Javier Díez-Espino

Effects of dietary fibre intake on risk factors for cardiovascular disease in subjects at high risk

Background: Epidemiological studies and feeding trials with supplements suggest that fibre intake is associated with a reduction in cardiovascular risk. However, the effects of changes in dietary fibre on risk factor levels have not been evaluated in free-living individuals. Thus, the effects of changes in dietary fibre intake on cardiovascular risk factors were assessed over 3 months in free-living high-risk subjects. Methods: 772 high-risk subjects (age 69±5 years) were assigned to a low-fat diet or two Mediterranean-style diets. All participants received behavioural and nutritional education, including recommendations for increasing the consumption of vegetables, fruits, and legumes. Changes in food and nutrient intake, body weight, blood pressure, lipid profiles, glucose control and inflammatory markers were evaluated. Results: Most participants increased consumption of vegetable products, but the increase in dietary fibre exhibited wide between-subject variability (6–65 g/day). Body weight, waist circumference, and mean systolic and diastolic blood pressure decreased across quintiles of fibre intake (p<0.005; all). Reductions in fasting glucose and total cholesterol levels, and increments in HDL cholesterol were highest among participants in the upper 20% of fibre intake (p = 0.04 and 0.02 respectively). Plasma concentrations of C-reactive protein, but not those of inflammatory cytokines, decreased in parallel with increasing dietary fibre (p = 0.04). Significant reductions in LDL cholesterol were observed only among participants with the greatest increases in soluble fibre intake (p = 0.04). Conclusions: Increasing dietary fibre intake with natural foods is associated with reductions in classical and novel cardiovascular risk factors in a high-risk cohort.

Rapid Folin-Ciocalteu method using microtiter 96-well plate cartridges for solid phase extraction to assess urinary total phenolic compounds, as a biomarker of total polyphenols intake

Nutritional markers have several advantages for epidemiologic and clinical assays, when compared to dietary data obtained by food frequency questionnaires. Few studies have assessed whether total polyphenol (TP) compounds provide a valid biomarker for TP intake. To date, there has been almost no literature describing methods to determine TP in complex matrices such as urine, which have many interfering substances. We report a rapid Folin-Ciocalteu method to determine TP in urine samples using Oasis((R)) MAX 96-well plate cartridges for solid phase extraction. These plates allow analysis of a high number of samples at the same time. We performed a prospective, randomized, crossover trial and one cross-sectional study with 60 volunteers from the PREDIMED trial, seeking to evaluate whether the TP in urine were correlated with polyphenol intake and could, therefore, be considered as a marker of intake of these compounds. The assay was optimized; the sensitivity and the polarity range of urine polyphenols were increased and the detection and quantification limits were significantly reduced. The metabolites in standards solution and urine samples were stable under the storage and handling conditions. In the clinical trial and the cross-sectional study, TP excreted in spot urine samples were positively correlated with TP intake, r=0.48, P<0.01 and r=0.257, P=0.04, respectively. The methodology described may be used to detect TP in urine samples, employing the high throughput of 96-well microtiter plates and reader. The method is fast and simple and it allows analysis of a large number of samples at the same time.

Lifestyles and Risk Factors Associated with Adherence to the Mediterranean Diet: A Baseline Assessment of the PREDIMED Trial

