The AUStralian MEDiterranean Diet Heart Trial (AUSMED Heart Trial): A randomized clinical trial in secondary prevention of coronary heart disease in a multiethnic Australian population: Study protocol

Application of Mediterranean Diet in Cardiovascular Diseases and Type 2 Diabetes Mellitus: Motivations and Challenges

Objective: Cardiovascular disease (CVD) is the leading cause of disability and death in many countries. Together with CVD, Type 2 diabetes mellitus (T2DM) accounts for more than 80% of all premature non-communicable disease deaths. The protective effect of the Mediterranean diet (MedDiet) on CVD and its risk factors, including T2DM, has been a constant topic of interest. Notwithstanding, despite the large body of evidence, scientists are concerned about the challenges and difficulties of the application of MedDiet. This review aims to explore the motivations and challenges for using MedDiet in patients with CVD and T2DM. Design: An electronic search was conducted for articles about MedDiet published in PubMed, ScienceDirect, Scopus, and Web of Science up to December 2021, particularly on CVD and T2DM patients. From a total of 1536 studies, the final eligible set of 108 studies was selected. Study selection involved three iterations of filtering. Results: Motivation to apply MedDiet was driven by the importance of studying the entire food pattern rather than just one nutrient, the health benefits, and the distinct characteristics of MedDiet. Challenges of the application of MedDiet include lacking universal definition and scoring of MedDiet. Influences of nutritional transition that promote shifting of traditional diets to Westernized diets further complicate the adherence of MedDiet. The challenges also cover the research aspects, including ambiguous and inconsistent findings, the inexistence of positive results, limited evidence, and generalization in previous studies. The review revealed that most of the studies recommended that future studies are needed in terms of health benefits, describing the potential benefits of MedDiet, identifying the barriers, and mainly discussing the effect of MedDiet in different populations. Conclusions: In general, there is consistent and strong evidence that MedDiet is associated inversely with CVD risk factors and directly with glycemic control. MedDiet is the subject of active and diverse research despite the existing challenges. This review informs the health benefits conferred by this centuries-old dietary pattern and highlights MedDiet could possibly be revolutionary, practical, and non-invasive approach for the prevention and treatment CVD and T2DM.

Perspective: Striking a Balance between Planetary and Human Health: Is There a Path Forward?

The global adoption of predominantly plant-based sustainable healthy diets will help reduce the risk of obesity- and malnutrition-related non-communicable diseases while protecting the future health of our planet. This review examines the benefits and limitations of different types of plant-based diets in terms of health and nutrition, affordability and accessibility, cultural (ethical and religious) acceptability, and the environment (i.e., the four pillars underlying sustainable healthy diets). Results suggest that, without professional supervision, traditional plant-based diets (vegan, vegetarian and pescatarian diets) can increase the risk of nutritional deficiencies among infants, children/adolescents, adult females, pregnant/lactating women and the elderly. In contrast, flexitarian diets and territorial diversified diets (TDDs, e.g., Mediterranean and New Nordic diets) that include large quantities of plant-sourced foods, low levels of red meat and moderate amounts of poultry, fish, eggs and dairy can meet the energy and nutrition needs of different populations without the need for dietary education or supplementation. Compared to vegan, vegetarian and pescatarian diets, more diverse flexitarian diets and TDDs are associated with reduced volumes of food waste and may be more acceptable and easier to maintain for people who previously followed western diets. Although flexitarian diets and TDDs have a greater impact on the environment than vegan, vegetarian and pescatarian diets, the negative effects are considerably reduced compared to western diets, especially if diets include locally-sourced seasonal foods. Further studies are required to define more precisely optimal sustainable healthy diets for different populations and to ensure that diets are affordable and accessible to people in all countries.

