Dietary stearic acid and palmitic acid do not differently affect ABCA1-mediated cholesterol efflux capacity in healthy men and postmenopausal women: A randomized controlled trial.

BACKGROUND: The saturated fatty acid stearic acid (C18:0) lowers HDL cholesterol compared with palmitic acid (C16:0). However, the ability of HDL particles to promote cholesterol efflux from macrophages (cholesterol efflux capacity; CEC) may better predict coronary heart disease (CHD) risk than HDL cholesterol concentrations. OBJECTIVE: We examined effects of exchanging dietary palmitic acid for stearic acid on ATP-binding cassette transporter A1 (ABCA1)-mediated CEC, and other conventional and emerging cardiometabolic risk makers. DESIGN: In a double-blind, randomized, crossover study with two 4-week isocaloric intervention periods, 34 healthy men and postmenopausal women (61.5 ± 5.7 years, BMI: 25.4 ± 2.5 kg/m2) followed diets rich in palmitic acids or stearic acids. Difference in intakes was 6% of daily energy. ABCA1-mediated CEC was measured from J774 macrophages to apolipoprotein (apo)B-depleted serum. RESULTS: Compared with the palmitic-acid diet, the stearic-acid diet lowered serum LDL cholesterol (-0.14 mmol/L; p = 0.010), HDL cholesterol (-0.09 mmol/L; p=<0.001), and apoA1 (-0.05 g/L; p < 0.001). ABCA1-mediated CEC did not differ between diets (p = 0.280). Cholesteryl ester transfer protein (CETP) mass was higher on stearic acid (0.11 mg/L; p = 0.003), but CETP activity was comparable. ApoB100 did not differ, but triacylglycerol concentrations tended to be higher on stearic acid (p = 0.100). Glucose concentrations were comparable. Effects on insulin and C-peptide were sex-dependent. In women, the stearic-acid diet increased insulin concentrations (1.57 µU/mL; p = 0.002), while in men, C-peptide concentrations were lower (-0.15 ng/mL; p = 0.037). Interleukin 6 (0.15 pg/mL; p = 0.039) and tumor necrosis factor alpha (0.18 pg/mL; p = 0.005), but not high-sensitivity C-reactive protein, were higher on stearic acid. Soluble intracellular adhesion molecule (9 ng/mL; p = 0.033), but not soluble vascular cell adhesion molecule and endothelial-selectin concentrations decreased after stearic-acid consumption. CONCLUSIONS: As expected, stearic-acid intake lowered LDL cholesterol, HDL cholesterol, and apoA1. Insulin sensitivity in women and low-grade inflammation might be unfavorably affected by stearic-acid intake. However, palmitic-acid and stearic-acid intakes did not differently affect ABCA1-mediated CEC. CLINICAL TRIAL REGISTRY: This trial was registered at clinicaltrials.gov as NCT02835651.

Fat composition of vegetable oil spreads and margarines in the USA in 2013: a national marketplace analysis.

Worldwide, the fat composition of spreads and margarines ("spreads") has significantly changed over the past decades. Data on fat composition of US spreads are limited and outdated. This paper compares the fat composition of spreads sold in 2013 to that sold in 2002 in the USA. The fat composition of 37 spreads representing >80% of the US market sales volume was determined by standard analytical methods. Sales volume weighted averages were calculated. In 2013, a 14 g serving of spread contained on average 7.1 g fat and 0.2 g trans-fatty acids and provided 22% and 15% of the daily amounts recommended for male adults in North America of omega-3 α-linolenic acid and omega-6 linoleic acid, respectively. Our analysis of the ingredient list on the food label showed that 86% of spreads did not contain partially hydrogenated vegetable oils (PHVO) in 2013. From 2002 to 2013, based on a 14 g serving, total fat and trans-fatty acid content of spreads decreased on average by 2.2 g and 1.5 g, respectively. In the same period, the overall fat composition improved as reflected by a decrease of solid fat (from 39% to 30% of total-fatty acids), and an increase of unsaturated fat (from 61% to 70% of total-fatty acids). The majority of US spreads no longer contains PHVO and can contribute to meeting dietary recommendations by providing unsaturated fat.

Sustained satiety induced by food foams is independent of energy content, in healthy adults.

