To date more than 100,000 papers have been published on the molecule.

“Nitric oxide or nitric oxcide was known for many years as a toxic air pollutant expelled from car exhaust. You can imagine the impact of the story when it was discovered that such a gaseous molecule is produced in our body. Even more remarkable is the fact that such a gas is produced within our body to serve as a signal for cell to cell communication or for the transduction of nerve impulses,” said Ignarro. Nitric oxcide regulates blood pressure, causes penile erection, and controls the action of almost every cell in our body, he said. The human immune system also uses nitric oxide in fighting viral, bacterial and parasitic infections, and tumors.

Nitric oxcide transmits messages between nerve cells and has been found to be associated with the processes of learning, memory, sleeping, feeling pain and depression. It is a key mediator in inflammation.

“Early studies on nitric oxcide stemmed from work with nitroglycerin and other nitrovasodilators as we attempted to understand how these medicines worked that had been used for hundreds of years. As we discovered, nitroglycerin makes nitric oxcide which accounts for its therapeutic efficacy for angina by dilating constricted and diseased blood vessels in the heart,” said Ignarro.

There is still much to be learned about the production and regulation of nitric oxcide within the human body. “The limitations to our understanding arise from the fact that its production is very complex and once produced, the nitric oxcide gas is degraded in less than one second as it diffuses to reach its cellular target or is quickly inactivated by reaction with oxygen, oxygen radicals or proteins. We do know, however, that the loss of our ability to form nitric oxcide, namely endothelial dysfunction, leads to a number of diseases including cardiovascular disease, the number one killer in the Western world,” said Ignarro, noting that loss of nitric oxcide function is one of the earliest indicators or markers of disease.

No documented cancer risk

Since the early 1980s there have been numerous associations made between nitrosamines and human cancers as a result of nitrite (sodium nitrite) being added to meat as a preservative. However, it remains unknown at what levels, if any, nitrosamines are formed in humans after they eat cured meat products, or for that matter what even constitutes a dangerous level in meat or in humans.

Likewise, a causative link between nitrite and nitrate exposure and cancer is still missing, said Bryan. A two-year study on the carcinogenicity of nitrite by the National Institute of Health conclusively found there was no increased evidence of carcinogenic activity in male or female rats or mice as a result.

Moreover, if nitrite were a carcinogen, Bryan said people would be advised to avoid swallowing since saliva contains nitrite. Nitrites also are pumped directly into the heart for therapy purposes when heart attacks occur.

"Nitrites and nitrates are naturally found in our bodies and are in no way a health risk. Quite simply, they are good for us and essential for our cardiovascular health," said Bryan.

Given his findings and those of other scientists working in this area, Bryan said he is concerned by what he calls the misinformation being distributed by some groups regarding the “health risks” of nitrites and nitrates.

The Cancer Project is one of those groups and initiated a campaign around the 2009 All-Star Game in St. Louis, Mo., where it used an image of hot dogs in a cigarette carton to push the message of: “One way we can help prevent cancer - in addition to not smoking - is to stop eating hot dogs and other processed meats.”

In 2006, 1.5 billion pounds of hot dogs were consumed. Sixty-two percent of all Americans eat some form of processed pork, with the average person eating 32 lb. of it a year.

According to the National Hot Dog & Sausage Council’s 2009 survey of hot dog and sausage consumption at major league ballparks in the United States, ballparks expected to sell 21 million hot dogs this season.

Bryan pointed out that since lettuce and other leafy green vegetables actually contain many more nitrites and nitrates than do cured meats, The Cancer Project and those with a concern about these vitamin-like molecules should also consider eliminating salads and all vegetables at ball games.

Actually, studies show that people normally consume more nitrates from their intake of vegetables than from the cured meat products they eat. Spinach, beets, radishes, celery and cabbages are among the vegetables that generally contain very high concentrations of nitrates.

An estimate out of the University of Minnesota puts 10% of the human exposure to nitrite in the digestive tract coming from cured meats and 90% coming from vegetables and other sources.

Nitrates can be reduced to nitrites by certain microorganisms present in foods and in the gastrointestinal tract, and this has resulted in nitrite toxicity in infants fed vegetables with a high nitrate level. However, no evidence currently exists implicating nitrite itself as a carcinogen.

“There is absolutely no scientific basis to single out cured and processed meats as a culprit in certain cancers,” said Bryan.

EDITOR’S NOTE: Trent Loos is a sixth-generation farmer/rancher and founder of Faces Of Agriculture. He is a regular contributor of commentary and articles to Feedstuffs and produces his own radio and television programs on matter related to food production.

TABLE: The original article in Feedstuffs also contains a table showing mean nitrate and nitrite contents of a convenience sample of fruit, vegetables, meats, and processed meats, from “Food sources of nitrates and nitrites: the physiologic context for potential health benefits” by Norman G Hord, Yaoping Tang, and Nathan S Bryan.

See: Feedstuffs