Effect of a nutritional intervention promoting the Mediterranean food pattern on electrophoretic characteristics of low-density lipoprotein particles in healthy women from the Québec City metropolitan area

The Impact of the Mediterranean Diet and Lifestyle Intervention on Lipoprotein Subclass Profiles among Metabolic Syndrome Patients: Findings of a Randomized Controlled Trial

Metabolic syndrome (MetS) is associated with alterations of lipoprotein structure and function that can be characterized with advanced lipoprotein testing (ADLT). The effect of the Mediterranean diet (MedDiet) and weight loss on the lipoprotein subclass profile has been scarcely studied. Within the PREDIMED-Plus randomized controlled trial, a sub-study conducted at Bellvitge Hospital recruiting center evaluated the effects of a weight loss program based on an energy-reduced MedDiet (er-MedDiet) and physical activity (PA) promotion (intervention group) compared with energy-unrestricted MedDiet recommendations (control group) on ADLT-assessed lipoprotein subclasses. 202 patients with MetS (n = 107, intervention; n = 95, control) were included. Lipid profiles were determined, and ADLT was performed at baseline, 6, and 12 months. Linear mixed models were used to assess the effects of intervention on lipoprotein profiles. Compared to the control diet, at 12 months, the er-MedDiet+PA resulted in a significant additional 4.2 kg of body weight loss, a decrease in body mass index by 1.4 kg/m2, reduction in waist circumference by 2.2 cm, decreased triglycerides, LDL-cholesterol and non-HDL-cholesterol, and increased HDL-cholesterol. In er-MedDiet+PA participants, ADLT revealed a decrease in small dense-LDL-cholesterol (sd-LDL-C), intermediate-density lipoproteins, VLDL-triglyceride, and HDL-Triglyceride, and an increase in large LDL and large VLDL particles. In conclusion, compared to an ad libitum MedDiet (control group), er-MedDiet+PA decreased plasma triglycerides and the triglyceride content in HDL and VLDL particles, decreased sd-LDL-C, and increased large LDL particles, indicating beneficial changes against cardiovascular disease.

Adherence to the Mediterranean diet and nuclear magnetic resonance spectroscopy biomarkers in older individuals at high cardiovascular disease risk: cross-sectional and longitudinal analyses

BACKGROUND

The Mediterranean diet (MedDiet) has been related to a decreased risk of cardiovascular disease (CVD) and diabetes.

OBJECTIVES

We aimed to prospectively assess the relationship between adherence to the MedDiet and advanced lipoprotein subclass profiles and glucose metabolism and inflammation markers, as determined by nuclear magnetic resonance (NMR) spectroscopy.

DESIGN

We conducted cross-sectional and longitudinal analyses within the framework of the PREvención con DIeta MEDiterránea study in 196 participants from the Reus-Tarragona center. Adherence to the MedDiet was assessed using a 14-item validated questionnaire [Mediterranean Diet Adherence Score (MEDAS)]. Plasma lipoprotein subclasses and molecular metabolite profiles were determined using NMR spectra collected on a Vantera Clinical Analyzer at baseline and after 1 y of follow-up. Baseline and 1-y categories of MEDAS were related to measures of lipoprotein atherogenicity and diabetes risk using multivariable-adjusted analysis of covariance models.

RESULTS

Compared with participants in the lowest category of baseline MEDAS, those in the highest category showed higher concentrations of total high-density lipoprotein (HDL) particles and H1P HDL, lower concentrations of very low-density lipoprotein (VLDL)-triglyceride, smaller size of VLDL, and lower concentrations of very large VLDL, as well as lower concentrations of branched-chain amino acids, leucine, and GlycA and reduced Diabetes Risk Index (DRI) scores. In addition, participants who increased by 3 or more points in their 1-y MEDAS showed an increase in concentrations of H7P-HDL, H5P-HDL, and citrate, and reduced acetone and DRI scores compared with those with lesser adherence increases.

CONCLUSIONS

In older adults at high cardiometabolic risk, higher MEDAS was associated with modest beneficial changes in lipoprotein and glucose metabolism. The results suggest that lipoprotein subclass distribution and glycemic control are potential mechanisms behind the well-known salutary effects of MedDiet on CVD and diabetes risk. Future clinical trials exploring the effects of the MedDiet on advanced lipoprotein subclass profiles and glucose metabolism markers are needed to confirm the results of our study.

TRIAL REGISTRATION NUMBER

This trial was registered at controlled-trials.com as ISRCTN35739639.

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.

