The atherogenic index of plasma (AIP), calculated as LOG 10 (triglycerides/high-density lipoprotein-cholesterol [HDL-C]), 1 is directly associated with cardiovascular disease (CVD) risk. 2 – 4 Triglycerides and HDL-C are both measured during a traditional lipid profile assessment, making this a
Rochelle R. Costa, Adriana C.K. Buttelli, Leandro Coconcelli, Laura F. Pereira, Alexandra F. Vieira, Alex de O. Fagundes, Juliano B. Farinha, Thais Reichert, Ricardo Stein and Luiz F.M. Kruel
Dyslipidemias are heterogeneous disorders of lipid metabolism arising from multiple etiologies that result in alterations in blood lipoproteins (low-density lipoprotein—LDL and high-density lipoprotein—HDL) and lipid (total cholesterol—TC and triglycerides—TG) concentrations. 1 In elderly women
Jacqueline R. Berning
Studies investigating fat as a fuel for exercise have found that increasing free fatty acids during exercise tends to spare muscle glycogen due to increased utilization of free fatty acids for energy, which in turn can enhance the capacity for endurance exercise. Medium-chain triglycerides do not delay gastric emptying or absorption. They are broken down by lipase in the stomach and duodenum to glycerol and medium-chain fatty acids (MCFA). Since MCFAs are metabolized as quickly as glucose, it has been speculated that they might provide an alternative carbon source for the muscle during prolonged exercise. While the majority of studies investigating the role of medium-chain triglycerides and exercise have found no sparing effect of muscle glycogen after consumption of medium-chain triglycerides, two recent studies have presented conflicting results. This review will investigate the speculated role of medium-chain triglycerides as an alternative fuel source for exercising muscles and will discuss the possibility that medium-chain triglycerides preserve muscle glycogen during exercise,
Daniela A. Rubin, Robert G. McMurray, Joanne S. Harrell, Barbara W. Carlson and Shrikant Bangdiwala
The purpose of this project was to determine the accuracy in lipids measurement and risk factor classification using Reflotron, Cholestech, and Ektachem DT-60 dry-chemistry analyzers. Plasma and capillary venous blood from fasting subjects (n = 47) were analyzed for total cholesterol (TC), high density lipoprotein (HDL-C), and triglycerides (TG) using these analyzers and a CDC certified laboratory. Accuracy was evaluated by comparing the results of each portable analyzer against the CDC reference method. One-way ANOVAs were performed for TC, HDL-C, and TG between all portable analyzers and the reference method. Chi-square was used for risk classification (2001 NIH Guidelines). Compared to the reference method, the Ektachem and Reflotron provided significantly lower values for TC (p < .05). In addition, the Cholestech and Ektachem values for HDL-C were higher than the CDC (p < .05). The Reflotron and Cholestech provided higher values of TG than the CDC (p < .05). Chi-squares analyses for risk classification were not significant (p > .45) between analyzers. According to these results, the Ektachem and Cholestech analyzers met the current NCEP III guidelines for accuracy in measurement of TC, while only Ektachem met guidelines for TG. All 3 analyzers provided a good overall risk classification; however, values of HDL-C should be only used for screening purposes.
Marc T. Hamilton, Enas Areiqat, Deborah G. Hamilton and Lionel Bey
Physical activity often declines with age because of a reduction in the spontaneous activities of daily living and because of less intense exercise. In controlled studies of young rats, it was shown that physical activities associated with walking and standing were especially important for maintaining a high level of lipoprotein lipase (LPL) activity in postural skeletal muscles (slowtwitch oxidative muscles). More intense contractions during run training were important for a high LPL activity in the fast-twitch glycolytic muscles. Aging also causes a fiber type–specific decrease of skeletal muscle LPL activity and LPL protein in weight-bearing skeletal muscles (and no aging effect in glycolytic muscles). Thus, contractile inactivity may be a significant factor causing sub-optimal triglyceride metabolism in skeletal muscles during both unloading in young animals and aging. Measurements of plasma LPL activity, plasma triglyceride (TG) clearance rates, postprandial hypertriglyceridemia after oral fat tolerance tests, and fasting TG levels were generally indicative of reduced plasma TG metabolism during middle or old age. In contrast, older endurance-trained individuals had a favorable blood lipid profile compared to age-matched or young controls, even when the controls were not overweight. Therefore, the poor TG metabolism that is frequently associated with aging may be caused by some of the same processes that lower skeletal muscle LPL activity of young sedentary individuals.
