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

From adolescence to adulthood: Mediterranean diet adherence and cardiometabolic health in a prospective cohort study

BACKGROUND AND AIMS

Recent investigations suggest that specific dietary patterns during adolescence may predict cardiometabolic complications later in life. In this study, we aimed to examine the association between Mediterranean diet score (MDS) during adolescence and cardiometabolic outcomes when participants reached adulthood.

METHODS AND RESULTS

This cohort study was conducted on 668 subjects, aged 10-19 years, in framework of the Tehran Lipid and Glucose Study. The MDS was determined based on eight components using a validated food-frequency questionnaire. Anthropometric measurements, fasting blood glucose (FBG), and lipid profile data were measured both at baseline and after a 6.8 ± 2.9-year follow-up. Using multivariable linear regression, we explored the association between MDS and changes in cardiometabolic risk factors. Moreover, multivariable-adjusted cox proportional hazard regression was used to estimate hazard ratios (HR) and 95 % confidence intervals (CIs) for cardiometabolic complications across MDS tertiles. The mean ± SD age of participants (43.5 % men) was 15.8 ± 2.47 years. The mean ± SD of MDS was 4.03 ± 1.56, with a median of 4.00 among all participants. Higher MDS was inversely associated with 6.8-year changes in waist circumference (WC), FBG, total cholesterol (TC), and high-density lipoprotein-cholesterol (Ptrend<0.05). Based on the HR analysis, after controlling for potential confounders, individuals in the highest tertile of MDS had a significantly lower risk of high-TC(HR = 0.36,95%CI:0.18-0.74,Ptrend = 0.004) compared to those in the lowest tertile. However, no significant association was observed between MDS and other cardiometabolic risk factors.

CONCLUSIONS

Greater adolescent adherence to a Mediterranean-type diet was associated with favorable cardiometabolic factors in adulthood, including improving the levels of WC, FBG, TC, as well as reduced risk of high-TC.

Diet in secondary prevention: the effect of dietary patterns on cardiovascular risk factors in patients with cardiovascular disease: a systematic review and network meta-analysis

BACKGROUND

Improving dietary habits is a first-line recommendation for patients with cardiovascular disease (CVD). It is unclear which dietary pattern most effectively lowers cardiovascular risk factors and what the short- and long-term effects are. Therefore, this network meta-analysis compared the effects of popular dietary patterns on cardiovascular risk factors in patients with established CVD.

METHODS

A systematic search of PubMed, Embase, the Cochrane library, SCOPUS and Web of Science was conducted up to 1 April 2023. Randomized controlled trials (RCTs) comparing the effect of popular dietary patterns (Mediterranean, moderate carbohydrate, low glycemic index, low-fat and minimal dietary intervention) on cardiovascular risk factors (body weight, systolic blood pressure, lipids) in CVD populations were selected. A random-effects network meta-analysis was performed.

RESULTS

Seventeen RCTs comprising 6,331 participants were included. The moderate carbohydrate diet had the most beneficial effect on body weight (-4.6 kg, 95%CrI -25.1; 15.8) and systolic blood pressure (-7.0 mmHg 95%CrI -16.8; 2.7) compared to minimal intervention. None of the included dietary patterns had a favorable effect on low-density lipoprotein cholesterol. After 12 months, the effects were attenuated compared to those at < 6 months.

CONCLUSIONS

In this network meta-analysis of 17 randomized trials, potentially clinically relevant effects of dietary interventions on CV risk factors were observed, but there was considerable uncertainty due to study heterogeneity, low adherence, or actual diminished effects in the medically treated CVD population. It was not possible to select optimal dietary patterns for secondary CVD prevention. Given recent clinical trials demonstrating the potential of dietary patterns to significantly reduce cardiovascular event risk, it is likely that these effects are effectuated through alternative physiological pathways.

Body composition analysis: A snapshot across the perimenopause

During the perimenopause, estrogen concentrations gradually decrease, and this is associated with changes to women's energy expenditure and intake. These changes result in weight gain and altered body fat distribution, with increased abdominal fat deposition and cardiometabolic risk via insulin resistance. Body composition analysis is a useful clinical tool in outpatient settings, as it is simple, not expensive and provides information on body mass index, skeletal mass, fat mass, fat percentage and basal metabolic rate. This review discusses body composition analysis as part of a health assessment for healthy women during the perimenopause and investigates the associations between body composition and cardiometabolic profile.

