Several years back, the World Health Organization announced that processed meats—such as bacon, hot dogs, sausages, and deli meats—have the potential to cause cancer. This assertion was primarily based on the understanding that many of these meats are cured using nitrates and nitrites, substances that have been viewed as harmful to health for many years. However, what if the numerous warnings and associations with negative health effects stem from inconclusive research? Furthermore, what if nitrates and nitrites could actually benefit human health, and that steering clear of them might be leading to a different health crisis?
Food fears are often based more on myths than on actual science. For instance, many people might recall the panic from the 1970s about nitrates being linked to cancer, which stemmed from a study that supposedly found lymphatic cancer in 13 rats. However, what most consumers didn’t know was that the initial research from MIT hadn’t been peer-reviewed before the FDA and USDA took action. Later, a group of scientists from these agencies, along with the NIH, looked into the data and found the study to be flawed. They even sent it to outside experts for further evaluation.
A 1983 risk assessment by the National Research Council pointed out that standard FDA review protocols were bypassed during this scare, which was seen as necessary at the time to safeguard public health in response to consumer advocacy; yet, “normal peer review would have exposed the critical errors in the MIT findings.”
In 1981, the National Academy of Sciences conducted a review of the scientific literature and concluded that there was no connection between nitrates or nitrites and human cancers, nor any evidence indicating that they are carcinogenic. Since that time, over 50 studies, along with various international scientific organizations, have explored the potential relationship between nitrates and cancer or mortality in humans, consistently finding no association.
Scientific evidence has increasingly demonstrated that nitrates can be beneficial to our health. Notably, our bodies produce more nitrite than we typically consume through food, and this compound plays several crucial roles in maintaining healthy immune and cardiovascular systems. Historically, since the Middle Ages, saltpetre (potassium nitrate) has been utilized in meat curing, not only for its unique flavor and to enhance the meat’s color but also for its ability to inhibit the growth of botulism and prevent spoilage. Early printed cookbooks from the 1700s reveal that it was used in significantly higher quantities—up to 50 times more than what is found in contemporary recipes.
What are Nitrates
Nitrates and nitrites are present in a variety of foods and play a crucial role in the meat curing process. However, there is considerable confusion regarding their specific functions. These compounds occur naturally in vegetables and are also added artificially to processed foods and cured meats as preservatives.
While some individuals express concerns about their safety, scientific evidence remains inconclusive, with certain studies suggesting potential health benefits. From a chemical perspective, nitrate consists of one nitrogen atom bonded to three oxygen atoms, whereas nitrite is composed of one nitrogen atom and two oxygen atoms. Thus, the primary distinction between the two lies in their oxygen content.
Nitrites function by extracting moisture from meats, thereby inhibiting bacterial growth and aiding in preservation. Additionally, nitrites contribute to the characteristic pink color of cured meats. This occurs as nitrites transform into nitric oxide, which interacts with oxygen-binding proteins in the meat, resulting in a red hue instead of brown.
Nitrates and nitrites occur naturally in both foods and the human body. The main dietary source of nitrites is vegetables, with smaller contributions from water and other food items. Contrary to common belief, processed meats contribute only a minor portion—less than 5-10%—to our overall nitrite intake, and commercially processed meats do not contain nitrates at all. Additionally, our bodies synthesize nitrites, which are released into saliva. These nitrites then enter the digestive system, where they serve an antimicrobial role, aiding in the elimination of harmful bacteria like Salmonella.
What’s the deal with those pricey “nitrate-free” hotdogs and cured meats that are marketed to people worried about chemicals?
They actually use “natural” sources of the same chemicals, like celery, beet juice, and sea salt. A chemical is a chemical, no matter its origin. NO3 is still NO3. These products aren’t any less loaded with nitrates and nitrites than regular hotdogs. So, when someone claims they steer clear of all foods containing nitrates and nitrites, they clearly don’t know much about the subject.
What led us to be afraid of nitrates and nitrites?
Nitrates and nitrites have developed a pretty negative reputation over the years. This concern really started back in the 1970s when scientists proposed that nitrites could turn into nitrosamines, which might be connected to cancers of the mouth and stomach. As time went on, more studies involving animals and labs added to the worries about the potential cancer risks associated with nitrosamines.
Over the years, studies on human health and observations have been pretty inconsistent. For the few that did find a link, the effect was minimal—almost nothing to worry about. In 2015, the International Agency for Research on Cancer (IARC) labeled processed meats as “carcinogenic” and said that red meat is “probably carcinogenic” to humans.
Since 2015, a lot of scientists have been critical of the IARC’s decision. Many of them argue that the evidence supporting it is not strong, and even if there is some connection, the actual impact would be really minor. Sadly, the classification system they used doesn’t consider this important detail. In a 2019 review and meta-analysis of cohort studies, researchers found that there was very weak evidence—what they called “low-certainty evidence”—indicating that cutting down on processed meat by three servings a week might lead to a tiny decrease in overall cancer deaths over a person’s lifetime. (report)
Nitrates and nitrites might have some surprising health advantages.
Is it possible that eating nitrates and nitrites can actually be beneficial for your health? New research suggests that it might be true.
A 2018 meta-analysis of various human studies discovered some positive effects of consuming nitrates and nitrites on heart health, including: lowering resting blood pressure enhancing the function of blood vessel linings decreasing inflammation in blood vessels lessening the narrowing of blood vessels reducing artery stiffness lowering the chances of blood clots forming.
Nitric oxide is a crucial molecule for human health, playing a vital role in maintaining blood vessel integrity, reducing blood pressure, and providing protection against heart attacks and strokes. It also regulates gut motility, functions as a neurotransmitter in the brain, and is involved in the apoptosis of cancer cells. Nathan Bryan, an adjunct assistant professor at Baylor College of Medicine and a leading expert on nitric oxide, emphasizes its significance, stating, “Nitric oxide is one of the most important molecules produced in the human body.” The body synthesizes nitric oxide through two main pathways: one involves the enzyme nitric oxide synthase, which transforms the amino acid L-arginine into nitric oxide, while the other occurs through the breakdown of nitrate- and nitrite-rich foods by oral bacteria.
Bryan points out that the majority of cardiovascular issues and chronic diseases stem from diminished nitric oxide production. He asserts that nitric oxide is essential for vasodilation and other health benefits, and its deficiency can lead to atherosclerosis.
Conclusion
Contrary to common belief, there is no scientific evidence supporting the idea that nitrates or nitrites lead to cancer in animals. Furthermore, there is no indication that consuming nitrites or nitrates is carcinogenic in humans. Multiple international studies have sought to establish any consistent or causal relationships between these compounds and cancer or congenital malformations in food and water, but they have largely failed to do so. Most of these studies found no correlation, and in some instances, a negative correlation was observed.
References:
https://www.jci.org/articles/view/20664
https://nap.nationalacademies.org/read/776/chapter/3#40
https://pubmed.ncbi.nlm.nih.gov/7443155/
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