Bacon--A health Food?

I thought this was pretty funny. Harold McGee writes for
the New York Times on the Science of Food and Cooking and this is about the science of nitrites. Think you know--think again. Susie

This is from Harold McGee's site
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In April's Curious Cook column in the New York Times I wrote about various ways of preserving the color of red meats, both industrial (carbon monoxide, lactates) and traditional (nitrite, time). Here's some additional information about an aspect of nitrite biology that puts the healthfulness of traditional nitrite-cured meats in a new, surprisingly positive light.

As I explain in the column and in On Food & Cooking, sodium nitrite and its precursor, sodium nitrate, have long been added to salt-cured meats for several reasons. Nitrite prevents the growth of botulism bacteria in the low-oxygen interior of sausages; it produces a characteristic flavor; and it preserves a red-pink color in the meat.

Nitrite keeps meat rosy in this way: the nitrite ion (NO2-) reacts with other substances in the meat to form nitric oxide (NO), which then binds tightly to the muscle pigment myoglobin, and prevents it from being attacked by oxygen or other substances that would alter it and dull its color. So nitrite-cured meats contain nitric oxide, plus residual nitrites and nitrate that hasn't been converted to nitric oxide.

When I first started writing about food in the late 1970s, cured meats had just come under suspicion of being a health hazard. Scientists had found that their nitrite could react in the stomach and during cooking to form compounds called nitrosamines--and nitrosamines were known to cause DNA damage and cancer in laboratory animals. As a result, manufacturers gradually lowered the residual nitrite levels in their cured meats, both by reducing how much they added in the first place, and by including ingredients like vitamin C which help convert remaining nitrite to nitric oxide.

Over the last couple of decades, persisting worries about nitrite-cured meats have been allayed by the realization that bacteria in our mouths convert some of the copious nitrates found in vegetables into nitrites even as we eat them, so meats contribute relatively little to our daily nitrite intake. Epidemiologists have also looked and failed to find any correlation between nitrite or nitrate intake and the incidence of stomach cancer in humans. There is a persistent association of very high intakes of salt-cured fish and meats with the incidence of digestive-system cancer in Asia and Eastern Europe, but this seems to be caused by the salt itself. Salt levels in many modern cured meats are also lower than they used to be, because the original preservative function of salt can now be augmented by refrigeration.

So cured meats are now thought to have the same disadvantages (mainly their saturated fat content) as fresh meats. They're no longer thought to be especially bad for us. In fact, it now looks as though their nitrite may be positively beneficial! There's a growing body of evidence that eating foods rich in nitrate and nitrite causes the production of nitric oxide in the stomach, where it increases blood flow in the protective mucosal layer, thickens that layer, and so makes the stomach less susceptible to ulcers.

I discovered this evidence in a 2004 review written by a researcher at the National Institutes of Health, Mark T. Gladwin, who also discusses the potential therapeutic uses of nitrite in treating various circulatory problems (like nitric oxide, nitrite itself causes blood vessels to relax and widen). Gladwin concludes that in light of these developments, because people still worry about cured meats, and because bacteria in our mouths contribute to our nitrite intake,

perhaps we should avoid mouthwash and feel slightly less guilty about eating hot dogs at the ball park.

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Gladwin, M. T. Haldane, hot dogs, halitosis, and hypoxic vasodilation: the emerging biology of the nitrite anion. Journal of Clinical Investigation 2004, 113, 19-20.