Advanced Quantitative Lipoprotein Characteristics Do Not Relate to Healthy Dietary Patterns in Adults from a Mediterranean Area

We aimed to assess the potential relationship between dietary patterns (i.e., Mediterranean diet and healthy eating) and the advanced lipoprotein profile (ALP) in a representative cohort of the Mediterranean population. Thus, ALP data from 1142 participants, including 222 with type 1 (19.4%) and 252 type 2 diabetes (22.1%), and 668 subjects without diabetes were used to study cross-sectional associations between quantitative characteristics of lipoproteins and adherence to the Mediterranean diet. The alternate Mediterranean diet score (aMED) and the alternate healthy eating index (aHEI) were calculated. The ALP was determined by nuclear magnetic resonance (NMR) spectrometry. Bivariable and multivariable analyses were performed. Participants in the third tertile of the aMED showed higher levels of low-density lipoprotein triglycerides (LDL-TG) (mean (SD) 17.5 (5.0); p = 0.037), large high-density lipoprotein particles (HDL-P) (0.3 (0.1); p = 0.037), and medium low-density lipoprotein particles (LDL-P) (434.0 (143.0); p = 0.037). In comparison with participants in the second and first tertiles of the aHEI, participants in the third tertile had higher levels of LDL-TG (17.7 (5.0); p = 0.010), and large HDL-P (0.3 (0.1); p = 0.002), IDL-C (11.8 (5.0); p = 0.001), intermediate-density lipoprotein triglycerides (IDL-TG) (13.2 (4.2); p < 0.001), LDL-TG (17.7(5.0); p = 0.010), high-density lipoprotein triglycerides (HDL-TG) (14.5 (4.4); p = 0.029,) large HDL-P (0.3 (0.1); p = 0.002) and very-low-density lipoprotein particles (VLDL-P) size (42.1 (0.2); p = 0.011). The adjusted-multivariable analysis for potential confounding variables did not show any association between the lipoproteins and dietary patterns (i.e., aMED and aHEI). In conclusion, none of the quantitative characteristics of lipoproteins were concomitantly associated with the extent of adherence to the Mediterranean diet measured using the aMED or aHEI scores in the studied population. Our findings also revealed that people with the highest adherence were older, had a higher body mass index (BMI) and more frequently had dyslipidemia, hypertension, or diabetes than those with the lowest adherence to the Mediterranean diet (MDiet). Thus, further research may be needed to assess the potential role of the dietary pattern on the ALP.

Sex Differences in the Impact of the Mediterranean Diet on LDL Particle Size Distribution and Oxidation

Sex differences have been previously highlighted in the cardioprotective effects of the Mediterranean diet (MedDiet). The objective of this study was to investigate whether sex differences also exist with regard to LDL particle size distribution and oxidation. Participants were 37 men and 32 premenopausal women (24–53 years) with slightly elevated LDL-C concentrations (3.4–4.9 mmol/L) or total cholesterol/HDL-C ≥5.0. Variables were measured before and after a four-week isoenergetic MedDiet. Sex differences were found in response to the MedDiet for the proportion of medium LDL (255–260 Å) (p for sex-by-time interaction = 0.01) and small, dense LDL (sdLDL; <255 Å) (trend; p for sex-by-time interaction = 0.06), men experiencing an increase in the proportion of medium LDL with a concomitant reduction in the proportion of sdLDL, while an opposite trend was observed in women. A sex difference was also noted for estimated cholesterol concentrations among sdLDL (p for sex-by-time interaction = 0.03), with only men experiencing a reduction in response to the MedDiet. The MedDiet marginally reduced oxidized LDL (oxLDL) concentrations (p = 0.07), with no sex difference. Results suggest that short-termconsumption of the MedDiet leads to a favorable redistribution of LDL subclasses from smaller to larger LDL only in men. These results highlight the importance of considering sex issues in cardiovascular benefits of the MedDiet.

Obesity, weight loss and conditional cardiovascular risk factors

Obesity is a pathological condition aggregating a substantial number of proatherogenic factors, such as insulin resistance, type 2 diabetes mellitus, dyslipidaemia and hypertension. In addition to these classic cardiometabolic risk factors, atherosclerosis may be aggravated by other non-classic factors, which are characterized as conditional, including homocysteine, fibrinogen, lipoprotein(a), LDL particle size and high-sensitivity CRP. Some of these biomarkers are disturbed in obesity because of a combination of dietary factors, hypertrophic adipose tissue, low-grade inflammation, insulin resistance and other parameters under investigation. For the reduction of these risk factors, weight loss exceeding 10-20% of the initial body weight is probably necessary, achieved through either conventional lifestyle measures or more drastic interventions such as bariatric surgery. It has been shown that certain well-balanced diets, such as the Mediterranean diet, constitute a means of improving in a concerted manner the levels of CRP, fibrinogen, homocysteine and small dense LDL particles, regardless of weight loss. The significance of considering these factors in weight management intervention is an issue that needs further investigation.

