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Root Vegetables: Potatoes
These root vegetables tend to absorb the fungicides, herbicides and pesticides in the soil they're grown in. By buying organic varieties, you avoid all of these threats. In case you can't find organic potatoes, try sweet potatoes; they are usually grown with less pesticides overall.

Cost: Organic potatoes cost about $1.49 per pound at grocery stores.
Celery and bell peppers

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Produce: Peppers and Celery
Both veggies react to pesticides in the same way: like a sponge, absorbing the chemicals through the skin. Because of this, you won't be able to reduce chemical ingestion by washing or peeling them. Always choose the organic variety.

Cost: Organic peppers and celery cost between $3.99 and $6.99 per pound at grocery stores.

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Leafy Greens: Lettuce, Spinach and Collard Greens
These plants are usually doused in pesticides to ward off insects. Organic growers use methods like non-toxic repellents to keep these vegetables free of pests.

Cost: Organic greens cost between $2.99 and $5.98 per pound.
Dairy products

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Dairy Products: Yogurt, Butter, Cheese and Ice Cream
It's important to go organic with these kitchen staples because we eat so much of them, so often. Non-organic dairy products may come from cows fed a diet of genetically modified corn, soy, and antibiotics.

Cost: Organic dairy products can be found at grocery stores and usually cost between $2.19 and $4.29.

Next: Dr. Oz's supermarket guide