Galactose mediated glycogen resynthesis
Research type
Research Study
Full title
Galactose mediated glycogen resynthesis and the effects on metabolism during subsequent exercise
IRAS ID
262942
Contact name
Brandon Shad
Contact email
Sponsor organisation
University of Birmingham
Duration of Study in the UK
1 years, 0 months, 1 days
Research summary
Summary of Research
During exercise, energy can be derived from fats and carbohydrates that are stored in the body. While fat stores are almost unlimited, carbohydrate stores are finite and can get depleted. We store carbohydrates in the form of a substance called glycogen in our liver and muscles. During exercise, carbohydrates stored in liver and muscle is used for energy and once the carbohydrate stores have run out, fatigue sets in. This highlights the need to consume carbohydrates to delay fatigue and speed-up recovery after exercise.A quick recovery of carbohydrate stores after exercise is especially important in sports disciplines where the recovery period between each exercise bout is short (i.e., a few hours) or when multiple training session are performed each day. Current nutrition guidelines recommend ingesting glucose-based carbohydrates in the recovery period. Lactose is the sugar contained within milk and consists of two components, glucose and galactose. Glucose from a variety of food sources, including specific sports nutrition products, is used extensively as an energy source by physically active individuals including competitive sports people. On the other hand, the use of galactose in sports nutrition is rare. Evaluation of the scientific literature suggests there is great potential for galactose, when co-ingested with glucose, to make meaningful contributions to energy metabolism for endurance exercise and recovery.
Previous research has shown that glucose is very effective in increasing post-exercise muscle glycogen stores, while galactose has shown to be better at increasing liver glycogen stores. However, it remains unknown how galactose alone, or in combination with glucose, affects replenishment of muscle glycogen after exhaustive endurance exercise.
Therefore, the primary aim of the present study is to compare short-term post-exercise muscle glycogen synthesis following combined galactose-glucose, glucose alone or galactose alone ingestion.
Summary of Results
Replenishment of muscle glycogen was superior with GLU relative to GAL+GLU and GAL, but was not significantly different between GAL and GAL+GLU. Plasma glucose and insulin concentrations were markedly higher in GLU and GAL+GLU as compared to GAL. Plasma galactose concentration was higher in GAL as compared to GLU and GAL+GLU, with no significant difference between GAL+GLU and GLU.CONCLUSIONS:
Superior muscle glycogen synthesis was observed with GLU, which suggests GAL+GLU may not be optimal for the short-term post-exercise replenishment of total body (i.e., liver and muscle) glycogen stores. Interestingly, GAL was equally effective as GAL+GLU despite absence of increased plasma glucose or insulin concentrations which are thought to be crucial for muscle glycogen synthesis. Whether galactose can be directly utilized by skeletal muscle and/or requires conversion to glucose in the liver before being incorporated into muscle glycogen requires further investigation.REC name
West Midlands - Black Country Research Ethics Committee
REC reference
19/WM/0150
Date of REC Opinion
18 Jun 2019
REC opinion
Further Information Favourable Opinion