Investigating the efficacy and feasibility of using a whole-of-diet approach to lower circulating levels of C-reactive protein in postmenopausal women: a mixed methods pilot study

OBJECTIVE

Chronic inflammation is associated with obesity and is an underlying pathophysiology for cardiovascular disease (CVD) development in postmenopausal women. This study aims to determine feasibility and efficacy of an anti-inflammatory dietary intervention to lower levels of C-reactive protein in weight stable postmenopausal women with abdominal obesity.

METHODS

This mixed-methods pilot study used a single arm pre-post design. Thirteen women followed a 4-week anti-inflammatory, dietary intervention, optimizing consumption of healthy fats, low glycemic index wholegrains, and dietary antioxidants. Quantitative outcomes included change in inflammatory and metabolic markers. Focus groups were undertaken and thematically analyzed to explore participants lived experience of following the diet.

RESULTS

There was no significant change in plasma high-sensitivity C-reactive, protein. Despite discouraging weight loss, median (Q1-Q3) body weight decreased by -0.7 (-1.3 to 0 kg, P = 0.02). This was accompanied by reductions in plasma insulin (0.90 [-0.05 to 2.20] mmol/L), Homeostatic Model Assessment of Insulin Resistance (0.29 [-0.03 to 0.59]), and low-density lipoprotein:high-density lipoprotein ratio (0.18 [-0.01 to 0.40]) ( P ≤ 0.023 for all). Thematic analysis revealed that postmenopausal women have a desire to improve meaningful markers of health status that do not focus on weight. Women were highly engaged with learning about emerging and innovative nutrition topics, favoring a detailed and comprehensive nutrition education style that challenged their proficient health literacy and cooking skills.

CONCLUSIONS

Weight-neutral dietary interventions targeting inflammation can improve metabolic markers and may be a viable strategy for CVD risk reduction in postmenopausal women. To determine effects on inflammatory status, a fully powered and longer-term randomized controlled trial is required.

Increased Adherence to a Mediterranean Diet Is Associated with Reduced Low-Grade Inflammation after a 12.7-Year Period: Results from the Moli-sani Study

BACKGROUND

There is little knowledge on the association of changes over time in adherence to a Mediterranean diet (MD) with changes in modifiable cardiovascular disease (CVD) risk factors and of markers of low-grade inflammation.

OBJECTIVE

To evaluate the association between long-term changes in MD adherence and concurrent changes in established CVD risk factors and in markers of low-grade inflammation among adult Italians.

DESIGN

A prospective cohort study was conducted. Dietary and health data were obtained both at baseline (2005-2010) and at follow-up (2017-2020). Adherence to the MD was estimated by a Mediterranean Diet Score ranging from zero to nine points, and the exposure was change in this score measured after a median 12.7-year period.

PARTICIPANTS/SETTING

This study included a subgroup of 897 men and 1,126 women aged ≥35 years at enrolment in the Moli-sani Study (n = 24,325).

MAIN OUTCOME MEASURES

Changes in two composite z scores, including nine established CVD risk factors (eg, serum lipid levels and blood pressure) and four inflammatory markers (including C-reactive protein), respectively, were measured both at enrolment and after the same 12.7-year period.

STATISTICAL ANALYSES PERFORMED

Multivariable-adjusted linear regression models were used.

RESULTS

In a multivariable-adjusted analysis, an increased Mediterranean Diet Score over time was associated with decreased levels in the Inflammatory score (β = -0.372, 95% CI -0.720 to -0.025), but had little or no influence on the CVD risk score (β = -0.200, 95% CI -0.752 to 0.351), compared with individuals who had decreased their MD adherence. Among individual food groups/nutrients included in the Mediterranean Diet Score, an increased intake of monounsaturated over saturated fats over time was associated with lower CVD Risk Score, whereas increased consumption of cereals was inversely linked to the Inflammatory Score, compared with the reduced consumption group.

CONCLUSIONS

An increased adherence to a traditional MD over time was associated with reduced low-grade inflammation. These findings suggest the potential of a traditional Mediterranean eating pattern to help reduce the long-term risk of inflammation-related chronic diseases in an ageing population.

