Insights by Goldie
Homemade baby food
Sound Consumer | May 2003
by Goldie Caughlan
Quality Standards Specialist
Question from Susann Brown
Several of us meet regularly in a new parents group, all with young babies who will soon be starting on baby food. We want to make our own baby food, but we've heard there may be some types of vegetables that should not be prepared at home, as they could have excess levels of nitrates. What would be the effects of this? Why would "home prepared" be potentially higher in nitrates? Which vegetables are of concern? And wouldn't organically grown produce have lower nitrates?
Goldie Caughlan replies
The issue is whether levels of nitrates in food or water might put young infants at risk for developing methemoglobi-nemia (medically abbreviated as MHB), commonly called "blue baby syndrome." Although very rare, there is a potential for a life-threatening condition, especially to very young infants. Excessive nitrates might interfere with the ability of the infant's red blood cells to carry oxygen, resulting in a type of anemia characterized by "ashen, bluish (cyanotic) hue to the skin and nails."
The American Academy of Pediatrics Committee on Nutrition addressed this in September 1970. Their brief three-page report titled "Infant Methemoglobinemia: The Role of Dietary Nitrate," Vol. 46, #3, p. 475-478, is available at www.aap.org/policy/356.html.
The report stated, "Nitrates, per se, are toxic only at levels higher than those encountered in foods. The potential hazard of nitrate in water or food is its conversion to nitrite either prior to or after ingestion. Conditions for reducing nitrate to nitrite during digestion must exist, or nitrate will be metabolized or excreted without adverse effect. Only infants, the pH of whose gastric juice is higher than 4 and who harbor nitrate-reducing bacteria in the upper GI tract, develop sufficient concentrations of nitrite to produce methemoglobinemia."
In other words, usually only very young infants with an atypical pH level in their digestive juices would likely be at risk. It was also pointed out that bacterial infections and diarrhea can also be associated with the condition.
The report continues, "Extensive reviews have failed to identify any infants with methemoglobinemia attributable to the ingestion of plant nitrate per se. Nitrate poisoning appears to be associated only with ingestion of nitrate in water rather than with naturally occurring nitrate in foods."
The reviewers theorized that if nitrate was excessive in drinking water, exposure might be higher, whereas nitrates from plant foods would likely be only intermittent. The report, written more than thirty years ago, noted that "nitrate contamination of drinking water from runoff from farms fertilized with nitrates" was emerging as a nitrate source "potentially capable of producing methemoglobinemia."
Agriculturally contaminated drinking water has now been documented in more than 40 states in the past few years. (See "Pouring it On," a report of the Environmental Working Group, at www.ewg.org/pub/home/Reports/Nitrate/NitrateRelease.html)
The pediatric report also warns that improperly stored produce could dramatically increase the conversion rate of high nitrates to nitrites. They tested spinach that was too tightly packed and shipped or stored in very warm conditions, and found a high rate of conversion of nitrates to nitrites.
(Reading this, I suddenly recalled that many years ago I read advice to discard old, wilted vegetables, such as celery — resisting the urge to make soup stock from them — as their nitrates could have converted to high nitrite levels).
Nutritionists writing in Maternal and Infant Nutrition Briefs, July/August 2001, reviewed a report published in Pediatrics 2001 titled "Methoglobinemia and consumption of vegetables in infants." They reviewed studies of puréed greens tested for nitrate to nitrite conversion immediately after cooking and puréeing and at intervals during refrigeration.
From this, they recommended that home-prepared vegetable purées be refrigerated for no longer than 12 hours, and leftovers should be discarded or frozen. They added that parents who are very concerned about nitrates might opt for commercially prepared baby foods since nitrate levels are regularly monitored in commercial baby food production.
I found one long, very technical agricultural report titled "Comparison of Nitrate Content in Leafy Vegetables from Organic and Conventional Farms in California" from June 1999. (No indication was given as to a journal or publication date.) The report concluded that the nitrate levels of conventionally grown spinach did "exceed the maximum levels specified by European Commission Regulation much more often than organic spinach." The report noted that the European Commission sets and monitors levels for nitrates.
It also commented that the U.S. Public Health Service and National Research Council have studied the issue for years and have suggested regulations, but no nitrate standards for vegetables have been introduced in this country. The report stated organic spinach, in the study, did sometimes have high nitrate levels, and it was suggested that guano (bat dung) and Chilean nitrate (a mined substance), when used in organic production, correlated with the higher nitrate levels, as opposed to lower levels found in organic spinach grown with composted materials.
So, how does a parent decide? The risk of exposing your baby to high nitrates or nitrites from home-prepared vegetables appears to be very low, but like many risk factors, it is not "zero." As you try to decide, ask around in your community of friends, co-workers and family members.
On the one hand, you'll hear that a great many of their babies have thrived on healthful, home-cooked baby foods, just as my kids and my grandchildren have. On the other hand, many practices of the past have to be reexamined in the present, so questioning whether this is right for you and your baby makes sense, too.
Ultimately, you as parents will have to decide for yourself. My "two bits" worth of advice is this: If you are sufficiently concerned about the issue of nitrates, then the logical approach is to apply the precautionary principle. As a precaution, just delay introduction of the particular vegetables that are generally mentioned as sometimes having higher levels of nitrates. That means you hold off on introducing carrots, any leafy greens, beets or turnips for just a few weeks (or else buy little jars of organic baby foods for those, if you prefer).
Meanwhile, go ahead and serve your baby home-made purées of many other nutritious organic vegetables, such as sweet potatoes, yams, pumpkin, hard shelled butternut or other hard squashes, fresh or frozen green peas, broccoli or cauliflower.
Also, the experts' advice not to store baby food in the refrigerator for longer than 12 hours makes good food safety sense for your little one's health and nutrition. It's best either to prepare your baby's food fresh each day, or make up several portions and immediately freeze little cubes in ice-cube trays. As soon as they are frozen (about 3-4 hours), transfer cubes to closed containers, label and date. They will be fine for a few weeks, conveniently (and inexpensively) ready to heat, serve and nourish your baby.