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Gut microbiota in nonalcoholic fatty liver disease: a PREDIMED-Plus trial sub analysis.
Gómez-Pérez, AM, Ruiz-Limón, P, Salas-Salvadó, J, Vioque, J, Corella, D, Fitó, M, Vidal, J, Atzeni, A, Torres-Collado, L, Álvarez-Sala, A, et al
Gut microbes. 2023;15(1):2223339
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Nonalcoholic fatty liver disease (NAFLD) is the main cause of chronic liver disease. The aim of this study was to evaluate the changes in the microbiota associated with changes in biochemical markers of NAFLD/NASH after an intervention. This substudy was conducted in the frame of the PREDIMED-Plus study, a 6-year, multicentre, randomised clinical trial for primary prevention of cardiovascular disease (CVD) conducted in men aged 55–75 years and women aged 60–75 years with overweight or obesity and metabolic syndrome. Results showed a relationship between liver disease biochemical indexes changes and gut microbiota changes within a context of a Mediterranean lifestyle. In fact, two noninvasive scores for liver steatosis and liver fibrosis, usually used in clinical practice, could differentiate gut microbiota populations. Authors conclude that their findings highlight the importance of lifestyle intervention in the modulation of gut microbiota and the management of metabolic syndrome and its hepatic manifestations.
Abstract
To evaluate the changes in the gut microbiota associated with changes in the biochemical markers of nonalcoholic fatty liver disease (NAFLD) after a lifestyle intervention with the Mediterranean diet. Participants (n = 297) from two centers of PREDIMED-Plus trial (Prevención con Dieta Mediterránea) were divided into three different groups based on the change tertile in the Hepatic Steatosis Index (HSI) or the Fibrosis-4 score (FIB-4) between baseline and one year of intervention. One-year changes in HSI were: tertile 1 (T1) (-24.9 to -7.51), T2 (-7.5 to -1.86), T3 (-1.85 to 13.64). The most significant differences in gut microbiota within the year of intervention were observed in the T1 and T3. According to the FIB-4, participants were categorized in non-suspected fibrosis (NSF) and with indeterminate or suspected fibrosis (SF). NSF participants showed higher abundances of Alcaligenaceae, Bacteroidaceae, Bifidobacteriaceae, Clostridiaceae, Enterobacteriaceae, Peptostreptococcaceae, Verrucomicrobiaceae compared to those with SF. Then, participants were divided depending on the FIB-4 tertile of change: T1 (-89.60 to -5.57), T2 (-5.56 to 11.4), and T3 (11.41 to 206.24). FIB-4 T1 showed a decrease in Akkermansia and an increase in Desulfovibrio. T2 had an increase in Victivallaceae, Clostridiaceae, and Desulfovibrio. T3 showed a decrease in Enterobacteriaceae, and an increase in Sutterella, Faecalibacterium, and Blautia. A relation between biochemical index changes of NAFLD/NASH (HSI and FIB-4) and gut microbiota changes were found. These observations highlight the importance of lifestyle intervention in the modulation of gut microbiota and the management of metabolic syndrome and its hepatic manifestations. What You Need to KnowWhat is the context:Obesity and metabolic syndrome have been associated with nonalcoholic fatty liver disease (NAFLD). Gut microbiota and its interaction with the environment may play a key role in NAFLD.What is new:Mediterranean diet and physical activity can modify the scores for liver steatosis (HSI) and liver fibrosis (FIB−4) in only one year. A relation between the changes in these scores and gut microbiota changes was found.What is the impact:The discovery of microbiota-based biomarkers for NAFLD and the development of strategies to modulate gut microbiota in the treatment of NAFLD.
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An Energy-Reduced Mediterranean Diet, Physical Activity, and Body Composition: An Interim Subgroup Analysis of the PREDIMED-Plus Randomized Clinical Trial.