Effects of a dietary intervention promoting the adoption of a Mediterranean food pattern on fast-food consumption among healthy French-Canadian women

It is expected that a dietary intervention based on the traditional Mediterranean food pattern should be associated with a reduction in fast-food consumption but this has never been tested before. We assessed the impact of a 12-week dietary intervention, promoting the adoption of a Mediterranean food pattern, on fast-food consumption among seventy-one healthy women aged between 30 and 65 years. The dietary intervention consisted of two group sessions and seven individual sessions with a dietitian. To determine the Mediterranean dietary score (MedScore) and fast-food consumption, an FFQ was administered. During the 12-week intervention, the MedScore significantly increased (from 21.1 (SD 3.6) units at baseline to 28.6 (SD 4.4) units at week 12, P < 0.0001), while the fast-food consumption significantly decreased (from 51.7 (SD 46.4) g/d at baseline to 20.5 (SD 18.2) g/d at week 12, P < 0.0001). Moreover, women who had a higher consumption of fast food at baseline decreased their fast-food consumption to the most (r - 0.50, P < 0.0001). When four subgroups were formed on the basis of median values of Medscore and fast-food consumption changes, it was found that only the subgroup of women which increased the most their MedScore and decreased the most their fast-food consumption experienced a significant decrease in BMI (P < 0.01). In conclusion, a dietary intervention promoting the Mediterranean food pattern led to a decrease in fast-food consumption among healthy women even if it was not a specific target of the intervention. Dietary strategies for increasing intake of healthy foods may be a useful approach for decreasing intake of less healthy foods.

Snack chips fried in corn oil alleviate cardiovascular disease risk factors when substituted for low-fat or high-fat snacks

BACKGROUND

The perception that all high-fat snacks are unhealthy may be wrong.

OBJECTIVE

We aimed to assess whether replacing low-fat and high-fat snacks with snacks rich in polyunsaturated fatty acids (PUFAs) and low in saturated and trans fatty acids would improve cardiovascular health.

DESIGN

Thirty-three adults participated in a randomized crossover trial of 3 controlled feeding phases of 25 d each in which a different type of snack was provided: low-fat (30.8% of energy from fat, 5.2% of energy from PUFAs), high-PUFA (36.3% of energy from fat, 9.7% of energy from PUFAs), or high-fat (37.9% of energy from fat, 5.8% of energy from PUFAs) snack.

RESULTS

Each diet reduced LDL- and total cholesterol concentrations, but reductions were greater with the low-fat and the high-PUFA diets than with the high-fat diet: LDL cholesterol (11.8% and 12.5% compared with 8.8%, respectively; P = 0.03 and 0.01), total cholesterol (10.5% and 10.7% compared with 7.9%, respectively; P = 0.03 and 0.02). The high-PUFA diet tended to reduce triacylglycerol concentrations (9.4%; P = 0.06), and this change was greater than that with the low-fat (P = 0.028) and high-fat (P = 0.0008) diets.

CONCLUSIONS

These data show that snack type affects cardiovascular health. Consuming snack chips rich in PUFA and low in saturated or trans fatty acids instead of high-saturated fatty acid and trans fatty acid or low-fat snacks leads to improvements in lipid profiles concordant with reductions in cardiovascular disease risk.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

Scientific evidence of interventions using the Mediterranean diet: a systematic review

The Mediterranean Diet has been associated with greater longevity and quality of life in epidemiological studies, the majority being observational. The application of evidence-based medicine to the area of public health nutrition involves the necessity of developing clinical trials and systematic reviews to develop sound recommendations. The purpose of this study was to analyze and review the experimental studies on Mediterranean diet and disease prevention. A systematic review was made and a total of 43 articles corresponding to 35 different experimental studies were selected. Results were analyzed for the effects of the Mediterranean diet on lipoproteins, endothelial resistance, diabetes and antioxidative capacity, cardiovascular diseases, arthritis, cancer, body composition, and psychological function. The Mediterranean diet showed favorable effects on lipoprotein levels, endothelium vasodilatation, insulin resistance, metabolic syndrome, antioxidant capacity, myocardial and cardiovascular mortality, and cancer incidence in obese patients and in those with previous myocardial infarction. Results disclose the mechanisms of the Mediterranean diet in disease prevention, particularly in cardiovascular disease secondary prevention, but also emphasize the need to undertake experimental research and systematic reviews in the areas of primary prevention of cardiovascular disease, hypertension, diabetes, obesity, infectious diseases, age-related cognitive impairment, and cancer, among others. Interventions should use food scores or patterns to ascertain adherence to the Mediterranean diet. Further experimental research is needed to corroborate the benefits of the Mediterranean diet and the underlying mechanisms, and in this sense the methodology of the ongoing PREDIMED study is explained.