Background The traditional Mediterranean dietary pattern (MedDiet) is associated with longevity and low rates of cardiovascular disease (CVD). However, there is little information on who is more likely to follow this food pattern. Aim To evaluate how different factors are associated with lower MedDiet adherence in older Spanish subjects. Methods We included 7305 participants (men aged 55–80 y, women 60–80 y) at high-risk of CVD recruited into the PREDIMED trial (ISRCTN35739639). Socioeconomic, anthropometric, lifestyle characteristics and CVD risk factors were recorded. A validated 14-item questionnaire was used to evaluate MedDiet adherence at baseline. Multivariate models were used to estimate odds ratios (OR) and 95% confidence intervals for lower adherence to the MedDiet (<9 points out of 14) and ascertain factors independently associated with it. Results Former smoking (OR = 0.87; 95% CI, 0.78–0.98), physical activity (OR for the 3rd vs. the 1sttertile: 0.69; 0.62–0.78), and higher educational level (OR for university vs. less than primary school: 0.54; 0.38–0.77) were associated with higher MedDiet adherence. Conversely, having a larger waist-to-height ratio (OR for 0.1 units, 1.35; 1.22–1.49), being diabetic (OR = 1.13; 1.03–1.24), being single (OR = 1.27; 1.01–1.61) or divorced or separated (OR = 1.44; 1.09–1.89), and current smoking (OR = 1.28; 1.11–1.47) were associated with lower adherence. Conclusions Participants with little education, a larger waist-to-height ratio, or diabetes and those who were less physically active, single, divorced or separated, or smokers were less likely to adhere to the MedDiet, an ideal model for food choices. Stronger efforts of health promotion are needed in these groups to foster adoption of the MedDiet.

Polymorphisms Cyclooxygenase-2 -765G>C and Interleukin-6 -174G>C Are Associated with Serum Inflammation Markers in a High Cardiovascular Risk Population and Do Not Modify the Response to a Mediterranean Diet Supplemented with Virgin Olive Oil or Nuts

Inflammation is involved in cardiovascular diseases. Some studies have found that the Mediterranean diet (MD) can reduce serum concentrations of inflammation markers. However, none of these studies have analyzed the influence of genetic variability in such a response. Our objective was to study the effect of the -765G>C polymorphism in the cyclooxygenase-2 (COX-2) gene and the -174G>C polymorphism in the interleukin-6 (IL-6) gene on serum concentrations of IL-6, C-reactive protein, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule-1 as well as their influence on the response to a nutritional intervention with MD. An intervention study in a high cardiovascular risk Mediterranean population (314 men and 407 women) was undertaken. Participants were randomly assigned to consume a low-fat control diet or a MD supplemented with virgin olive oil or nuts. Measures were obtained at baseline and after a 3-mo intervention period. At baseline, the COX-2 -765G>C polymorphism was associated with lower serum IL-6 (5.85 +/- 4.82 in GG vs. 4.74 +/- 4.14 ng/L in C-allele carriers; P = 0.002) and ICAM-1 (265.8 +/- 114.8 in GG vs. 243.0 +/- 107.1 microg/L in C-carriers; P = 0.018) concentrations. These differences remained significant after multivariate adjustment. The IL-6 -174G>C polymorphism was associated with higher (CC vs. G-carriers) serum ICAM-1 concentrations in both men and women and with higher serum IL-6 concentrations in men. Following the dietary intervention, no significant gene x diet interactions were found. In conclusion, although COX-2 -765G>C and IL-6 -174G>C polymorphisms were associated with inflammation, consuming a MD (either supplemented with virgin olive oil or nuts) reduced the concentration of inflammation markers regardless of these polymorphisms.

Fiber intake and all-cause mortality in the Prevención con Dieta Mediterránea (PREDIMED) study

BACKGROUND Few observational studies have examined the effect of dietary fiber intake and fruit and vegetable consumption on total mortality and have reported inconsistent results. All of the studies have been conducted in the general population and typically used only a single assessment of diet. OBJECTIVE We investigated the association of fiber intake and whole-grain, fruit, and vegetable consumption with all-cause mortality in a Mediterranean cohort of elderly adults at high cardiovascular disease (CVD) risk by using repeated measurements of dietary information and taking into account the effect of a dietary intervention. DESIGN We followed up 7216 men (55-75 y old) and women (60-75 y old) at high CVD risk in the Prevención con Dieta Mediterránea (PREDIMED) trial for a mean of 5.9 y. Data were analyzed as an observational cohort. Participants were initially free of CVD. A 137-item validated food-frequency questionnaire administered by dietitians was repeated annually to assess dietary exposures (fiber, fruit, vegetable, and whole-grain intakes). Deaths were identified through the continuing medical care of participants and the National Death Index. An independent, blinded Event Adjudication Committee adjudicated causes of death. Cox regression models were used to estimate HRs of death during follow-up according to baseline dietary exposures and their yearly updated changes. RESULTS In up to 8.7 y of follow-up, 425 participants died. Baseline fiber intake and fruit consumption were significantly associated with lower risk of death [HRs for the fifth compared with the first quintile: 0.63 (95% CI: 0.46, 0.86; P = 0.015) and 0.59 (95% CI: 0.42, 0.82; P = 0.004), respectively]. When the updated dietary information was considered, participants with fruit consumption >210 g/d had 41% lower risk of all-cause mortality (HR: 0.59; 95% CI: 0.44, 0.78). Associations were strongest for CVD mortality than other causes of death. CONCLUSION Fiber and fruit intakes are associated with a reduction in total mortality. PREDIMED was registered at controlled-trials.com as ISRCTN35739639.

