Why Does My Kid Have Gas After Taking Prebiotics? How to Reduce Bloating

Is Gas Normal After Starting Prebiotics?

If your kiddo has started taking a daily prebiotic—like Growing Up Prebiotics—and suddenly seems extra gassy or bloated, you’re not alone. Mild tummy changes, including increased gas, are actually a normal and expected part of adjusting to prebiotic fiber. 

And the good news? It’s usually temporary.

Prebiotics like chicory root inulin and Human Milk Oligosaccharides (HMOs) work by feeding the good bacteria in your little one’s gut. As these bacteria ferment the fiber, they produce beneficial short-chain fatty acids, but also some gas as a byproduct [1]. That means your kiddo’s microbiome is responding, just a little noisily at first.

What Causes the Gas and Bloating?

The gas and bloating after starting a prebiotic are signs ofmicrobial fermentation, especially if your kid isn't used to a high-fiber diet.

Common reasons for bloating after prebiotics include:

• A sudden increase in fiber (especially fermentable fibers like inulin)

• Low baseline fiber intake before starting

• Not enough water to help the fiber move through the gut

• Naturally sensitive tummies, which may need more gradual changes

In a randomized trial by Closa-Monasterolo et al. [2], some children experienced mild bloating and flatulence when starting chicory inulin—but symptoms were generally mild, transient, and improved over time with consistent intake.

How Long Will It Last?

In most cases, bloating and gasimprove within 1 to 2 weeks as the gut microbiota adjusts to the increased fiber load. Your kiddo’s gut bacteria essentially “learn” how to handle this new food source.

The key is not to stop the prebiotic completely, but toslow down and support the process.

What You Can Do to Reduce Gas and Bloating

Here are six science-backed tips to ease the adjustment period:

1. Start Low and Go Slow
Begin with ahalf or quarter dose of the prebiotic, especially if your kiddo isn’t used to fiber. Gradually increase the serving over 1–2 weeks.

2. Mix with Meals
Adding the prebiotic to food (like smoothies, oatmeal, or yogurt) can help slow digestion and reduce rapid fermentation that causes gas.

3. Hydration is Key
Water helps fiber do its job. Encourage sips throughout the day—not just at meals. Aim for at least 4–6 cups per day depending on age.

4. Add Fiber Gradually in the Diet
Support your kid’s gut with gentle, whole food fiber sources:

• Bananas

• Steamed carrots

• Oats

• Cooked apples

These are easier on the belly than raw veggies or beans at the beginning.

5. Tummy Massage and Movement
Encourage light activity like walking, dancing, or even gentle belly massage. Movement helps trapped gas pass more easily.

6. Be Consistent
Skipping days or starting and stopping can prolong the adjustment phase. Stick with a daily routine to help the gut adapt more smoothly.

When to Call Your Pediatrician

While some bloating and gas are normal, reach out to your provider if your kid experiences:

• Severe or painful bloating

• Ongoing diarrhea or vomiting

• Weight loss or poor appetite

• Blood in stool

These may be signs of something more serious, like food intolerances or digestive disorders.

Summary

It’s totally normal for your kid to experience a little gas or bloating when starting prebiotics. That’s the gut microbiome adjusting and it’s a sign that the fiber is doing its job. With a slow start, plenty of water, and daily consistency, most kiddos adjust within a couple of weeks and go on to enjoy the long-term gut health benefits of prebiotic fiber like that inGrowing Up Prebiotics.