Impact of the level of adherence to the Mediterranean Diet on blood pressure: A systematic review and meta-analysis of observational studies

Dietary Salt Restriction and Adherence to the Mediterranean Diet: A Single Way to Reduce Cardiovascular Risk?

The dietary restriction of salt intake and the adhesion to Mediterranean dietary patterns are among the most recommended lifestyle modifications for the prevention of cardiovascular diseases. A large amount of evidence supports these recommendations; indeed, several studies show that a higher adherence to Mediterranean dietary patterns is associated with a reduced risk of cardiovascular disease. Likewise, findings from observational and clinical studies suggest a causal role of excess salt intake in blood pressure increase, cardiovascular organ damage, and the incidence of cardiovascular diseases. In this context, it is also conceivable that the beneficial effects of these two dietary patterns overlap because Mediterranean dietary patterns are typically characterized by a large consumption of plant-based foods with low sodium content. However, there is little data on this issue, and heterogeneous results are available on the relationship between adherence to salt restriction and to Mediterranean dietary patterns. Thus, this short review focuses on the epidemiological and clinical evidence of the relationship between the adherence to Mediterranean dietary patterns and dietary salt restriction in the context of cardiovascular risk.

High Versus Low Adherence to the Mediterranean Diet for Prevention of Diabetes Mellitus Type 2: A Systematic Review and Meta-Analysis

Diabetes mellitus type 2 (DMT-2) presents with a growing incidence, and its complications contribute mainly to cardiovascular disease and overall mortality. DMT-2 prevention and early stage management include lifestyle modification by adopting healthy eating patterns and increasing physical activity levels. The Mediterranean diet (MD) is associated with beneficial effects on human health and has been found effective for preventing and managing DMT-2. The purpose of this meta-analysis is to investigate whether the level of MD adherence plays a role in DMT-2 prevention and to what extent. A systematic literature search in PubMed, EMBASE, Web of Science Core Collection, Scopus, and Google Scholar databases was conducted until November 2022, and related observational studies fulfilling the eligibility criteria were included. The literature search concluded with 24 studies in the qualitative analysis and 23 studies in the quantitative analysis. Of those, 18 cohort studies were eligible for meta-analysis with hazard ratio as effect size and five studies providing odds ratio as effect size. The cohort studies included 248,140 participants with a mean follow-up of 10.8 years (3 to 22 years). Individuals with high adherence to MD presented an 11% and 18% decrease in risk and odds, respectively, of developing DMT-2 compared to those with low MD adherence (HR 0.89, 95%CI 0.83 to 0.95) and (OR 0.82, 95%CI 0.72 to 0.93). In studies where the follow-up was longer than 10 years, the 12% decrease in the risk of developing DMT-2 remained (HR 0.88 95%CI 0.84 to 0.92), whereas in studies where follow-up was less than 10 years, no difference between groups with different levels of adherence was found. Long-term high MD adherence is associated with a reduced risk of developing DMT-2, but further studies are needed to confirm these results.

Mediterranean Diet Adherence and Its Relationship to Metabolic Markers and Body Composition in Portuguese University Students

BACKGROUND

Transitioning to university involves several changes, which might affect dietary habits. The present study aimed to assess the potential relationships involving adherence to the MedDiet, body composition, and metabolic markers within a Portuguese university sample.

METHODS

A cross-sectional study involved 70 participants, 52 women, and 18 men (23.00 ± 7.00 years old and a BMI of 21.99 ± 2.79 kg/m²). The average MedDiet adherence of participants was 9.23 points, as evaluated by the 14 point validated questionnaire, with classifications of low and high (under or over 9 points, respectively). Body composition was assessed using X-ray dual densitometry (DXA), and metabolic markers were collected from capillary blood.

RESULTS

Statistically significant differences in HDL cholesterol and the total/HDL cholesterol ratio were found between groups. Lower levels (p < 0.05) of visceral (VAT) and subcutaneous adipose tissue (SAT), BMI, and waist circumference were found in the higher MedDiet adherence group. Those measures were negatively correlated (p < 0.05) with the adherence scores to the MedDiet.

CONCLUSION

Higher adherence to MedDiet seemed to have a favorable and important impact on lipid profiles, primarily HDL-c. A positive relationship between MedDiet adherence and body composition distribution was also described, mostly due to the influence of higher adherence to MedDiet at lower levels of VAT and SAT in Portuguese university students.

Critical evaluation of the questionnaires assessing adherence to the Mediterranean diet that are based on servings

BACKGROUND AND AIMS

The Mediterranean Diet (MD) is characterized by a high intake of vegetables, fruit, legumes, nuts, and olive oil, and moderate fish, dairy, and wine intake. A high adherence to MD has been associated with numerous health benefits, including reduced risk of chronic diseases such as cardiovascular disease, cancer, and type 2 diabetes. The clinical assessment of MD adherence is complicated by the absence of a univocally accepted tool and by the abundance of questionnaires developed to determine adherence, whose reliability and validity is uncertain. In this inter-associative document, we critically evaluated servings-based questionnaires for the assessment of MD adherence, aiming to identify the most valuable tool for the use in clinical practice.

