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Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dietary oils are a significant contributor to overall energy and fatty acid intakes. Changes in the amount and/or type of dietary oils consumed have the potential to impact human health. Clinical trials represent the gold standard for testing the health impacts of such changes in dietary oils. The objective of this review is to explore best practices for clinical trials examining impacts of dietary oils including 1) pre-clinical topics such as research question generation, study design, participant population, outcome measures and intervention product selection and/or preparation; 2) clinical trial implementation topics such as recruitment, trial management, record keeping and compliance monitoring; and 3) post-clinical trial topics dealing with sample analysis and storage as well as management, publication and data access. The use of digital case report forms, and the best practices in reporting and publishing results are also addressed. In summary, properly designed and implemented clinical trials studying dietary oils produce strong scientific evidence-guiding their use. [ABSTRACT FROM AUTHOR]

Abstract: Plant sterols/stanols-enriched foods possess well-documented low-density lipoprotein (LDL)-cholesterol−lowering effect. However, the relative efficacy of plant sterols/stanols as supplements (tablets/capsules) compared with other dietary forms still needs to be determined. Our aim was to precisely identify and quantify the LDL-cholesterol−lowering effect of plant sterols/stanols as supplements in contrast to food-based approaches. Eight eligible clinical trials published from January 1992 to April 2013 were identified from five databases. A random effect model was used to calculate weighted mean effect sizes for net differences in LDL-cholesterol concentrations. Among the included trials with the duration between 4 and 6 weeks, plant sterol/stanol dose ranged from 1.0 to 3.0 g/day administrated mainly with the main meals (2 or 3 times/day). Intake of plant sterol/stanol supplements decreased LDL-cholesterol concentrations by 12 mg/dL (0.31 mmol/L) (95% CI −0.39 to −0.23; P<0.000) compared with placebo. The test of heterogeneity was not significant (χ2 , P=0.50, I 2=0%). Further analysis showed no significant difference between the LDL-cholesterol−lowering action of plant sterols/stanols supplements (−12 mg/dL [−0.31 mmol/L]; 95% CI −0.39 to −0.24; P<0.0001) vs foods enriched with plant sterols/stanols (−12 mg/dL [−0.31 mmol/L]; 95% CI −0.35 to −0.27; P<0.0001). Plant sterol/stanol supplements as part of a healthy diet represent an effective means of delivering LDL-cholesterol−lowering similar to plant sterols/stanols delivered in various food formats. [Copyright &y& Elsevier]

Abstract: At present, dyslipidemia is most commonly treated with lipid-altering pharmacological therapies. However, safety concerns regarding the use of these agents have prompted the need for safe and efficacious nonpharmacological lipid-altering interventions. One such natural therapy is the combination of plant sterols and endurance training. This combination lifestyle intervention has been shown to decrease total cholesterol, low-density lipoprotein (LDL) cholesterol and triglyceride concentrations while increasing high-density lipoprotein (HDL) cholesterol concentrations. However, the mechanisms that underlie these positive lipid alterations have yet to be clarified. Thus, the purpose of this review is to evaluate individual effects of plant sterols and exercise training on lipid levels while attempting to elucidate the possible independent and synergistic mechanisms of action responsible for these modulations. Results reveal that plant sterols decrease both total and LDL cholesterol levels by reducing exogenous cholesterol absorption by way of cholesterol displacement in the intestinal lumen. Additionally, the intestinal membrane transport proteins, ABCG5, ABCG8, as well as NPC1L1, have also been implicated in plant sterol-mediated cholesterol lowering. Conversely, exercise decreases triglyceride levels by reducing hepatic very low-density lipoprotein secretion and increasing skeletal lipoprotein lipase activity. In addition, endurance training was shown to increase HDL cholesterol levels by way of HDL subfraction alterations, in conjunction with changing reverse cholesterol transport enzyme activities. Moreover, plant sterols and exercise may work synergistically to alter lipid levels by modulating lipoprotein transport, composition, release and metabolism. In sum, the present review lends further insight as to the metabolic benefits of adopting a healthy lifestyle, including plant sterols and endurance training, in the treatment of dyslipidemia. [Copyright &y& Elsevier]

The objective of this study was to examine the effects of the antioxidant α-lipoic acid (ALP) versus a medium chain triglyceride oil mixture (MCTo), which was designed to increase energy expenditure and to improve lipid profiles containing medium chain triglycerides, phytosterols, and omega-3 fatty acids in the form of flaxseed oil. A total of 48 hamsters were fed a) hypercholesterolemic (HC) control, b) HC MCTo, c) HC ALP, or d) HC MCTo/ALP diet for 4 weeks. No differences were observed on food intake, body weight, total body water, lean and fat mass, and tissue thiobarbituric acid reactive substances (TBARS). ALP alone had no effect on total cholesterol (TC); however, MCTo feeding increased TC with (P < 0.03) and without (P < 0.003) ALP when compared with control. ALP increased HDL levels compared with control (P < 0.04) and MCTo/ALP (P < 0.007) groups. MCTo, with (P < 0.0001) or without (P < 0.006) ALP, increased non-HDL cholesterol levels versus control. The non-HDL:HDL cholesterol ratio was decreased by ALP compared with MCTo (45%) and MCTo/ALP (68%) (P < 0.0001), a similar trend was seen when compared with the HC control (22%) group (P < 0.14). Triglyceride levels were not altered by any dietary treatment. Liver and heart tissue reduced glutathione (GSH) was increased (P < 0.05) by all three treatments when compared with control. Both tissues showed an increase (P < 0.05) in oxidized glutathione (GSSG) when fed ALP as compared with other treatments. Hamsters fed ALP had a lower (P < 0.05) GSH/GSSG ratio compared with other treatment groups. In conclusion, MCTo feeding does not elicit beneficial effects on circulating plasma lipids and measures of body composition. In addition, our results do not clearly support an improvement in oxidative status through supplementation of ALP. However, our results do support the existence of beneficial effects of ALP on circulating lipoprotein content in the hamster. [Copyright &y& Elsevier]