BHB Salt Cuts Alcohol Intake and Reshapes Brain Reward Chemistry in Rodents
A new rodent study finds that beta-hydroxybutyrate salt reduces alcohol consumption in both sexes and alters dopamine signaling in the brain's reward center.
Summary
Researchers at the University of Gothenburg tested two formulations of the ketone body beta-hydroxybutyrate (BHB) — a salt and an ester — for their ability to reduce alcohol-related behaviors in rodents. The BHB salt more effectively elevated blood ketone levels, lowered the glucose-ketone index, and blocked alcohol-induced locomotor stimulation in male mice compared to the ester. In male and female rats following 10 weeks of intermittent alcohol access, BHB salt dose-dependently reduced alcohol intake, with females responding to lower doses than males. Microdialysis in the nucleus accumbens revealed that BHB salt elevated dopamine, noradrenaline, and their metabolites — potentially explaining its dampening effect on alcohol reward. These findings suggest BHB salt supplementation may be a promising, accessible intervention for alcohol use disorder.
Detailed Summary
Alcohol use disorder (AUD) is a serious psychiatric condition driven in part by alcohol's rewarding properties, particularly its ability to trigger dopamine release in the nucleus accumbens (NAc). While approved pharmacotherapies exist, adherence and efficacy remain challenges. Ketosis — the state of elevated blood ketone bodies such as beta-hydroxybutyrate (BHB) — has emerged as a candidate therapeutic strategy, supported by evidence that ketogenic diets reduce alcohol intake and withdrawal severity. However, dietary compliance is difficult, making exogenous BHB supplements a practical alternative. This study, published in Addiction Biology, is among the first to directly compare BHB salt and BHB ester formulations on alcohol-related outcomes in rodents.
In male NMRI mice, both BHB salt (1.5–3 g/kg SC) and BHB ester (0.45–2 g/kg SC) were tested for effects on general locomotor activity and exogenous ketosis. Neither formulation altered baseline locomotion at any dose, confirming they do not produce sedation or motor impairment. Both raised blood ketone levels and lowered the glucose-ketone index (GKI), but BHB salt did so more robustly — only the highest ester dose (2 g/kg) significantly elevated ketones, while BHB salt produced significant elevations at 2 and 3 g/kg. Delta-value comparisons confirmed that BHB salt had significantly greater effects on ketone levels and GKI than the ester. Alcohol-induced locomotor stimulation — a well-validated proxy for mesolimbic dopamine activation and reward — was inhibited by both formulations, though BHB salt at 3 g/kg produced the clearest suppression. BHB ester did not measurably alter blood alcohol levels, ruling out pharmacokinetic interference as an explanation for its behavioral effects.
Based on these initial findings, BHB salt was selected for the alcohol intake experiments. Male and female Wistar rats underwent 10 weeks of intermittent access two-bottle choice drinking (20% alcohol vs. water) before receiving BHB salt or vehicle 30 minutes prior to an alcohol session. BHB salt dose-dependently reduced alcohol intake measured at both 4 and 24 hours, without significantly affecting food or water consumption or body weight. Notably, female rats responded to lower doses (0.5–1 g/kg) than males (2–3 g/kg), suggesting meaningful sex differences in ketone sensitivity or alcohol-reward modulation.
To explore underlying mechanisms, in vivo microdialysis in the NAc of male mice revealed that BHB salt (3 g/kg SC) significantly elevated extracellular dopamine, noradrenaline, and their metabolites (3-MT, HVA, DOPAC, NM), while serotonin and 5-HIAA were unaffected. This monoamine elevation in the NAc is intriguing — it may reflect a compensatory neurochemical shift that reduces the marginal reward value of alcohol, though the exact mechanism warrants further investigation.
The study's overall picture is that exogenous BHB salt supplementation can suppress alcohol reward-related behavior and intake in rodents of both sexes, likely through modulation of mesolimbic monoamine signaling. These preclinical findings build a case for clinical trials of BHB supplements in AUD patients, particularly given the supplement's accessibility and favorable safety profile. Key caveats include the exclusive use of subcutaneous injection (limiting translational relevance to oral supplementation), rodent-only models, and an incomplete mechanistic picture for the observed NAc monoamine changes.
Key Findings
- BHB salt more potently elevated blood ketone levels and lowered the glucose-ketone index than BHB ester in male mice.
- Both BHB salt and ester suppressed alcohol-induced locomotor stimulation without affecting baseline motor activity.
- BHB salt dose-dependently reduced alcohol intake in both male and female rats over 24 hours.
- Female rats responded to lower BHB salt doses than males, indicating significant sex-based differences.
- BHB salt elevated dopamine and noradrenaline and their metabolites in the nucleus accumbens, suggesting a reward-modulating mechanism.
Methodology
The study used male NMRI mice and male/female Wistar rats in a series of experiments including open-field locomotor tests, intermittent access two-bottle choice drinking (10 weeks baseline, 20% alcohol), subcutaneous BHB salt or ester administration, blood ketone/glucose measurement, and in vivo NAc microdialysis with HPLC-EC for monoamine quantification. Statistical analyses included one-way ANOVA, two-way repeated-measures ANOVA, and unpaired t-tests with Bonferroni corrections.
Study Limitations
The study used only subcutaneous injection rather than oral administration, limiting direct translation to human supplement use. All mechanistic data (NAc monoamines) were collected from male mice only, leaving female neurochemical mechanisms unexplored. The rodent models, while well-validated, may not fully capture the complexity of human AUD.
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