Mediterranean Diet and Obesity-related Disorders: What is the Evidence?

PURPOSE OF REVIEW

Obesity is a chronic disease, a major public health problem due to its association with non-communicable diseases and all-cause mortality. Indeed, people with obesity are at increased risk for a variety of obesity-related disorders including hypertension, dyslipidemia, type 2 diabetes mellitus, cardiovascular disease, and several cancers. Many popular diets with very different macronutrient composition, including the Mediterranean diet (MD), have been used, proposed, and studied for prevention and management of obesity. In particular, MD has been the subject of countless studies over the years and now boasts a large body of scientific literature. In this review, we aimed to update current knowledge by summarizing the most recent evidence on the effect of MD on obesity and obesity-related disorders.

RECENT FINDINGS

The negative effects of obesity are partly reversed by substantial weight loss that can be achieved with MD, especially when low-calorie and in combination with adequate physical activity. In addition, the composition of MD has been correlated with an excellent effect on reducing dyslipidemia. It also positively modulates the gut microbiota and immune system, significantly decreasing inflammatory mediators, a common ground for many obesity-related disorders. People with obesity are at increased risk for a variety of medical disorders including hypertension, dyslipidemia, type 2 diabetes mellitus, and cardiovascular disease. Therefore, there is an inevitable need for measures to manage obesity and its related disorders. At this point, MD has been proposed as a valuable nutritional intervention. It is characterized by a high consumption of vegetables, fruit, nuts, cereals, whole grains, and extra virgin olive oil, as well as a moderate consumption of fish and poultry, and a limited intake of sweets, red meat, and dairy products. MD proves to be the healthiest dietary pattern available to tackle obesity and prevent several non-communicable diseases, including cardiovascular disease and type 2 diabetes.

The effect of high-polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial

BACKGROUND

Mediterranean (MED) diet is a rich source of polyphenols, which benefit adiposity by several mechanisms. We explored the effect of the green-MED diet, twice fortified in dietary polyphenols and lower in red/processed meat, on visceral adipose tissue (VAT).

METHODS

In the 18-month Dietary Intervention Randomized Controlled Trial PoLyphenols UnproceSsed (DIRECT-PLUS) weight-loss trial, 294 participants were randomized to (A) healthy dietary guidelines (HDG), (B) MED, or (C) green-MED diets, all combined with physical activity. Both isocaloric MED groups consumed 28 g/day of walnuts (+ 440 mg/day polyphenols). The green-MED group further consumed green tea (3-4 cups/day) and Wolffia globosa (duckweed strain) plant green shake (100 g frozen cubes/day) (+ 800mg/day polyphenols) and reduced red meat intake. We used magnetic resonance imaging (MRI) to quantify the abdominal adipose tissues.

RESULTS

Participants (age = 51 years; 88% men; body mass index = 31.2 kg/m²; 29% VAT) had an 89.8% retention rate and 79.3% completed eligible MRIs. While both MED diets reached similar moderate weight (MED: - 2.7%, green-MED: - 3.9%) and waist circumference (MED: - 4.7%, green-MED: - 5.7%) loss, the green-MED dieters doubled the VAT loss (HDG: - 4.2%, MED: - 6.0%, green-MED: - 14.1%; p < 0.05, independent of age, sex, waist circumference, or weight loss). Higher dietary consumption of green tea, walnuts, and Wolffia globosa; lower red meat intake; higher total plasma polyphenols (mainly hippuric acid), and elevated urine urolithin A polyphenol were significantly related to greater VAT loss (p < 0.05, multivariate models).

CONCLUSIONS

A green-MED diet, enriched with plant-based polyphenols and lower in red/processed meat, may be a potent intervention to promote visceral adiposity regression.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT03020186.

