2.7 THIS IS HOW WE DO IT: Do anti-acid drugs impair digestion and increase the risk of food allergies?

2.7 THIS IS HOW WE DO IT: Do anti-acid drugs impair digestion and increase the risk of food allergies?

Your stomach is a pretty extreme environment compared with the rest of your body—at least when it comes to acidity. In the previous section, we saw that hydrochloric acid produced in your stomach creates an extremely acidic environment, with a pH between 1 and 3.

How does the stomach’s acidic environment aid in digestion?

Your stomach’s high acidity aids in breaking down chemicals in the food you eat—particularly proteins. (It also helps your body fight against bacterial infections.) This is important because proteins that pass through the stomach undigested can trigger an allergic response, and your body will treat them as a sort of foreign invader and health risk, mounting an immune response to them.

54

But for millions of people, the acidity in their stomach can lead to discomfort. For a wide variety of complaints—including ulcers, heartburn, and acid reflux—many people take medications (called antacids) that neutralize stomach acids or medications that reduce the stomach’s production of acids or the major protein-digesting enzymes. In fact, one of these medications, Prilosec, is one of the best-selling drugs in the United States, with sales of more than $700 million in 2013.

Does reducing stomach acidity have health consequences? How could we evaluate whether acidity-reducing medications increase the potential for food allergy?

Researchers have suspected that anti-acid medications might reduce protein digestion, and that undigested proteins stimulate allergies. To test this idea, they explored two experimental strategies.

  • 1. First they evaluated the effectiveness of protein-digesting enzymes at several different levels of acidity. For this, they simply combined these enzymes and common dietary proteins in test tubes, at body temperature.

The result? At the typical stomach pH of 2, they found that the proteins in milk are completely digested within 1 minute. Conversely, at less acidic pH values of 3 and 5, the milk proteins were largely undigested, even after 1 hour.

From these results, what could the researchers conclude about the role of stomach acidity in digesting proteins?

  • 2. In their second experimental strategy, the researchers observed 152 people who were seeking treatment for an ulcer, before and after a three-month anti-acid treatment. They evaluated each participant for signs of allergic reactions to a variety of proteins.

The result? Before the three-month anti-acid treatment, 10% of the subjects exhibited signs of having had an immune response to at least 1 of the 19 dietary proteins the researchers tested. After three months of anti-acid treatment, 26% of the subjects exhibited signs of having had an immune response to at least 1 of the 19 tested dietary proteins.

From these results, what could the research team conclude about the role of anti-acid medications in causing normal dietary proteins to stimulate an allergic response?

The researchers also made observations on 50 control subjects, who were not seeking anti-ulcer treatment. (What do you think was the purpose of these controls?) As with the other subjects prior to anti-acid treatment, just 10% exhibited signs of having had an immune response to at least 1 of the 19 tested dietary proteins.

From their results, the researchers concluded that anti-acid drugs “hamper the biological gate-keeping function of the stomach.”

TAKE-HOME MESSAGE 2.7

Dietary proteins are not digested by the stomach when the stomach’s pH is increased as a result of medications taken to treat ulcers, heartburn, and other digestive problems. This can put people who take anti-acid medications at risk for developing allergic responses to common foods.

Explain how researchers investigated the question, “Do anti-acid drugs impair digestion and increase the risk of food allergies?” What did they conclude?

55