Cured meats have been demonized a lot lately. They bear the brunt of the “processed meats” label. Marketers have confused things even more by labeling their meats as “un-cured” even when they decidedly are, in fact, cured. In today’s post, I will take a closer look at cured meats, and what it means for health implications, particularly relating to stomach cancer. I have a vested interest in this topic as a bacon-curer, sausage-eater, and dry-curer of meats. I wanted to know the truth behind this issue, which is why I did the research that I did (and why I am sharing it with you as well).
This is part two of a series on stomach cancer and how it relates to ferments. In part one, I looked at kimchi consumption and its correlation to high rates of stomach cancer in Korea. In this second part, I will take a look at cured meats as well as nitrate consumption, and how these factors relate to cancer rates.
Sodium Nitrite: A little chunk of chemistry
I shared earlier that there are many risk factors for stomach cancer (also known as gastric cancer). As it turns out, one of the risk factors comes from a class of compounds called nitrosamines. These are carcinogenic compounds that can be formed from sodium nitrite, which is a curing salt.
Here’s how it works. Sodium nitrite (or sometimes sodium nitrate)** is added to cured meats to give it flavor, color, and to create a safer product. It’s what turns your pork from a roast into a ham, or what transforms your beef into corned beef. It also plays an important safety role in sausages that are smoked or dry cured. In the case of fermented or dry-cured sausages, it keeps your meat safe by inhibiting deadly botulism from growing in the interior of the sausage. It’s kinda important.
**(Side note: sodium nitrate is chemically and functionally similar to sodium nitrite, except that it has one extra oxygen atom. It is often added to dry-cured meats. The sodium nitrate slowly transforms over time to sodium nitrite, which is what gives the meat its curing properties.)
The sodium nitrite molecules can do one of two things. They can form nitric oxide by losing an oxygen atom (which is actually an important and helpful signaling molecule in the body). Or they can combine with amines from the protein in the meat to form nitrosamines (which are carcinogenic and may increase the risk of several different types of cancer). One of the big question is: how do we know whether or not nitrosamines will form from the sodium nitrite molecules?
There are three factors (that I am aware of) that can affect nitrosamine formation. The most influential is heat. In fact, a study on bacon seems to be what started this whole mess of villainizing nitrites. When bacon is heated to extremely high temperatures, nitrosamines form. The hotter you cook your bacon, the more likely it is that nitrosamines will form. This isn’t such a problem if you’re eating raw salami or even cooked ham, but it’s a possible source of carcinogens if you are prone to burning your bacon or cooking it until very well done.
The second factor is vitamin C. When nitrites are consumed in conjunction with vitamin C, there is a reduced risk of nitrosamine formation. If you are eating your fruits and veggies at the same time as your cured meats, you are more likely to convert the nitrites into nitric oxide instead of nitrosamines. Nowadays, commercial producers of meats add ascorbic acid (vitamin C) to cured meat products as a way to minimize nitrosamine formation.
Finally, old fashioned processing methods for meat allowed for days of curing instead of just hours, which is the common practice by commercial providers nowadays. The additional time may be a factor in reducing nitrosamine compounds as well. This isn’t the best news for cured meat lovers, but all the more reason to make your own.
Less villainized sources of nitrites:
1. We tend to think of nitrites as coming solely from cured meats, but that is hardly the case. You may not have realized it, but many of the vegetables that you eat have a far higher nitrate content than any cured meats you may encounter (and remember that nitrates naturally convert into nitrites and can have the same effect on the body, regardless of their source). Celery, beets, and lettuce are three veggies with crazy high levels of nitrates. Now, whether or not these nitrates are being converted into carcinogenic nitrosamines is debatable. These vegetables have a high vitamin C content, which does inhibit nitrosamine formation. Unlike cured meats, they don’t have a high protein content, which means that there are fewer sources of amines available for conversion into nitrosamine compounds. Takeaway: veggies are pretty safe to eat. The nitrates are probably forming primarily nitric oxide, which is beneficial to the body.