Jonathan. P. Little, Scott C. Forbes, Darren G. Candow, Stephen M. Cornish and Philip D. Chilibeck
Creatine (Cr) supplementation increases muscle mass, strength, and power. Arginine α-ketoglutarate (A-AKG) is a precursor for nitric oxide production and has the potential to improve blood flow and nutrient delivery (i.e., Cr) to muscles. This study compared a commercial dietary supplement of Cr, A-AKG, glutamine, taurine, branchedchain amino acids, and medium-chain triglycerides with Cr alone or placebo on exercise performance and body composition. Thirty-five men (~23 yr) were randomized to Cr + A-AKG (0.1 g · kg−1 · d−1 Cr + 0.075 g · kg−1 · d−1 A-AKG, n = 12), Cr (0.1 g · kg−1 · d−1, n = 11), or placebo (1 g · kg−1 · d−1 sucrose, n = 12) for 10 d. Body composition, muscle endurance (bench press), and peak and average power (Wingate tests) were measured before and after supplementation. Bench-press repetitions over 3 sets increased with Cr + A-AKG (30.9 ==6.6 → 34.9 ± 8.7 reps; p < .01) and Cr (27.6 ± 5.9 → 31.0 ± 7.6 reps; p < .01), with no change for placebo (26.8 ± 5.0 → 27.1 ± 6.3 reps). Peak power significantly increased in Cr + A-AKG (741 ± 112 → 794 ± 92 W; p < .01), with no changes in Cr (722 ± 138 → 730 ± 144 W) and placebo (696 ± 63 → 705 ± 77 W). There were no differences in average power between groups over time. Only the Cr-only group increased total body mass (79.9 ± 13.0→81.1 ± 13.8 kg; p < .01), with no significant changes in lean-tissue or fat mass. These results suggest that Cr alone and in combination with A-AKG improves upper body muscle endurance, and Cr + A-AKG supplementation improves peak power output on repeated Wingate tests.
Renata Moraes Bielemann, Virgílio Viana Ramires, Denise Petrucci Gigante, Pedro Curi Hallal and Bernardo Lessa Horta
The purpose of this study was to evaluate cross-sectional and longitudinal associations between physical activity and triglyceride and HDLc levels in young male adults.
We used information about males belonging 1982 Pelotas Birth Cohort. Physical activity in 4 domains (leisure time, transportation, household, and occupation) was assessed by self-report in participants of the cohort at ages of 18 and 23 years. Subjects were active if reached the recommendation of 150 min/week of moderate to vigorous physical activity. At 23 years of age, blood sample was collected, and triglycerides and HDLc levels estimated. Multivariate linear and Poisson regression were used to adjust the estimates for confounders.
Males who were inactive at 18 and active at 23 years had 41% lower risk (β = 0.59; 95% confidence interval: 0.40; 0.89) for borderline-high triglycerides (≥ 150 mg/dL) as compared with those who were inactive at both follow-ups. No association was found between changes of physical activity and HDLc level. In cross-sectional analyses, greater HDLc levels were found in active subjects in 4 domains, whereas there was no difference in HDL levels according physical activity during leisure time.
Becoming active from adolescence to early adulthood reduced the risk for high triglycerides. Current physical activity was associated with greater HDLc levels.
