Effects of almond consumption on the post-lunch dip and long-term cognitive function in energy-restricted overweight and obese adults.
The post-lunch dip in cognition is a well-established phenomenon of decreased alertness, memory and vigilance after lunch consumption. Lunch composition reportedly influences the post-lunch dip. Moreover, dieting is associated with cognitive function impairments. The negative effects of dieting have been reversed with nut-supplemented diets. The aims of this study were to (1) evaluate the acute effect of an almond-enriched high-fat lunch or high-carbohydrate lunch on the post-lunch decline in cognitive function, and (2) evaluate the effects of chronic almond consumption as part of an energy-restricted diet on the memory and attention domains of cognitive function. In total, eighty-six overweight and obese adults were randomised to consume either an almond-enriched diet (AED) or a nut-free control diet (NFD) over a 12-week weight loss intervention. Participants were also randomised to receive either an almond-enriched high-fat lunch (A-HFL) (>55 % energy from fat, almonds contributing 70-75 % energy) or a high-carbohydrate lunch (HCL) (>85 % energy from carbohydrates) at the beginning and end of the weight loss intervention. Memory and attention performance indices decreased after lunch consumption (P<0·001). The A-HFL group ameliorated the decline in memory scores by 57·7 % compared with the HCL group (P=0·004). Both lunch groups had similar declines in attention. Moreover, memory and attention performance indices increased after the 12-week intervention period (P<0·05) with no difference between the AED and NFD groups. In conclusion, almond consumption at a midday meal can reduce the post-lunch dip in memory. However, long-term almond consumption may not further improve cognitive function outcomes in a weight loss intervention.
Almond Consumption Is Associated with Better Nutrient Intake, Nutrient Adequacy, and Diet Quality in Adults: National Health and Nutrition Examination Survey 2001-2010.
Purpose: The purpose of this study was to examine the association between almond consumption, the most widely consumed tree nut in the US, and nutrient intake, nutrient adequacy, diet quality, and weight/adiposity in adults. Methods: Data from adults (N=24,808), 19+ years, participating in the NHANES 2001-2010 were used. The NCI method was used to estimate the usual intake of almonds and selected nutrients. Almond consumers were defined as those consuming any amount of almonds/almond butter. Percentages of the consumers/non-consumers below the Estimated Average Requirement (EAR) or above the Adequate Intake (AI) for select nutrients were determined. To assess significant differences for the percentage of almond consumers vs. non-consumers with intakes less than the EAR or above the AI, a Z-statistic for differences in population proportions was used. Covariate-controlled linear regression was used to determine differences in diet quality, measured by the Healthy Eating Index-2010 (HEI-2010), between the consumer groups. Body mass indices and waist circumference were assessed. P was set at p < 0.01. Results: Almond consumers were more likely to be non-Hispanic white, older, of higher income, more physically active, and were less likely to be a current smoker than non-consumers. Usual intake of almonds among consumers was 29.5 ± 1.5 g/day. Usual intake of protein; dietary fiber; vitamins A, D, E, and C; thiamin; niacin; riboflavin; folate, calcium, copper, magnesium, iron, phosphorus, selenium, zinc, and potassium was higher in almond consumers. Almond consumers were less likely to be below the EAR for protein, vitamins A, D, E, B12, and C; riboflavin; calcium; copper; magnesium; iron; phosphorus; and zinc. They were also more likely to be above the AI for dietary fiber and potassium. Total HEI-2010 scores were approximately 15 points higher in almond consumers. Body mass indices and waist circumference measures were lower in almond consumers. Conclusions: Moderate consumption of almonds should be encouraged as part of a healthy diet.
Influence of a Mediterranean Dietary Pattern on Body Fat Distribution: Results of the PREDIMED-Canarias Intervention Randomized Trial.
OBJECTIVE: To assess the influence of a Mediterranean dietary pattern (MeDiet) on anthropometric and body composition parameters in one of the centers of the PREDIMED randomized dietary trial. SUBJECTS/SETTINGS: 351 Canarian free-living subjects aged 55 to 80 years, with type 2 diabetes or ≥3 cardiovascular risk factors. INTERVENTION: Participants were randomly assigned to one of 3 different dietary interventions: MeDiet + extra-virgin olive oil (EVOO), MeDiet + nuts (walnuts, almonds, and hazelnuts), or a control low-fat diet. Total energy intake was ad libitum. OUTCOME MEASURES: Measures included changes in anthropometric measures (weight, body mass index [BMI] and waist circumference [WC]), body fat distribution, energy, and nutrient intake after 1 year. Body composition (percentage of total body fat [%TBF], total fat mass [TFM], free fat mass [FFM], percentage of truncal fat [%TrF], truncal fat mass [TrFM]) and total body water (TBW) were estimated by octapolar electrical impedance analysis. STATISTICAL ANALYSES: Paired t tests were conducted to assess within-group changes. Analyses of variance (ANOVAs) were used to assess the effect of the dietary intervention on the percentage change in anthropometric variables, body composition, and dietary intake profile. All pairwise comparisons that were statistically significant in ANOVA were subsequently adjusted using the Benjamini-Hochberg test, which penalizes for multiple comparisons. RESULTS: After 1 year of intervention, significant within-group reductions in all anthropometric variables were observed for the MeDiet + EVOO and the control group. The MeDiet + nuts group exhibited a significant reduction in WC and TBW. The control group showed a significant increase in %TBF and a reduction in TBW. The control group showed a significant increase in the percentage of total body fat and a reduction in TBW. However, we did not find any between-group significant difference in anthropometric or body composition changes. CONCLUSIONS: Mediterranean diets enriched with EVOO or specific mixed nuts (walnuts, almonds, hazelnuts) that contain approximately 40% total fat can be alternative options to low-fat diets for weight maintenance regimes in older overweight or obese adults.
