Do you eat lunch meat, hot dogs, bacon, sausages or other packaged or cured meats? If so, all of these products contain added nitrates and nitrites which preserve the meats and fix color, add flavor, and prevent the fats from going bad.
Nitrates and nitrites have become hot topics in recent years because of reports of cancer in animals. You may have noticed grocery store packaged meats with labels touting, “No added Nitrates!” Try googling“nitrate” or “nitrite” and see the long list of articles belittling these compounds. So, what’s the bottom line on nitrates, nitrites, and cancer?
1) What are Nitrates and Nitrites?
Nitrates and nitrites in food are converted in the body to many different compounds, both good and bad. While in the mouth, esophagus, and stomach, nitrates are converted to nitrites, which can be further converted to a group of compounds called ‘nitrosoamines’ – the compounds implicated as carcinogens.
Prior to the 1970s, case reports of illness and death in infants due to nitrites in drinking water, and accounts of the environmental pollution caused by nitrogen oxide compounds led to the initial animal studies showing higher cancer rates with exposure to nitrates and nitrites. In fact, in the 1970s, nitrates and nitrites were nearly banned in meat processing.
2) Where are nitrates and nitrites found?
The World Health Organization estimates average daily dietary intakes for nitrates and nitrites. While 15% of our nitrate intake is from water, the rest comes from foods, mostly vegetables like spinach, beets, celery, lettuce, and other dark green leafy vegetables plus cured meats.
3) What does the research say about cancer in humans?
Nitrosamines have been linked to cancer since the early 1980s when nitrosamines from chewing and smoking tobacco were shown to be strongly associated with oral cancers. Studies also showed higher rates of esophageal, stomach, and colorectal cancers in Chinese and Western societies. Additional support was provided with animal studies showing that diets high in nitrates but lacking antioxidants such as vitamin C and vitamin E resulted in higher gastrointestinal cancer rates.
So, eat your vegetables and avoid process foods folks!
But wait. New research findings have thrown this advice for a tailspin. We now know that nitric oxide, a derivative of nitrate and nitrite, plays a critical role in heart health. So critical, in fact, that we treat heart attacks with a drug that converts to nitric oxide. Some scientists even speculate that the more nitric oxide the better.
In what is likely the best study of its kind on nitrosamines and their association with cancer, the European Prospective Investigation into Cancer and Nutrition (EPIC-Norfolk) Study evaluated over 23,000 participants’ dietary nitrosamines, nitrites and their impact on cancer rates for an average of over 11 years. EPIC showed no significant associations in cancer risk, regardless of the intake of nitrosamines.
Many other recent studies show the same results. If there is an effect of nitrosamines on cancer rates, they are at worst very, very weak. So, while the “gossip” about dietary nitrates, nitrates, nitrosamines and cancer will likely continue, you can sit back and enjoy some salami and cheese.
August 2015. This post was authored by Kevin Conley, University of Illinois at Chicago medical student and Susan Buchanan, MD, MPH, Director of the Great Lakes Center for Children’s Environmental Health – Region 5 Pediatric Environmental Health Specialty Unit (PEHSU).
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