Samuel N. Marcus M.D., Ph.D.

EL CAMINO GI MEDICAL ASSOCIATES

CROHN'S & COLITIS MEDICAL CLINIC

Hydrogen Breath Testing

What is a Hydrogen Breath Test?

There is only one reason why your breath would test positive for higher-than-normal levels of hydrogen; the presence of very specific, anaerobic bacteria that produce hydrogen as a byproduct of eating sugar/carbs. These bacteria live in the colon. When they are exposed to unabsorbed food particles – primarily sugars and carbohydrates – they eat on them and excrete hydrogen gas.

This hydrogen, which can be tested via the breath, is a sign that something is wrong with your digestive tract – specifically the small intestine, where the bulk of nutrient absorption occurs. If your small intestine was healthy, those unabsorbed particles wouldn’t make it all the way down to the colon in the first place.

Over a period of time, as the bacteria and their hydrogen byproduct increases in number, they can actually back up into the small intestine. When this happens, the hydrogen will eventually be absorbed into the blood stream, make its way into your lungs, and is expelled when you exhale.

The result is measurable hydrogen levels, read by our hydrogen breath test, causing us to do further exploration and diagnosis so we can select the right treatment for your particular digestive issue.

When is Hydrogen Breath Testing Used?

There are three different conditions that are diagnosed using hydrogen breath testing:

  1. Certain sugar intolerances. If those aforementioned bacteria have access to unabsorbed sugar, we can assume that your body has a particular sugar intolerance. The most common version of this is lactose intolerance (the sugar found in milk), however people can also have difficulty digesting other sugars, like fructose, sorbitol or sucrose.
  2. Bacteria overgrowth. Your body relies on a balance of flora and fauna. If the bacteria colonizing the small intestine are overpopulated, it causes digestive issues.
  3. Rapid passage of food. Sometimes, food simply moves too fast through the gastrointestinal (GI) tract, which causes its own share or problems, ranging from abdominal pain, and excess gas to bloating, distension and diarrhea.

Each of these things can be tested for as monitor the levels of hydrogen in your breath as your body processes (or doesn’t process, more likely) certain sugars.

What Happens During the Test?

Your hydrogen breath test takes a series of hours (often five or more) to complete so you will need to take the day off from work. Patients must also fast for at least 12 hours before the test to ensure we get accurate readings.

To start, you will be asked to blow into a balloon and we will measure the level of hydrogen. Then, you will be given a particular sugar to drink and we will begin to test your breath again – roughly every 15 minutes. These measurements, over time, paint a picture of what is happening, and when it’s happening, as the sugar makes its way along your GI tract.

For example, a higher hydrogen reading will indicate the sugar made its way through to the colon, rather than being absorbed by the small intestine, as it should have been. If excess hydrogen appears on the quicker side, then we know rapid passage of food is an issue, because the sugar made it there faster than it should have. In cases where bacteria levels are elevated in the small intestine, we’ll see a pattern of two different increases in hydrogen levels – first from the small intestine and a second one from the colon.

There are limitations to hydrogen breath testing, but even in cases where the tests aren’t entirely accurate, the results can help us move to other diagnostic tools, including blood tests or the culturing of fluid from the small intestine to see if harmful bacteria are present.

Your treatment will be based on the results of these tests. Thus, a particular sugar intolerance is typically treated by eliminating that sugar from the diet. Bacterial overgrowths can typically be treated with a round of antibiotics and perhaps a change in diet and/or lifestyle, and so on.

You can contact the office of Dr. Marcus to learn more about hydrogen breath tests or to schedule yours.  (650) 603-5436.