Dispel myths about the danger of nitrates
June 24, 1999
This spring, the Register printed an editorial warning of the dangers to “infants and pregnant women” of nitrates in Des Moines’ drinking water and calling for more responsible farming to stop “the problem at the source.” While the goal of limiting nitrogen losses from farmland is sound, the editorial missed the boat on the health risks from nitrates.
The health concern is blue baby syndrome which can strike infants less than six months old. Until recently, nitrates in drinking water had been thought to be a major cause of this potentially-fatal condition. Fortunately, we now know that nitrates are much less a threat than we once believed.
Blue baby syndrome was always relatively rare. A survey conducted in the late 1940s by the American Public Health Association turned up less than 300 cases nationwide over a period of several years. Today, blue baby syndrome is essentially non-existent: there has been only one reported case of blue baby syndrome linked to nitrate-contaminated water in the U.S. over the last 25 years. This isn’t because we cleaned up the nitrates from our drinking water. The Environmental Protection Agency estimates that over 65,000 infants per year in the U.S. are exposed to drinking water above the federal limit of 10 parts per million (ppm) nitrate-nitrogen.
If that’s true, why aren’t we seeing more blue baby victims? The answer is that nitrates don’t cause blue baby syndrome. In experiments conducted in the 1940s, healthy infants were fed only formula made with water containing ten times the current allowable limit of nitrates. After more than a week the infants still showed no health problems whatsoever.
Scientists have known from the beginning that there were critical factors involved other than simply nitrates in the water, they just didn’t know exactly what those factors were. Since virtually all blue baby victims had some nitrates in their drinking water, it was believed that limiting exposure to nitrates would prevent blue baby. It didn’t.
Scientists have now documented hundreds of blue baby cases in areas with low-nitrate water. The common element in all of these cases is some sort of gastrointestinal problem, such as diarrhea or gastroenteritis. Looking back at the medical reports, the number one symptom reported in blue baby cases with nitrate-contaminated water is also diarrhea. What’s the connection? It was recently discovered that gastrointestinal inflammation can cause our bodies to produce a chemical called nitric oxide as part of the immune response. This chemical is broken down into nitrite, the cause of blue baby syndrome in young infants. Even protein intolerance, such as to cow’s milk-based formula, has been proven to cause blue baby syndrome in some infants, although it is rarely life-threatening.
Public health records show that the vast majority of blue baby cases on which the current regulation is based were from rural farm households served by shallow, poorly-constructed wells located too close to a barnyard, cesspool or septic tank. These wells were contaminated with both nitrates and fecal bacteria (these contaminants migrate through the soil together). It’s no wonder then that these infants suffered diarrhea and, in a few cases, blue baby syndrome.
Which brings us back to today.
Nitrates are not an imminent threat to infant health. Only if an infant is suffering from a gastrointestinal problem will there even be the chance for blue baby, regardless if there are nitrates in the water. Because of modern medicine, these chances are exceedingly rare, as evidenced by the lack of blue baby cases.
Nor are nitrates a threat to pregnant women or a cancer risk, as some researchers claim. The prestigious National Research Council of the National Academy of Sciences examined these questions in detail several years ago and dismissed such concerns for the simple reason that nitrates are an unavoidable fact of life. Half of the nitrates we are exposed to are produced by our own bodies and over 90% of the rest come naturally from our food, primarily vegetables. If nitrates posed a cancer risk or were a health threat to pregnant women, fresh veggies would be a strict no-no.
The bottom line is that the current regulation on nitrates in drinking water was established during a time when we knew very little. It was the right decision to play it safe and limit nitrates in drinking water. But that time has passed. While many scientists believe that it makes sense to avoid higher levels of nitrates in our water (>40 ppm or more), there is no reason to maintain the current 10 ppm limit. Raising the federal standard to just 20 ppm would not raise the health risk to small infants or the general public, but it would eliminate the need to treat Des Moines’ drinking water, saving millions of dollars. It would also save rural homeowners the thousands of dollars many of them are currently spending for expensive in-home nitrate removal systems.
It is unfortunate that so many have been so afraid for so long. It is time that we put the myths about nitrates to rest.
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