Effects of Mediterranean Diet or Low-Fat Diet on Blood Fatty Acids in Patients with Coronary Heart Disease. A Randomized Intervention Study

The Mediterranean diet (MD) prevents cardiovascular disease by different putative mechanisms, including modifications in the blood fatty acid (FA) profile. Polytherapy for secondary cardiovascular prevention might mask the effect of MD on the FA profile. This study was aimed to assess whether MD, in comparison with a low-fat diet (LFD), favorably modifies the blood FA profile in patients with coronary heart disease (CHD) on polytherapy. One hundred and twenty patients with a recent history of coronary stenting, randomized to MD or to LFD, completed 3 months of this open-label dietary intervention study. Diet Mediterranean-ness was evaluated using the Mediterranean Diet Adherence Screener (MeDAS) score. Both diets significantly reduced saturated FA (p < 0.01). Putative favorable changes in total n-3 FA (p = 0.03) and eicosapentaenoic acid plus docosahexaenoic acid (EPA + DHA; p = 0.04) were significantly larger with MD than with LFD. At 3 months, in the whole cohort, the MeDAS score correlated inversely with palmitic acid (R = −0.21, p = 0.02), and with palmitoleic acid (R = −0.32, p = 0.007), and positively with total n-3 FA (R = 0.19, p = 0.03), EPA (R = 0.28, p = 0.002), and EPA + DHA (R = 0.21, p = 0.02). In CHD patients on polytherapy, both MD and LFD shift FA blood composition towards a healthier profile, with a more favorable effect of MD on omega−3 levels.

Introducing Plant-Based Mediterranean Diet as a Lifestyle Medicine Approach in Latin America: Opportunities Within the Chilean Context

Latin America is experiencing a significant epidemiological and nutritional transition, with a trend toward higher incidence of food-related chronic diseases. In this context, Lifestyle Medicine (LM) is a growing field focused on assisting individuals in adopting healthy behaviors for the prevention and treatment of these chronic diseases, including, among other pillars, a great emphasis on healthy eating. There is also a growing interest worldwide in environmental sustainability of dietary patterns, with increasing concern about their effects on planetary health. In this context, whole-food, plant-based diets -such as the Mediterranean diet (MD)- have emerged as a solution for both healthier eating and lowering environmental impact. Yet in order to be effective at these goals and achieve a high adherence to any nutritional prescription, the sociocultural reality of the community or population where we aim to practice must also be taken into account. In this review, we specifically highlight the plant-based MD as a LM-contextualized dietary pattern that is adaptable, applicable, and sustainable within the Chilean context and has the potential to address the current trend of chronic diseases in our country.

Mediterranean Lifestyle to Promote Physical, Mental, and Environmental Health: The Case of Chile

Chile is currently experiencing a progressive epidemiological transition towards chronic diseases. In this country, >50% of annual deaths are attributed to cardiovascular disease and cancer. Moreover, health surveys have shown high prevalence of obesity, diabetes, hypertension, and elevated cardiovascular disease risk. In addition, mental health issues are also frequent among Chilean adults. On the other hand, the agri-food system contributes to 21-37% of greenhouse gases emissions worldwide. Overall, current health and food chain situation calls out for design and implementation of evidence-based feasible and effective nutritional interventions needed to promote physical and mental health along with addressing food sustainability in Chile. Nowadays, the Mediterranean diet is recognized as one of the healthiest dietary patterns based on observational and interventional studies linked to a wide variety of health outcomes. However, a Mediterranean lifestyle goes well beyond food intake: it includes promotion of psychosocial resources, community life as well as cultural traditions. Indeed, Mediterranean lifestyle is a true modus vivendi that integrally promotes physical, mental, and social well-being. In addition, the Mediterranean diet stands out for its environmental sustainability because it is characterized mainly as a plant-based dietary pattern with low carbon and water footprints. Remarkably, Central Chile has a Mediterranean-like setting with plant and animal food production and availability patterns comparable to those present in countries located around the Mediterranean Sea. Therefore, this article reviews how promotion of Mediterranean lifestyle adherence in Chile offers great potential for management of the ongoing epidemiological transition to chronic diseases as well to promote psychological well-being within a unique food system and dietary sustainability vision for this Latin American country.

