Is sodium nitrate and nitrite safe during pregnancy?

What does the evidence say about sodium nitrate and nitrite during pregnancy?

1. Nitrite is what gives processed meat its characteristic color and flavor, and it holds back the growth of pathogens including Salmonella typhimurium and Clostridium botulinum, though under oxidative and low pH conditions it can react with secondary amines to form nitrosamines, some of which are mutagenic. 1
2. Ascorbate blocks that chemistry: no non-volatile nitrosamines were detected in a cooked meat model containing ascorbate, regardless of how much nitrite was added, which is why ascorbate or erythorbate appears alongside nitrite on processed meat labels. 1
3. Measured against real diets, nitrite exposure from meat products in a study of 145 pregnant women fell far below the European acceptable daily intake of 0.07 mg per kilogram of body weight per day, drawing on nitrite analysis of 3,047 meat product samples. 2
4. The US limit for nitrate in public drinking water is 10 mg per litre as nitrate-nitrogen, average daily intake from food runs 30 to 130 mg per day as nitrate, and formation of the N-nitroso compounds implicated in nitrate-associated health effects is held back by ascorbic acid and polyphenols found at high levels in most vegetables. 3
5. Pooling 16 studies covering more than 7.2 million participants, higher nitrate in drinking water was associated with a modestly increased chance of preterm birth and of neural tube defects, with the authors concluding the findings warrant regular review as new evidence appears. 4

Is sodium nitrate and nitrite safe in each trimester?

• First trimester. If you drink from a private well, the first trimester is the moment to get it tested, because public supplies are regulated to a maximum of 10 mg per litre of nitrate-nitrogen and private wells are not. This is a separate issue from the deli counter and a more actionable one.
• Second trimester. Most dietary nitrate comes from vegetables, not from the deli counter, and those same vegetables carry vitamin C and polyphenols that hold back the formation of the nitrogen compounds people actually worry about. Eating the spinach is not the problem.
• Third trimester. For processed meat, the listeria question matters more in late pregnancy than the nitrite question does. Heating deli meat until steaming addresses that risk, and our deli meat page covers it. Keeping charcuterie occasional handles the nitrosamine side at the same time.