No Evidence of Increased Risk of Stroke with Consumption of Refined Grains: A Meta-analysis of Prospective Cohort Studies

Refined grain intake and cardiovascular disease: Meta-analyses of prospective cohort studies

Refined grains are included as part of an unhealthy, or Western, dietary pattern, which has been shown to be associated with increased risk of cardiovascular disease (CVD). To clarify the association between refined grain intake and CVD risk, Pubmed and Scopus databases were searched for relevant cohort studies from database inception to June 30, 2022. Only studies that examined refined grains as a distinct consumption category and not as part of a dietary pattern, were included. Meta-analyses were performed using Cochrane's RevMan 5.4.1 software, applying inverse variance risk ratios in random effects models for each outcome of interest. Heterogeneity was assessed with Cochrane's Q (chi2) and I2 statistics. Meta-analyses of hazard ratios (HR) and 95% confidence intervals (CI) obtained from 17 prospective cohort studies (>875,000 participants) indicated that refined grain intake was not associated with risk of CVD (HR = 1.08, 95% CI, 0.99-1.18, I2 = 70%; 9 cohorts), stroke (HR = 1.06, 95% CI 0.92-1.23, I2 = 70%; 9 cohorts), or heart failure (HR = 0.95, 95% CI 0.77-1.16, I2 = 10%; 5 cohorts). White rice intake was also not associated with risk of CVD (HR = 0.93, 95% CI 0.86-1.00, I2 = 25%; 7 cohorts) or stroke (HR = 1.03, 95% CI 0.93-1.14, I2 = 22%; 7 cohorts). No significant publication bias was evident (Egger's test P values all > 0.05). The lack of association between refined grain intake and CVD risk was observed in meta-analyses of studies that restricted analyses to only staple grain foods (e.g., bread, cereal, pasta, white rice), as well as for meta-analyses of studies that included both staple and indulgent grain foods (e.g., cakes, cookies, doughnuts, brownies, muffins, pastries). Probable confounding from unmeasured variables in studies included in the meta-analyses diminishes the overall quality of evidence. Although refined grains are included as a component of the Western dietary pattern, the results of the meta-analyses suggest that refined grains do not contribute to the higher CVD risk associated with this unhealthy dietary pattern. This information should be considered in formulation of future dietary recommendations.

Dietary Recommendations for Ethiopians on the Basis of Priority Diet-Related Diseases and Causes of Death in Ethiopia: An Umbrella Review

Food-based dietary guidelines (FBDG) need to be evidence-based. As part of the development of Ethiopian FBDG, we conducted an umbrella review to develop dietary recommendations. Protein-energy malnutrition (PEM), deficiencies of vitamin A, zinc, calcium, or folate, cardiovascular diseases (CVD), and type 2 diabetes mellitus (T2DM) were selected as a priority. Systematic reviews were eligible if they investigated the impact of foods, food groups, diet, or dietary patterns on priority diseases. After a search, 1513 articles were identified in PubMed, Scopus, and Google Scholar published from January 2014 to December 2021. The results showed that 19 out of 164 systematic reviews reported the impact of diet on PEM or micronutrient deficiencies. Daily 30-90 g whole-grain consumption reduces risk of CVD and T2DM. Pulses improve protein status, and consuming 50-150 g/d is associated with a reduced incidence of CVD and T2DM. Nuts are a good source of minerals, and consuming 15-35 g/d improves antioxidant status and is inversely associated with CVD risk. A daily intake of 200-300 mL of milk and dairy foods is a good source of calcium and contributes to bone mineral density. Limiting processed meat intake to <50 g/d reduces CVD risk. Fruits and vegetables are good sources of vitamins A and C. CVD and T2DM risks are reduced by consuming 200-300 g of vegetables plus fruits daily. Daily sugar consumption should be below 10% of total energy to lower risk of obesity, CVD, and T2DM. Plant-based fat has favorable nutrient profiles and modest saturated fat content. The association of saturated fatty acids with CVD and T2DM is inconclusive, but intake should be limited because of the low-density lipoprotein cholesterol-raising effect. Plant-based diets lower risk of CVD and T2DM but reduce micronutrient bioavailability. The review concludes with 9 key dietary recommendations proposed to be implemented in the Ethiopian FBDG. This review was registered at PROSPERO (CRD42019125490).

