On Monday I wrote about an article called Think Twice Before You Buy This Type of Burger by The Food Babe, aka Vani Hari, which is basically a case study in chemophobia. Today I continue my 5-part series on this article...
Textured Vegetable Protein (TVP) & Nitrite:
Hari’s next problem is with textured vegetable protein (TVP), a high protein soy product that is used in various foods including some veggie burgers. According to Hari TVP is filled with, “artificial and natural flavors, MSG, colorings, emulsifiers and thickening agents, including nitrosamine, which is a carcinogen no one should be consuming.” In reality this is just a blanket appeal to chemophobia. One issue mentioned that may be a concern is that of nitrosamines, a class of compounds which are created from added of naturally occurring nitrite during the processing, cooking, and digestion of certain foods that have been implicated in certain cancers. This actually forms part of the basis for anti-hot dog/bacon/processed meat campaigns by vegan organizations such as the PCRM. But little nitrite is converted to nitrosamines under normal conditions and the evidence for harm from consuming high nitrite foods is not conclusive while at the same time there is growing evidence of the positive physiological roles of nitrite. According to a more recent report from the European Food Safety Authority, “Epidemiological studies do not suggest that nitrate intake from diet or drinking water is associated with increased cancer risk. Evidence that high intake of nitrite might be associated with increased cancer risk is equivocal.”
And, what’s more, even if we ignore the seemingly overstated nature of these concerns, highlighting soy as a dangerous source of nitrosamines is misleading. The precursor to nitrosamines, nitrite, can be found in many foods particularly in certain meats, grains, and leafy vegetables in particular, often at significantly higher levels. And while some surveys do show vegetarian diets having above average intakes of nitrite, their source, as with the general-non-vegetarian population, is mostly from vegetables (where the presence of vitamin C might mitigate the formation of nitrosamines) and the calculated amounts generally do not exceed the conservative EU acceptable daily intake (ADI). The FDA, for their part, does not believe that meat analogs pose a risk to consumers either,
The SCOGS report estimated the maximum daily nitrite consumption for a vegetarian eating meat alternatives prepared from soy protein to be 0.04 mg/kilogram (kg) body weight (or 2.8 mg for a 70-kg person). The report estimated daily per capita intake of nitrite from other foods of plant origin and cured meats to be about 2.4 mg and daily exposure to nitrite from saliva to be 15 mg. The report estimated that nitrite formed in the intestine from reduction of ammonia or organic nitrogen compounds contributed about 90 mg/day. Given the relatively minor potential contribution of soy protein to total nitrite exposure, and the fact that no data were submitted to document the current levels of nitrites or nitrosamines in soy protein isolates, FDA is not persuaded of the necessity for establishing specifications for acceptable levels of these compounds.
So you can probably enjoy your veggie burger in peace. Any nitrite in soy should not present a problem for the average vegan consumer and testing of soy protein isolate found no detectable nitrosamines. Additionally when researchers in Taiwan looked at nitrite exposure from soy they found an inverse relationship with the type of cancer under investigation due to an inhibitory agent in soy. All in all, I remain unconvinced that avoiding soy is warranted on the basis of nitrite concerns.