Dietary fibre intake is inversely associated with carotid intima-media thickness: a cross-sectional assessment in the PREDIMED study

Objective:To assess the association between the intake of dietary fibre and carotid intima-media thickness (IMT) in a Mediterranean population at high cardiovascular risk.Methods:Baseline cross-sectional assessment of 457 men and women (average age 67 years) from two different Spanish centres of the PREDIMED trial. A previously validated food frequency questionnaire (137 food items) was administered by trained dieticians in a face-to-face interview. Mean common carotid IMT was measured using B-mode ultrasound imaging of the right and left carotid arteries by four certified sonographers who used a common protocol. Anthropometric and blood pressure measurements were performed and samples of fasting blood were obtained. Participants were categorized into four groups (roughly quartiles: ⩽21; >21 to ⩽25; >25 to ⩽31 and >31 g/day) of energy-adjusted intake of dietary fibre. Multiple linear regression models were used to adjust for age, sex, centre, smoking, body mass index, diabetes, blood pressure, lipid levels and statin use.Results:In the crude analyses, energy-adjusted fibre intake showed a significant inverse correlation with IMT (r=−0.27, P<0.001). In multivariate analyses, a modest, though statistically significant (P=0.03) inverse association between energy-adjusted fibre intake and IMT was also found. The multivariate-adjusted difference in average IMT was −0.051 mm (95% confidence interval: −0.094 to−0.009, P=0.02) for participants whose intake was >35 g/day, (n=47) when compared with those whose intake was <25 g/day (n=224).Conclusions:Our results suggest that high fibre intake is inversely associated with carotid atherosclerosis.

Association between dietary fibre intake and fruit, vegetable or whole-grain consumption and the risk of CVD: results from the PREvención con DIeta MEDiterránea (PREDIMED) trial

Prospective studies assessing the association between fibre intake or fibre-rich food consumption and the risk of CVD have often been limited by baseline assessment of diet. Thus far, no study has used yearly repeated measurements of dietary changes during follow-up. Moreover, previous studies included healthy and selected participants who did not represent subjects at high cardiovascular risk. We used yearly repeated measurements of diet to investigate the association between fibre intake and CVD in a Mediterranean cohort of elderly adults at high cardiovascular risk. We followed-up 7216 men (55-80 years) and women (60-80 years) initially free of CVD for up to 7 years in the PREvención con DIeta MEDiterránea study (registered as ISRCTN35739639). A 137-item validated FFQ was repeated yearly to assess diet. The primary end point, confirmed by a blinded ad hoc Event Adjudication Committee, was a composite of cardiovascular death, myocardial infarction and stroke. Time-dependent Coxs regression models were used to estimate the risk of CVD according to baseline dietary exposures and to their yearly updated changes. We found a significant inverse association for fibre (P for trend=0·020) and fruits (P for trend=0·024) in age-sex adjusted models, but the statistical significance was lost in fully adjusted models. However, we found a significant inverse association with CVD incidence for the sum of fruit and vegetable consumption. Participants who consumed in total nine or more servings/d of fruits plus vegetables had a hazard ratio 0·60 (95 % CI 0·40, 0·96) of CVD in comparison with those consuming <5 servings/d.

