Hey guys,
I think it’s time for another addition to my ‘Close Up’ series. Today, I want to write a little bit about the lactose/fructose tolerance hydrogen breath test.
Preparation
The prep for these kind of tests is fairly easy compared to a gastroscopy or colonoscopy.
It’s important to eat the last meal not a minute later than 10pm if your test is scheduled at 8am. The last liquid should be consumed at least 6 hours before the test starts.
It’s not necessary to stop eating the substance you might have an intolerance to until you have the results. So continue eating your normal diet unless your symptoms are unpleasant.
If you are taking medication, check with your doctor about the possibility of a false negative result. Also, do not smoke or brush your teeth in the morning!

The lactose/fructose tolerance test
Your doctor first checks the amount of hydrogen in your breath without lactose/fructose influence.
Then, this test requires you to drink a glass of water containing high amounts of lactose/fructose.
Your doctor measures the amount of hydrogen in your breath at regular intervals, often every 30 minutes. The whole process can last 2-3 hours.
It is crucial to do this test under supervision, just in case you are experiencing harsh symptoms like abdominal cramps, vomiting or diarrhea.
Normally, only small amounts of hydrogen is detectable. However, if a body doesn’t digest the lactose, it will ferment in the colon, then start releasing hydrogen and other gases which are absorbed by the intestines and eventually exhaled. Larger than normal amounts of exhaled hydrogen measured during a breath test indicate that that person’s body can’t fully digest and absorb lactose.
Tips
- Take something, to take your mind of waiting, with you. A book or music.
- Drink lots of fluids the day before, so you don’t feel the urge to replenish yourself. While the test is going on, you’re still not allowed to consume any foods or liquids.
- Set your test as early in the morning as possible.
- Take a companion with you. Just in case of a bad reaction. This person can drive you to the next emergency room or home.
- Take something to eat and drink with you (for after the test).
So, that’s it. Results for hydrogen breath tests are delivered immediately when finished. Well, half an hour between the last breath check and the results. This is why you should bring food 😀
There are also other ways to test lactose/fructose tolerance, but this is the most accurate one. The others are more or less inconclusive, so just do this one, if you need to.
I can happily write I’m neither fructose nor lactose intolerant. This is confirmed through two tests: a blood test and a hydrogen breath test for each.
Have you done a lactose/fructose tolerance test or are you about to? What was your result?
Keep strong,
*This post is based on research and personal experience. All products (if any mentioned) are bought and tried by myself if not written otherwise.