Are Nitrite-Free and Grass-Fed Meats Less Harmful?
The short answer is we don’t know. Some of these newer animal products like nitrite-free and pasture-raised meats have not been studied heavily, according to the American Institute for Cancer Research (AICR). One study found less multi-drug resistant bacteria contamination on organic chicken, compared with conventional chicken. Organic chicken has been shown to contain arsenic in 1/3 of chicken tested, vs 3/4 of conventional chicken. Free-range vs. conventional eggs may be a bit better as well, due to less contamination. And the same goes for wild. vs. farmed fish. So there are many ways to choose organic if eating animal-based foods. However, when discussing the carcinogenic effects of meat in particular there is no data to suggest nitrate-free meat is more healthful.
New statements by the World Health Organization claim red and processed meats are carcinogenic. What counts as “processed meat”? AICR defines processed meat as “meat preserved by smoking, curing or salting, or addition of chemical preservatives.” Ham, bacon, pastrami, sausages, hot dogs and cold cuts are all considered processed meat.
Suzanne Dixon M.P.H., R.D., from the Oncology Nutrition Dietetic Practice Group of the Academy of Nutrition and Dietetics says:
“How you raise the meat does not affect whether or not it is carcinogenic. Both conventional, feedlot meat and grass fed organic meat are probable carcinogens. And once you process either of these into “processed meat,” they are definitive carcinogens, per the World Health Organization (WHO) and other large health/research agencies.
In addition to the nitrates/nitrites in processed meats, three key issues to consider with meat in general are heme iron, polycyclic aromatic hydrocarbons (PAHs), and heterocyclic amines (HCAs). Ample evidence suggests heme iron contributes to chronic disease risk, particularly heart disease and possibly digestive tract cancers, including colon cancer. Heme iron in particular is a strong pro-oxidant; in processed meat, heme iron likely interacts to worsen the carcinogenic effects of the nitrites. I heard an interview on the WHO statement, and heme iron was mentioned as one of the leading hypotheses regarding why/how meat is pro-carcinogenic.
As for PAHs and HCAs, you cannot avoid these if you eat cooked flesh. These compounds are generated due to the precursor compounds in the meat. HCAs are formed when amino acids, sugars, and creatine (found in muscle) react at high temperatures. PAHs are formed when fat and juices from meat grilled directly over an open fire drip onto the fire, causing flames and smoke, which rise up and coat the meat. So you can reduce PAHs by not grilling over open flame, but HCAs are formed regardless, simply because it’s meat plus heat.
You can grill your carrots and eggplant until they resemble a charcoal briquette, and you will not form PAHs or HCAs, because vegetables don’t contain the precursor compounds. You may get other noxious compounds, but PAHs and HCAs, which are carcinogenic, are particular to cooked animal flesh.
While it isn’t definitively known that PAHs and HCAs directly cause cancer in humans, evidence suggests this is the case.
So for cured meat, it makes no difference if it’s grass-fed or conventionally-raised, you still have nitrates/nitrites, heme iron, PAHs, and HCAs. For uncured red meat, it makes no difference if it’s grass-fed or conventionally-raised, you still have heme iron, PAHs, and HCAs.