Joel B. Mitchell, James R. Rowe, Meena Shah, James J. Barbee, Austen M Watkins, Chad Stephens and Steve Simmons
To examine the effect of prior exercise on the postprandial lipid response to a high-carbohydrate meal in normal-weight (NW = BMI h25) and overweight (OW = BMI ≥25) women (age 18–25), 10 NW and 10 OW participants completed 2 conditions separated by 1 month. In the morning, the day after control (CT = no exercise) or exercise conditions (EX = 60 min cycling at 60% VO2peak), participants consumed a high-carbohydrate meal (80% CHO, 15% protein, 5% fat; 75 kJ/kg BM) followed by 6 hr of hourly blood sampling. Blood was analyzed for triglycerides (TG), blood glucose (BG), and insulin (IN). TG levels over the 6-hr period were lower in NW than OW (p = .021) and lower in EX than in CT (p = .006). Area under the curve (AUC) for TG was lower in NW than OW (p = .016) and EX than CT (p = .003). There were nonsignificant tendencies for reduced BG over time (p = .053) and AUC (p = .083), and IN AUC was lower in EX than in CT (p = .040) for both groups and lower in NW than in OW (p = .039). Prior exercise improved TG levels after a high-carbohydrate meal in both groups, and OW women demonstrated a greater postprandial lipemic response than NW regardless of condition. There were tendencies for improved glucose removal with prior exercise in NW vs. OW. Acute exercise can improve postprandial TG responses and might also improve postprandial BG and IN after a large meal in NW and OW young women.
Jeff S. Volek, Noel D. Duncan, Scott A. Mazzetti, Margot Putukian, Ana L. Gómez and William J. Kraemer
In order to examine the effects of heavy resistance training and the influence of creatine supplementation on nonperformance measures of health status, 19 healthy resistance-trained men were matched and then randomly assigned in a double-blind fashion to either a creatine (n = 10) or placebo (n = 9) group. Periodized heavy resistance training was performed 3—4 times per week for 12 weeks. During the first week of training, creatine subjects consumed 25 g creatine monohydrate per day, while the placebo group ingested an equal number of placebo capsules. Five grams of supplement per day was consumed for the remainder of the study. Body composition, fasting serum creatinine, lipo-proteins and triglycerides, and reported changes in body function were determined prior to and after 12 weeks of training and supplementation. After training, significant increases in body mass and fat-free mass were greater in creatine (5.2 and 4.3 kg, respectively) than placebo (3.0 and 2.1 kg. respectively) subjects. There was no change in percent body fat. Dietary energy and macronutrient distribution was not significantly different during Weeks 1 and 12. Serum creatinine was significantly elevated in creatine subjects after 1(11.6%) and 12 weeks (13.8%); however, values were within normal limits for healthy men. There were no effects of training or supplementation on serum total cholesterol, HDL-cholesterol, LDL-cholesterol. or triglycerides. In healthy men, a 12-week heavy resistance training program, with or without creatine supplementation, did not significantly influence serum lipid profiles, subjective reports of body functioning, or serum creatinine concentrations.
Lynn B. Panton, Michael R. Kushnick, J. Derek Kingsley, Robert J. Moffatt, Emily M. Haymes and Tonya Toole
To evaluate physical activity with pedometers and health markers of chronic disease in obese, lower socioeconomic African American women.
Thirty-five women (48 ± 8 y) wore pedometers for 2 weeks. One-way analyses of variances were used to compare age, weight, body mass indices (BMI), and health markers of chronic disease (including blood pressure, cholesterol, triglycerides, glycosylated hemoglobin, fibrinogen, C-reactive protein) between women who were classified by steps per day as sedentary (SED < 5,000; 2,941 ± 1,161 steps/d) or active (ACT ≥ 5,000; 7,181 ± 2,398 steps/d).
ACT had significantly lower BMI (ACT: 37.2 ± 5.6; SED: 44.4 ± 7.2 kg/m2) and hip circumferences (ACT: 37.2 ± 5.6; SED: 44.4 ± 37.2 cm) and higher total cholesterol (ACT: 230 ± 53; SED: 191 ± 32 mg/dL) than SED. There were no differences in health markers of chronic disease between SED and ACT. Pearson product moment correlations showed significant negative correlations between steps/d and weight (r = –.42), BMI (r = –.46), and hip circumference (r = –.47).
Increased levels of physical activity were associated with reduced BMI and hip circumferences but were not associated with lower health markers for chronic disease in obese, lower socioeconomic African American women.