Predictive role of modifiable factors in stroke: an umbrella review

BACKGROUND

A growing number of meta-analyses reviewed the existing associations between modifiable factors and stroke. However, the methodological quality of them and quality of evidence remain to be assessed by validated tools. Thus, this umbrella review was conducted to consolidate evidence from systematic reviews and meta-analyses of cohort studies investigating the association between modifiable factors and incidence of stroke.

METHODS

PubMed, Web of Science, Embase, Wanfang and China National Knowledge Infrastructure databases for systematic reviews and meta-analyses of cohort studies from inception until March 2021. Assess the methodological quality of systematic reviews 2 was used to evaluate the methodological quality of each included published meta-analysis. Excess significance test was used to investigate whether the observed number of studies (O) with nominally significant results ('positive' studies, p<0.05) was larger than the expected number of significant results (E). Statistically significant (p<0.05) associations were rated into five levels (strong, highly suggestive, suggestive, weak and no) using specific criteria. Sensitivity analyses were performed.

RESULTS

2478 records were identified through database searching. At last, 49 meta-analyses including 70 modifiable factors and approximately 856 801 stroke cases were included in the present review. The methodological quality of three meta-analyses was low, while others were critically low. Evidence of walking pace was strong. High suggestive evidence mainly included total meat, processes meat, chocolate, sodium, obesity, pulse pressure, systolic blood pressure, diastolic blood pressure, sleep duration and smoking. Suggestive evidence mainly included dietary approaches to stop hypertension (DASH) diet, vitamin C, magnesium, depression and particulate matter 2.5. After sensitivity analyses, evidence of DASH diet, magnesium and depression turned to weak. No publication bias existed, except only one study which could be explained by reporting bias.

DISCUSSION

Diet with rich macronutrients and micronutrients, healthy dietary patterns and favourable physical, emotional health and environmental management should be promoted to decrease the burden of stroke.

PROSPERO REGISTRATION NUMBER

CRD42021249921.

Role of diet in stroke incidence: an umbrella review of meta-analyses of prospective observational studies

BACKGROUND

Stroke is one of the major challenges for the global healthcare system, which makes it necessary to explore the relationship between various modifiable factors and stroke risk. Recently, numerous meta-analyses of prospective observational studies have reported that dietary factors played a key role in the occurrence of stroke. However, the conclusions of previous studies have remained controversial and unclear. Accordingly, we conducted an umbrella review synthesizing and recalculating available evidence to assess the certainty of the associations between dietary factors and stroke.

METHODS

Relevant meta-analyses examining the associations between dietary factors and stroke were searched in PubMed and Embase databases up to September 1, 2021. For each eligible meta-analysis, two independent reviewers appraised the methodologic quality using the AMSTAR 2 criteria and estimated the summary effect size, 95% confidence intervals, 95% prediction intervals, heterogeneity between studies, and small-study effects. Moreover, we further assessed the associations between dietary factors and ischemic stroke as well as hemorrhagic stroke. Lastly, a set of pre-specified criteria was applied to qualitatively evaluate the epidemiological credibility of each dietary factor.

RESULTS

Overall, our umbrella review included 122 qualified meta-analyses for qualitative synthesis, involving 71 dietary factors related to food groups, foods, macronutrients, and micronutrients. Using the AMSTAR 2 criteria, 5 studies were assessed as high quality, 4 studies as moderate quality, and 113 studies as low or critically low quality. We identified 34 dietary factors associated with stroke occurrence, 25 dietary factors related to ischemic stroke, and 11 factors related to hemorrhagic stroke. Among them, high/moderate certainty epidemiological evidence demonstrated an inverse association between intake of fruits (RR: 0.90) and vegetables (RR: 0.92) and stroke incidence, but a detrimental association between red meat (RR: 1.12), especially processed red meat consumption (RR:1.17), and stroke incidence. Besides, the evidence of high/moderate certainty suggested that the intake of processed meat, fruits, coffee, tea, magnesium, and dietary fiber was associated with ischemic stroke risk, while consumption of tea, fruits, and vegetables was relevant to hemorrhagic stroke susceptibility.

CONCLUSIONS

Our study has reported that several dietary factors have a significant impact on stroke risk and offered a new insight into the relationship between dietary modification and stroke occurrence. Our results may provide an effective strategy for stroke prevention.

