Effects of potato resistant starch intake on insulin sensitivity, related metabolic markers and appetite ratings in men and women at risk for type 2 diabetes: a pilot cross-over randomised controlled trial.

BACKGROUND: The intake of certain types of resistant starch (RS) has been associated in some studies with increased whole-body insulin sensitivity. This randomised, cross-over pilot trial evaluated the effect of consuming cooked, then chilled potatoes, a source of RS, compared to isoenergetic, carbohydrate (CHO)-containing control foods, on insulin sensitivity and related markers. METHODS: Nineteen adults with body mass index 27.0-39.9 kg m-2 consumed 300 g day-1 RS-enriched potatoes (approximately two potatoes; ~18 g RS) or CHO-based control foods, as part of lunch, evening and snack meals, over a 24-h period. After an overnight fast, insulin sensitivity, CHO metabolism markers, free fatty acids, breath hydrogen levels and appetite were assessed for up to 5 h after the intake of a standard breakfast. The primary endpoint was insulin sensitivity, assessed with the Matsuda index. P < 0.05 (one-sided) was considered statistically significant. RESULTS: Insulin sensitivity was not significantly different between the potato and control conditions. The potato intervention resulted in higher postprandial breath hydrogen (P = 0.037), lower postprandial free fatty acid concentrations (P = 0.039) and lower fasting plasma glucose (P = 0.043) compared to the control condition. Fullness ratings were significantly lower after potato versus control (P = 0.002). No other significant effects were observed; however, there was a trend toward lower fasting insulin (P = 0.077) in the potato versus the control condition. CONCLUSIONS: The results of this pilot study suggest RS-enriched potatoes may have a favourable impact on carbohydrate metabolism and support the view that additional research in a larger study sample is warranted.

Corn oil intake favorably impacts lipoprotein cholesterol, apolipoprotein and lipoprotein particle levels compared with extra-virgin olive oil.

BACKGROUND: Corn oil (CO) and extra-virgin olive oil (EVOO) are rich sources of unsaturated fatty acids (UFA), but UFA profiles differ among oils, which may affect lipoprotein levels. OBJECTIVES: The objective of this study was to assess the effects of CO versus EVOO intake on fasting lipoprotein and subfraction cholesterol levels, apolipoprotein (apo) A1, apo B, and low-density lipoprotein particle concentrations in men and women. SUBJECTS/METHODS: As part of a weight maintenance diet, men and women were provided with food items prepared with 54 g per day of CO or EVOO (21-day treatment, 21-day washout) in a randomized, double-blind, controlled-feeding, crossover trial. Fasting lipoprotein cholesterol and related variables were determined with density gradient ultracentrifugation. RESULTS: Among the 54 completers, CO reduced total cholesterol, low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), apo B and LDL particle concentration to a greater extent compared with EVOO intake. Changes in LDL-C and VLDL-C contributed to the larger reduction in non-HDL-C with CO compared with EVOO intake (-0.39 mmol/l vs -0.04 mmol/l; P<0.001). The larger reduction in LDL-C by CO intake was attributable to changes (P<0.05) caused by CO vs EVOO in large LDL1+2-C (-0.22 mmol/l) and intermediate-density lipoprotein cholesterol (-0.12 mmol/l). HDL-C responses did not differ between treatments, but apo A1 increased more with EVOO compared with CO intake (4.6 versus 0.7 mg/dl, respectively, P=0.016). CONCLUSIONS: CO intake reduced atherogenic lipoprotein cholesterol and particle concentrations to a larger extent than did EVOO, which may have implications for cardiovascular disease risk.

Safety and lipid-altering efficacy of a new omega-3 fatty acid and antioxidant-containing medical food in men and women with elevated triacylglycerols.