METHODS AND RESULTS

For each questionnaire, we analyzed the structure, evidence on health-related outcomes and agreement with the recommendations of MD. We found that most questionnaires do not accurately reflect the principles of MD in terms of the food groups and their optimal consumption frequency. Additionally, the comparison of questionnaires revealed low agreement and some concerns with regard to the scoring assumptions.

CONCLUSIONS

Among the available questionnaires, we suggest the use of the 15-Items Pyramid based Mediterranean Diet Score (PyrMDS), which is the one with fewer flaws and a strong supporting body of theoretical and scientific evidence. The use of the PyrMDS may facilitate the assessment of MD adherence in clinical practice, which is instrumental in reducing the risk of non-communicable chronic diseases.

Dietary Approaches to Stop Hypertension via Indo-Mediterranean Foods, May Be Superior to DASH Diet Intervention

Western-type diet with high salt and sugar, sedentary behavior, obesity, tobacco and alcoholism are important risk factors for hypertension. This review aims to highlight the role of western diet-induced oxidative stress and inflammation in the pathogenesis of hypertension and the role of various types of diets in its prevention with reference to dietary approaches to stop hypertension (DASH) diet. It seems that it is crucial to alter the western type of diet because such diets can also predispose all CVDs. Western diet-induced oxidative stress is characterized by excessive production of reactive oxygen species (ROS) with an altered oxidation-reduction (redox) state, leading to a marked increase in inflammation and vascular dysfunction. Apart from genetic and environmental factors, one important cause for differences in the prevalence of hypertension in various countries may be diet quality, deficiency in functional foods, and salt consumption. The role of the DASH diet has been established. However, there are gaps in knowledge about the role of some Indo-Mediterranean foods and Japanese foods, which have been found to decrease blood pressure (BP) by improving vascular function. The notable Indo-Mediterranean foods are pulses, porridge, spices, and millets; fruits such as guava and blackberry and vegetables, which may also decrease BPs. The Japanese diet consists of soya tofu, whole rice, in particular medical rice, vegetables and plenty of fish rich in fish oil, fish peptides and taurine that are known to decrease BPs. Epidemiological studies and randomized, controlled trials have demonstrated the role of these diets in the prevention of hypertension and metabolic diseases. Such evidence is still meager from Japan, although the prevalence of hypertension is lower (15-21%) compared to other developed countries, which may be due to the high quality of the Japanese diet. Interestingly, some foods, such as berries, guava, pumpkin seeds, carrots, soya beans, and spices, have been found to cause a decrease in BPs. Omega-3 fatty acids, fish peptide, taurine, dietary vitamin D, vitamin C, potassium, magnesium, flavonoids, nitrate and l-arginine are potential nutrients that can also decrease BPs. Larger cohort studies and controlled trials are necessary to confirm our views.

Adherence to the Mediterranean diet and its association with environmental footprints among women of childbearing age in the United Arab Emirates

PURPOSE

To examine the association of adherence to the Mediterranean Diet (MD) with Environmental Footprints (EFPs) among women of childbearing age in the United Arab Emirates (UAE).

METHODS

Data belonging to a nationally representative sample of 482 women (19-50 years) were derived from a previous survey in the UAE. In face-to-face interviews, participants completed questionnaires addressing sociodemographic, physical activity, and dietary intake characteristics; the latter assessed using a multiple pass 24-h recall. The composite Mediterranean (c-MED) index was used to examine the adherence to the MD. Metrics for the EFPs (water use, energy use, and GHG emissions) were calculated using Life Cycle Analyses. Descriptive statistics and linear regressions were used in data analysis.

RESULTS

In the study sample, the distribution of the c-MED scores was skewed to the right, indicating a low adherence to the MD. The lowest contributions to the total c-MED score were observed for legumes (2.9%) and olive oil (1.8%). The EFPs associated with food consumption per 1000 kcal were: water use: 1256.89 ± 544.95 L/day; energy use: 18.01 ± 7.85 MJ/day, and GHG: 2.46 ± 1.46 kg CO_{2 eq}/day. After adjustment for age, energy intake, and potential confounders, being adherent to the MD was associated with 540.57 [95% CI (- 726.6; - 354.54)] units decrease in water use and 0.94 units decrease in GHG emissions [95% CI (- 1.45; - 0.43)].

CONCLUSIONS

The findings of this study revealed an inverse association between adherence to the MD and EFPs. As such, the MD may represent a promising dietary strategy to improve health outcomes and reduce the environmental impact. Public health programs addressing the low adherence to the MD among women of childbearing age in the UAE are warranted.