2. Another source of nitrites? “Uncured” meats. All those meats from the grocery store that are touted as “uncured” or being “nitrate-free” are pretty much a giant scam. They’re preying on customer ignorance and weird USDA labeling laws. Because while they aren’t adding synthesized sodium nitrite, per say, they are adding celery juice, which is just another source of curing salts. (Remember how in the paragraph above I mentioned that celery has crazy high levels of nitrates? . . .) And celery juice is even worse than adding sodium nitrite: because it doesn’t always have consistent levels of nitrates in it, the producer must add higher levels of celery juice to the meat to produce a consistently-cured product. So those “uncured” meats that you may be buying are chemically equivalent to any other cured meat out there (though with potentially higher levels of nitrites).
3. Drinking water. Runoff from agricultural sources can contaminate water with a whole lot of nitrate fertilizers. In fact, vegetables and drinking water are the primary sources of nitrate exposure that we have. Studies in Hungary and Spain have linked nitrate-contaminated water with higher levels of stomach cancer, and a study in Iowa linked nitrate contamination with several cancers, including bladder and ovarian cancer. To my way of thinking, if we’re going to worry about nitrosamines at all, drinking water is the first source to consider. Especially if you live in a highly agricultural area or are drinking non-treated well water, you may want to consider your nitrate consumption from your water source first before you tackle cured meats.
Some good news.
Nitrosamines are carcinogenic. It’s true, they’re bad news. But ingesting high levels of nitrates is not definitely correlated to stomach cancer. Some studies have shown that there is no obvious relationship. In fact, one study showed that geographical regions with low risks for gastric cancer actually had higher levels of nitrites and nitrates in their saliva than regions that had high rates of stomach cancer. Their study suggests, in fact, that nitrates may have a protective effect against stomach cancer.
Another thought to consider is that while meat consumption is on the rise in the US (and 22% of meat comes from “processed” sources), rates of gastric cancer are significantly on the decline. The advent of refrigeration has allowed us to eat more fruits and veggies (lots of good vitamin C). Regulation in nitrite content in meats has led to lower levels of nitrites. And we have stopped using the more unreliable curing salt of potassium nitrate (saltpeter) and are using sodium nitrate instead. All of these factors have helped us to have healthier stomachs and lower cancer rates.
And finally, there is quite a bit of evidence to suggest that Helicobacter Pylori (or H. Pylori) is the primary cause of gastric cancer. This of course is not good news for someone infected with H. Pylori bacteria (though for most people with it, it doesn’t seem to negatively affect them health-wise at all), but it is good news for the majority of the bacon-loving population. For those who do begin to experience stomach troubles or ulcers, the good news is that antibiotic treatment can be effective in eradicating H. Pylori and decreasing gastric cancer rates.
I’m not terribly concerned about nitrites in my cured meats. I would worry far more about death from botulism if I didn’t use them in my fermented sausages. But if I am concerned, I can glean information from the research that is available, and strive to be healthier with how I eat by doing the following:
- I can: not burn my bacon. Instead of cooking it on high heat, I can cook it at a lower temperature for longer. It’s actually healthiest to cook in the microwave, so maybe I’ll try that.
- I can: eat fruits and veggies alongside cured meats (for the added vitamin C). This isn’t terribly hard to do, especially since I try to eat veggies at most meals. And even bacon and eggs can be veggied-up with some fermented pickles or cooked greens.
- I can: use the recommended amounts of curing salts when making my own cured meats. I do this anyway, but it doesn’t hurt to be reminded that excess nitrites aren’t necessary in cured products. I always weigh my ingredients to be sure I’m adding the right amount.
- I can: use my water filter to reduce the amount of nitrates in my drinking water (I have a berkey). I can’t say exactly how much the filter reduces this contaminant (their website is rather vague), but it’s something I’ll be mindful about from now on. When the annual water report comes in the mail, I’ll be sure to note the amount of nitrates in my water supply.
What do you think? Are you convinced? Not convinced? Are you going to swear off all “processed” meats . . . or embrace them with love? Is this traditional method of preservation a wonderful, tasty endeavor . . . or a cancer-inducing mistake?
In this house, we love our bacon. Homemade and otherwise. We love our dry-cured meats and fermented sausages. We love good food. And what we eat, we eat with care. Our food is prepared with love, and more than anything, I think our preparation and concern for balance will help keep us healthy and whole.
Here’s wishing you healthy good eats,