—quercetin and kaempferol—in tomatoes. They found that tomatoes grown in organic fields yielded significantly higher amounts of these nutrients (an average of 79% and 97%, respectively) than their conventional counterparts.

Quercetin and kaempferol are members of a larger group of antioxidants known as flavonoids, which when consumed in foods have been associated with reduced risks of chronic health conditions like heart disease, certain cancers and even some forms of dementia. The team also found that the greater the number of seasons tomatoes are grown in organic fields, the higher the soil quality becomes and the higher the level of the flavonoids climbs.

Impressive as these findings are, they alone may not be enough to advocate shelling out the extra bucks or driving those few miles farther to buy organic. For starters, the study was conducted in a highly controlled setting, so it's not clear we'd get the same results in the real world of organic farming, where conditions vary from farm to farm and field to field. Also, Mitchell points out that tomatoes are what is known as a botanical fruit, something that isn't necessarily comparable to, say, the leaves of organic spinach. "It's a totally different part of the plant, so would the results be the same? We just don't know yet," she says.

Since affordability definitely plays a role in most people's decisions to buy organic, Mitchell offers some guidelines on picking and choosing. First, the skin factor: if you're going to eat the peel of a fruit or vegetable, consider buying organic. "If your kid only eats grapes, then buying organic grapes makes sense to reduce pesticide exposure and increase nutrient density," she suggests. Also think about where the produce comes from: if your organic produce has to be shipped to you from overseas, you may not be reaping as much benefit as you would from a locally grown conventional option, since compounds like vitamin C are not indestructible and can break down over time. Finally, don't be seduced by organic produce included in processed foods like frozen meals and spaghetti sauce. The act of processing significantly changes the chemical composition of foods, possibly erasing the benefits you think you're getting.

In a fast-food world in which too many people eat too little fresh produce, the first step for most folks might be simply to get their fruit and veggie consumption up, no matter which rack in the supermarket they buy from. Going organic may be a fine step two—one that will probably become more attractive as more science comes in.

Sanjay Gupta's Fit Nation series airs on House Call on CNN, Saturdays and Sundays, at 8:30 a.m. E.T.

—With reporting by Shahreen Abedin