Konieczna, J, Ruiz-Canela, M, Galmes-Panades, AM, Abete, I, Babio, N, Fiol, M, Martín-Sánchez, V, Estruch, R, Vidal, J, Buil-Cosiales, P, et al
JAMA network open. 2023;6(10):e2337994
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The Mediterranean diet (MedDiet), which focuses on whole grains, lean meat, fruits, vegetables, and low amounts of minimally processed foods has been shown in previous research to improve body composition and decrease fat storage around the middle. This randomised control trial of 1556 older adults aimed to determine the effects of combining a 30% lower energy version of the MedDiet in combination with physical exercise on body composition. After 3 years, the results showed that compared to a normal MedDiet without exercise, the lower energy version in combination with exercise improved body composition by decreasing total fat, and the fat stored around the organs and increasing muscle mass. However, benefits were more pronounced after 1 year and decreased slightly at 3 years. It was concluded that a low energy MedDiet in combination with physical activity may be able to improve the body composition of overweight and older adults with obesity. This study could be used by healthcare professionals to recommend a low energy MedDiet to older adults to promote weight loss, whilst attenuating muscle loss associated with ageing.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The addition of exercise to an energy-reduced diet, which focuses on whole grains, healthy fats, lean protein, and fruits and vegetables can emphasise positive effects on body composition in older adults.
- However, there is a loss of lean mass associated with this type of diet (contrary to author conclusions) and measures should be taken to monitor and increase protein intake to prevent or limit this loss.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
This study aimed to determine the long-term effects of an energy reduced MedDiet in combination with physical activity on body composition.
Methods
- This is a predetermined 3-year interim analysis of a 6-year single-blind, randomised control trial of 1556 individuals aged 55-75 who are overweight or obese with metabolic syndrome.
- 760 individuals on 30% energy reduced MedDiet with limited processed foods, plus 45 minutes walking 6 days per week and behavioural and motivational support. [Intervention group]
- 761 on standard MedDiet without physical activity. [Control]
Results
Within group comparisons showed that individuals in the intervention group lost (P value represents baseline vs year 3):
- Total fat mass percentage (1-year vs baseline, −1.14%; 95% CI, −1.32% to −0.96%; 3-year vs baseline, −0.52%; 95% CI, −0.71% to −0.33% P=<0.001)
- Absolute visceral fat (1-year vs baseline, −154 g; 95% CI, −191 to −116 g; 3-year vs baseline, −75.1 g, 95% CI, −115 to −35.3 g P=<0.001)
- Absolute total fat after 1 year (mean change at 1 year vs baseline, −1677 g; 95% CI, −1930 to −1424 g) but regained some at year 3 (mean change at 3 years vs baseline, −1018 g; 95% CI, −1280 to −756 g P=<0.001)
- Absolute lean mass (mean change at 1 year vs baseline −300 g; 95% CI, −439 to −162 g) with further losses at year 3 (−626 g; 95% CI, −770 to −483 g P=0.001).
Within group comparisons also showed significantly increased:
- Total lean mass percentage, which was greater at year 1 than year 3 (1-year vs baseline, 1.07%; 95%CI, 0.90%-1.25%; 3-year vs baseline, 0.47%; 95% CI, 0.29%-0.65% P=<0.001).
As a result of total fat loss and some lean mass in the intervention group, the lean:fat mass ratio improved and was unchanged in the control group (between group differences (P=<0.001).
Compared to women, men may find the MedDiet + exercise more beneficial as it was shown that body composition changes were slightly more pronounced in men.
Conclusion
An energy-reduced MedDiet plus exercise emphasised positive changes to body composition compared to standard MedDiet in older adults who are overweight or have obesity.
Clinical practice applications:
- The recommendation of a reduced energy MedDiet in combination with physical activity to older people who are overweight or obese may improve body composition.
- Although lean mass loss slowed between years 1 and 3, other practices should be employed to attenuate the loss of lean mass associated with an energy-reduced MedDiet and ageing.
Considerations for future research:
- The research has not yet concluded but when it does, it will address the incidence of cardiovascular disease along with body composition changes.
- It will also look at long-term effects of the diet to determine longevity.
- Future research could focus on how to limit lean mass loss through the possibility of changing the type of exercise that accompanies the MedDiet.
