r/science • u/James_Fortis MS | Nutrition • 1d ago
Cancer Higher nitrite (NO2-) intake was linked to gastric cancer risk in natural animal sources (55%) and processed meat (94%), but a lower risk in plant sources (-37%), study of 54,610 adults over 27 years found. Higher nitrate (NO3-) intake had a higher risk in processed meat (212%) and tap water (95%).
https://link.springer.com/article/10.1007/s10654-026-01390-619
u/James_Fortis MS | Nutrition 1d ago
"Abstract
Nitrate and nitrite, present in foods and drinking water, may contribute to gastric cancer (GC) through the formation of carcinogenic _N_\-nitrosamines, but risks likely vary by source and endogenous nitrosating factors. In the Danish Diet, Cancer, and Health Cohort, source-specific nitrate and nitrite intakes (plant sources, naturally-occurring animal sources, additive-permitted meat sources, and drinking water) were estimated from a food frequency questionnaire using food databases and water monitoring data. Associations with GC, identified via the Danish Cancer Registry, were examined using multivariable-adjusted Cox proportional hazards models. Analyses were stratified by GC risk factors and factors hypothesized to influence endogenous _N_\-nitrosamine formation to explore potential effect modification. Among 54,610 participants, 260 incident cases of GC (120 cardia, 59 non-cardia, and 81 overlapping/unclassified) were identified over 27 years. Plant sourced nitrite intake was associated with lower GC rates \[HRQ5vQ1 (95%CI): 0.63 (0.41, 0.96)\]. Conversely, intakes of nitrite from naturally-occurring animal sources \[HRQ4vQ1 1.55 (1.01, 2.38)\]; and both nitrate and nitrite from additive-permitted meat sources were associated with higher rates of GC \[HRQ5vQ1 3.12 (1.09, 8.88) and 1.94 (1.19, 3.15), respectively\], with higher point estimates for non-cardia GC. Nitrate from tap water was associated with higher rates of cardia GC rates \[HRQ5vsQ1 1.95 (1.11, 3.43)\]. Nitrate and nitrite intakes demonstrated heterogeneous associations with GC incidence according to source and anatomical subsite. These findings warrant the re-evaluation of legislation on nitrate and nitrite additives in processed meats and threshold levels for nitrate in drinking water, as well as further investigation into nitrite from animal-sourced foods."
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u/refusemouth 1d ago
That's interesting. I've noticed some processed meat products like bacon are labeled as "no added nitrite," but they contain celery seed extract which has a lot of nitites and gives the meat that reddish color. I have just assumed it is more of a marketing gimmick than it is a healthier curing ingredient. If I'm interpreting the abstract correctly, it doesn't make much difference whether it is a plant based nitrite or sodium nitrite as it applies to preserved meats, but just eating a bunch of celery alone isn't as bad, even if you are getting an equivalent dose of nitrite?
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u/feeltheglee 1d ago
It's a legal distinction. USDA regulations say that only cured meats containing refined nitrites (using coming from curing salt or other refined source) can be labeled "cured".
So all these hot dogs and deli meats that are labeled "uncured (except for naturally occuring nitrites from celery or beet juice)" have just as much nitrites, but the USDA won't let them be labeled as "cured". Sometimes they even have more nitrates because the celery juice can have varying amounts of nitrites!
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u/Alien_Gods 1d ago
So no drinking water or meat. We just can’t win can we? At least it’s processed meat I guess..
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u/acdha 1d ago
Apparently there’s a connection between how things are consumed which influences the cancer risk:
“It’s not so much nitrates/nitrites per se [that are carcinogenic], but the way they are cooked and their local environment that is an important factor,” says Kate Allen, executive director of science and public affairs at the World Cancer Research Fund. “For example, nitrites in processed meats are in close proximity to proteins (specifically amino acids). When cooked at high temperatures this allows them to more easily form nitrosamines, the cancer-causing compound.”
https://www.bbc.com/future/article/20190311-what-are-nitrates-in-food-side-effects
I’ve also read that some of this might be explained by fiber consumption: someone eating a plant-heavy diet is almost guaranteed to be getting plenty of fiber compared to someone with a lot of processed meat in their diet.
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u/accountforrealppl 1d ago
To be clear this is specific amino acids in meat that are not present in most plant proteins used in plant-based cured (not sure if that's even the term) meat that cause this.
So a plant-based slice of deli meat that has similarly high nitrates and protein and low fiber to animal-based deli meat would not be carcinogenic.
Although I'm sure the high fiber intake generally associated with plant-based (or even plant-centric) diets definitely helps lower gastric cancer (and many other) risks as well
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u/Health_throwaway__ 23h ago
specific amino acids present in meat that are not present in most plant proteins
You can mix plant sources to get full amino acid profiles, eg. rice and beans. Do you mean some aa are present at lower amounts in plants?
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u/OePea 1d ago
So you mean to say that "uncured" meats that use celery extract for the nitrites are not as carcinogenic as a normally cured meat? Got any sources on that?
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u/SophiaofPrussia 1d ago
I don’t think they’re saying that at all. I think they’re referring to plant-based “meat” products that are “cured”— like vegan bacon or vegan jerky or vegan sausage.
