Nitroso compounds

About specific vitamines, minerals or fiber, for example
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RRM
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Nitroso compounds

Postby RRM » Wed 10 Oct 2012 10:19

Nitrosamine.png
Nitrosamines are mostly (90%) carcinogenic.
They are found in cigarette smoke, latex products and many foods.
In foods, nitrosamines are produced from nitrites and amines, mostly from protein.
Acidic conditions (as in the stomach) and high temperatures (cooking) favor the formation of nitrosamines.

In the stomach (not in colon = neutral pH)
nitrite forms HNO2, which splits into the nitrosonium cation N≡O+ and water: H2NO2+ = H2O + NO+.
(NO+) + amine = nitrosamine.
Examples:

dimethylnitrosamine
4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol

N-nitroso compounds (extra N) are more carcinogenic.
Nitrosation is adding NO+
Vitamin C favors nitrosylation instead of nitrosation, thus inhibiting formation of N-nitroso compounds.
High nitrite (from saliva or food), high protein (amines) and high heme (red meat) favor formation of N-nitroso compounds.
Examples of N-nitroso compounds:

N-Nitrosonornicotine
N-Nitrosodimethylamine
N-Nitrosodiethylamine
N-Nitrosoanabasine
N-Nitrosoanatabine
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Re: Nitroso compounds

Postby RRM » Wed 10 Oct 2012 11:28

Heme (from red meat) potentiates endogenous N-nitrosation,
inducing nitrosation of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ = a heterocyclic amine) into 14C-2-nitrosoamino-3-methylimidazo[4,5-f]quinoline (N-NO-IQ). "A linear increase in N-NO-IQ formation was observed from 1 to 10 microM hemin." Lakshmi VM et al
Dietary sugar inhibits formation of N-nitroso compounds (NOC) in the stomach. Holtrop G et al
Fiber does not inhibit NOC formation. Bingham SA et al
"Most nitrite entering the healthy acid-secreting stomach is derived from dietary nitrate. ... It is recognized that an elevated nitrite/vitamin C ratio predisposes to the formation of potentially carcinogenic N -nitroso compounds" Mowat C et al
Salivary nitrite is higher in older subjects Mirvish SS et al
"reduced gastric acid secretion is not a necessary precursor to the formation of carcinogenic N-nitroso compounds" Viani F et al


"women in the highest intake quintile of dietary nitrate had a 31% increased risk of epithelial ovarian cancer, compared with those in the lowest intake quintile." Aschebrook-Kilfoy B et al

"There is a direct average correlation between the intake of nitrates and the digestive malignancy morbidity rates" Assesorova IuIu et al

"higher breast cancer risk was observed with higher intake of nitrate/folate (ratio)" Yang YJ et al

"both animal and plant sources of nitrite were associated with elevated ORs for T-cell lymphoma." Kilfoy BA et al

"A high intake of total nitrite as well as nitrate and nitrite from animal sources doubled the gastric cancer risk." Hernández-Ramírez RU et al

"it supports the hypothesis that the high level of nitrate in drinking water is involved in the development of gastric cancer." Sandor J et al

"Mean dietary nitrate intake was significantly higher in patients with detectable levels of adducts in tumor samples. Estimated intakes of dimethylamine and N-nitrosodimethylamine correlated with total levels of O6-alkylguanines in noninvolved gastric mucosa. These findings support a role for N-nitroso compounds from dietary sources in the etiology of gastric cancer." Palli D et al

"These ecologic data support the hypothesis that there is a positive association between nitrate in drinking water and non-Hodgkin lymphoma and colorectal cancer." Gulis G et al
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Re: Nitroso compounds

Postby dime » Wed 10 Oct 2012 13:31

Did I understand well that red meat then is a bad idea regarding these nitrosamines? I'm eating a lot of it slow-cooked.
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Re: Nitroso compounds

Postby RRM » Wed 10 Oct 2012 14:56

No, the endogenous formation of NOC is a combination of factors.
If you ingest hardly any nitrate / nitrite, there is little nitrosation going on (no NO+ available).
Additional vitamin C (sips of OJ) further inhibits nitrosation.
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Re: Nitroso compounds

Postby dime » Wed 10 Oct 2012 19:56

Oh right, that's why they add vitamin C to many processed meats.
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Re: Nitroso compounds

Postby RRM » Thu 11 Oct 2012 05:53

Exactly.
dime wrote:red meat then is a bad idea regarding these nitrosamines?
BTW; If they used nitrates / nitrite to color the meat red, then it IS a bad idea...
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Re: Nitroso compounds

Postby dime » Thu 11 Oct 2012 06:17

Probably they do, because typically it's way too red.. but I don't know, I'm not sure if I've seen meat without nitrites.
When I cut it usually only the outside is very bright red, the inside is much darker, more like maroon color.
It's not allowed to add nitrites to organic meat I think, but I've observed the above in bio/organic meat too so I'm not sure.
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Re: Nitroso compounds

Postby panacea » Thu 11 Oct 2012 20:35

ive never really seen meat before it's cooked up close (can you imagine that haha) but common sense tells me the outside should be darker, naturally, than the inside, due to oxidation. so if it's really red on the outside it probably has been tampered with!

@RRM
I'm actually going to be experimenting with a raw meat diet (with watermelon or cantalope juice for "water"+vitamin c, but only when thirsty),
I plan on using 85% lean ground raw beef (15% fat), and also "primal ground" raw beef which has the animal's liver, heart, spleen, etc mixed in.
Of course I'm going to do my best to get it from the highest quality source as possible (by doing it online) so as to avoid as much of the parasite/e coli risk as possible,
but I'm curious now as how important the 'heat' element is in the nitroamine formation, because raw meat might be really safe in this regard.
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Re: Nitroso compounds

Postby dime » Fri 12 Oct 2012 14:01

panacea wrote:ive never really seen meat before it's cooked up close (can you imagine that haha) but common sense tells me the outside should be darker, naturally, than the inside, due to oxidation. so if it's really red on the outside it probably has been tampered with!
Yeah with beef it's always like this.. I haven't noticed it with any other fresh meat.
I just bought pig heart for example, and this is same color (dark redish) everywhere.
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Re: Nitroso compounds

Postby RRM » Sat 13 Oct 2012 14:22

I always buy meat from a moroccan butcher, and here the meat is always as it should be:
equally dark redish on the outside as on the inside.
Dime wrote:I've observed the above in bio/organic meat too so I'm not sure.
The good news is: there are a number of ways to color the meat red. It may even be the betanin (E162) from beetroot.
Nowadays the use of nitrates for food coloring is regulated and limited to 200 ppm,
though considered irreplacable in cured dry sausages. Wiki
panacea wrote:I'm curious now as how important the 'heat' element is in the nitroamine formation, because raw meat might be really safe in this regard.
If you dont eat any veggies or high-nitrate fruits (eg non-organic strawberries) with it, and if it is not colored by the use of nitrates, its safe indeed.
Both endogenous nitrosation and the formation of nitroso compounds due to cooking require nitrate or nitrite.
However if the heat is very intense, the N can also 'be taken' from amino acids or amines,
in as much as new HCAs are formed,
but i dont think this is the case with slow cooking (low temp).

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