Abstract
IMPORTANCE Strategies targeting body composition may help prevent chronic diseases in persons with excess weight, but randomized clinical trials evaluating lifestyle interventions have rarely reported effects on directly quantified body composition. OBJECTIVE To evaluate the effects of a lifestyle weight-loss intervention on changes in overall and regional body composition. DESIGN, SETTING, AND PARTICIPANTS The ongoing Prevención con Dieta Mediterránea-Plus (PREDIMED-Plus) randomized clinical trial is designed to test the effect of the intervention on cardiovascular disease prevention after 8 years of follow-up. The trial is being conducted in 23 Spanish research centers and includes men and women (age 55-75 years) with body mass index between 27 and 40 and metabolic syndrome. The trial reported herein is an interim subgroup analysis of the intermediate outcome body composition after 3-year follow-up, and data analysis was conducted from February 1 to November 30, 2022. Of 6874 total PREDIMED-Plus participants, a subsample of 1521 individuals, coming from centers with access to a dual energy x-ray absorptiometry device, underwent body composition measurements at 3 time points. INTERVENTION Participants were randomly allocated to a multifactorial intervention based on an energy-reduced Mediterranean diet (MedDiet) and increased physical activity (PA) or to a control group based on usual care, with advice to follow an ad libitum MedDiet, but no physical activity promotion. MAIN OUTCOMES AND MEASURES The outcomes (continuous) were 3-year changes in total fat and lean mass (expressed as percentages of body mass) and visceral fat (in grams), tested using multivariable linear mixed-effects models. Clinical relevance of changes in body components (dichotomous) was assessed based on 5% or more improvements in baseline values, using logistic regression. Main analyses were performed in the evaluable population (completers only) and in sensitivity analyses, multiple imputation was performed to include data of participants lost to follow-up (intention-to-treat analyses). RESULTS A total of 1521 individuals were included (mean [SD] age, 65.3 [5.0] years; 52.1% men). In comparison with the control group (n=761), participants in the intervention arm (n=760) showed greater reductions in the percentage of total fat (between group differences after 1-year, -0.94% [95% CI, -1.19 to -0.69]; 3 years, -0.38% [95% CI, -0.64 to -0.12] and visceral fat storage after 1 year, -126 g [95% CI, -179 to -73.3 g]; 3 years, -70.4 g [95% CI, -126 to -15.2 g] and greater increases in the percentage of total lean mass at 1 year, 0.88% [95% CI, 0.63%-1.12%]; 3-years 0.34% [95% CI, 0.09%-0.60%]). The intervention group was more likely to show improvements of 5% or more in baseline body components (absolute risk reduction after 1 year, 13% for total fat mass, 11% for total lean mass, and 14% for visceral fat mass; after 3-years: 6% for total fat mass, 6% for total lean mass, and 8% for visceral fat mass). The number of participants needed to treat was between 12 and 17 to attain at least 1 individual with possibly clinically meaningful improvements in body composition. CONCLUSIONS AND RELEVANCE The findings of this trial suggest a weight-loss lifestyle intervention based on an energy-reduced MedDiet and physical activity significantly reduced total and visceral fat and attenuated age-related losses of lean mass in older adults with overweight or obesity and metabolic syndrome. Continued follow-up is warranted to confirm the long-term consequences of these changes on cardiovascular clinical end points. TRIAL REGISTRATION isrctn.org Identifier: ISRCTN89898870.
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Increased ultra-processed food consumption is associated with worsening of cardiometabolic risk factors in adults with metabolic syndrome: Longitudinal analysis from a randomized trial.
González-Palacios, S, Oncina-Cánovas, A, García-de-la-Hera, M, Martínez-González, MÁ, Salas-Salvadó, J, Corella, D, Schröder, H, Martínez, JA, Alonso-Gómez, ÁM, Wärnberg, J, et al
Atherosclerosis. 2023;377:12-23
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Evidence is increasing linking the consumption of ultra-processed foods (UPF) and an increased risk for the development of heart disease. However, there is still uncertainty surrounding how changes in UPF consumption can affect heart disease risk factors. This secondary analysis of a randomised control trial, which looked at the effects of an energy restricted Mediterranean diet in combination with exercise on the prevention of heart disease, aimed to determine how changes in UPF consumption can affect indicators of heart disease risk over a 12-month period. The results showed that high UPF consumption was associated with higher heart disease risk factors including weight, body mass index, waist circumference, diastolic blood pressure, blood sugar levels, measures of insulin resistance, and triglycerides. Further detrimental effects were seen with UPF consumption increasing, and high-density lipoprotein cholesterol decreasing. No associations were seen with systolic blood pressure, total cholesterol, and low-density lipoprotein cholesterol. It was concluded that high UPF consumption has a detrimental effect on heart disease risk. This study could be used by healthcare professionals to recommend a diet low or devoid of UPF to stay heart healthy.