The Cardio-Med survey tool: development and pilot validation of a FFQ in a multicultural cardiology cohort

OBJECTIVE

(i) Describe the development of a multipurpose Cardio-Med survey tool (CMST) comprising a semi-quantitative FFQ designed to measure dietary intake in multicultural patients with or at high risk of CVD and (ii) report pilot evaluation of test-retest reliability and validity of the FFQ in measuring energy and nutrient intakes.

DESIGN

The CMST was developed to identify CVD risk factors and assess diet quality over 1 year using an FFQ. Design of the ninety-three-item FFQ involved developing food portion photographs, and a list of foods appropriate for the Australian multicultural population allowing the capture of adherence to a Mediterranean diet pattern. The FFQ was administered twice, 2 weeks apart to assess test-retest reliability, whilst validity was assessed by comparison of the FFQ with a 3-d food record (3DFR).

SETTING

The Northern Hospital and St Vincent's Hospital, Melbourne, Australia.

PARTICIPANTS

Thirty-eight participants aged 34-81 years with CVD or at high risk.

RESULTS

Test-retest reliability of the FFQ was good: intraclass correlation coefficient (ICC) ranged from 0·52 (Na) to 0·88 (alcohol) (mean 0·79), with energy and 70 % of measured nutrients being above 0·75. Validity was moderate: ICC ranged from 0·08 (Na) to 0·94 (alcohol) (mean 0·59), with energy and 85 % of measured nutrients being above 0·5. Bland-Altman plots demonstrated good levels of agreement between the FFQ and 3DFR for carbohydrates, protein, alcohol, vitamin D and Na.

CONCLUSIONS

The CMST FFQ demonstrated good test-retest reliability and moderate validity for measuring dietary energy and nutrients in a multicultural Australian cardiology population.

Effects of total fat intake on body fatness in adults

BACKGROUND

The ideal proportion of energy from fat in our food and its relation to body weight is not clear. In order to prevent overweight and obesity in the general population, we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population.

OBJECTIVES

To assess the effects of proportion of energy intake from fat on measures of body fatness (including body weight, waist circumference, percentage body fat and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) of at least six months duration.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Clinicaltrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) to October 2019. We did not limit the search by language.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included adults aged at least 18 years, 3) randomised to a lower fat versus higher fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party.

DATA COLLECTION AND ANALYSIS

We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of body fatness (body weight, BMI, percentage body fat and waist circumference) independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity, funnel plot analyses and GRADE assessment.

MAIN RESULTS

We included 37 RCTs (57,079 participants). There is consistent high-quality evidence from RCTs that reducing total fat intake results in small reductions in body fatness; this was seen in almost all included studies and was highly resistant to sensitivity analyses (GRADE high-consistency evidence, not downgraded). The effect of eating less fat (compared with higher fat intake) is a mean body weight reduction of 1.4 kg (95% confidence interval (CI) -1.7 to -1.1 kg, in 53,875 participants from 26 RCTs, I² = 75%). The heterogeneity was explained in subgrouping and meta-regression. These suggested that greater weight loss results from greater fat reductions in people with lower fat intake at baseline, and people with higher body mass index (BMI) at baseline. The size of the effect on weight does not alter over time and is mirrored by reductions in BMI (MD -0.5 kg/m², 95% CI -0.6 to -0.3, 46,539 participants in 14 trials, I² = 21%), waist circumference (MD -0.5 cm, 95% CI -0.7 to -0.2, 16,620 participants in 3 trials; I² = 21%), and percentage body fat (MD -0.3% body fat, 95% CI -0.6 to 0.00, P = 0.05, in 2350 participants in 2 trials; I² = 0%). There was no suggestion of harms associated with low fat diets that might mitigate any benefits on body fatness. The reduction in body weight was reflected in small reductions in LDL (-0.13 mmol/L, 95% CI -0.21 to -0.05), and total cholesterol (-0.23 mmol/L, 95% CI -0.32 to -0.14), with little or no effect on HDL cholesterol (-0.02 mmol/L, 95% CI -0.03 to 0.00), triglycerides (0.01 mmol/L, 95% CI -0.05 to 0.07), systolic (-0.75 mmHg, 95% CI -1.42 to -0.07) or diastolic blood pressure(-0.52 mmHg, 95% CI -0.95 to -0.09), all GRADE high-consistency evidence or quality of life (0.04, 95% CI 0.01 to 0.07, on a scale of 0 to 10, GRADE low-consistency evidence).