Consumption of Walnuts in Combination with Other Whole Foods Produces Physiologic, Metabolic, and Gene Expression Changes in Obese C57BL/6J High-Fat-Fed Male Mice.
BACKGROUND: Although a reductionist approach has sought to understand the roles of individual nutrients and biochemicals in foods, it has become apparent that there can be differences when studying food components in isolation or within the natural matrix of a whole food. OBJECTIVE: The objective of this study was to determine the ability of whole-food intake to modulate the development of obesity and other metabolic dysfunction in mice fed a high-fat, Western-style obesogenic diet. To test the hypothesis that an n-3 (ω-3) polyunsaturated fatty acid-rich food could synergize with other, largely polyphenol-rich foods by producing greater reductions in metabolic disease conditions, the intake of English walnuts was evaluated in combination with 9 other whole foods. METHODS: Eight-week-old male C57Bl/6J mice were fed low-fat (LF; 10% fat) and high-fat (HF) control diets, along with an HF diet with 8.6% (wt:wt) added walnuts for 9 wk. The HF control diet contained 46% fat with added sucrose (10.9%, wt:wt) and cholesterol (1%, wt:wt); the added sucrose and cholesterol were not present in the LF diet. Other groups were provided the walnut diet with a second whole food-raspberries, apples, cranberries, tart cherries, broccoli sprouts, olive oil, soy protein, or green tea. All of the energy-containing whole foods were added at an energy level equivalent to 1.5 servings/d. Body weights, food intake, and glucose tolerance were determined. Postmortem, serum lipids and inflammatory markers, hepatic fat, gene expression, and the relative concentrations of 594 biochemicals were measured. RESULTS: The addition of walnuts with either raspberries, apples, or green tea reduced glucose area under the curve compared with the HF diet alone (-93%, -64%, and -54%, respectively, P < 0.05). Compared with HF-fed mice, mice fed walnuts with either broccoli sprouts or green tea (-49% and -61%, respectively, P < 0.05) had reduced hepatic fat concentrations. There were differences in global gene expression patterns related to whole-food content, with many examples of differences in LF- and HF-fed mice, HF- and walnut-fed mice, and mice fed walnuts and walnuts plus other foods. The mean ± SEM increase in relative hepatic concentrations of the n-3 fatty acids α-linolenic acid, eicosapentanoic acid, and docosapentanoic acid in all walnut-fed groups was 124% ± 13%, 159% ± 11%, and 114% ± 10%, respectively (P < 0.0001), compared with LF- and HF-fed mice not consuming walnuts. CONCLUSIONS: In obese male mice, walnut consumption with a high-fat Western-style diet caused changes in hepatic fat concentrations, gene expression patterns, and fatty acid concentrations. The addition of a second whole food in combination with walnuts produced other changes in metabolite concentrations and gene expression patterns and other physiologic markers. Importantly, these substantial changes occurred in mice fed typical amounts of intake, representing only 1.5 servings each food/d.
Effect of a high-fat Mediterranean diet on bodyweight and waist circumference: a prespecified secondary outcomes analysis of the PREDIMED randomised controlled trial.