Abstract
BACKGROUND AND AIMS The association between changes in ultra-processed food (UPF) consumption and cardiometabolic risk (CMR) factors remains understudied. We evaluated the association between changes in UPF consumption over 12 months of follow-up and changes in CMR factors in adults diagnosed with metabolic syndrome. METHODS We analysed data from 5373 adults (aged 55-75 years) participating in the PREDIMED-Plus trial. Diet was evaluated at baseline, 6- and 12-month visits using a validated food frequency questionnaire, and UPF consumption (in grams/day and percentage of total daily dietary intake in grams) was categorized based on NOVA classification. We used mixed-effects linear models with repeated measurements at baseline, 6 and 12 months of follow-up to assess the associations between changes in UPF consumption and changes in CMR factors adjusting for sociodemographic and lifestyles variables. RESULTS In multivariable-adjusted models, when comparing the highest versus the lowest quartile of UPF consumption, positive associations were found for several CMR factors: weight (kg, β = 1.09; 95% confidence interval 0.91 to 1.26); BMI (kg/m2, β = 0.39; 0.33 to 0.46); waist circumference (cm, β = 1.03; 0.81 to 1.26); diastolic blood pressure (mm Hg, β = 0.67; 0.29 to 1.06); fasting blood glucose (mg/dl, β = 1.66; 0.61 to 2.70); HbA1c (%, β = 0.04; 0.01 to 0.07); triglycerides (mg/dl, β = 6.79; 3.66 to 9.91) and triglycerides and glucose index (β = 0.06; 0.04 to 0.08). CONCLUSIONS Higher UPF consumption was associated with adverse evolution in objectively measured CMR factors after 12 months of follow-up in adults with metabolic syndrome. Further research is needed to explore whether these changes persist for longer periods.
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Nordic dietary patterns and cardiometabolic outcomes: a systematic review and meta-analysis of prospective cohort studies and randomised controlled trials.
Massara, P, Zurbau, A, Glenn, AJ, Chiavaroli, L, Khan, TA, Viguiliouk, E, Mejia, SB, Comelli, EM, Chen, V, Schwab, U, et al
Diabetologia. 2022;65(12):2011-2031
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Dietary patterns high in plant foods such as the Mediterranean diet, Dietary Approaches for Stopping Hypertension (DASH), Portfolio and healthy vegetarian are associated with a lower risk of cardio vascular disease (CVD) and certain cardiometabolic risk factors in adults with and without diabetes. In Northern European countries it may be more difficult to apply these dietary principals due to availability and cost of specific foods. Nordic dietary patterns include foods such as rye, oats and barley, berries and temperate fruits like apples and pears, vegetables (especially root and cruciferous vegetables), legumes, fish/shellfish, nuts and canola oil/rapeseed oil and low-fat dairy foods. The benefits of Nordic dietary patterns have been recognised but to update the clinical practice guidelines for the European Association for the Study of Diabetes (EASD), a systematic review and meta-analysis was commissioned. 15 cohort studies and 6 RCTs were included. Adopting Nordic dietary patterns is associated with small important reductions in the risk of major CVD outcomes and diabetes. These are supported by similar reductions in LDL-cholesterol and other cardiometabolic risk factors. The available evidence provides a generally good indication of the likely benefits of Nordic dietary patterns in people with or at risk for diabetes.