AUTHORS' CONCLUSIONS

Trials where participants were randomised to a lower fat intake versus a higher fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI, waist circumference and percentage body fat compared with higher fat arms. Greater fat reduction, lower baseline fat intake and higher baseline BMI were all associated with greater reductions in weight. There was no evidence of harm to serum lipids, blood pressure or quality of life, but rather of small benefits or no effect.

Dietary measures among patients with coronary heart disease in Europe. ESC EORP Euroaspire V

OBJECTIVE

Assess the dietary recommendations provided to patients hospitalized for a coronary heart disease (CHD) event.

DESIGN

Cross-sectional, multicentre observational study (ESC EORP Euroaspire V).

METHODS

8261 participants (25.8% women, 9.3% aged<50 years) from 27 countries, 6 to 24 months after hospitalization for a CHD event were included. Participants were asked if they had been advised to reduce salt, fat or sugar intake, change type of fat consumed, and increase consumption of plant stanols/sterols, fruit & vegetables, fish and oily fish. Self-reported changes were recorded.

RESULTS

Advice to reduce energy intake, salt, fat and sugar was provided to 64.5% [range: 9.2-90.5], 73.2% [38.6-95.2], 77.3% [42.3-95.6] and 67.0% [39.4-93.3] of patients, respectively. Advice to change fat type, increase consumption of plant stanols/sterols, fruit & vegetables, fish and oily fish was provided to 68.3% [33.7-92.3], 36.7% [0.6-75.2], 73.2% [39.2-93.6], 66.5% [8.0-90.8] and 53.5% [3.7-83.3] of patients, respectively. Advices were more frequently provided to patients aged 50 to 69, with a high educational level, or obesity. One-eighth [0-55.0] of patients reported having consulted a dietician. Reductions in energy intake, salt, fat and sugar were reported by 57.7% [4.9-81.0], 69.9% [32.1-85.9], 71.8% [40.4-88.4] and 61.2% [29.0-84.0] of patients, respectively. Changes in fat type and increased consumption of plant stanols/sterols, fruit & vegetables, fish and oily fish were reported by 60.9% [4.9-81.0], 25.8% [0.6-54.1], 69.2% [27.7-88.4], 54.8% [4.0-80.1] and 40.4% [2.0-66.8] of patients, respectively.

CONCLUSION

Dietary advice is not systematically provided to patients with CHD, and considerable differences exist between European countries.

Translation of a Mediterranean-Style Diet into the Australian Dietary Guidelines: A Nutritional, Ecological and Environmental Perspective

A Mediterranean diet (MedDiet) has been widely investigated and promoted as one of the 'healthiest' dietary patterns with respect to reductions in chronic disease risk and longevity. Moreover, it also emphasizes a plant-based dietary pattern consistent with an environmentally sustainable healthy reference diet conveyed by the EAT-Lancet Commission report. Nevertheless, the MedDiet does not exclude, but rather moderates consumption of animal-based foods, and therefore has emerged as a dietary pattern that could address both health and environmental concerns. However, whether non-Mediterranean countries such as Australia can adhere to such dietary principles is less clear. In this narrative review, we present evidence from eight randomized control trials conducted in Australia which demonstrates impressive and sustained adherence to a MedDiet intervention. However, we also report heterogeneity in the dietary protocols and prescriptive interpretation of a MedDiet across all studies presented in this review, making interpretations of the efficacy and adherence challenging. Based on the observable health benefits, translating key dietary elements of a Mediterranean-style diet within the Australian population remains attractive. However, adapting or modernizing traditional dietary patterns to satisfy the population's nutritional requirements and/or acceptability warrants further exploration.

Associations between miR-146a rs2910164 polymorphisms and risk of ischemic cardio-cerebrovascular diseases

BACKGROUND

Many studies investigated the association between miR-146a rs2910164 polymorphisms and risk of ischemic cardio-cerebrovascular diseases. However, the results were inconsistent.

