One of the possible benefits of the increasing use of refrigeration in the United States during the early 1900's was a rapid decrease in the stomach cancer rate, which appears to be largely due to the decreasing use of nitrate-based salts for meat preservation. Stomach cancer was the leading cause of US cancer mortality in 1930. The stomach cancer death rate dropped by a factor of 2 from 1930 to 1950 and kept on dropping until it is now about one-tenth of the 1930 rate and isn't even in the top-ten list for cancer mortality. In countries where highly salted foods are still prevalent (e.g. Japan and South Korea), stomach cancer remains a leading cause of cancer death in spite of the increased use of refrigeration.
And yet many Americans continue to eat "hot dogs, ham, bacon and turkey bacon, corned beef, pepperoni, salami, smoked turkey, bologna and other luncheon and deli meats, sausages, corned beef, biltong or beef jerky, canned meat and meat-based preparations and sauces, among others" without understanding the risk.
What might be some examples of Japanese and Korean foods which use nitrate-based salts for meat preservation? I assume meats marinated or cooked with high levels of regular salt are not what you are referring to? This looks like a gap in my knowledge on healthy eating. I'm based in an Asian country and Google was not very forthcoming on this topic.
Pickled vegetables and salt-cured fish appear to be the most significant culprits in Asia. Also, both high levels of regular table salt (sodium chloride) as well as high levels of nitrate have each been linked to stomach cancer, so it doesn't have to be a nitrate-based salt to be of concern.