Mediterranean Diet and SARS-COV-2 Infection: Is There Any Association? A Proof-of-Concept Study

The aim of this observational study was investigating the possible correlation between adherence to the Mediterranean diet (MeD) and SARS-COV-2 infection rates and severity among healthcare professionals (HCPs). An online self-administrated questionnaire (evaluating both MeD adherence and dietary habits) was filled out by HCPs working in Piedmont (Northern Italy) from 15 January to 28 February 2021. Out of the 1206 questionnaires collected, 900 were considered reliable and analyzed. Individuals who reported the SARS-COV-2 infection (n = 148) showed a significantly lower MeD score, with a lower adherence in fruit, vegetables, cereals, and olive oil consumption. In a logistic regression model, the risk of infection was inversely associated with the MeD score (OR = 0.88; 95% CI 0.81–0.97) and the consumption of cereals (OR = 0.64; 0.45–0.90). Asymptomatic individuals with SARS-COV-2 infection reported a lower intake of saturated fats than symptomatic; individuals requiring hospitalization were significantly older and reported worse dietary habits than both asymptomatic and symptomatic individuals. After combining all symptomatic individuals together, age (OR = 1.05; 1.01–1.09) and saturated fats intake (OR = 1.09; 1.01–1.17) were associated with the infection severity. HCPs who reported a SARS-COV-2 infection showed a significantly lower MeD score and cereal consumption. The infection severity was directly associated with higher age and saturated fat intake.

Perspective: Whole and Refined Grains and Health-Evidence Supporting "Make Half Your Grains Whole"

Research-based dietary guidelines suggest that consumers "make half their grains whole." Yet some advocate ingesting only whole-grain foods (WGFs) and avoiding all refined-grain foods (RGFs). Some even recommend avoiding all grain-based foods (GBFs). This article will provide arguments to counter negative deductions about GBFs and RGFs, especially staple ones, and to support dietary guidance recommending a balance of GBFs-achieved through the right mix, type, and quantity of WGFs and RGFs. Studies looking at early mortality, body weight, and glucose tolerance and diabetes will be used as examples to characterize the literature about GBFs. The following issues are highlighted: 1) inconsistent findings between epidemiological and interventional studies and impacts of GBFs on health outcomes, and the underreporting of findings showing RGFs neither raise nor lower health risks; 2) multiple confounding and potential interactions make adequate statistical adjustment difficult; 3) nonuniform WGF definitions among studies make comparison of results challenging, especially because some WGFs may contain 49-74% refined grain (RG); 4) binary categorization of GBFs creates bias because nearly all categories of WGFs are recommended, but nearly half the RGF categories are not; 5) ingestion of >5 (30-g) servings RGFs/d and <1 serving WFGs/d creates dietary imbalance; 6) pattern names (e.g., "white bread") may impugn RGFs, when names such as "unbalanced" or "few fruits and vegetables" may more fairly characterize the dietary imbalance; 7) avoidance of all enriched RGs may not only impair status of folate and other B vitamins and certain minerals such as iron and zinc but also decrease acceptability of WGFs; 8) extrapolation beyond median documented intakes in high-WGF consumers (∼48 g whole grain/d) in most cohorts is speculative; 9) recommended dietary patterns such as the Mediterranean diet demonstrate that the right mix of WGFs and RGFs contributes to positive health outcomes.

Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals.

RESULTS

Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Perspective: Refined Grains and Health: Genuine Risk, or Guilt by Association?

Refined grain intake is widely assumed to be associated with adverse health outcomes, including increased risk for cardiovascular disease (CVD), type 2 diabetes (T2D), and obesity. The 2015 Dietary Guidelines Advisory Committee recommended that to improve dietary quality, the US population should replace most refined grains with whole grains. This recommendation was based largely on results from studies that examined dietary patterns, not separate food groups. A Western dietary pattern typically includes red and processed meat, sugar-sweetened foods and beverages, French fries, and high-fat dairy products, as well as refined grains, and has been linked to increased risk of many chronic diseases. However, when evaluated as a distinct food category, 11 meta-analyses of prospective cohort studies, which included a total of 32 publications with data from 24 distinct cohorts, demonstrated that refined grain intake was not associated with all-cause mortality, T2D, CVD, coronary heart disease (CHD), stroke, hypertension, or cancer. By contrast, consumption of red and processed meat was consistently associated with increased risk of these same health outcomes. Refined grain consumption up to 6-7 servings/d (1 serving = 30 g) was not associated with higher risk of CHD, T2D, hypertension, or all-cause mortality. Moreover, total grain intake was not associated with risk of CVD, CHD, stroke, or cancer, but was associated with lower risk of all-cause mortality. Consequently, the recommendation to reduce refined grain intake based on results from studies linking a Western dietary pattern to numerous adverse health outcomes is contrary to a substantial body of published scientific evidence. Future research needs to better define refined grain intake to distinguish between staple grain foods and indulgent grain foods, and to better design randomized controlled trials to resolve discrepancies between results from observational studies and such trials with regard to determining the benefits of whole grains compared with refined grains.

