Amy G. Preston

Effects of almond consumption on the reduction of LDL-cholesterol: a discussion of potential mechanisms and future research directions

Diet plays a seminal role in the prevention and treatment of cardiovascular disease. Consumption of tree nuts has been shown to reduce low-density lipoprotein cholesterol (LDL-C), a primary target for coronary disease prevention, by 3-19%. Almonds have been found to have a consistent LDL-C-lowering effect in healthy individuals, and in individuals with high cholesterol and diabetes, in both controlled and free-living settings. Almonds are low in saturated fatty acids, rich in unsaturated fatty acids, and contain fiber, phytosterols, and plant protein. Other cardioprotective nutrients unique to almonds include α-tocopherol, arginine, magnesium, copper, manganese, calcium, and potassium. Mechanisms responsible for the LDL-C reduction observed with almond consumption are likely associated with the nutrients almonds provide. Biologically active by nature, these nutrients target primary mechanistic routes of LDL-C reduction, including decreased (re)absorption of cholesterol and bile acid, increased bile acid and cholesterol excretion, and increased LDL-C receptor activity. The nutrients present in almonds may regulate enzymes involved in de novo cholesterol synthesis and bile acid production. Research is needed to understand all mechanisms by which almonds reduce cardiovascular disease risk.

Dose-dependent increases in flow-mediated dilation following acute cocoa ingestion in healthy older adults.

An inverse relation exists between intake of flavonoid-rich foods, such as cocoa, and cardiovascular-related mortality. Favorable effects of flavonoids on the endothelium may underlie these associations. We performed a randomized, double-blind, placebo-controlled study to test the hypothesis that acute cocoa ingestion dose dependently increases endothelium-dependent vasodilation, as measured by an increase in brachial artery flow-mediated dilation (FMD), in healthy older adults. Measurements were obtained before (preingestion) and after (1- and 2-h postingestion) ingestion of 0 (placebo), 2, 5, 13, and 26 g of cocoa in 23 adults (63 ± 2 yr old, mean ± SE). Changes in brachial artery FMD 1- and 2-h postingestion compared with preingestion were used to determine the effects of cocoa. FMD was unchanged 1 (Δ-0.3 ± 0.2%)- and 2-h (Δ0.1 ± 0.1%) after placebo (0 g cocoa). In contrast, FMD increased both 1-h postingestion (2 g cocoa Δ0.0 ± 0.2%, 5 g cocoa Δ0.8 ± 0.3%, 13 g cocoa Δ1.0 ± 0.3%, and 26 g cocoa Δ1.6 ± 0.3%: P < 0.05 compared with placebo for 5, 13, and 26 g cocoa) and 2-h postingestion (2 g cocoa Δ0.5 ± 0.3%, 5 g cocoa Δ1.0 ± 0.3%, 13 g cocoa Δ1.4 ± 0.2%, and 26 g cocoa Δ2.5 ± 0.4%: P < 0.05 compared with placebo for 5, 13, and 26 g cocoa) on the other study days. A serum marker of cocoa ingestion (total epicatechin) correlated with increased FMD 1- and 2-h postingestion (r = 0.44-0.48; both P < 0.05). Collectively, these results indicate that acute cocoa ingestion dose dependently increases brachial artery FMD in healthy older humans. These responses may help to explain associations between flavonoid intake and cardiovascular-related mortality in humans.

Effects of dark chocolate and cocoa consumption on endothelial function and arterial stiffness in overweight adults

The consumption of cocoa and dark chocolate is associated with a lower risk of CVD, and improvements in endothelial function may mediate this relationship. Less is known about the effects of cocoa/chocolate on the augmentation index (AI), a measure of vascular stiffness and vascular tone in the peripheral arterioles. We enrolled thirty middle-aged, overweight adults in a randomised, placebo-controlled, 4-week, cross-over study. During the active treatment (cocoa) period, the participants consumed 37 g/d of dark chocolate and a sugar-free cocoa beverage (total cocoa = 22 g/d, total flavanols (TF) = 814 mg/d). Colour-matched controls included a low-flavanol chocolate bar and a cocoa-free beverage with no added sugar (TF = 3 mg/d). Treatments were matched for total fat, saturated fat, carbohydrates and protein. The cocoa treatment significantly increased the basal diameter and peak diameter of the brachial artery by 6% (+2 mm) and basal blood flow volume by 22%. Substantial decreases in the AI, a measure of arterial stiffness, were observed in only women. Flow-mediated dilation and the reactive hyperaemia index remained unchanged. The consumption of cocoa had no effect on fasting blood measures, while the control treatment increased fasting insulin concentration and insulin resistance (P= 0·01). Fasting blood pressure (BP) remained unchanged, although the acute consumption of cocoa increased resting BP by 4 mmHg. In summary, the high-flavanol cocoa and dark chocolate treatment was associated with enhanced vasodilation in both conduit and resistance arteries and was accompanied by significant reductions in arterial stiffness in women.