This randomized, double-blind, placebo-controlled multi-center trial investigated the lipid-altering effects of a medical food (PDL-0101) providing 1.8 g/d eicosapentaenoic acid; 12 mg/d astaxanthin, a marine algae-derived carotenoid; and 100 mg/d tocopherol-free gamma/delta tocotrienols enriched with geranylgeraniol, extracted from annatto, on triacylglycerols (TAG), other lipoprotein lipids, and oxidized low-density lipoprotein (LDL) in 102 subjects with TAG 150-499 mg/dL (1.69-5.63 mmol/L) and LDL cholesterol (LDL-C) ≥70 mg/dL (1.81 mmol/L). Compared to placebo, after eight weeks of treatment, PDL-0101 significantly reduced median TAG (-9.5% vs. 10.6%, p<0.001), while not significantly altering mean LDL-C (-3.0% vs. -8.0% for PDL-0101 and placebo, respectively, p=0.071), mean high-density lipoprotein cholesterol (~3% decrease in both groups, p=0.732), or median oxidized LDL concentrations (5% vs. -5% for PDL-0101 and placebo, respectively, p=0.112). These results demonstrate that PDL-0101 is an effective medical food for the management of elevated TAG.

Chitin-glucan fiber effects on oxidized low-density lipoprotein: a randomized controlled trial.

BACKGROUND/OBJECTIVES: Elevated oxidized low-density lipoprotein (OxLDL) may promote inflammation, and is associated with increased risk of atherosclerotic coronary heart disease and worsening complications of diabetes mellitus. The primary objective of this study was to evaluate the efficacy of chitin-glucan (CG), alone and in combination with a potentially anti-inflammatory olive oil (OO) extract, for reducing OxLDL in subjects with borderline to high LDL cholesterol (LDL-C) levels. SUBJECTS/METHODS: This 6-week, randomized, double-blind, placebo-controlled study of a novel, insoluble fiber derived from the Aspergillus niger mycelium, CG, evaluated 130 subjects free of diabetes mellitus with fasting LDL-C 3.37-4.92 mmol/l and glucose ≤ 6.94 mmol/l. Participants were randomly assigned to receive CG (4.5 g/day; n=33), CG (1.5 g/day; n=32), CG (1.5 g/day) plus OO extract (135 mg/day; n=30), or matching placebo (n=35). RESULTS: Administration of 4.5 g/day CG for 6 weeks significantly reduced OxLDL compared with placebo (P=0.035). At the end of study, CG was associated with lower LDL-C levels relative to placebo, although this difference was statistically significant only for the CG 1.5 g/day group (P=0.019). CG did not significantly affect high-density lipoprotein cholesterol, triglycerides, glucose, insulin or F2-isoprostane levels. Adverse events did not substantively differ between treatments and placebo. CONCLUSIONS: In this 6-week study, CG (4.5 g/day) reduced OxLDL, an effect that might affect the risk for atherosclerosis.

Effects of duration of treatment and dosage of eicosapentaenoic acid and stearidonic acid on red blood cell eicosapentaenoic acid content.

OBJECTIVE: The purpose of this randomized, controlled, parallel group study was to characterize the relationships between dosages of stearidonic acid (SDA) and eicosapentaenoic acid (EPA), and incorporation of EPA into red blood cell (RBC) membranes over time. METHODS: Healthy subjects (n=131) received capsules with placebo (safflower oil), SDA (0.43, 1.3, 2.6, or 5.2 g/d) or EPA (0.44, 1.3, or 2.7 g/d) for 12 weeks. RBC fatty acids were analyzed biweekly. RESULTS: RBC %EPA increased in all EPA and SDA groups (p<0.02 vs. control) except the 0.43 g/d SDA group (p=0.187). For theoretical intakes of EPA of 0.25, 0.5, and 0.89 g/d, the amounts of SDA needed to achieve equivalent RBC EPA enrichment were 0.61, 1.89, and 5.32 g/d (conversion efficiencies of 41%, 26%, and 17%), respectively. CONCLUSIONS: SDA increased RBC %EPA in a dosage and time-dependent manner at intakes as low as 1.3 g/d.

A low-viscosity soluble-fiber fruit juice supplement fails to lower cholesterol in hypercholesterolemic men and women.

