Ms. JSLE found an article online about how sodium nitrite causes a 67% increase in pancreatic cancer. As a result she is now going about banning it from our house and diet. As a fan of hot dogs, I find this upsetting but as a fan of real science, I am even more upset.
I found no shortage of links online touting the figure but none of them were from what I consider reputable sources - mostly sites that are advocating diets that don’t involve meat at all (yet I also read that sodium nitrite occurs naturally in spinach and lettuce, so I guess my salad is out too) or other agendas.
What is the Straight Dope on this issue? Any citations that I can trust?
Nitrites are converted into nitrosamines in the body, which, to some extent, are carcinogenic. I have not eaten hot dogs for many years for that reason, and rarely eat any food cured with sodium nitrites. However, they occur in many natural products as you noted. The small amount in natural products are not a concern: http://www.extension.umn.edu/distribution/nutrition/DJ0974.html
One thing to be careful about with such figures is that they can sound very large – 67% increase! – without necessarily being a significant risk. I don’t know the specifics in this case, but if you start with a risk of 1 case in a bazillion and Toxic Substance X increases your risk to 1.67 in a bazillion, I personally wouldn’t worry much about changing my habits. If, on the other hand, it increases the risk from 1 case in 10 to 1.67 cases in 10, that would be pretty scary stuff.
ETA: Also, it’s important to find out how much of the substance in question it takes to produce the observed effect. “The dosage makes the poison” is axiomatic for a reason.
The June issue of the U.of Cal., Berkeley Wellness Letter (which, coincidentally, I received today) states the following. (This is not on their website.)
So we are looking for relevance of the number, whether the amount tested accurately represents an amount that I might ingest, and now the stuff might be good for you.
I know nitrates are not nitrites, but the conversions in the body are similar, and hot dogs and cured meats contain but nitrites and nitrates. The article referred to nitrates, but the same reasoning can apply to nitrites.
I just heard this some time ago, but don’t know the source: they claimed that “spinach in winter is bad because high in nitrates which will be converted into bad nitrites” is based on a study done on babies, which are at risk for Blue Baby Syndrome from nitrates, but a normal adult is not at risk. So while babies still shouldn’t eat spinach, adults can.
With cured meat, the problem is that grilling changes nitrites into nitrosamines which are bad. You usually don’t barbecue your salad, only your meat, and only meat treated with nitrites (from pickling salt) is the problem here, not meat generally.
Grilling does not convert nitrites into nitrosamines, but into heterocyclic amines, another carcingogen: http://www.tuftshealthletter.com/
Coincidentally again, the print issue of the June 2011 of Tufts Health &Nutrition Letter, which I received today, states that although a connection between red and processed meat and bladder cancer (does not mention pancreatic cancer) is “biologically plausible,” it didn’t show up in the data on 481,419 people over almost nine years. It notes that “the research is the first to also look at cancer risk and two key constituents of red and processed meat: nitrosamines (compounds formed in the digestion of nitrates and nitrites added to processed meat such as bacon) and a type of iron, heme iron, found in red meat.”
That issue also states that the UK advises cutting down on red meat. The UK Dept. of Health advised people to eat no more than 500 grams of red meat per week. The change was prompted by a report from the independent expert Scientific Advisory Committee on Nutrition, which concluded that eating red and processed meat likely increases the risk of bowel cancer.
Coincidentally again, that issue states that while incidence of relatively rare but deadly pancreatic cancer has plateaued in the US, rates continue to rise in Asia - “a consequence, some experts suspect, of a trend toward a more westernized lifestyle and diet, including soft drinks. A study that followed 60,524 Singapore adults over 14 years supports that theory. Researchers found that participants who drank two or more soft drinks per week were 82% more likely to develop pancreatic cancer.”