Associations of the Mediterranean-Style Dietary Pattern Score with Coronary Artery Calcification and Pericardial Adiposity in a Sample of US Adults

Several studies have identified improvements in the risks of cardiovascular disease in adults following a Mediterranean dietary pattern. However, data are scarce on its association with coronary artery calcification (CAC) and pericardial adiposity (PAT) in US adults with and without diabetes. To address this gap, we conducted a case-control study using baseline data from the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study [n = 1255; Type 1 Diabetes (T1D): n = 563; non-Diabetes Mellitus (non-DM): n = 692]. Participants completed a validated food frequency questionnaire, fasting (12 h overnight fast) biochemical analyses, and a physical examination including anthropometric measures. CAC and PAT were measured using electron beam-computed tomography. Logistic regression models were used to examine the associations of the Mediterranean-Style Dietary Pattern Score (MSDPS) with CAC (presence or absence), and linear regression models were applied to PAT analyses. In all of the adjusted models, no significant associations with CAC were found. For PAT, an increasing MSDPS was consistently associated with its lower volume in models adjusted for age, sex, diabetes status, total calories, and body mass index (all p < 0.05). The association between MSDPS and PAT was attenuated after adjusting for serum lipids and physical activity. In conclusion, the baseline data from the CACTI study show that a greater adherence to MSDPS is associated with a lower PAT volume and provide evidence that the Mediterranean dietary pattern is associated with lower cardiovascular risk markers.

Anti-Inflammatory Properties of Diet: Role in Healthy Aging

Inflammation is a physiological process involved in the defenses of the body and the repair of tissues. It is acutely activated by infections, trauma, toxins, or allergic reactions. However, if it becomes chronic, inflammation can end up stimulating the development of diseases such as cardiovascular disease, autoimmune disease, neurological disease, or cancer. Additionally, during aging, inflammation becomes increasingly more chronic. Furthermore, we found that certain foods, such as saturated fats, have pro-inflammatory activity. Taking this into account, in this review we have discussed different diets with possible anti-inflammatory activity, the commonly ingested components of each diet and their active compounds. In addition, we have proposed some dietary guidelines, as well as a list of compounds present in foods with anti-inflammatory activity, outlining how to combine them to achieve optimal anti-inflammatory effects. Therefore, we can conclude that the compounds in our diet with anti-inflammatory activity could help alleviate the inflammatory processes derived from diseases and unhealthy diets, and thereby promote healthy aging.

Impact of the Level of Adherence to Mediterranean Diet on the Parameters of Metabolic Syndrome: A Systematic Review and Meta-Analysis of Observational Studies

High adherence to the Mediterranean diet (MD) has been associated with a lower prevalence of Metabolic Syndrome (MetS). The present study aimed to investigate the impact of MD adherence on parameters of MetS. A systematic literature search was performed in PubMed, Cochrane Central Registry of Clinical Trials (CENTRAL), Scopus, EMBASE, Web of Science and Google Scholar databases. Observational studies that recorded adherence to MD and components/measures of the MetS, such as waist circumference (WC), blood pressure (BP), fasting blood glucose (FBG), high-density lipoprotein (HDL) cholesterol and triglycerides (TG), were included in this study. A total of 58 studies were included in our study. WC and TG were significantly lower in the high adherence MD group (SMD: -0.20, (95%CI: -0.40, -0.01), SMD: -0.27 (95%CI: -0.27, -0.11), respectively), while HDL cholesterol was significantly higher in the same group (SMD: -0.28 (95%CI: 0.07, 0.50). There was no difference in FBG and SBP among the two groups (SMD: -0.21 (95%CI: -0.54, 0.12) & SMD: -0.15 (95%CI: -0.38, 0.07), respectively). MD may have a positive impact on all parameters of MetS. However, further research is needed in this field.

Anthropometric variables as mediators of the association of changes in diet and physical activity with inflammatory profile

BACKGROUND

Mechanisms underlying the associations of high levels of physical activity (PA) and adherence to the Mediterranean Diet (MedDiet) with a better inflammatory profile remain unclear. Our objective was to assess the mediating role of changes in body mass index (BMI) and waist circumference (WC), as markers of body fat in the association of changes in PA and adherence to the MedDiet, with changes in the inflammatory profile.

METHODS

This study included 489 adults, aged 55 to 75 years, from the PREDIMED-Plus multi-centre lifestyle intervention trial. An inflammatory score was calculated, based on 8 blood biomarkers: high-sensitivity C-reactive protein, interleukin 6, interleukin 8, interleukin 18, monocyte chemo-attractant protein-1, C-peptide, leptin, and regulated on activation, normal T-cell expressed and secreted chemokine (RANTES). Biomarkers, levels of PA, score of MedDiet adherence, BMI and WC were measured at baseline and at one-year follow-up. Linear regression models were fitted according to the Baron and Kenny framework for mediation analysis.