Background: Because of the high density of fat, high-fat diets are perceived as likely to lead to increased bodyweight, hence health-care providers are reluctant to recommend them to overweight or obese individuals. We assessed the long-term effects of ad libitum, high-fat, high-vegetable-fat Mediterranean diets on bodyweight and waist circumference in older people at risk of cardiovascular disease, most of whom were overweight or obese. Methods: PREDIMED was a 5 year parallel-group, multicentre, randomised, controlled clinical trial done in primary care centres affiliated to 11 hospitals in Spain. 7447 asymptomatic men (aged 55–80 years) and women (aged 60–80 years) who had type 2 diabetes or three or more cardiovascular risk factors were randomly assigned (1:1:1) with a computer-generated number sequence to one of three interventions: Mediterranean diet supplemented with extra-virgin olive oil (n=2543); Mediterranean diet supplemented with nuts (n=2454); or a control diet (advice to reduce dietary fat; n=2450). Energy restriction was not advised, nor was physical activity promoted. In this analysis of the trial, we measured bodyweight and waist circumference at baseline and yearly for 5 years in the intention-to-treat population. The PREDIMED trial is registered with ISRCTN.com, number ISRCTN35739639. Findings: After a median 4·8 years (IQR 2·8–5·8) of follow-up, participants in all three groups had marginally reduced bodyweight and increased waist circumference. The adjusted difference in 5 year changes in bodyweight in the Mediterranean diet with olive oil group was −0·43 kg (95% CI −0·86 to −0·01; p=0·044) and in the nut group was −0·08 kg (–0·50 to 0·35; p=0·730), compared with the control group. The adjusted difference in 5 year changes in waist circumference was −0·55 cm (–1·16 to −0·06; p=0·048) in the Mediterranean diet with olive oil group and −0·94 cm (–1·60 to −0·27; p=0·006) in the nut group, compared with the control group. Interpretation: A long-term intervention with an unrestricted-calorie, high-vegetable-fat Mediterranean diet was associated with decreases in bodyweight and less gain in central adiposity compared with a control diet. These results lend support to advice not restricting intake of healthy fats for bodyweight maintenance.
A Randomized Controlled Trial of the Effects of an Almond-enriched, Hypocaloric Diet on Liver Function Tests in Overweight/Obese Women
BACKGROUND: Gradual weight reduction has been shown to be associated with improvements in liver enzymes. However, some evidence demonstrated that liver enzymes may transiently increase immediately after a diet-induced weight loss. OBJECTIVES: This study was designed to assess the effects of a hypocaloric, almond-enriched diet (AED) compared with a hypocaloric nut-free diet (NFD) on liver function tests in the context of a three-month weight reduction program in overweight/obese women. PATIENTS AND METHODS: This randomized controlled clinical trial was registered at Iranian Registry of Clinical Trials with ID number of IRCT2013062313751N1. Overweight and obese Iranian women [n = 108; age = 42.7 y, body mass index = 29.6 kg/m(2)] were randomly assigned to consume an AED or NFD. The carefully planned hypocaloric diets were identical for both groups except for the AED group who consumed 50 grams of almonds daily for three months. Anthropometric measurements and laboratory measurements including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and γ-glutamyltransferase (GGT) were assessed before and immediately after the intervention. RESULTS: Of 108 participants, 50 women in AED group and 50 women in NFD group completed the protocol of the study (response rate: 92.6 %). The AED led to a median weight loss of 3.79 kg (interquartile range: 4.4 kg). Significant decreases within AED and NFD were observed in ALT (-16.6 ± 16.3 and -11.7 ± 16.8, P < 0.001, respectively). Similar significant decreases were observed in AST (-13.6 ± 15.7 and -7.7 ± 16.1; P < 0.001, respectively). The decrease in GGT was also significant in both groups (-11.4 ± 21.6 and -6.2 ± 19.8; P < 0.001 respectively). ALT, AST and GGT decreased significantly in the AED group compared to the NFD group (P < 0.001). CONCLUSIONS: AED improved liver enzymes in obese women. However, mild, transient increases in ALT and AST values can be observed immediately after an NFD in women.
Energy compensation and nutrient displacement following regular consumption of hazelnuts and other energy-dense snack foods in non-obese individuals.
PURPOSE: Regular nut consumption reduces cardiovascular disease risk, partly from improvements to dietary quality. Examining how individuals make dietary changes when consuming nuts may reveal key behavioural eating patterns beneficial for the development of dietary interventions. We examined the effects of nuts in comparison with other energy-dense snacks on energy compensation, nutrient displacement, and food group patterns. METHODS: This was a 12-week randomised, controlled, parallel study with four arms: ~1100 kJ/day for each of hazelnuts (42 g), chocolate (50 g), potato crisps (50 g), or no added snack food. Diet records, body composition, and physical activity were measured at baseline and week 12, in 102 non-obese participants. RESULTS: Significant improvements in diet quality were observed in the hazelnut group, particularly when consumed as snacks. Intakes of monounsaturated fat (MUFA) and vitamin E were significantly higher (all P < 0.05), whereas saturated fat and carbohydrate were significantly lower (both P ≤ 0.022) in the hazelnut group compared to the other groups. Partial energy compensation did not differ significantly between groups, but nutrient displacement values for MUFA and fibre differed significantly. Within the hazelnut group, there was nearly complete displacement for fibre, partial displacement for energy, protein, total fat, MUFA, PUFA, potassium, folate, and vitamin E, and overcompensation for carbohydrate and sugar. CONCLUSIONS: Our results demonstrate that energy compensation occurs for all three intervention snacks in this non-obese population. Regular nut consumption significantly improves nutrient profiles compared to other snacks with changes occurring at the snack level.