Once upon a time, all food was "organic." Farmers used natural means to enrich the soil, control weeds and eliminate pests because there were no other options.

That was true until the middle of the 20th century. That's when agriculture started employing chemical-based fertilizers, pesticides and herbicides to increase yields.

We've now come full circle. Driven by concerns about sustainability and toxin exposure, organic food is a growing market segment.

According to the Organic Trade Association, organic food sales rose from $3.4 billion in 1997 to more than $45 billion in 2017—an increase the group says has been fostered by the USDA Organic program.

Young families are helping to fuel this trend.

"Millennials are the largest consumer group in the US, and they're choosing organic," says the OTA's Laura Batcha. "As more members of this generation become parents, their presence in the organic market will just get stronger."

Health From the Ground Up

Organic farming's main efforts lie in building healthier soil and using natural methods to control plants and animals you don't want.

That means, for example, employing compost and green manure—crops that are tilled directly into the soil—to increase fertility and planting different kinds of crops together to increase the number of pest-consuming insects.

A key reason people buy organic is to avoid the residues often left on conventionally farmed food.

It's not just pesticides on plants, either. For example, evidence suggests that the digestive systems of cows fed grain, instead of the grass these animals were designed to eat, may harbor harmful strains of E. coli, which can enter the human food supply during the butchering process.

What's more, going organic may help the environment.

According to one study, organically farmed soil has a greater potential for long-term storage of carbon—a key factor in reducing greenhouse gas emissions. What's more, evidence suggests that organic farming may help stem the loss of bees, numbers of which have been declining over the past decade.

Green Power

Just as important as what you don't get in organic food is what you do get: more nutrition.

"Conventional farming practices can damage production of the vitamins, minerals, proteins and phytonutrients in fruits and vegetables," says the Rodale Institute, which conducts research on organic farming practices. The Mayo Clinic concurs, stating, "Studies have shown small to moderate increases in some nutrients in organic produce."

In addition, feeding cattle and other livestock grass instead of grain increases levels of healthful omega-3 fatty acids.

To find organic food, look for the green-and-white USDA Organic label; products containing multiple foods can use the label if at least 95% of the ingredients are organic. If at least 70% of the ingredients qualify, the product can be labeled "made with organic" but can't carry the USDA seal.