RESULTS

Changes in BMI and WC mediated the association of both changes in PA and changes in the MedDiet adherence with the inflammatory score. BMI mediated 26% of the association of changes in total PA with the inflammatory profile, and 27% of the association of changes in the MedDiet, while WC mediated 13% and 12% of these associations, respectively.

CONCLUSION

In older adults at high cardiovascular risk, increasing PA levels and adherence to a MedDiet during 1 year were associated with a lower inflammatory score, which was partly mediated by a reduction in body fat.

Mediterranean diet and blood pressure reduction in adults with and without hypertension: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

It is unclear whether the Mediterranean diet (MedDiet) has a favorable effect on blood pressure (BP) levels because among randomized controlled trials (RCTs) investigating the MedDiet-mediated BP reduction significant methodological and clinical differences are observed. The purpose of this study was to comprehensively assess the MedDiet BP-effect compared to the usual diet or another dietary intervention (e.g. low-fat diet) in adults with and without hypertension, accounting for methodological and clinical confounders.

METHODS

We systematically searched Medline and the Cochrane Collaboration Library databases and identified 35 RCTs (13,943 participants). Random-effects model was used to calculate the mean attained systolic BP (SBP) and diastolic BP (DBP) differences during follow-up. Subgroup and meta-regression analyses were also conducted.

RESULTS

Compared to the usual diet and all other active intervention diets the MedDiet reduced SBP and DBP (difference in means: -1.5 mm Hg; 95% CI: -2.8, -0.1; P = 0.035, and -0.9 mm Hg; 95% CI: -1.5, -0.3; P = 0.002, respectively). Compared only to the usual diet the MedDiet reduced SBP and DBP, while compared to all other active intervention diets or only to the low-fat diet the MedDiet did not reduce SBP and DBP. The MedDiet reduced DBP levels to a higher extent in trials with mean baseline SBP ≥130 mm Hg, while both SBP and DBP were reduced more in trials with a mean follow-up period ≥16 weeks. The quality of evidence was rated as moderate for both outcomes according to the grading of recommendations, assessment, development and evaluation (GRADE) approach.

CONCLUSIONS

The adoption of the MedDiet was accompanied by a relatively small, but yet significant BP reduction, while higher baseline SBP levels and longer follow-up duration enhanced the BP-lowering effect of the intervention. This meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO) as CRD42020167308.

REGISTRY NUMBER

CRD42020167308.

Multidimensional Impact of Mediterranean Diet on IBD Patients

BACKGROUND & AIMS

Malnutrition with the accumulation of fat tissue and nonalcoholic fatty liver disease (NAFLD) are conditions associated with inflammatory bowel disease (IBD). Visceral fat and NAFLD-related liver dysfunction can both worsen intestinal inflammation. Because the Mediterranean diet (Md) has been shown to ameliorate both obesity and NAFLD, the aim of this study was to analyze the impact of Md on the nutritional state, liver steatosis, clinical disease activity, and quality of life (QoL) in IBD patients.

METHODS

Patients with IBD, both Crohn's disease (CD) and ulcerative colitis (UC), followed Md for 6 months. Their body mass index (BMI), body tissue composition, liver steatosis and function, serum lipid profile, clinical disease activity, and inflammatory biomarkers (C-reactive protein and fecal calprotectin) were collected at baseline (T0) and compared with those obtained after 6 months (T180) to evaluate the impact of Md.

RESULTS

One hundred forty-two IBD patients, 84 UC and 58 CD, followed Md for 6 months. At T180, diet-adherent CD and UC improved BMI (UC -0.42, P = 0.002; CD -0.48, P = 0.032) and waist circumference (UC -1.25 cm, P = 0.037; CD -1.37 cm, P = 0.041). Additionally, the number of patients affected by liver steatosis of any grade was significantly reduced in both groups (UC T0 31 of 84 [36.9%] vs T180 18 of 84 [21.4%], P = 0.0016; CD T0 27 of 58 [46.6%] vs T180 18 of 58 [31.0%], P < 0.001) after dietary intervention. Finally, after 6 months of the diet, fewer UC and CD patients with stable therapy had active disease (UC T0 14 of 59 [23.7%] vs T180 4 of 59 [6.8%], P = 0.004; CD T0 9 of 51 [17.6%] vs T180 2 of 51 [3.0%], P = 0.011) and elevated inflammatory biomarkers. Mediterranean diet improved QoL in both UC and CD, but neither serum lipid profile nor liver function were modified by the diet.

