# Cholecystectomy Is Linked With Lower Respiratory Exchange Ratio and Higher Lipid Oxidation and Sleep Energy Expenditure

## TL;DR

Having a gallbladder removed is linked to changes in how the body burns energy, especially during sleep and through fat oxidation.

## Contribution

This study shows that gallbladder removal is associated with lower respiratory exchange ratio and increased lipid oxidation and sleep energy expenditure, independent of body composition and other factors.

## Key findings

- GBX(+) participants had lower RER compared to GBX(−) individuals.
- GBX(+) participants showed higher lipid oxidation and sleep energy expenditure.
- These effects were independent of body composition, age, sex, and glucose regulation.

## Abstract

Cholecystectomy (GBX) may alter energy metabolism, but human evidence is limited. We examined whether GBX alters energy expenditure (EE), respiratory exchange ratio (RER), and substrate oxidation.

A total of 384 healthy Southwestern Indigenous American adults (222 males, age 28 ± 6 years) were studied, including individuals with a history of gallbladder surgery [GBX(+), n = 39] and without surgery [GBX(−), n = 345]. In addition, 24‐h energy metabolism was measured in a respiratory chamber. General linear models were adjusted for age, sex, body composition, and glucose regulation. RER and macronutrient oxidation rates were further adjusted for energy balance.

GBX(+) participants were older (31 ± 7 vs. 27 ± 6 years, p = 0.0002) and mostly female (95% vs. 36%, p < 0.0001), and they had higher body fat (40% ± 5% vs. 32% ± 8%, p < 0.0001), although body composition differences were sex related. Adjusted models showed lower RER (β = −0.01, p = 0.01), higher lipid oxidation (β = 79 kcal/day, p = 0.03), and higher sleep EE (β = 78 kcal/day, p = 0.006) in the GBX(+) group. Other EE variables and macronutrient oxidation rates were not significantly associated with GBX history (all p's > 0.1).

Independent of obesity, an absent gallbladder is associated with decreased RER and increased lipid oxidation and sleep EE rates, indicating that the gallbladder may have a role in metabolic fuel selection that has implications for metabolic health.

ClinicalTrials.gov identifiers: NCT00339482, NCT00340132

What is already known?○Cholecystectomy (GBX) alters bile acid circulation and may impact energy and glucose metabolism.○Animal studies and limited human data suggest possible changes in energy expenditure after GBX.
What does this study add?○Prior GBX is associated with increased sleep energy expenditure, higher lipid oxidation, and lower respiratory exchange ratio.○These effects are independent of body composition, age, sex, and glucose regulation status
How might these results change the direction of research or the focus of clinical practice?○GBX may have lasting effects on energy metabolism and substrate utilization, highlighting the need to consider metabolic outcomes when deciding on surgery and managing patients post surgery.

What is already known?○Cholecystectomy (GBX) alters bile acid circulation and may impact energy and glucose metabolism.○Animal studies and limited human data suggest possible changes in energy expenditure after GBX.

Cholecystectomy (GBX) alters bile acid circulation and may impact energy and glucose metabolism.

Animal studies and limited human data suggest possible changes in energy expenditure after GBX.

What does this study add?○Prior GBX is associated with increased sleep energy expenditure, higher lipid oxidation, and lower respiratory exchange ratio.○These effects are independent of body composition, age, sex, and glucose regulation status

Prior GBX is associated with increased sleep energy expenditure, higher lipid oxidation, and lower respiratory exchange ratio.

These effects are independent of body composition, age, sex, and glucose regulation status

How might these results change the direction of research or the focus of clinical practice?○GBX may have lasting effects on energy metabolism and substrate utilization, highlighting the need to consider metabolic outcomes when deciding on surgery and managing patients post surgery.

GBX may have lasting effects on energy metabolism and substrate utilization, highlighting the need to consider metabolic outcomes when deciding on surgery and managing patients post surgery.