Here's just the first of ACSH's top 10 examples of groundless health scares from 2007, as condensed by the Toronto Star on January 4, 2008:
Condensed from the American Council on Science and Health's list of medical stories that made us worry unnecessarily in 2007:
1. The (Unfounded) Scare: People who eat the most sodium-nitrite-containing meats, such as hot dogs or bacon, are more likely to have chronic obstructive pulmonary disease (COPD) compared to those who eat none or very little. By the late 19th century, scientists had figured out sodium nitrate acted as a preservative in meat.. In the 1920s it was discovered that sodium nitrite, a breakdown product of sodium nitrate, did the same thing more effectively and, by the 1950s, research had also shown that nitrite prevented germination of the bacterial spores that cause botulism in canned goods.
Origin of the Scare: In 1970, a paper in the journal Nature concluded that nitrites reacted in the body with other agents in food to form nitrosamines, substances know to be animal carcinogens. Rodent studies have shown a link between nitrite consumption and reduced lung function. In April, a new study in the American Journal of Respiratory and Critical Care Medicine concluded that eating cured meat was directly linked to an increased risk for COPD.
The Bottom Line: Nitrites have been used to cure meat for almost a century with no evidence of any risk to human health. Studies showing nitrites to be harmful have been done in high-dose animal experiments not comparable to the small amounts to which humans are exposed. Also, nitrite levels in cured meat have dropped by 80 per cent since the 1970s and vitamin C is now added to cured meat to prevent the formation of nitrosamines.