Can Kids with PKU Take Growing Up Prebiotics?

What Is PKU?

Phenylketonuria (PKU) is a rare genetic disorder in which the body cannot break down an amino acid calledphenylalanine. Left unmanaged, high levels of phenylalanine can build up in the blood and cause serious health problems, including brain damage and developmental delays. 

That’s why kiddos with PKU must follow astrict low-protein, low-phenylalanine diet for life, especially during early growth.

Even small amounts of phenylalanine in unexpected foods, medications, or supplements can be a concern for parents managing PKU. So it’s natural to ask:Can my kid with PKU safely take Growing Up Prebiotics?

The Short Answer: Likely Yes—but Ask Your Doctor First

Growing Up Prebiotics is atasteless, textureless powder designed to support gut health in toddlers and kids. It containsno added protein andno phenylalanine as an active ingredient. 

However, because it includes a small amount of2’-fucosyllactose (2’-FL)—a human milk oligosaccharide (HMO) fermented from lactose—there may betrace amounts of residual protein in the final product.

While the protein content is extremely low, it may still be relevant in the context of PKU, whereevery milligram of phenylalanine counts.

What’s Actually in Growing Up Prebiotics?

The powder contains:

• 2’-FL HMO – a prebiotic fiber structurally identical to that in breast milk

• Chicory root inulin – a plant-based fiber that feeds beneficial gut bacteria

• No added sugar, protein, or phenylalanine

That said, trace residual protein from the HMO fermentation process may be present at no more than 0.01% by weight. Based on the serving size of 2 grams, that equates to less than 0.2 mg of total protein per serving—a minuscule amount that may or may not include phenylalanine depending on the protein fragment, which is not actively added or measured.

Why Prebiotics May Be Helpful in PKU

Kids with PKU often face challenges with gut motility and constipation due to a very low-protein diet. Prebiotic fibers likeinulin andHMOs can help by:

• Feeding good gut bacteria (likeBifidobacteria)

• Improving stool frequency and softness

• Supporting immune health and microbial diversity

A healthier gut may also help with better absorption of PKU-safe formulas, vitamins, and other nutrients [1].

What to Ask Your Healthcare Team

Before startingGrowing Up Prebiotics, consult your Pediatrician, metabolic specialist, or Registered Dietitian managing your child’s PKU. Here’s what to ask:

• Can my child tolerate supplements with trace amounts of residual protein?

• Will this product impact my child’s daily phenylalanine allowance?

• Would you like to review the full ingredient breakdown and manufacturing details?

Summary

Growing Up Prebiotics contains no added phenylalanine and an extremely low amount of residual protein, making it likely safe for kids with PKU. There are no current studies on contraindications between prebiotics and PKU.

However, due to the strict nature of PKU dietary management, it’s essential to speak with your healthcare provider before adding any supplement, even one as low-risk as a prebiotic powder. When approved, it may be a helpful tool to support gut health in kiddos with highly restricted diets.