Nitrates are preservatives found in virtually all cooked and cured meats. Nitrates have a cosmetic function in that they preserve the pinkish color of meats. The concern with nitrates is that when they combine with gastric juices in the stomach, they form a chemical called nitrosamine. Nitrosamines have been found to be carcinogenic in most species of animals tested. Antioxidants like vitamin E, A and C when consumed at the same time may offer protection against its cancer-causing effects.
Nitrates also have an effect on the hemoglobin which carries oxygen in the blood cells.
Because infants have less hemoglobin, they are at risk for side effects from nitrates. Nitrates are banned from baby foods because of this recognized toxicity. Other symptoms of nitrate toxicity can include difficulty breathing, dizziness, headaches, nausea, and vomiting. Some European countries have banned nitrates from their food supply. For this reason, foods with nitrates should be given sparingly to children.