Abstract
AIMS/HYPOTHESIS Nordic dietary patterns that are high in healthy traditional Nordic foods may have a role in the prevention and management of diabetes. To inform the update of the EASD clinical practice guidelines for nutrition therapy, we conducted a systematic review and meta-analysis of Nordic dietary patterns and cardiometabolic outcomes. METHODS We searched MEDLINE, EMBASE and The Cochrane Library from inception to 9 March 2021. We included prospective cohort studies and RCTs with a follow-up of ≥1 year and ≥3 weeks, respectively. Two independent reviewers extracted relevant data and assessed the risk of bias (Newcastle-Ottawa Scale and Cochrane risk of bias tool). The primary outcome was total CVD incidence in the prospective cohort studies and LDL-cholesterol in the RCTs. Secondary outcomes in the prospective cohort studies were CVD mortality, CHD incidence and mortality, stroke incidence and mortality, and type 2 diabetes incidence; in the RCTs, secondary outcomes were other established lipid targets (non-HDL-cholesterol, apolipoprotein B, HDL-cholesterol, triglycerides), markers of glycaemic control (HbA1c, fasting glucose, fasting insulin), adiposity (body weight, BMI, waist circumference) and inflammation (C-reactive protein), and blood pressure (systolic and diastolic blood pressure). The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to assess the certainty of the evidence. RESULTS We included 15 unique prospective cohort studies (n=1,057,176, with 41,708 cardiovascular events and 13,121 diabetes cases) of people with diabetes for the assessment of cardiovascular outcomes or people without diabetes for the assessment of diabetes incidence, and six RCTs (n=717) in people with one or more risk factor for diabetes. In the prospective cohort studies, higher adherence to Nordic dietary patterns was associated with 'small important' reductions in the primary outcome, total CVD incidence (RR for highest vs lowest adherence: 0.93 [95% CI 0.88, 0.99], p=0.01; substantial heterogeneity: I2=88%, pQ<0.001), and similar or greater reductions in the secondary outcomes of CVD mortality and incidence of CHD, stroke and type 2 diabetes (p<0.05). Inverse dose-response gradients were seen for total CVD incidence, CVD mortality and incidence of CHD, stroke and type 2 diabetes (p<0.05). No studies assessed CHD or stroke mortality. In the RCTs, there were small important reductions in LDL-cholesterol (mean difference [MD] -0.26 mmol/l [95% CI -0.52, -0.00], pMD=0.05; substantial heterogeneity: I2=89%, pQ<0.01), and 'small important' or greater reductions in the secondary outcomes of non-HDL-cholesterol, apolipoprotein B, insulin, body weight, BMI and systolic blood pressure (p<0.05). For the other outcomes there were 'trivial' reductions or no effect. The certainty of the evidence was low for total CVD incidence and LDL-cholesterol; moderate to high for CVD mortality, established lipid targets, adiposity markers, glycaemic control, blood pressure and inflammation; and low for all other outcomes, with evidence being downgraded mainly because of imprecision and inconsistency. CONCLUSIONS/INTERPRETATION Adherence to Nordic dietary patterns is associated with generally small important reductions in the risk of major CVD outcomes and diabetes, which are supported by similar reductions in LDL-cholesterol and other intermediate cardiometabolic risk factors. The available evidence provides a generally good indication of the likely benefits of Nordic dietary patterns in people with or at risk for diabetes. REGISTRATION ClinicalTrials.gov NCT04094194. FUNDING Diabetes and Nutrition Study Group of the EASD Clinical Practice.
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Effects of Mediterranean Diet and Physical Activity on Pulmonary Function: A Cross-Sectional Analysis in the ILERVAS Project.
Gutiérrez-Carrasquilla, L, Sánchez, E, Hernández, M, Polanco, D, Salas-Salvadó, J, Betriu, À, Gaeta, AM, Carmona, P, Purroy, F, Pamplona, R, et al
Nutrients. 2019;11(2)
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The Mediterranean diet is characterised by an abundant consumption of extra-virgin olive oil, fruits, vegetables, nuts, and legumes, a moderate consumption of fish and seafood, poultry, fermented dairy products, and red wine with meals, and low intakes of sweetened beverages, red meat and ready meals. The aim of the study was to evaluate the association between adherence to a Mediterranean diet and physical activity on pulmonary function in a large middle-aged population at low-to-moderate cardiovascular risk. The study is an ongoing study that between 2015 and 2017 enrolled a total of 3020 subjects – women aged between 50 to 70 years and men aged between 45 to 65 years – with the presence of at least one cardiovascular risk factor. Results indicate that a low adherence to the Mediterranean diet was linked with impaired breathing patterns and higher prevalence of abnormal lung function when compared to participants with a higher adherence to this dietary pattern. Additionally, vigorous physical activity was accompanied by better results in lung function than that observed in inactive subjects. The study provides initial clinical evidence about the independent and deleterious effect of both low adherence to the Mediterranean diet and low physical activity practice on lung function in participants without known pulmonary disease.
