Research by US nutritionalist Virginia Worthington showed that organic crops contained significantly more vitamin C, iron, magnesium, and phosphorus and significantly less nitrates, than conventional crops.

Food plants become contaminated with nitrates when they take up more nitrate than they can use from synthetic fertilisers in the soil. Nitrates are not carcinogenic in themselves but are thought to convert into highly carcinogenic compounds called nitrosamines. They are converted mainly within the body, particularly in the mouth and stomach, but also during some food processing techniques. Vitamins C and E are thought to slow down or stop this conversion process.

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