METHODS

We searched the PubMed, EMBASE, Cochrane library, Web of Science, Chinese National Knowledge Infrastructure, VIP, and Wanfang databases for appropriate studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the associations. Heterogeneity, sensitivity, and publication bias were conducted to measure the robustness of our findings.All analyses were based on previous published studies, thus, no ethical approval and patient consent are required.

RESULTS

We conducted a meta-analysis to evaluate the relationship between miR-146a rs2910164 polymorphisms and risk of ischemic cardio-cerebrovascular diseases. A total of 26 related studies involving 11,602 cases and 14,016 controls were identified and included in our meta-analysis. After considering the heterogeneity of the global analysis, we inferred that rs2910164 polymorphisms were associated with a lower risk of coronary heart disease (CHD) significantly in all genetic models. In addition, it was also found that the miR-146a rs2910164 polymorphisms were associated with the low risk of ischemic cardio-cerebrovascular diseases in large sample size subgroup analysis.

CONCLUSION

These results indicate that miR-146a rs2910164 polymorphisms were significantly associated with a lower risk of ischemic cardio-cerebrovascular. The miR-146a rs29101164 might be recommended as a predictor for susceptibility of ischemic cardio-cerebrovascular diseases.

Optimal Non-invasive Strategies to Reduce Recurrent Atherosclerotic Cardiovascular Disease Risk

PURPOSE OF REVIEW

Cardiovascular disease (CVD) remains the leading cause of death worldwide, with coronary artery disease (CAD) responsible for the vast majority of these deaths. Incidence is increasing in developing countries, and prevalence is increasing globally as populations age. Once CAD is manifest, recurrent event risk remains high.

RECENT FINDINGS

Multiple therapeutic avenues have had significant recent developments, including diet, low-density lipoprotein cholesterol management, triglycerides, hypoglycemic agents, antiplatelet agents, and oral anticoagulants. Combined approaches involving specific, tailored lifestyle, and pharmacological interventions will provide the most effective strategy for reducing the risk of recurrent CVD events. Here, we review risk prediction and non-invasive non-pharmacologic and pharmacologic approaches to mitigate residual coronary artery disease risk.

Dissimilar Impact of a Mediterranean Diet and Physical Activity on Anthropometric Indices: A Cross-Sectional Study from the ILERVAS Project

There is a close relationship between lifestyle behaviors and excess adiposity. Although body mass index (BMI) is the most used approach to estimate excess weight, other anthropometric indices have been developed to measure total body and abdominal adiposity. However, little is known about the impact of physical activity and adherence to a Mediterranean diet on these indices. Here we report the results of a cross-sectional study with 6672 middle-aged subjects with low to moderate cardiovascular risk from the Ilerda Vascular (ILERVAS) project. The participants' adherence to physical activity (International Physical Activity Questionnaire short form) and MedDiet (Mediterranean Diet Adherence Screener) was evaluated. Measures of total adiposity (BMI, Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE), and Deurenberg's formula), central adiposity (waist and neck circumferences, conicity index, waist to height ratio, Bonora's equation, A body adiposity index, and body roundness index), and lean body mass (Hume formula) were assessed. Irrespective of sex, lower indices of physical activity were associated with higher values of total body fat and central adiposity. This result was constant regardless of the indices used to estimate adiposity. However, the association between MedDiet and obesity indices was much less marked and more dependent on sex than that observed for physical activity. Lean body mass was influenced by neither physical activity nor MedDiet adherence. No joint effect between physical activity and MedDiet to lower estimated total or central adiposity indices was shown. In conclusion, physical activity is related to lower obesity indices in a large cohort of middle-aged subjects. MedDiet showed a slight impact on estimated anthropometric indices, with no joint effect when considering both lifestyle variables. ClinTrials.gov Identifier: NCT03228459.

