Gastrointestinal symptoms associated with sodium bicarbonate supplementation protocols: A systematic review
Poster #: 192
Session/Time: A
Author:
Ian P Winter, MS
Mentor:
Patrick Wilson, PhD, RDN
Research Type: Review Article
Abstract
INTRODUCTION:
Sodium bicarbonate positively impacts performance in many sports. However, gastrointestinal symptoms (GIS) secondary to sodium bicarbonate supplementation may limit its use. This systematic review aimed to synthesize literature that has evaluated GIS associated with sodium bicarbonate supplementation and to offer suggestions to mitigate the onset of these undesirable, limiting side effects. This review provides suggestions to mitigate the onset of undesirable GIS with sodium bicarbonate supplementation, as well as serves a guide for subsequent research to address shortcomings in the literature.
MAIN BODY:
Searches of PubMed, SPORTDiscus, and Web of Science and two previously published systematic reviews were performed between February and December 2024. Eligible studies were those that provided ≥5 grams of sodium bicarbonate in a 24-hour period or, if a multi-day protocol, at least one day involving ≥5 grams dosing. Included studies needed to have a placebo group/condition or a comparison group/condition that created a contrast in terms of sodium bicarbonate delivery method, form, or dose. Ninety-one investigations were included in six categories: acute single dosing (n=33); acute spread dosing (n=23); chronic dosing (n=7); acute vs. chronic dosing (n=5); delivery form (n=15); and other (n=8). Existing literature suggests that the most common acute dose (0.3 g/kg), along with doses near it (0.2-0.4 g/kg), elicits mild-to-severe GIS for some individuals. Additionally, GIS seem to increase in a dose-dependent manner (from 0.2 to 0.5 g/kg) when sodium bicarbonate is ingested in a single dose. Strategies to reduce GIS with acute dosing include spreading intake over several hours, using enteric-coated capsules/tablets, and ingesting a product made of sodium bicarbonate mini-tablets within a hydrogel (Maurten Bicarb System). However, direct comparisons of these strategies are nonexistent. Consuming a carbohydrate-containing meal/snack alongside acute supplementation was reported to reduce GIS in one study, but research to date is limited. Multi-day dosing may offer some defense against GIS, but symptom documentation throughout the entire supplementation period has been poorly characterized. Variations in number and types of GIS measured, timing and frequency of measurements, scale used, and statistical analyses make direct comparisons between studies difficult.
CONCLUSION:
Making clear recommendations about optimal sodium bicarbonate supplementation strategies to minimize GIS remains challenging despite the plethora of published literature. Specific GIS should be clearly described, and if confusion may exist regarding a particular symptom's nature, an operational definition should be provided. GIS assessments should be collected at regular intervals after supplementation (e.g., every 15-30 minutes) in addition to baseline pre-supplementation assessments. When summarizing GIS as a total or aggregate score, details of the calculation should be provided. Further, the range of possible values on the calculated variable should be described so that readers can make their own judgements about severity.
METHODS:
of evaluating the distribution of GIS data should be explained, along with any data transformations that are applied to deal with non-normality. Given high individual variation, reporting peak GIS severity for individual participants may be valuable. Major needs remain for direct comparisons between supplementation protocols meant to minimize GIS and improved consistency in data collection, reporting, and analysis.
Sodium bicarbonate positively impacts performance in many sports. However, gastrointestinal symptoms (GIS) secondary to sodium bicarbonate supplementation may limit its use. This systematic review aimed to synthesize literature that has evaluated GIS associated with sodium bicarbonate supplementation and to offer suggestions to mitigate the onset of these undesirable, limiting side effects. This review provides suggestions to mitigate the onset of undesirable GIS with sodium bicarbonate supplementation, as well as serves a guide for subsequent research to address shortcomings in the literature.
MAIN BODY:
Searches of PubMed, SPORTDiscus, and Web of Science and two previously published systematic reviews were performed between February and December 2024. Eligible studies were those that provided ≥5 grams of sodium bicarbonate in a 24-hour period or, if a multi-day protocol, at least one day involving ≥5 grams dosing. Included studies needed to have a placebo group/condition or a comparison group/condition that created a contrast in terms of sodium bicarbonate delivery method, form, or dose. Ninety-one investigations were included in six categories: acute single dosing (n=33); acute spread dosing (n=23); chronic dosing (n=7); acute vs. chronic dosing (n=5); delivery form (n=15); and other (n=8). Existing literature suggests that the most common acute dose (0.3 g/kg), along with doses near it (0.2-0.4 g/kg), elicits mild-to-severe GIS for some individuals. Additionally, GIS seem to increase in a dose-dependent manner (from 0.2 to 0.5 g/kg) when sodium bicarbonate is ingested in a single dose. Strategies to reduce GIS with acute dosing include spreading intake over several hours, using enteric-coated capsules/tablets, and ingesting a product made of sodium bicarbonate mini-tablets within a hydrogel (Maurten Bicarb System). However, direct comparisons of these strategies are nonexistent. Consuming a carbohydrate-containing meal/snack alongside acute supplementation was reported to reduce GIS in one study, but research to date is limited. Multi-day dosing may offer some defense against GIS, but symptom documentation throughout the entire supplementation period has been poorly characterized. Variations in number and types of GIS measured, timing and frequency of measurements, scale used, and statistical analyses make direct comparisons between studies difficult.
CONCLUSION:
Making clear recommendations about optimal sodium bicarbonate supplementation strategies to minimize GIS remains challenging despite the plethora of published literature. Specific GIS should be clearly described, and if confusion may exist regarding a particular symptom's nature, an operational definition should be provided. GIS assessments should be collected at regular intervals after supplementation (e.g., every 15-30 minutes) in addition to baseline pre-supplementation assessments. When summarizing GIS as a total or aggregate score, details of the calculation should be provided. Further, the range of possible values on the calculated variable should be described so that readers can make their own judgements about severity.
METHODS:
of evaluating the distribution of GIS data should be explained, along with any data transformations that are applied to deal with non-normality. Given high individual variation, reporting peak GIS severity for individual participants may be valuable. Major needs remain for direct comparisons between supplementation protocols meant to minimize GIS and improved consistency in data collection, reporting, and analysis.