Abstract
A few studies showed that both adherence to Mediterranean diet (MedDiet) and physical activity practice have a positive impact on pulmonary function in subjects with lung disease. These associations are not well studied in subjects free from lung disease. In a cross-sectional study conducted in 3020 middle-aged subjects free of lung disease, adherence to the MedDiet using the Mediterranean Diet Adherence Screener, and physical activity practice using the International Physical Activity Questionnaire short form were recorded. Respiratory function was assessed using forced spirometry and the results were evaluated according to the Global initiative for Chronic Obstructive Lung Disease. Logistic regression models were used to analyze the associations between adherence to the MedDiet and physical activity practice with the presence of ventilatory defects. Participants with a high adherence to MedDiet, in comparison to those with low adherence, had both higher forced vital capacity (FVC; 100 (87⁻109) vs. 94 (82⁻105) % of predicted, p = 0.003) and forced expired volume in the first second (FEV1; 100 (89⁻112) vs. 93 (80⁻107) % of predicted, p < 0.001). According to their degree of physical activity, those subjects with a high adherence also had both higher FVC (100 (88⁻107) vs. 94 (83⁻105) % of predicted, p = 0.027) and FEV1 (100 (89⁻110) vs. 95 (84⁻108) % of predicted, p = 0.047) in comparison with those with low adherence. The multivariable logistic regression models showed a significant and independent association between both low adherence to MedDiet and low physical activity practice, and the presence of altered pulmonary patterns, with differences between men and women. However, no joint effect between adherence to MedDiet and physical activity practice on respiratory function values was observed. Low adherence to MedDiet and low physical activity practice were independently associated with pulmonary impairment. Therefore, the lung mechanics seem to benefit from heart-healthy lifestyle behaviors.
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Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial.
Valls-Pedret, C, Sala-Vila, A, Serra-Mir, M, Corella, D, de la Torre, R, Martínez-González, MÁ, Martínez-Lapiscina, EH, Fitó, M, Pérez-Heras, A, Salas-Salvadó, J, et al
JAMA internal medicine. 2015;175(7):1094-1103
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There is increasing evidence associating dietary habits and cognitive function, and oxidative stress is known to play a major role in cognitive decline. The Mediterranean diet is a plant-based, antioxidant rich dietary pattern and large observational studies have elucidated that Mediterranean diet adherence is associated with better cognitive function. The aim of this study was to investigate whether a Mediterranean diet supplemented with antioxidant-rich foods influences cognitive function compared with a control diet. Participants were randomly assigned to a Mediterranean diet supplemented with extra virgin olive oil, a Mediterranean diet supplemented with mixed nuts or a control diet with dietary advice. The study included 447 cognitively healthy volunteers at high cardiovascular risk and rates of cognitive change were followed for an average of four years. According to the findings of this study, a long-term Mediterranean diet supplemented with olive oil or nuts is associated with improved cognitive function and may counteract age-related cognitive decline. It is hypothesised that this effect is attributed to the abundance of antioxidants and anti-inflammatory agents of the Mediterranean diet and may contribute to effective interventions to prevent or delay the onset of cognitive decline.