Ad libitum Mediterranean diet reduces subcutaneous but not visceral fat in patients with coronary heart disease: A randomised controlled pilot study

BACKGROUND & AIMS

The Mediterranean diet (MedDiet) is recognised to reduce risk of coronary heart disease (CHD), in part, via its anti-inflammatory and antioxidant properties, which may be mediated via effects on body fat distribution. Diet efficacy via these mechanisms is however unclear in patients with diagnosed CHD. This study aimed to determine: (1) the effect of ad libitum MedDiet versus low-fat diet intervention on adiposity, anti-inflammatory marker adiponectin, oxidative stress marker malondialdehyde (MDA) and traditional CVD risk markers, and (2) whether improvement in MedDiet adherence score in the pooled cohort was associated with these risk markers, in a pilot cohort of Australian patients post coronary event.

METHODS

Participants (62 ± 9 years, 83% male) were randomised to 6-month ad libitum MedDiet (n = 34) or low-fat diet (n = 31). Pre- and post-intervention, dietary adherence, anthropometry, body composition (Dual-energy X-ray Absorptiometry) and venepuncture measures were conducted.

RESULTS

The MedDiet group reduced subcutaneous adipose tissue (SAT) area compared to the low-fat diet group (12.5 cm² more, p = 0.04) but not visceral adipose tissue or other body composition measures. In the pooled cohort, participants with greatest improvement in MedDiet adherence score had significantly lower waist circumference (-2.81 cm, p = 0.01) and SAT area (-27.1 cm², p = 0.04) compared to participants with no improvement in score at 6-months. There were no changes in adiponectin, MDA or other risk markers in the MedDiet compared to low-fat diet group, and no differences in 6-month levels between categories of improvement in MedDiet score (p > 0.05). Within the MedDiet group only, the proportion of participants taking beta-blocker medication reduced from baseline to 6-months (71% vs. 56%, p-trend = 0.007).

CONCLUSIONS

Adherence to 6-month ad libitum MedDiet reduced subcutaneous fat and waist circumference which discounts the misconception that this healthy but high fat diet leads to body fat gain. The effect of MedDiet on body fat distribution and consequent anti-inflammatory and antioxidant effects, as well as need for medications, in patients with CHD warrants exploration in larger studies. Clinically significant effects on these markers may require adjunct exercise and/or caloric restriction.

TRIAL REGISTRATION

ACTRN12616000156482.

Mediterranean-style diet for the primary and secondary prevention of cardiovascular disease

BACKGROUND

The Seven Countries study in the 1960s showed that populations in the Mediterranean region experienced lower coronary heart disease (CHD) mortality probably as a result of different dietary patterns. Later observational studies have confirmed the benefits of adherence to a Mediterranean dietary pattern on cardiovascular disease (CVD) risk factors but clinical trial evidence is more limited.

OBJECTIVES

To determine the effectiveness of a Mediterranean-style diet for the primary and secondary prevention of CVD.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 9); MEDLINE (Ovid, 1946 to 25 September 2018); Embase (Ovid, 1980 to 2018 week 39); Web of Science Core Collection (Thomson Reuters, 1900 to 26 September 2018); DARE Issue 2 of 4, 2015 (Cochrane Library); HTA Issue 4 of 4, 2016 (Cochrane Library); NHS EED Issue 2 of 4, 2015 (Cochrane Library). We searched trial registers and applied no language restrictions.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) in healthy adults and adults at high risk of CVD (primary prevention) and those with established CVD (secondary prevention). Both of the following key components were required to reach our definition of a Mediterranean-style diet: high monounsaturated/saturated fat ratio (use of olive oil as main cooking ingredient and/or consumption of other traditional foods high in monounsaturated fats such as tree nuts) and a high intake of plant-based foods, including fruits, vegetables and legumes. Additional components included: low to moderate red wine consumption; high consumption of whole grains and cereals; low consumption of meat and meat products and increased consumption of fish; moderate consumption of milk and dairy products. The intervention could be dietary advice, provision of relevant foods, or both. The comparison group received either no intervention, minimal intervention, usual care or another dietary intervention. Outcomes included clinical events and CVD risk factors. We included only studies with follow-up periods of three months or more defined as the intervention period plus post intervention follow-up.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data and assessed risk of bias. We conducted four main comparisons:1. Mediterranean dietary intervention versus no intervention or minimal intervention for primary prevention;2. Mediterranean dietary intervention versus another dietary intervention for primary prevention;3. Mediterranean dietary intervention versus usual care for secondary prevention;4. Mediterranean dietary intervention versus another dietary intervention for secondary prevention.

