Galactose promotes fat mobilization in obese lactating and nonlactating women.
BACKGROUND
Galactose consumption as the only carbohydrate source results in little increase in plasma glucose and insulin concentrations when compared with fasting. Lower insulin might promote endogenous lipolysis during meal absorption, which may facilitate fat loss.


OBJECTIVE
The objective was to test the hypothesis that consumption of an isocaloric, isonitrogenous galactose drink will result in higher rates of lipolysis and fat oxidation than consumption of a glucose drink in obese lactating and nonlactating women.


METHODS
Seven healthy, obese, exclusively breastfeeding women and 7 healthy, obese, nonlactating women were studied on 2 occasions according to a randomized, crossover, single-blinded design. Subjects received drinks providing ≈70% of the daily estimated energy requirement, of which 60% was either glucose or galactose. The primary outcomes were the rate of appearance (Ra) of glycerol and palmitate, and the secondary outcomes were glucose Ra, milk production, energy expenditure, and substrate oxidation.


RESULTS
Plasma glucose and insulin concentrations were lower (P < 0.05) and those of glycerol, palmitate, free fatty acids, and triglycerides were higher (P < 0.05) during galactose than during glucose feeding in both nonlactating and lactating women. During galactose feeding, glucose Ra was lower (P < 0.01) and glycerol, palmitate, and free fatty acid Ra were higher (P < 0.01) in both groups. During galactose feeding in all women combined, fat oxidation was higher (P = 0.01) and protein oxidation was lower (P < 0.01). Milk production, energy expenditure, and carbohydrate oxidation were similar between glucose and galactose feeding.


CONCLUSIONS
Galactose consumption is associated with higher endogenous fat mobilization and oxidation during meal absorption. Long-term studies are required to determine whether galactose as an exclusive carbohydrate source would promote body fat loss in obese subjects.
Department of Pediatrics, Children's Nutrition Research Center, US Department of Agriculture/Agricultural Research Service, Baylor College of Medicine, Houston, TX 77030-2600, USA.
Mahmoud A
MA
Mohammad
Agneta L
AL
Sunehag
Luisa A
LA
Rodriguez
Morey W
MW
Haymond
D000328:Adult; D019440:Anti-Obesity Agents / Q000494:pharmacology / Q000627:therapeutic use; D001786:Blood Glucose / Q000378:metabolism*; D001942:Breast Feeding; D018592:Cross-Over Studies; D019422:Dietary Sucrose / Q000008:administration & dosage*; D005260:Female; D005690:Galactose / Q000494:pharmacology* / Q000627:therapeutic use; D005947:Glucose / Q000494:pharmacology*; D005990:Glycerol / Q000097:blood; D006801:Humans; D007223:Infant; D007328:Insulin / Q000097:blood*; D007774:Lactation; D050356:Lipid Metabolism / Q000187:drug effects*; D015227:Lipid Peroxidation / Q000187:drug effects; D008055:Lipids / Q000097:blood; D009765:Obesity / Q000097:blood / Q000178:diet therapy / Q000378:metabolism*; D019308:Palmitic Acid / Q000097:blood; D050050:Protein Carbonylation / Q000187:drug effects; D016037:Single-Blind Method
D019440:Anti-Obesity Agents; D001786:Blood Glucose; D019422:Dietary Sucrose; D007328:Insulin; D008055:Lipids; D019308:Palmitic Acid; D005947:Glucose; D005990:Glycerol; D005690:Galactose