GERD is more than just heartburn

Q: I'm a 44-year-old man, and I'm a bit overweight. I've been having trouble with what I thought was heartburn, but my doctor says it's actually something called GERD. How is that different from heartburn? She prescribed medication, but I wonder what else I can do that might help.

A: Your doctor has diagnosed you with a form of heartburn known as gastroesophageal reflux disease, or GERD. Although it's often referred to simply as acid reflux, GERD is more severe. For anyone lucky enough not to have experienced heartburn, the term refers to a painful burning sensation that spreads through the center of the chest, typically behind the breastbone. It may also be accompanied by a sour taste at the back of the mouth or throat.

These symptoms occur because some of the acidic contents of the stomach have moved upward and into the esophagus. That's the tube that connects the mouth and throat to the stomach. Unlike the lining of the stomach, which is designed to withstand extremes in pH, the inner tissues of the esophagus are quite delicate. This leaves them vulnerable to both short- and long-term damage from the incursion of stomach acid.

The one-way flow of food from the esophagus to the stomach relies on the proper function of a flexible ring of muscle known as the lower esophageal sphincter. It relaxes to let the swallowed contents of the mouth pass into the stomach. Other than that, the sphincter remains tightly closed, which protects the esophagus from stomach acids. Heartburn is the result of an occasional breach of this barrier.

But in GERD, the lower esophageal sphincter repeatedly fails to constrict adequately. This results in repeated esophageal injury from stomach acid. Left untreated, it can cause a range of health issues, including esophageal ulcers, a precancerous condition known as Barrett's esophagus and an increased risk of esophageal cancer.

Risk factors of GERD include older age, being overweight, smoking, being sedentary and the size and timing of meals. The medications your doctor has prescribed will lower stomach acid production and give the esophagus time to heal. But the behavioral changes you are asking about are important, as well. In fact, they are considered to be crucial to managing the condition.

Most important is to reach a healthy weight, as carrying extra pounds is a significant risk factor for GERD. Your doctor has also likely counseled you against smoking and to begin regular exercise. Remain upright as you eat and afterward, as lying down puts pressure on the already-weakened lower esophageal sphincter. For this same reason, it is beneficial to stop eating two to three hours before bedtime.

Stress increases stomach acid production, so relaxation techniques such as meditation, yoga and tai chi can help. Good sleep hygiene is also important. There is some evidence that sleeping on a wedge, which elevates the torso, can offer relief. For side sleepers, lying on the left side rather than the right can be effective.

There is no single magic bullet when it comes to GERD. Give yourself the best chance of improvement with a consistent and multipronged approach.

Q: How important is it to get the new COVID-19 booster? My husband and I are in our mid-40s and in good health. We both got the Moderna vaccine when it first came out, and we got a booster, too. What's in this new shot? Also, is it true that it's a good idea to switch up vaccine brands?

A: We think it's important for everyone who is medically eligible to be fully vaccinated against COVID-19 and to remain up-to-date with boosters. And yes, this includes the new bivalent vaccine, which was authorized by the Food and Drug Administration at the end of August.

The latest data show 90% of all new COVID-19 infections in the United States are now caused by omicron BA.5, the newest subvariant. That speaks to the fact that it is the most easily spread strain of the coronavirus to date. The vaccine booster that you're asking about includes components of the original coronavirus that causes COVID-19 and the omicron variant that has become the dominant strain. The boosters have proved to be effective at preventing serious disease as well as helping to prevent against initial infection.

Vaccines work by training the immune system to recognize one or more specific molecular characteristics of an invader. This allows the body to quickly mobilize its defenses and neutralize the threat. In the case of the coronavirus that causes COVID-19, the identifying marker was the distinctive spike protein on its outer surface.

The new bivalent booster trains the immune system to recognize the spike protein from the original virus. It also includes a "tutorial" that's specific to the omicron variant. By targeting these two distinct spike proteins - that's the "bivalent" part of the vaccine - the hope is that the new boosters will provide the person who receives the shot with more robust protection.

For the approximately 30% of people in the U.S. who remain unvaccinated, the guidance is to begin with the original two-dose series of the vaccine. You are considered to be up to date when you have completed the primary two-dose COVID-19 vaccine series and continue to receive the most recent booster dose that is recommended for you by CDC. This guidance varies by each person's age, their specific COVID-19 vaccination history, the timing of their most recent dose and their medical history. You can find information about the coronavirus vaccines and boosters, as well as vaccination sites near you, at vaccine.gov.

You also asked about a mix-and-match approach to vaccines and boosters. This refers to the practice of switching between the Moderna and the Pfizer vaccines. There is reliable evidence that this practice may lead to enhanced immunity. People produce antibody responses from all three booster vaccines, no matter which vaccine they have originally received. But studies show that a subsequent dose of a different vaccine causes similar or higher antibody responses than a booster of the same vaccine.

Based on data from several studies into this approach, the FDA has authorized the use of mix-and-match doses for currently available COVID-19 vaccines.

• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.