MAIN RESULTS

In this substantive review update, 30 RCTs (49 papers) (12,461 participants randomised) and seven ongoing trials met our inclusion criteria. The majority of trials contributed to primary prevention: comparisons 1 (nine trials) and 2 (13 trials). Secondary prevention trials were included for comparison 3 (two trials) and comparison 4 (four trials plus an additional two trials that were excluded from the main analyses due to published concerns regarding the reliability of the data).Two trials reported on adverse events where these were absent or minor (low- to moderate-quality evidence). No trials reported on costs or health-related quality of life.Primary preventionThe included studies for comparison 1 did not report on clinical endpoints (CVD mortality, total mortality or non-fatal endpoints such as myocardial infarction or stroke). The PREDIMED trial (included in comparison 2) was retracted and re-analysed following concerns regarding randomisation at two of 11 sites. Low-quality evidence shows little or no effect of the PREDIMED (7747 randomised) intervention (advice to follow a Mediterranean diet plus supplemental extra-virgin olive oil or tree nuts) compared to a low-fat diet on CVD mortality (hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.50 to 1.32) or total mortality (HR 1.0, 95% CI 0.81 to 1.24) over 4.8 years. There was, however, a reduction in the number of strokes with the PREDIMED intervention (HR 0.60, 95% CI 0.45 to 0.80), a decrease from 24/1000 to 14/1000 (95% CI 11 to 19), moderate-quality evidence). For CVD risk factors for comparison 1 there was low-quality evidence for a possible small reduction in total cholesterol (-0.16 mmol/L, 95% CI -0.32 to 0.00) and moderate-quality evidence for a reduction in systolic (-2.99 mmHg (95% CI -3.45 to -2.53) and diastolic blood pressure (-2.0 mmHg, 95% CI -2.29 to -1.71), with low or very low-quality evidence of little or no effect on LDL or HDL cholesterol or triglycerides. For comparison 2 there was moderate-quality evidence of a possible small reduction in LDL cholesterol (-0.15 mmol/L, 95% CI -0.27 to -0.02) and triglycerides (-0.09 mmol/L, 95% CI -0.16 to -0.01) with moderate or low-quality evidence of little or no effect on total or HDL cholesterol or blood pressure.Secondary preventionFor secondary prevention, the Lyon Diet Heart Study (comparison 3) examined the effect of advice to follow a Mediterranean diet and supplemental canola margarine compared to usual care in 605 CHD patients over 46 months and there was low-quality evidence of a reduction in adjusted estimates for CVD mortality (HR 0.35, 95% CI 0.15 to 0.82) and total mortality (HR 0.44, 95% CI 0.21 to 0.92) with the intervention. Only one small trial (101 participants) provided unadjusted estimates for composite clinical endpoints for comparison 4 (very low-quality evidence of uncertain effect). For comparison 3 there was low-quality evidence of little or no effect of a Mediterranean-style diet on lipid levels and very low-quality evidence for blood pressure. Similarly, for comparison 4 where only two trials contributed to the analyses there was low or very low-quality evidence of little or no effect of the intervention on lipid levels or blood pressure.

AUTHORS' CONCLUSIONS

Despite the relatively large number of studies included in this review, there is still some uncertainty regarding the effects of a Mediterranean-style diet on clinical endpoints and CVD risk factors for both primary and secondary prevention. The quality of evidence for the modest benefits on CVD risk factors in primary prevention is low or moderate, with a small number of studies reporting minimal harms. There is a paucity of evidence for secondary prevention. The ongoing studies may provide more certainty in the future.

Effects of Mediterranean Diet and Physical Activity on Pulmonary Function: A Cross-Sectional Analysis in the ILERVAS Project

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.