Facilitators and barriers to weight loss and weight loss maintenance: a qualitative exploration

BACKGROUND The present study aimed to explore facilitators and barriers to weight loss (WL) and weight loss maintenance (WLM) in women who participated in a primary, 18-week comparative trial that promoted WL with an energy-restricted diet. METHODS Twenty-three women participated in seven focus groups conducted by a moderator and co-facilitator using open-ended questions and probes. Focus groups were held in a private room and audio tape-recorded. Tapes were transcribed verbatim and thematic analysis was used to evaluate transcripts for common themes. RESULTS Accountability to others, social support, planning ahead, awareness and mindfulness of food choices, basic nutrition education, portion control, exercise, and self-motivation were perceived as key facilitators for WL and WLM by women. Identified barriers included life transitions, health status changes, internal factors, environmental pressures, lack of accountability and an absence of social support. CONCLUSIONS Future interventions should address these salient facilitators and barriers to promote sustainable changes in women across their WL and WLM journeys.

A Reduced-Calorie Dietary Pattern Including a Daily Sweet Snack Promotes Body Weight Reduction and Body Composition Improvements in Premenopausal Women Who Are Overweight and Obese: A Pilot Study

Reduced-calorie diets are difficult to follow because they often require elimination of certain foods, leading to poor compliance and limited success. However, a low-calorie, nutrient-dense diet has the potential to accommodate a daily snack without exceeding energy requirements, even during weight loss. This pilot study evaluated the effects of a reduced-calorie diet including either a daily dark chocolate snack or a non-chocolate snack on anthropometric and body composition measurements. In a randomized clinical trial, 26 overweight and obese (body mass index ≥25 to ≤43) premenopausal women were assigned to a reduced-calorie diet that included either a daily dark chocolate snack or non-chocolate snack (n=13 per group) for 18 weeks. At baseline and end of study, body weight and waist and hip circumferences were measured along with fat mass, lean mass, and body fat percentage by dual-energy x-ray absorptiometry. Energy and macronutrient intakes were estimated from 4-day food records. Within- and between-group changes from baseline were analyzed using paired t tests and independent t tests, respectively. Women in both snack groups reduced estimated daily energy intake (P<0.001). Women in both the dark chocolate snack and non-chocolate snack groups, respectively, experienced decreases (P<0.001) in body weight (-5.1 vs -5.1 kg), hip circumference (-5.8 vs -5.4 cm), waist circumference (-5.7 vs -3.5 cm), fat mass (-3.9 vs -3.6 kg), and body fat percentage (-3.4% vs -3.1%), with no change in lean mass. Improvements in anthropometric and body composition measurements among overweight and obese premenopausal women can be achieved with a reduced-calorie diet including either a daily dark chocolate snack or non-chocolate snack.

Changes in body weight, blood pressure and selected metabolic biomarkers with an energy-restricted diet including twice daily sweet snacks and once daily sugar-free beverage

BACKGROUND/OBJECTIVES The type of sweet snack incorporated into an energy-restricted diet (ERD) may produce differential effects on metabolic improvements associated with body weight (BW) loss. This study compared effects of incorporating either twice daily energy-controlled dark chocolate snacks plus once daily sugar-free cocoa beverage (DC) to non-chocolate snacks plus sugar-free non-cocoa beverage (NC) into an ERD on BW loss and metabolic outcomes. MATERIALS/METHODS In an 18-week randomized comparative trial, 60 overweight/obese premenopausal women were assigned to DC (n = 30) or NC group (n = 30). Dietary intake was measured at baseline and week 18, and BW, anthropometrics, blood pressure (BP) and serum glucose, insulin and lipid concentrations were measured at baseline, and weeks 6, 12 and 18. Data were analyzed using repeated measures ANOVA. RESULTS Using intention-to-treat analysis, women in DC and NC groups reduced energy intake (both P < 0.001) and lost 4.4 ± 0.6 kg and 5.0 ± 0.9 kg (both P < 0.001), respectively. Both groups lowered systolic and diastolic BP [DC = 2.7 (P < 0.05), 2.7 (P < 0.01); NC = 3.4 (P < 0.01), 4.2 (P < 0.01) mmHg, respectively]. Glucose and insulin concentrations decreased by 0.72 mmol/L (P < 0.001) and 13.20 pmol/L (P < 0.01) in DC group and by 0.83 mmol/L (P < 0.001) and 13.20 pmol/L (P < 0.01), respectively, in NC group. Total cholesterol increased in NC group (P < 0.05), with no significant lipid changes in DC group. There were no significant differences in biomarker outcomes between groups. CONCLUSIONS Overweight/obese premenopausal women following an 18-week ERD that included either DC or NC sweet snack and sugar-free beverage lost equivalent amounts of BW and improved BP measurements and glucose and insulin concentrations.