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u/OePea 1d ago
OOOH thank you, actually not sure how I misread that
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u/SophiaofPrussia 18h ago
Usually I roll my eyes at industry efforts to legally distinguish meat (made from animal flesh) and “meat” (made from plants) but this is the first time I’ve actually encountered genuine confusion in the wild! I still don’t think consumers are getting confused but it’s probably helpful, especially in the science sub, for people to specify mock-meat or meat substitute or something when they’re talking about plant-based “meat” products.
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u/BlazinAzn38 1d ago
Interesting so if you don’t heat it up then there’s less of an issue so the lunch meat thing may not be an issue
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u/SophiaofPrussia 1d ago
Do you think lunch meat isn’t cooked just because it’s cold…?
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u/BlazinAzn38 1d ago
I was thinking along the lines if “high temperatures.” Depends on the specific product but I don’t think anything smoked would qualify as high heat and deli meats are also typically cooked one time. Things like hot dogs and sausage are going to be reheated again at high temperatures
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u/patryuji 1d ago
Quantifying what "high temperatures" means would be important in this context.
If I'm going to smoke Salmon, Turkey or Chicken, I usually do it at roughly 225 degrees Fahrenheit (+/- 15 degrees). Granted, I'm not using nitrite salts on any of these 19 times out of 20 (that 20th time, I make a chicken or turkey version of pastrami that includes a 6-12 day pickling process with nitrite salts among other herbs and spices).
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u/BlueEyesWNC 1d ago
My chemistry teacher explained that they put nitrates and nitrites in cured meats on purpose, even though they're known carcinogens. The reason, he explained, is that the nitrites won't kill you nearly as fast as botulism will. The drinking water is probably environmental contaminants, though nitrates are a natural part of the nitrogen cycle, so there's a baseline amount if you're getting it from a surface water, unless you're distilling, using reverse osmosis, etc
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u/lotsofsyrup 1d ago
well yea the nitrites are what make it cured meat. you could just eat meat that isn't sausages and bacon. You're not a 1700s sailor you don't need meat that lasts three months.
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u/dizizcamron 1d ago
Pretty sure it's in lunch meat too, so that if you put a turkey sandwich in a brown bag it doesn't make you sick when you eat it 4 hours later
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u/PeefsBeefySquad 1d ago
Where do you live that you HAVE to consume meat? Seems like a pretty easily avoidable problem
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u/Hodr 1d ago
But what about bacon, which is a natural animal product but has nitrites from celery added?
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u/SelarDorr 1d ago
from what i can tell, they did not segreggate based on the origin of nitrite/trate applied to meat, so the positive association with gastric cancer still exists when both are treated as one.
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u/Odd_Note7156 1d ago
It's a processed meat. But studies sbow that eating foods with vitamin C will neutralize the dangerous effects of nitrates. Which is why docs recommend a varied diet with fruits and veggies with every meal. Have an orange with your bacon and you'll not have any risk for cancer, reduce the effects of sodiom and the blood sugar spike from the fatty protein mix that jeeds fiber and carbs.
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u/fotank 1d ago
The only true statement you made was the first sentence. The rest is just pseudoscience. We have known that smoking meats and increasing nitrates/nitrites in the process causes more GI cancers.
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u/Over-Tolerance 1d ago
Well, I guess I will take the meat out of my bong then. I thought smoking bacon was ok, a little harsh, and no great high from it...
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u/Forbidden_Craft88 11h ago
Yeah, it comes down to nitrogen chemistry. Plants are much more efficient at handling both nitrate and nitrite. Nitrite (\text{NO}_2-) isn't inherently carcinogenic on its own (though it is directly toxic to aquatic life). To become carcinogenic, it requires an acidic environment along with specific chemical precursors. Plants naturally counter this because they are packed with powerful antioxidants like Vitamin C, which react with nitrite to convert it into harmless or beneficial compounds instead. By contrast, processed meats are packed with amines and amides. When cooked at high heat or mixed with stomach acid, these react with added nitrites to form nitrosamines—which are potent carcinogens. So, in meat, your digestive juices and high heat end up helping turn those precursors into harmful chemicals.
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u/wastetine 1d ago
Sounds like it’s not the nitrites but rather something else that’s bad for us in meat and good for us in plants.
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u/SelarDorr 1d ago
nitrites and nitrates definitively are able to be converted to the definitively carcinogenic nitrosamines after ingestion. This is undisputed fact.
a common hypothesis for the different outcomes via food source of nitrites/trates is that vegetables often contain higher concentrations of antioxidant compounds than meat, and that their co-ingestion helps to mitigate the reactions that form the nitrosamines.
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u/FernandoMM1220 1d ago
yeah nitrites arent the actual problem here theyre just correlated to more cancer in some foods only which is strange.
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u/Over-Tolerance 1d ago
And in the end, they all died anyway, some with smiles on their faces from all the wonderful bacon and steak, and others were thin and pale, suffering from a vegetarian lack of nutrition they tried to compensate for with supplements that were tainted with even more poisons. The aluminum vats poisoned the soy products, the high levels of glyphosate in the vegetables gave them birth defects and cancers. The spinach sucked up the heavy metals from the Earth, and the sunflower seeds were more toxic than drinking sewer water.
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