Lack of effect of a high-calorie dextrose or maltodextrin meal on postprandial oxidative stress in healthy young men
 
 
Journal Title (Medline/Pubmed accepted abbreviation): Int. J. Sport Nutr. Exerc. Metabol.
Year: 2010
Volume: 20
Number:
Page numbers: 393-400
doi (if applicable):

Summary of Background and Research Design

Background:It is common practice for athletes to ingest high doses of fast-absorbing carbohydrate (ex. maltodextrin) either during training (carb loading) or after a workout to regenerate glycogen stores. However, it has been shown that carbohydrate-rich meals, due to their large increases in postprandial glycemia, may lead to the formation of potentially harmful reactive oxygen and nitrogen species (RONS) in different tissues (e.g., vascular endothelial cells).

Hypothesis/purpose of study:The authors hypothesized that meals of either dextrose or maltodextrin would increase markers of oxidative stress, with greater responses observed for dextrose versus maltodextrin.

Subjects:10 healthy, male, nonsmokers, age 27 ± 7 yrs, BMI 25 ± 4 kg/m2

Experimental design:crossover

Treatments and protocol:Participants completed food diaries for the 6 days prior to laboratory testing.
Participants arrived at the laboratory after an overnight fast. A baseline venous blood sample was collected and then participants consumed 2.25 g/kg body weight of either dextrose or maltodextrin (182.25 ± 42.75 g, 729 ± 171 kcal) in an aqueous solution (~730 kcal per participant). Additional blood samples were acquired at 1, 2, 4, and 6 hrs after carbohydrate consumption. Markers of oxidant stress (e.g., malondialdehyde, hydrogen peroxide, nitrates/nitrites), antioxidant capacity (e.g., Trolox-equivalent antioxidant capacity, or TEAC), and metabolic status (e.g., glucose, triacylglycerol) were measured in the blood samples.

Summary of research findings:
  • The glycemic response was higher after dextrose consumption than after maltodextrin consumption (468.04 ± 28.52 mg/(dl*6 hr) for glucose, 365.80 ± 21.26 mg/(dl*6 hr) for maltodextrin, p = 0.04).
  • There was no significant difference between treatments in postprandial oxidative stress biomarkers, TEAC, or triacylglycerols.

Interpretation of findings/Key practice applications:

  • The recruits were not necessarily athletes. Athletes may have different glucose metabolism than nonathletes.
  • No exercise was included in the protocol. Exercise causes oxidative stress, and the combination of postprandial oxidative stress and exercise-induced oxidative stress may be different with different meal compositions.
  • These subjects were relatively young, nonobese, and nondiabetic. Young, healthy people often have more efficient pancreatic ß-cell function and insulin secretion to allow for increased glucose uptake from the blood stream into body cells. This reduces the chance for the glucose to cause oxidative damage and associated responses.
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