Date: Wed, 07 Apr 2004 09:16:55 -0400

From: Alex Avery <aavery@rica.net>

Subject: Re: Nitrates

Most importantly, you should know that I am not alone in thinking that we implicated nitrates in water used to reconstitute infant formula--and set the 10 ppm MCL in drinking water--well before we really understood the etiology of infantile methemoglobinemia. Dr. Nigel Benjamin, head of the Dept of Clinical Pharmacology, St. Barts hospital, London, and Dr. Tom Addiscott. Dr. Benjamin has conducted extensive research into this topic and the newly realized fact that if we do not consume enough nitrates, our bodies will produce them and concentrate them in our saliva -- likely as a defense against pathogens.

The ONLY reason why nitrates are regulated in drinking water is the presumed blue baby threat to infants 6 months and younger from formula reconstituted with nitrate-contaminated water. For the rest of us, nitrates are likely beneficial (Dr. Benjamin's work)

As for blue baby, we now know that infantile methemoglobinemia is caused primarily via endogenous overproduction of nitric oxide in response to infection, gastroenteritis, etc.

The drinking water MCL for nitrates was established through a flawed survey of state public health departments by the Am Public Health Association conducted in 1949-1950 (17 states responded, reporting 214 cases with nitrate concentration levels reported). Only 5 of those 214 cases occurred at drinking water nitrate levels between 10-20 ppm nitrate-nitrogen. Yet almost surely those 5 cases (and perhaps all below 50 ppm) were endogenous cases with incidental nitrate contamination of the water. The survey was guaranteed to implicate all nitrate levels above background (3-5 ppm) because the survey asked the state public health departments for any info on blue baby cases "definitely linked to nitrate-contaminated water." Any blue baby case that occurred with above background nitrate levels was assumed to have been caused by the nitrates. We now know that blue baby can be caused simply by giving an infant an offending allergenic protein (cows milk, for instance) and without any exogenous nitrate or nitrite exposure whatsoever.

In fact, in 1948, Drs. Cornblath and Hartmann were unable to initiate methemoglobinemia in young infants already hospitalized for blue baby ostensibly caused by nitrate-contaminated water, even with formula contaminated at 100 ppm nitrate-nitrogen. If nitrates were such a danger, giving infants pureed spinach and other high-nitrate vegetables would be fatal, but it's not.

Below is a small section of a book I'm writing on organic foods that discusses this further. If you have any questions, please feel free to contact or call me on the phone.

Alex Avery

Hudson Institute

(540) 337-6354 or -6387

aavery@cgfi.org

Nitrate Nonsense

Food nitrate content is often analyzed in comparing organic to non-organic foods, under the false notion that nitrate (NO3) is toxic. One of the supposed nutritional advantages of organic foods touted by activists is its lower nitrate content.

However, nitrate is not toxic and is not nutritionally harmful. Our bodies produce nitrate constantly, accounting for half of a typical persons total nitrate exposure. Nitrate may, in fact, be an important dietary component, as recent research shows that the human body will manufacture nitrate and concentrate it in our saliva if not enough is consumed in the diet.

Nitrates are naturally present in nearly all fruits and vegetables, with leafy green vegetables sometimes having high levels (>2,000 parts per million). Research does suggest that organic fruits and vegetables often have lower nitrate levels, typically 10-40% lower. This is because of the lower soil nitrogen levels from the slow-release organic fertilizers. Because nitrogen is the limiting factor on crop growth, any nitrate that is taken up by organic crops is quickly incorporated into other nitrogen-containing stuff, like proteins, etc.

There is a serious kernel of truth to the worry over nitrates. Nitrite (NO2), chemically related to nitrate (NO3), is toxic. At higher exposures, nitrite binds to the oxygen-carrying hemoglobin in our blood, causing a form of chemical suffocation called methemoglobinemia. Bacteria can convert nitrate into nitrite through anaerobic respiration.

Young infants are particularly susceptible to methemoglobinemia, called blue baby syndrome, and there have been a few nitrite poisonings (non-fatal) in young infants from spoiled carrots and spinach. Carrots typically contain between 100-300 ppm nitrate, in both organic and non-organic samples. Spinach contains 100-1,000 ppm nitrate, organic and non-organic. If these vegetables are prepared into purees, juices, or broths for infant feeding and proper food safety, hygiene, and refrigeration techniques are not followed; bacteria will proliferate in the juice/broth and convert any nitrate present into nitrite. The concentration of toxic nitrite in the juice/broth will increase over time, depending on the bacterial levels.

In fact, this bacterial conversion of non-toxic nitrate to toxic nitrite can even happen in the leaves and whole fruit and vegetables themselves if they are stored for long periods in hot, humid conditions. Instances of spinach leaves exceeding 2,000 ppm of toxic nitrite have been documented.

But it must be remembered that it is nitrite, not nitrate that is toxic. Moreover, this toxic occurrence can occur just as readily in inappropriately stored organic foods. Unspoiled, properly prepared purees and juices are fine for infants, even when nitrate levels are seemingly high. Beets and spinach typically have nitrate levels as high as 1,000-2,000 ppm, but are perfectly safe to feed to infants when prepared and stored properly. The Committee on Nutrition of the American Academy of Pediatrics, being concerned over nitrite poisoning, stated in 1970, "More than 350 million jars of canned spinach and beets have been used in the United States and Canada over the last 20 years without causing any proven instances of [nitrite poisoning]." To this day, none have been reported.