Our previous research demonstrated high, sustained satiety effects of stabilized food foams relative to their non-aerated compositions. Here we test if the energy and macronutrients in a stabilized food foam are critical for its previously demonstrated satiating effects. In a randomized, crossover design, 72 healthy subjects consumed 400 mL of each of four foams, one per week over four weeks, 150 min after a standardized breakfast. Appetite ratings were collected for 180 min post-foam. The reference was a normal energy food foam (NEF1, 280 kJ/400 mL) similar to that used in our previous research. This was compared to a very low energy food foam (VLEF, 36 kJ/400 mL) and 2 alternative normal energy foams (NEF2 and NEF3) testing possible effects of compositional differences other than energy (i.e. emulsifier and carbohydrate source). Appetite ratings were quantified as area under the curve (AUC) and time to return to baseline (TTRTB). Equivalence to NEF1 was predefined as the 90% confidence interval of between-treatment differences in AUC being within -5 to +5 mm/min. All treatments similarly affected appetite ratings, with mean AUC for fullness ranging between 49.1 and 52.4 mm/min. VLEF met the statistical criterion for equivalence to NEF1 for all appetite AUC ratings, but NEF2 and NEF3 did not. For all foams the TTRTB for satiety and fullness were consistently between 150 and 180 min, though values were shortest for NEF2 and especially NEF3 foams for most appetite scales. In conclusion, the high, sustained satiating effects of these food foams are independent of energy and macronutrient content at the volumes tested.

Fasting ghrelin does not predict food intake after short-term energy restriction.

OBJECTIVE: To study the role of ghrelin as a hunger signal during energy restriction and to test the hypothesis that changes in fasting leptin concentrations during energy restriction are associated with changes in fasting ghrelin concentrations. RESEARCH METHODS AND PROCEDURES: Thirty-five healthy, lean men (23 +/- 3 years of age; BMI: 22.3 +/- 1.6 kg/m(2)) participated in a controlled intervention study. Fasting ghrelin and leptin concentrations were measured before and after 2 days of 62% energy restriction and after a 2-day period of ad libitum food intake. Energy intake during the latter period was assessed. RESULTS: On average, ghrelin concentrations did not change (0.05 mug/liter; 95% confidence interval, -0.03; 0.12) during energy restriction. Changes in ghrelin concentration during energy restriction were not associated with energy intake during the ad libitum period (r = 0.07; not significant). Ad libitum energy intake was, however, associated with the change in ghrelin concentrations during the same period (r = -0.34; p = 0.05). Ghrelin and leptin concentrations were not associated. In addition, the ratio of percentage changes in ghrelin and leptin during energy restriction was not correlated with ad libitum food intake after energy restriction (r = -0.26; p = 0.14). DISCUSSION: Fasting ghrelin concentrations did not rise after a 2-day energy restriction regimen. Moreover, changes in ghrelin concentrations during energy restriction were not associated with subsequent ad libitum food intake, suggesting that fasting ghrelin does not act as a hunger signal to the brain. The data did not support our hypothesis that leptin suppresses ghrelin levels.

Effect of a high-protein breakfast on the postprandial ghrelin response.

BACKGROUND: The most satiating macronutrient appears to be dietary protein. Few studies have investigated the effects of dietary protein on ghrelin secretion in humans. OBJECTIVE: This study was designed to investigate whether a high-protein (HP) breakfast is more satiating than a high-carbohydrate breakfast (HC) through suppression of postprandial ghrelin concentrations or through other physiologic processes. DESIGN: Fifteen healthy men were studied in a single-blind, crossover design. Blood samples and subjective measures of satiety were assessed frequently for 3 h after the consumption of 2 isocaloric breakfasts that differed in their protein and carbohydrate content (58.1% of energy from protein and 14.1% of energy from carbohydrate compared with 19.3% of energy from protein and 47.3% of energy from carbohydrate). The gastric emptying rate was indirectly assessed with the acetaminophen absorption test. RESULTS: The HP breakfast decreased postprandial ghrelin secretion more than did the HC breakfast (P < 0.01). Ghrelin concentrations were correlated with glucose-dependent insulinotropic polypeptide (r = -0.65; 95% CI: -0.85, -0.29) and glucagon concentrations (r = -0.47; 95% CI: -0.75, -0.03). Compared with the HC breakfast, the HP breakfast increased glucagon (P < 0.0001) and cholecystokinin (P < 0.01), tended to increase glucose-dependent insulinotropic polypeptide (P = 0.07) and glucagon-like peptide 1 (P = 0.10), and decreased the gastric emptying rate (P < 0.0001). Appetite ratings were not significantly different between the 2 treatments, and the HP breakfast did not significantly affect ad libitum energy intake. CONCLUSIONS: The HP breakfast decreased postprandial ghrelin concentrations more strongly over time than did the HC breakfast. High associations between ghrelin and glucose-dependent insulinotropic polypeptide and glucagon suggest that stimulation of these peptides may mediate the postprandial ghrelin response. The HP breakfast also reduced gastric emptying, probably through increased secretion of cholecystokinin and glucagon-like peptide 1.

