Homemade Baby Food: The Danger of Nitrates

Many parents want to make homemade baby food. And why not? The thought of fresh produce from the local grocer… or your backyard garden… sure seems like a nutritional (and palatable) alternative to brand-name jar food that has sat on the shelf for who knows how long. But danger lurks in that good-looking meal, primarily in the form of nitrate contamination and botulism. Today we begin a three-part series on homemade baby food with a close look at nitrates.

So What Are Nitrates and How Do They Get into Your Baby’s Food?

Nitrates are chemicals found in fertilizer. Plants love them because nitrates release nitrogen into the soil. Nitrogen is an important plant nutrient and ensures healthy growth. But nitrates aren’t contained by the soil. They also contaminate the outside of the plant, especially those plants which grow in (or close to) the ground, things like carrots, beets, squash, spinach, and green beans.

The makers of commercially-jarred baby food are careful to clean their vegetables. Unfortunately washing doesn’t remove all the chemicals, so companies test the end-product for nitrates… to make sure your baby’s food is safe. Parents can (and should) wash produce before making homemade baby food. But trouble comes in testing for nitrates, unless you are a bench scientist skilled at performing diphenylamine and copper turning tests.

Okay, so don’t use fertilizer in the backyard garden. That will ensure safety, right? Not so fast. Overuse of agricultural fertilizer has saturated large swathes of American soil with nitrates. These chemicals have leached into ground water and spread into urban areas. Homemade baby food carries the risk of nitrate contamination. Backyard gardens are not immune, and diligent cleaning does not ensure safety.

So What’s the Big Deal? What Will Nitrates Do to My Baby?

Well, you’ve probably heard of hemoglobin. It’s a chemical compound found in red blood cells and instrumental in carrying oxygen to body tissues. Nitrates are bad because they react with hemoglobin, turning the hemoglobin into a compound called methemoglobin. Methemoglobin also carries oxygen, but it doesn’t like giving oxygen to the tissues… it holds the oxygen tightly, and tissues go without. As more and more hemoglobin is converted to methemoglobin, a condition known as methemoglobinemia sets in. At this point, tissues are seriously starved of oxygen. The result? Pale/blue skin color (cyanosis), respiratory distress, seizures, coma, cardiac arrest and death!

Now for the Good News.

Red blood cells contain enzymes which convert methemoglobin back to hemoglobin. Yay! However, young babies have a limited supply of these enzymes, and the protective mechanism is quickly overrun if too many nitrates are ingested. The age at which the body starts making more of these enzymes is between 3 and 6 months of age. So if you wait until 6 months of age to introduce homemade food, most babies will be safe.

Notice I said “most babies.”

Some children have disorders which result in a lifetime of diminished enzyme protection. Diseases such as pyruvate kinase deficiency and G6PD deficiency increase the risk of methemoglobinemia well beyond the age of 6 months.

Nitrates aren’t the only cause of methemoglobinemia. Certain antibiotics and the numbing agent found in teething gels can also convert hemoglobin to methemoglobin. And baby food isn’t the only dietary source of nitrates. Drinking water (especially well water) can contain high levels of nitrates from fertilizer run-off. In fact, the most common cause of methemoglobinemia in babies (including those older than 6 months of age) is the ingestion of infant formula made with nitrate-containing well water!

So What’s a Parent to Do?

Don’t offer homemade baby food containing high-risk ingredients (carrots, beets, squash, spinach and green beans) until after the age of 6 months. This should be easy because solid foods of any kind are not recommended until 6 months of age. If you plan to use well water to make infant formula, ask your local health department to test the well for nitrates (and microorganisms). City water and commercially-bottled water are safe alternatives. Antibiotics and teething gel should only be used under the strict supervision of your baby’s doctor.

Finally, watch for signs of illness in any baby of any age. Don’t ignore symptoms such as pale/blue discoloration of the skin, rapid breathing or trouble breathing. Methemoglobinemia can be treated, but only if you recognize the problem and seek medical attention immediately.

Stay tuned for part 2 of our series… homemade baby food and botulism!

To learn more about homemade baby food, listen to our latest PediaCast episode with Dr. Mike!