The influence of dietary sugars and acute exercise on postprandial lipemia in premenopausal women
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Postprandial lipemia (PPL) is elevation in triglyceride (TG) concentration within the blood in the hours following the ingestion of a meal and is a risk factor for cardiovascular disease (CVD) and may be a greater risk in women compared to men. Women completing aerobic exercise prior to ingesting a high-fat meal have reported a lower postprandial TG concentration. It is unclear if prior aerobic exercise would lower the postprandial TG concentration in women following the ingestion of a high-carbohydrate meal comprised of high amounts of glucose and fructose sugars. This investigation examined the effect of prior exercise on postprandial (PP) triglyceride concentration following a mixed meal (MM) made with either glucose or fructose. Sedentary premenopausal women (n=16; age=28.2 ± 6.1yrs; VO2max= 30.8 ± 4.2 ml -1˙kg-1˙min) completed four trials in random order: 1) Rest-Fructose: RF, 2) Rest-Glucose: RG, 3) Exercise-Fructose: EF, 4) Exercise-Glucose: EG. Exercise was treadmill walking at 70%VO2max expending 500 kcal. Rest was 1 hr of supine rest. The morning after each trial, a fasting (12 hr) blood sample was collected followed by consumption of the MM with a macronutrient composition of 55% carbohydrate (CHO), 15% protein, and 30% fat. The MM was blended with whole food items plus a glucose or fructose powder that accounted for half of the total carbohydrate content within the MM. Blood was collected again at 0.5, 1, 1.5, 2, 3, 4, 5, and 6 hr post-MM and analyzed for triglyceride concentration. Postprandial responses were quantified via the area under the curve (AUC) using the trapezoidal method. Significant differences (p < .05) between trials were determined using a repeated measures ANOVA and Bonferroni post hoc test. The PPTG AUC (mg˙dl -1˙6hr-1) following the EG trial (346.8±178.1) was significantly lower (p < .028) compared to the RF (476.2 ± 279.5) and RG (485.0 ± 309.7) trials, but not compared to the EF trial. Postprandial TG concentration was reduced only in the EG trial. The RG, RF, and EF trials had a similar postprandial TG concentration. The lack of difference in the TG concentration between the RG, RF, and EF trails is unclear.