Abstract
IMPORTANCE Oxidative stress and vascular impairment are believed to partly mediate age-related cognitive decline, a strong risk factor for development of dementia. Epidemiologic studies suggest that a Mediterranean diet, an antioxidant-rich cardioprotective dietary pattern, delays cognitive decline, but clinical trial evidence is lacking. OBJECTIVE To investigate whether a Mediterranean diet supplemented with antioxidant-rich foods influences cognitive function compared with a control diet. DESIGN, SETTING, AND PARTICIPANTS Parallel-group randomized clinical trial of 447 cognitively healthy volunteers from Barcelona, Spain (233 women [52.1%]; mean age, 66.9 years), at high cardiovascular risk were enrolled into the Prevención con Dieta Mediterránea nutrition intervention trial from October 1, 2003, through December 31, 2009. All patients underwent neuropsychological assessment at inclusion and were offered retesting at the end of the study. INTERVENTIONS Participants were randomly assigned to a Mediterranean diet supplemented with extravirgin olive oil (1 L/wk), a Mediterranean diet supplemented with mixed nuts (30 g/d), or a control diet (advice to reduce dietary fat). MAIN OUTCOMES AND MEASURES Rates of cognitive change over time based on a neuropsychological test battery: Mini-Mental State Examination, Rey Auditory Verbal Learning Test (RAVLT), Animals Semantic Fluency, Digit Span subtest from the Wechsler Adult Intelligence Scale, Verbal Paired Associates from the Wechsler Memory Scale, and the Color Trail Test. We used mean z scores of change in each test to construct 3 cognitive composites: memory, frontal (attention and executive function), and global. RESULTS Follow-up cognitive tests were available in 334 participants after intervention (median, 4.1 years). In multivariate analyses adjusted for confounders, participants allocated to a Mediterranean diet plus olive oil scored better on the RAVLT (P = .049) and Color Trail Test part 2 (P = .04) compared with controls; no between-group differences were observed for the other cognitive tests. Similarly adjusted cognitive composites (mean z scores with 95% CIs) for changes above baseline of the memory composite were 0.04 (-0.09 to 0.18) for the Mediterranean diet plus olive oil, 0.09 (-0.05 to 0.23; P = .04 vs controls) for the Mediterranean diet plus nuts, and -0.17 (-0.32 to -0.01) for the control diet. Respective changes from baseline of the frontal cognition composite were 0.23 (0.03 to 0.43; P = .003 vs controls), 0.03 (-0.25 to 0.31), and -0.33 (-0.57 to -0.09). Changes from baseline of the global cognition composite were 0.05 (-0.11 to 0.21; P = .005 vs controls) for the Mediterranean diet plus olive oil, -0.05 (-0.27 to 0.18) for the Mediterranean diet plus nuts, and -0.38 (-0.57 to -0.18) for the control diet. All cognitive composites significantly (P < .05) decreased from baseline in controls. CONCLUSIONS AND RELEVANCE In an older population, a Mediterranean diet supplemented with olive oil or nuts is associated with improved cognitive function. TRIAL REGISTRATION isrctn.org Identifier: ISRCTN35739639.
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Mediterranean dietary pattern and depression: the PREDIMED randomized trial.
Sánchez-Villegas, A, Martínez-González, MA, Estruch, R, Salas-Salvadó, J, Corella, D, Covas, MI, Arós, F, Romaguera, D, Gómez-Gracia, E, Lapetra, J, et al
BMC medicine. 2013;11:208
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The role of diet in preventing mental disorders has been increasingly explored in the past few years. Few observational studies have associated the traditional Mediterranean diet (MD) with a reduced risk of depression, however this available information is limited and inconclusive. The aim of this trial was to compare the efficacy of two variations of the MD on depression among patients at high risk of cardiovascular disease. The diets included MD supplemented with extra-virgin olive oil or mixed nuts, and a control group advised to follow a low-fat diet. The study included 3923 participants aged 55-80 the median follow-up was 5.4 years. The findings of this trial did not show a significant decrease in depression risk among participants assigned to either MD group compared with the control. However when the specific cohort of subjects with type 2 diabetes was analysed, the depression risk was significantly reduced compared with the control group. Based on this study, the authors suggest a beneficial effect of the MD on depression for patients with type 2 diabetes though further investigation is required.
