Adaptive metabolic response to 4 weeks of sugar-sweetened beverage consumption in healthy, lightly active individuals and chronic high glucose availability in primary human myotubes.
OBJECTIVE
Chronic sugar-sweetened beverage (SSB) consumption is associated with obesity and type 2 diabetes mellitus (T2DM). Hyperglycaemia contributes to metabolic alterations observed in T2DM, such as reduced oxidative capacity and elevated glycolytic and lipogenic enzyme expressions in skeletal muscle tissue. We aimed to investigate the metabolic alterations induced by SSB supplementation in healthy individuals and to compare these with the effects of chronic hyperglycaemia on primary muscle cell cultures.


METHODS
Lightly active, healthy, lean subjects (n = 11) with sporadic soft drink consumption underwent a 4-week SSB supplementation (140 ± 15 g/day, ~2 g glucose/kg body weight/day, glucose syrup). Before and after the intervention, body composition, respiratory exchange ratio (RER), insulin sensitivity, muscle metabolic gene and protein expression were assessed. Adaptive responses to hyperglycaemia (7 days, 15 mM) were tested in primary human myotubes.


RESULTS
SSB supplementation increased fat mass (+1.0 kg, P < 0.05), fasting RER (+0.12, P < 0.05), fasting glucose (+0.3 mmol/L, P < 0.05) and muscle GAPDH mRNA expressions (+0.94 AU, P < 0.05). PGC1α mRNA was reduced (-0.20 AU, P < 0.05). Trends were found for insulin resistance (+0.16 mU/L, P = 0.09), and MondoA protein levels (+1.58 AU, P = 0.08). Primary myotubes showed elevations in GAPDH, ACC, MondoA and TXNIP protein expressions (P < 0.05).


CONCLUSIONS
Four weeks of SSB supplementation in healthy individuals shifted substrate metabolism towards carbohydrates, increasing glycolytic and lipogenic gene expression and reducing mitochondrial markers. Glucose-sensing protein MondoA might contribute to this shift, although further in vivo evidence is needed to corroborate this.
College of Health and Behavioural Sciences, Bangor University, George Building, Bangor, Gwynedd, LL57 2PZ, UK.
Francesco
F
Sartor
Matthew J
MJ
Jackson
Cesare
C
Squillace
Anthony
A
Shepherd
Jonathan P
JP
Moore
Donald E
DE
Ayer
Hans-Peter
HP
Kubis
D000103:Acetyl-CoA Carboxylase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D001823:Body Composition; D002253:Carbonated Beverages / Q000009:adverse effects*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D061215:Energy Drinks / Q000009:adverse effects*; D005260:Female; D005786:Gene Expression Regulation; D005947:Glucose / Q000009:adverse effects* / Q000378:metabolism; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000209:etiology* / Q000378:metabolism; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D002352:Carrier Proteins; D006360:Heat-Shock Proteins; C485496:MLXIP protein, human; C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C486715:TXNIP protein, human; D014157:Transcription Factors; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D000103:Acetyl-CoA Carboxylase; D005947:Glucose