During pregnancy, foods that are completely safe at other times may be dangerous to you or your growing baby. There are also some foods -- nitrate-preserved meats among them -- that present a health concern at all times but are particularly harmful during pregnancy. It's important to avoid nitrate-containing foods and their detrimental effects during your pregnancy.
Sodium Nitrate
Nitrates are most common in the diet in the form of the sodium nitrate salt, which consists of a positively charged sodium particle and a negatively charged nitrate particle. While nitrate is not particularly reactive under many circumstances, it is highly reactive under the right conditions. Nitrate is a powerful antimicrobial, meaning that it can inhibit the growth of bacteria in certain foods. Specifically, the food industry uses nitrates to preserve meats, especially cured and salted meats like bacon and some hams.
Reasons for Concern
Nitrates aren't a health problem in their own right. However, they react chemically to become related compounds called nitrites. Nitrites are also preservatives and are sometimes added to foods directly. Any food that contains sodium nitrate as a preservative also contains sodium nitrite, since the nitrate converts into nitrite so readily. Nitrites can react with chemicals called secondary amines, which are plentiful in proteins like meat. This results in the formation of a third class of chemicals called nitrosamines, which are carcinogens.
Pregancy
While you'd ideally want to limit your exposure to nitrates -- and therefore to nitrites and nitrosamines -- at all times, it's especially important to do so during pregnancy. This is because there is the potential for nitrates and the compounds they become when used to preserve foods to cause damage to a developing fetus. Not only can nitrates, nitrites and nitrosamines cross the placenta, but there's evidence that levels of nitrates in the fetus can actually exceed those in the mother's blood, meaning that the placenta can concentrate nitrates on the fetal side.
Foods to Avoid
In order to make sure that you avoid sources of nitrates during pregnancy, you should avoid cured meats such as bacon, most ham and hot dogs. Not all ham is nitrate-preserved; check the ingredients before you buy it. Some canned foods also contain added nitrates, which the ingredients list will reflect. You may have heard that certain fruits and vegetables also contain nitrates. While this is true, naturally occurring nitrates aren't nearly as harmful as added nitrates. Not only are they present in smaller concentrations, but they also occur in foods that tend to be higher in vitamin C, which naturally helps prevent the conversion of nitrates into harmful nitrites and nitrosamines.