CONCLUSIONS

A significant reduction of malnutrition-related parameters and liver steatosis was observed in both CD and UC patients after short-term dietary intervention based on the adoption of Md, and this was associated with a spontaneous improvement of disease activity and inflammatory markers.

The Effect of the Mediterranean Diet on Metabolic Health: A Systematic Review and Meta-Analysis of Controlled Trials in Adults

The Mediterranean diet (MD) may provide metabolic benefits but no systematic review to date has examined its effect on a multitude of outcomes related to metabolic health. This systematic review with meta-analysis (International Prospective Register of Systematic Reviews, PROSPERO; number CRD42019141459) aimed to examine the MD’s effect on metabolic syndrome (MetSyn) incidence, components and risk factors (primary outcomes), and incidence and/or mortality from MetSyn-related comorbidities and receipt of pharmacologic treatment for MetSyn components and comorbidities (secondary outcomes). We searched Pubmed, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science for controlled trials published until June 2019, comparing the MD with no treatment, usual care, or different diets in adults. Studies not published in English and not promoting the whole MD were excluded. Two authors independently extracted data and assessed risk of bias using the Cochrane Collaboration’s and Risk of Bias in non-randomised studies (ROBINS-I) tools. Reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Random-effects meta-analyses, subgroup analyses and meta-regressions were performed, and heterogeneity was quantified using the I² statistic. We identified 2654 reports and included 84 articles reporting 57 trials (n = 36,983). In random effects meta-analyses, the MD resulted in greater beneficial changes in 18 of 28 MetSyn components and risk factors (body weight, body mass index, waist circumference, systolic and diastolic blood pressure, glucose, insulin, homeostatic model assessment of insulin resistance (HOMA-IR) index, total-, low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol, triglycerides, alanine transaminase, hepatic fat mass, C-reactive protein, interleukin-6, tumour necrosis factor-a, and flow-mediated dilatation) and lower risk of cardiovascular disease incidence (risk ratio (RR) = 0.61, 95% confidence intervals (CI) 0.42–0.80; I² = 0%), and stroke (RR = 0.67, 95% CI 0.35–0.98; I² = 0%). Only six studies reported effects on pharmacotherapy use, and pooled analysis indicated no differences between diet groups. Lack of consistency in comparator groups and other study characteristics across studies resulted in high heterogeneity for some outcomes, which could not be considerably explained by meta-regressions. However, a consistent direction of beneficial effect of the MD was observed for the vast majority of outcomes examined. Findings support MD’s beneficial effect on all components and most risk factors of the MetSyn, in addition to cardiovascular disease and stroke incidence. More studies are needed to establish effects on other clinical outcomes and use of pharmacotherapy for MetSyn components and comorbidities. Despite the high levels of heterogeneity for some outcomes, this meta-analysis enabled the comparison of findings across studies and the examination of consistency of effects. The consistent direction of effect, suggesting the MD’s benefits on metabolic health, supports the need to promote this dietary pattern to adult populations.

The Mediterranean diet and menopausal health: An EMAS position statement

INTRODUCTION

Globally, 985 million women are aged 50 and over, leading to increasing concerns about chronic conditions such as cardiovascular disease, osteoporosis, dementia, and cognitive decline, which can adversely affect quality of life and independent living.

AIM

To evaluate the evidence from observational studies and randomized trials on the effects of the Mediterranean diet on short- and long-term menopausal health: estrogen deficiency symptoms, cardiovascular disease, osteoporosis, cognitive and mental health, breast cancer, and all-cause mortality.

MATERIALS AND METHODS

Literature review and consensus of expert opinion.

SUMMARY RECOMMENDATIONS

The Mediterranean diet is a non-restrictive dietary pattern common in the olive-growing areas of the Mediterranean basin. It may improve vasomotor symptoms, cardiovascular risk factors such as blood pressure, cholesterol and blood glucose levels, as well as mood and symptoms of depression. Long-term adherence may: improve cardiovascular risk and events, and death; improve bone mineral density; prevent cognitive decline; and reduce the risk of breast cancer and all-cause mortality.

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.

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.