Effects of theobromine and caffeine on mood and vigilance.

Abstract Like caffeine, theobromine crosses the blood-brain barrier and binds to adenosine receptors, suggesting it might share caffeine’s beneficial effects on mood and vigilance. Therefore, the purpose of this study was to assess the effect of theobromine doses commonly found in foods on mood and vigilance parameters sensitive to caffeine. Caffeine was tested as a positive control. Twenty-four men (age, 23 [3] years) completed 6 double-blind trials during which they consumed experimental beverages, assessed their mood using standardized self-report questionnaires, and completed a 2-hour visual vigilance task. Three experimental doses (100, 200, and 400 mg theobromine) were delivered in a cocoa-based beverage; 3 matched control treatments (0 mg theobromine, 400 mg theobromine, and 100 mg caffeine) were delivered in a non–cocoa beverage. Mean salivary concentrations of theobromine exhibited significant dose-dependent differences (400 mg trials > 200 mg trial > 100 mg trial > 0 mg trials; P < 0.005). At every dose tested, theobromine failed to consistently affect mood state or vigilance (P > 0.05), but 100-mg caffeine significantly decreased lethargy/fatigue and increased vigor (P = 0.006 and 0.011, respectively). These findings indicate theobromine does not influence mood and vigilance when administered in nutritionally relevant doses, despite sharing many of caffeine’s structural characteristics.

The comparative effects of nutritional drinks designed to augment athletic performance and recovery

Methods 22 males (24.9 ± 4.4) completed 4 exercise test visits, each involving an exhaustive exercise protocol intended to induce muscle soreness (30 minutes, -10 degree decline, 75% HRmax) and 4 hours later, a TTE performance trial. In a crossover, partially double-blinded manner, subjects were provided 2 servings of the beverage (11-13.7 oz), 15 minutes and 2 hours after the exhaustive exercise. Muscle recovery was assessed via the rate of return to baseline of CPK and LDH over the 72-hour post exercise period. Exercise test visits were at least 1 week apart to allow for muscle recovery.

Effects of Dark Chocolate and Almonds on Cardiovascular Risk Factors in Overweight and Obese Individuals: A Randomized Controlled‐Feeding Trial

Background Consumption of almonds or dark chocolate and cocoa has favorable effects on markers of coronary heart disease; however, the combined effects have not been evaluated in a well‐controlled feeding study. The aim of this study was to examine the individual and combined effects of consumption of dark chocolate and cocoa and almonds on markers of coronary heart disease risk. Methods and Results A randomized controlled, 4‐period, crossover, feeding trial was conducted in overweight and obese individuals aged 30 to 70 years. Forty‐eight participants were randomized, and 31 participants completed the entire study. Each diet period was 4 weeks long, followed by a 2‐week compliance break. Participants consumed each of 4 isocaloric, weight maintenance diets: (1) no treatment foods (average American diet), (2) 42.5 g/d of almonds (almond diet [ALD]), (3) 18 g/d of cocoa powder and 43 g/d of dark chocolate (chocolate diet [CHOC]), or (4) all 3 foods (CHOC+ALD). Compared with the average American diet, total cholesterol, non–high‐density lipoprotein cholesterol, and low‐density lipoprotein cholesterol after the ALD were lower by 4%, 5%, and 7%, respectively (P<0.05). The CHOC+ALD decreased apolipoprotein B by 5% compared with the average American diet. For low‐density lipoprotein subclasses, compared with the average American diet, the ALD showed a greater reduction in large buoyant low‐density lipoprotein particles (−5.7±2.3 versus −0.3±2.3 mg/dL; P=0.04), whereas the CHOC+ALD had a greater decrease in small dense low‐density lipoprotein particles (−12.0±2.8 versus −5.3±2.8 mg/dL; P=0.04). There were no significant differences between diets for measures of vascular health and oxidative stress. Conclusions Our results demonstrate that consumption of almonds alone or combined with dark chocolate under controlled‐feeding conditions improves lipid profiles. Incorporating almonds, dark chocolate, and cocoa into a typical American diet without exceeding energy needs may reduce the risk of coronary heart disease. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT01882881.