Adherence to the Mediterranean Diet in Patients with Type 2 Diabetes Mellitus and HbA1c Level

Rationale and Objective: The Mediterranean diet (MeDiet) has beneficial effects on cardiovascular risk factors. We analyzed the association between adherence of a MeDiet in patients with type 2 diabetes mellitus (T2DM) and levels of HbA1c. Patients and Methods: This was a cross-sectional study in individuals with T2DM participating in the PREDIMED trial at the centre of Pamplona. Information on diet was collected with a validated 14 point scale of adherence to the MeDiet and blood samples were obtained to assess HbA1c levels. Results: We studied 383 participants with T2DM, 53.4% women (mean age 69 ± 6 years). HbA1c data were available in 262 cases (mean 6.9 ± 1.5%). Although there was a potential inverse non-significant association between adherence to MeDiet and HbA1c levels after adjusting for age and sex, it was not statistically significant. Multivariate analysis additionally adjusted for physical activity, smoking, time of evolution of the T2DM, body mass index and insulin treatment found similar findings (OR = 0.69, 95% CI 0.17–2.83). Conclusions: Although we found not enough evidence to support that a MeDiet is associated with lower levels of HbA1c in patients with T2DM, our results suggested an inverse trend. Future studies with larger sample size are necessary.

Macronutrient Intake and Metabolic Syndrome in Subjects at High Cardiovascular Risk

Background: The effect of macronutrient intake on the metabolic syndrome (MS) is still controversial. Our aim in this study was to assess the relationships between macronutrient intake and the risk of developing the MS in subjects at high cardiovascular risk. Methods: In this cross-sectional study, 967 high-risk men and women (55–80 years) were assessed according to the MS criteria defined by the National Cholesterol Education Program Adult Treatment Panel III (ATP3) and those established by the International Diabetes Federation (IDF). A 137-item validated food frequency questionnaire was used. Odds ratios (OR) for macronutrient intake and MS were calculated and adjustments were made for potential confounders. Results: When applying the ATP3 criteria, an inverse association was found for fiber and polyunsaturated fatty acid (PUFAs) intake, with ORs of 0.55 (95% CI: 0.35–0.86) and 0.60 (95% CI: 0.39–0.94), respectively, for the 5th versus the 1st quintile. Using the IDF criteria, an inverse association between fiber intake and the MS was obtained whereas a direct association was found between carbohydrate intake and the MS: OR = 1.71 (95% CI: 1.05–2.79) for the highest versus the lowest quintile. Conclusions: A diet rich in fiber and PUFAs is correlated with a reduced risk of MS in subjects at high cardiovascular risk.

Consumption of Fruit or Fiber-Fruit Decreases the Risk of Cardiovascular Disease in a Mediterranean Young Cohort

Fiber and fiber-rich foods have been inversely associated with cardiovascular disease (CVD), but the evidence is scarce in young and Mediterranean cohorts. We used Cox regression models to assess the association between quintiles of total fiber and fiber from different sources, and the risk of CVD adjusted for the principal confounding factors in a Mediterranean cohort of young adults, the SUN (Seguimiento Universidad de Navarra, Follow-up) cohort. After a median follow-up of 10.3 years, we observed 112 cases of CVD among 17,007 participants (61% female, mean age 38 years). We observed an inverse association between fiber intake and CVD events (p for trend = 0.024) and also between the highest quintile of fruit consumption (hazard ratio (HR) 0.51, 95% confidence interval (CI) 0.27–0.95) or whole grains consumption (HR 0.43 95% CI 0.20–0.93) and CVD compared to the lowest quintile, and also a HR of 0.58 (95% CI 0.37–0.90) for the participants who ate at least 175 g/day of fruit. Only the participants in the highest quintile of fruit-derived fiber intake had a significantly lower risk of CVD (HR 0.52, 95% CI 0.28–0.97). The participants who ate at least one serving per week of cruciferous vegetables had a lower risk than those who did not (HR 0.52, 95% CI 0.30–0.89). In conclusion, high fruit consumption, whole grain consumption, or consumption of at least one serving/week of cruciferous vegetables may be protective against CVD in young Mediterranean populations.