This study was designed to determine whether a soluble dietary fiber supplement containing gum arabic and pectin in apple juice would lower serum lipids in 110 hypercholesterolemic men and women. Subjects were stabilized on an American Heart Association Phase I Diet for 8 wk. Those with elevated low density lipoprotein cholesterol levels, despite dietary modification, continued to follow the diet and were randomly assigned to receive 720 mL/d of apple juice containing 0 (control), 5, 9 or 15 g of gum arabic and pectin (4:1 ratio) for 12 wk, followed by a 6-wk apple juice-only washout phase. Serum lipid profiles, body weight and 3-day diet records were collected at 3-wk intervals. No significant differences among groups were observed in serum lipid responses during treatment or washout. During the treatment phase, mean serum total cholesterol and triglyceride concentrations increased by 3.5 and 28.5%, respectively (all groups combined, P < 0.0001). The high density lipoprotein cholesterol level did not change significantly from baseline in any group. During washout, mean total cholesterol concentration rose by an additional 2.4% (P < 0.05) compared with the value at the end of the treatment period, suggesting that the apple juice used to deliver the fiber supplement may have contributed to the adverse changes observed in the serum lipid profile. These findings do not support the hypothesized hypocholesterolemic effect of the gum arabic/pectin (4:1) mixture studied, but do underline the importance of selecting appropriate vehicles for delivery of dietary fiber mixtures.

Long-term effects of consuming foods containing psyllium seed husk on serum lipids in subjects with hypercholesterolemia.

The effects of consuming foods containing 0 (control), 3.4, 6.8, or 10.2 g psyllium seed husk (PSH)/d for 24 wk on the serum lipid profile were assessed in this randomized, double-blind controlled study. Men and women (n = 286) with LDL-cholesterol concentrations between 3.36 and 5.68 mmol/L (130 and 220 mg/dL) were randomly assigned to one of four treatment groups after following a low-fat diet for > or = 8 wk. At week 24, LDL cholesterol was 3% above baseline in the control group. In the group consuming 10.2 g PSH/d, LDL cholesterol remained below baseline during treatment, with a value 5.3% below that of the control group at week 24 (P < 0.05 compared with the control group). No significant differences were observed in HDL cholesterol or triacylglycerol. Although modest, the effect of 10.2 g PSH/d on LDL cholesterol (relative to the control) persisted throughout the 24-wk treatment period, indicating potential for long-term benefit.

Separate and joint effects of marine oil and simvastatin in patients with combined hyperlipidemia.

Marine oil plus simvastatin is an effective therapy for improving serum triglycerides, non-high-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in patients with combined hyperlipidemia. Concurrent administration does not attenuate the individual effects of either marine oil or simvastatin on the serum lipid profile.

Effects of docosahexaenoic acid on serum lipoproteins in patients with combined hyperlipidemia: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: The objective of this study was to evaluate the effects of daily dietary supplementation with 1.25 g or 2.5 g of docosahexaenoic (DHA), in the absence of eicosapentaenoic acid (EPA), on serum lipids and lipoproteins in persons with combined hyperlipidemia (CHL) [serum low-density lipoprotein cholesterol (LDL-C) 130 to 220 mg/dL and triglycerides 150 to 400 mg/dL]. METHODS: After a 6-week dietary stabilization period, subjects entered a 4-week single-blind placebo (vegetable oil) run-in phase. Those with adequate compliance during the the run-in were randomized into one of three parallel groups (placebo, 1.25, or 2.5 g/day DHA) for 6 weeks of treatment. Supplements were administered in a triglyceride form contained in gelatin capsules. Primary outcome measurements were plasma phospholipid DHA content, serum triglycerides, high-density lipoprotein cholesterol (HDL-C). LDL-C and non-HDL-C. RESULTS: The DHA content of plasma phospholipids increased dramatically (2 to 3 fold) in a dose-dependent manner. Significant (p < 0.05) changes were observed in serum triglycerides (17 to 21% reduction) and HDL-C (6% increase) which were of similar magnitude in both DHA groups. Non-HDL-C [+1.6 (NS) and +5.7% (p < 0.04)] and LDL-C [+9.3% (NS) and +13.6% (p < 0.001)] increased in the DHA treatment groups. All lipid effects reached an apparent steady state within the first 3 weeks of treatment. CONCLUSION: Dietary DHA, in the absence of EPA, can affect lipoprotein cholesterol and triglyceride levels in patients with combined hyperlipidemia. The desirable triglyceride and HDL-C changes were present at a dose which did not significantly increased non-HDL-C or LDL-C. These preliminary findings suggest that dietary supplementation with 1.25 g DHA/day, provided in a triglyceride form, may be an effective tool to aid in the management of hypertriglyceridemia.