PHGG Supplement: Gut Health Links to Memory & Sleep
TL;DR: A 2024 double-blind RCT found 5g/day PHGG for 12 weeks improved visual memory and waking sleepiness (less morning grogginess) in healthy adults 60+, with no PHGG-related adverse events reported.
If you’ve ever thought “fibre is just for the bathroom,” a newer clinical trial suggests that a PHGG supplement may do more than support regularity - it may also support visual memory and sleep quality in older adults.
What is a PHGG supplement?
PHGG (partially hydrolysed guar gum) is a water-soluble prebiotic fibre.
“Prebiotic” means it feeds beneficial gut bacteria.
Because it dissolves well and is low in thickness compared with some fibres, it’s often easier to take daily.
The study, simplified
A 2024 study published in Nutrients tested whether a PHGG supplement could support brain and sleep outcomes in healthy adults over 60.
- People took 5 g PHGG daily (or a placebo) for 12 weeks
- The study was randomized and double-blind (stronger design for credibility)
- Researchers tested cognition, sleep, and mood
Key Result: Visual Memory Improved
The standout cognitive change was visual memory - the brain’s ability to remember shapes and visual information (think: recalling what you saw on a screen, remembering layouts, recognising items, navigating routines).
After 12 weeks, the PHGG group scored better than placebo on visual memory.
That matters, because visual memory is tied to everyday independence:
- remembering visual instructions
- navigating places and routines
- recognizing objects and patterns
- keeping track of “where things go”
Sleep: Less “Brain Fog”
The PHGG supplement group also reported better sleepiness on rising - basically, waking up feeling less foggy and more mentally switched on.
That improvement was seen at 8 weeks compared with placebo, with a similar direction continuing at 12 weeks.
Inside the PHGG group (compared to their own baseline), sleep measures also improved (like getting to sleep and staying asleep).
Mood & Vitality
Mood didn’t clearly beat placebo overall, but within the PHGG group:
- Vigor/activity increased
- Confusion/bewilderment decreased
If you’re looking at this through a “how do people actually feel?” lens, this points toward:
- more “get-up-and-go”
- less mental muddiness
Why would a PHGG supplement affect memory or sleep?
The study focuses on the gut–brain axis.
The simple idea:
Feed gut microbes → they produce helpful compounds → those signals can influence inflammation, stress response, and brain function.
PHGG is known to be highly fermentable, which may increase short-chain fatty acids (SCFAs) — metabolites often discussed in gut–brain research.
This study didn’t prove the exact mechanism in humans - but it provides a practical, real-world signal:
Daily PHGG was linked to measurable improvements in visual memory and waking freshness.
Who might consider a PHGG supplement?
This study was done in healthy adults 60+, so the most relevant audience is:
- older adults wanting to support memory + sleep quality
- people who want a prebiotic fibre with broader wellbeing potential
- anyone wanting a routine that supports gut health without harsh laxative-style effects
Practical takeaway
If you’re choosing a PHGG supplement, you’re not just choosing “fibre.” Based on this study, you may be choosing something that supports:
- visual memory (12 weeks)
- waking freshness and sleep quality (8–12 weeks)
- vitality signals (within-group changes
We offer this post for education purposes only. Please consult your Health Practitioner for personalised and specific information.
