Effects of Exogenous Ketones on Cognitive Function in Older Adults With Prediabetes?

Summary

Brief Summary

The goal of this clinical trial is to learn whether older adults with prediabetes, but no diagnosed cognitive impairment, show early changes in brain energy use and thinking speed compared to older adults with normal blood sugar levels. The study will also test whether a single dose of an exogenous ketone supplement can improve brain energy use and cognitive processing speed.

The main questions it aims to answer are:

Do older adults with prediabetes have lower brain glucose uptake and slower cognitive processing speed compared to those with normal glucose levels?

Does a single dose of an exogenous ketone monoester supplement improve cognitive processing speed and brain glucose uptake?

Researchers will compare older adults with prediabetes to older adults with normal glucose levels to determine whether differences exist in brain glucose metabolism and cognitive performance. In a subset of participants, researchers will also compare brain and cognitive outcomes before and after consuming a ketone monoester supplement (DeltaG, Oxford, England).

Participants will:

Complete metabolic testing to determine glucose status

Undergo brain imaging using fluorodeoxyglucose positron emission tomography combined with magnetic resonance imaging (18FDG-PET/MRI) while performing a cognitive processing speed task

Consume a single dose of a commercially available ketone monoester supplement during one study visit

Complete cognitive testing during imaging to measure processing speed and brain activity

The results of this study will help determine whether early metabolic dysfunction is linked to reduced brain energy use and whether ketones can temporarily support brain function in individuals at risk for dementia.

Conditions

• Prediabetes
• Healthy (Controls)

Interventions

DIETARY_SUPPLEMENT

Ketone Monoester (KE)

The intervention is a single acute oral dose of a commercially available ketone monoester supplement (DeltaG®, Oxford, England). The active ingredient, (R)-3-hydroxybutyl (R)-3-hydroxybutyrate, is rapidly metabolized after ingestion to raise circulating beta-hydroxybutyrate concentrations without requiring dietary carbohydrate restriction or fasting. The supplement is administered under supervised conditions during a study visit. Brain imaging with fluorodeoxyglucose F18 positron emission tomography combined with magnetic resonance imaging is performed during the post-ingestion period while participants complete a cognitive processing speed task. This protocol evaluates the immediate metabolic and neurocognitive effects of exogenous ketone administration within a single session.

DIETARY_SUPPLEMENT

Placebo

The placebo consists of a taste-, color-, and volume-matched beverage formulated to mimic the sensory characteristics of the ketone monoester supplement but containing no active ketone ingredient. The placebo does not contain (R)-3-hydroxybutyl (R)-3-hydroxybutyrate) and does not elevate circulating beta-hydroxybutyrate concentrations. The placebo beverage will be administered orally under supervised research conditions during a study visit using procedures identical to the active supplement condition. Brain imaging with fluorodeoxyglucose F18 positron emission tomography combined with magnetic resonance imaging will be performed during the post-ingestion period while participants complete a cognitive processing speed task. This control condition allows isolation of the metabolic effects of ketone elevation from expectancy or beverage-related effects.

Sponsors & Collaborators

• University of Alabama at Birmingham

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

60 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-05-20

Primary Completion

2026-05-31

Completion

2026-05-31

Countries

• United States

Study Locations