Abstract
BACKGROUND A few observational studies have found an inverse association between adherence to a Mediterranean diet and the risk of depression. Randomized trials with an intervention based on this dietary pattern could provide the most definitive answer to the findings reported by observational studies. The aim of this study was to compare in a randomized trial the effects of two Mediterranean diets versus a low-fat diet on depression risk after at least 3 years of intervention. METHODS This was a multicenter, randomized, primary prevention field trial of cardiovascular disease (Prevención con Dieta Mediterránea (PREDIMED Study)) based on community-dwelling men aged 55 to 80 years and women aged 60 to 80 years at high risk of cardiovascular disease (51% of them had type 2 diabetes; DM2) attending primary care centers affiliated with 11 Spanish teaching hospitals. Primary analyses were performed on an intention-to-treat basis. Cox regression models were used to assess the relationship between the nutritional intervention groups and the incidence of depression. RESULTS We identified 224 new cases of depression during follow-up. There was an inverse association with depression for participants assigned to a Mediterranean diet supplemented with nuts (multivariate hazard ratio (HR) 0.78; 95% confidence interval (CI) 0.55 to 1.10) compared with participants assigned to the control group, although this was not significant. However, when the analysis was restricted to participants with DM2, the magnitude of the effect of the intervention with the Mediterranean diet supplemented with nuts did reach statistical significance (multivariate HR = 0.59; 95% CI 0.36 to 0.98). CONCLUSIONS The result suggest that a Mediterranean diet supplemented with nuts could exert a beneficial effect on the risk of depression in patients with DM2. TRIAL REGISTRATION This trial has been registered in the Current Controlled Trials with the number ISRCTN 35739639.
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Primary prevention of cardiovascular disease with a Mediterranean diet.
Estruch, R, Ros, E, Salas-Salvadó, J, Covas, MI, Corella, D, Arós, F, Gómez-Gracia, E, Ruiz-Gutiérrez, V, Fiol, M, Lapetra, J, et al
The New England journal of medicine. 2013;368(14):1279-90
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The traditional Mediterranean diet has been shown to have cardiovascular protective effects based on previous observational cohort studies and a secondary prevention trial. While the mechanism for the beneficial effects of this diet have not been established, small trials have suggested that it fosters favourable changes in the pathways involved in cardio-metabolic disease. The aim of this randomised trial was to test the efficacy of two variations of the Mediterranean diet on reducing the incidence of cardiovascular events. These diets included Mediterranean diet supplemented with extra-virgin olive oil or mixed nuts, and a control diet (advised to reduce dietary fat). The study included 7,447 participants aged 55-80 and participants were followed for an average of 4.8 years. Both groups showed good adherence to the diets. The findings of this study showed that among persons at high cardiovascular risk, both variations of the Mediterranean diet resulted to a significant risk reduction of cardiovascular events, notably stroke. Based on this study, the authors’ conclusions support the benefits of the Mediterranean diet for the primary prevention of cardiovascular disease.
Abstract
BACKGROUND Observational cohort studies and a secondary prevention trial have shown an inverse association between adherence to the Mediterranean diet and cardiovascular risk. We conducted a randomized trial of this diet pattern for the primary prevention of cardiovascular events. METHODS In a multicenter trial in Spain, we randomly assigned participants who were at high cardiovascular risk, but with no cardiovascular disease at enrollment, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat). Participants received quarterly individual and group educational sessions and, depending on group assignment, free provision of extra-virgin olive oil, mixed nuts, or small nonfood gifts. The primary end point was the rate of major cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes). On the basis of the results of an interim analysis, the trial was stopped after a median follow-up of 4.8 years. RESULTS A total of 7447 persons were enrolled (age range, 55 to 80 years); 57% were women. The two Mediterranean-diet groups had good adherence to the intervention, according to self-reported intake and biomarker analyses. A primary end-point event occurred in 288 participants. The multivariable-adjusted hazard ratios were 0.70 (95% confidence interval [CI], 0.54 to 0.92) and 0.72 (95% CI, 0.54 to 0.96) for the group assigned to a Mediterranean diet with extra-virgin olive oil (96 events) and the group assigned to a Mediterranean diet with nuts (83 events), respectively, versus the control group (109 events). No diet-related adverse effects were reported. CONCLUSIONS Among persons at high cardiovascular risk, a Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events. (Funded by the Spanish government's Instituto de Salud Carlos III and others; Controlled-Trials.com number, ISRCTN35739639.).