Effects of gastric emptying on the postprandial ghrelin response.

Distension and chemosensitization of the stomach are insufficient to induce a ghrelin response, suggesting that postgastric feedback is required. This postgastric feedback may be regulated through insulin. We investigated the relation between gastric emptying rate and the postprandial ghrelin response as well as the role of insulin and other hormones possibly mediating this response. Fifteen healthy men [BMI 21.6 kg/m2 (SD 1.9), age 20.5 yr (SD 2.5)] were studied in a single-blind, crossover design. Subjects received two treatments separated by 1 wk: 1) a dairy breakfast in combination with a 3-h intravenous infusion of glucagon-like peptide-1 (GLP-1), which delays gastric emptying, and 2) a dairy breakfast in combination with a 3-h intravenous infusion of saline. Blood samples were drawn before breakfast and during the infusion. Postprandial ghrelin (total) responses were lower following the saline infusion compared with the GLP-1 infusion (P < 0.05). Acetaminophen concentrations, an indirect measurement of gastric emptying rate, were inversely correlated with total ghrelin concentrations (saline r = -0.76; 95% CI = -0.90, -0.49, GLP-1 r = -0.47; 95% CI = -0.76, -0.04). Ghrelin concentrations were only weakly correlated with insulin concentrations (saline r = -0.36; 95% CI = -0.69, 0.09; GLP- 1 r = -0.42; 95% CI = -0.73, 0.03), but strongly inversely correlated with GIP concentrations (saline r = -0.74; 95% CI= -0.89, -0.45; GLP-1 r = -0.63; 95% CI = -0.84, -0.27). In conclusion, our results support the hypothesis that ghrelin requires postgastric feedback, which may not be regulated through insulin. Conversely, our data suggest a role of glucose-dependent insulinotropic polypeptide in ghrelin secretion.

Ghrelin response to carbohydrate-enriched breakfast is related to insulin.

BACKGROUND: Ghrelin plays an important role in the regulation of food intake. Little is known about how ghrelin concentrations are modified by dietary factors. OBJECTIVE: We examined the effects of both amount and type of carbohydrate on ghrelin concentrations and all correlations among the variables ghrelin, glucose, insulin, leptin, and all 4 subjective measures of appetite. DESIGN: Twenty healthy nonobese men were studied in a double-blind, randomized, crossover design. Subjective measures of appetite and concentrations of ghrelin, glucose, insulin, and leptin were frequently assessed for 4 h after liquid breakfast meals differing in energy content and carbohydrate structure-ie, water, low-calorie (LC) meal, high-calorie simple carbohydrate (HC-SC) meal, and high-calorie complex carbohydrate (HC-CC) meal. RESULTS: Ghrelin concentrations decreased after the HC-SC breakfast by 41%, after the HC-CC breakfast by 33%, and after the LC breakfast by 24%. No significant differences in ghrelin concentration among the 3 breakfasts were observed until 120 min. Ghrelin concentrations were correlated with subjective measures of hunger (r=0.51) and fullness (r=-0.44). The percentage decrease in ghrelin between 0 and 30 min was inversely correlated with the percentage increases in insulin (r=-0.76) and glucose (r=-0.79) but not with changes in leptin (r=0.10). The percentage changes in ghrelin concentrations between 30 and 180 min were correlated with the percentage changes in insulin (r=-0.53) and leptin (r=-0.47) but not with changes in glucose (r=0.22). CONCLUSION: The results support the hypothesis that ghrelin requires postgastric feedback, which may be regulated through insulin.