Meat that has been preserved by smoking, curing, salting, or adding preservatives may lead to the development of leukemia and brain tumors. The ingredients contained in such meat -- sodium and potassium nitrates -- should not be trifled with. During the process of cooking certain meat, nitrites combine with naturally present amines to form carcinogenic N-nitroso compounds. These N-nitroso (called nitrosamins) compounds are carcinogens associated with cancer of the oral cavity, urinary bladder, esophagus, stomach, and brain.
Not All Nitrites Are Harmful
You may have heard about the naturally occurring nitrates in vegetables and wonder if you should also avoid these. Vegetables are, indeed, the primary source of nitrites, but they come with vitamin C and other compounds that inhibit conversion into nitrosamines. On top of that, the human body also produces nitrates in large amounts and secretes them into saliva. Numerous studies also show that dietary nitrites/nitrates can enhance physical performance, especially during high intensity endurance exercise.
Nitrites can only turn into the carcinogen nitrosamine if in the presence of amino acids and when they are exposed to very high heat. Because most bacon, hot dogs, and processed meat contains a lot of sodium nitrite and they are high in protein (a source of amino acids), the risk of them turning into nitrosamine is in place. So, if you prepare such meats at a lower heat for longer time it would have less nitrosamines than if you prepare them on high heat for a short time. You should keep this in mind.
There also is a nitrites-free meat available on the market. You may notice that the color is somewhat dull, which just doesn’t produce the impression of freshness. Nitrites are used for processed meat preservation and they give the cured meat that nice pink or red color.
The Risk
According to the International Agency for Research on Cancer, an additional 50 gram portion of processed meat eaten in a daily diet increases the risk of colorectal cancer by 18%. Children who eat more than 12 hot dogs per month have nine times the normal risk of developing childhood leukemia.
In October 2015, the World Health Organization (WHO) definitively linked eating red meat and processed meats — like hot dogs, ham, and lunch meat — to an increased risk for colorectal cancer, which consistently ranks in the top three deadliest cancers.