Consumo de alimentos y ataque cerebrovascular isquémico agudo. Estudio multicéntrico de casos y controles

Introducción. La dieta es uno de los factores asociados al ataque cerebrovascular (ACV) con un impacto particular sobre las diferentes poblaciones.Objetivo. Evaluar la asociación entre el consumo de alimentos y el ACV isquémico en una muestra de pacientes adultos en Colombia.Materiales y métodos. Estudio de casos (n=357) y controles (n=348) con casos incidentes de ACV isquémico agudo. El consumo de alimentos fue evaluado mediante un cuestionario de frecuencia de consumo. Se calculó el odds ratio (OR) con sus respectivos intervalos de confianza (IC) del 95% mediante modelos de regresión logística.Resultados. Se identificaron 10 alimentos asociados con el ACV isquémico agudo. Según la escala propuesta (número de modelos con asociación significativa), un solo alimento se ubicó en la categoría de evidencia fuerte de asociación (gallina), cuatro en categoría débil (chocolate, harina de trigo, manteca, aguacate) y cinco en la categoría sospechosa (pollo con piel, pollo sin piel, arroz, arracacha, yuca).Conclusiones. El consumo de chocolate de mesa (preparado en leche con una composición de 70% azúcar y 30% cacao), aguacate y pollo sin piel podría sugerir un efecto protector, mientras la alta ingesta de harina de trigo, gallina, manteca, atún en agua, arroz, pollo con piel, arracacha y yuca podría aumentar el riesgo de presentar ACV isquémico agudo.

Diet and primary prevention of stroke: Systematic review and dietary recommendations by the ad hoc Working Group of the Italian Society of Human Nutrition

BACKGROUND AND AIMS

To systematically review the latest evidence on established and emerging nutrition-related risk factors for incidence of and mortality from total, ischemic and haemorrhagic strokes. The present review was conducted in the framework of the work carried out through 2015 and 2016 for the preparation of the Italian Guidelines for the Prevention and Treatment of Stroke, 8th Edition, by ISO-SPREAD (Italian Stroke Organization and the Stroke Prevention and Educational Awareness Diffusion).

METHODS AND RESULTS

Systematic review of articles focused on primary prevention of stroke published between January 2013 to May 2016 through an extensive search of the literature using MEDLINE/PUBMED, EMBASE and the Cochrane Library. Articles were ranked according to the SIGN methodology while the GRADE system was used to establish the strength of recommendations. As a result of our literature search, we examined 87 meta-analyses overall (mainly of prospective studies), a few isolated more recent prospective studies not included in the meta-analyses, and a smaller number of available randomized controlled trials and case-control studies. Based on the analysis of the above articles, 36 Syntheses of the available evidence and 36 Recommendations were eventually prepared. The present document was developed by organizing the available evidence into three individual areas (nutrients, food groups and dietary patterns) to provide a systematic and user-friendly overview of the available evidence on the relationship between nutrition and primary prevention of stroke. Yet analysis of foods and food patterns allowed translating the information about nutrients in a tool more amenable to use in daily life also in the light of the argument that people eat foods rather than nutrients.

CONCLUSIONS

The present literature review and dietary recommendations provide healthcare professionals and all interested readers with a useful overview for the reduction of the risk of total, ischemic and haemorrhagic stroke through dietary modifications.

Stroke and food groups: an overview of systematic reviews and meta-analyses

OBJECTIVE

Numerous systematic reviews of prospective studies on the association of stroke risk with the consumption of various food groups have been published. A review of the evidence across the existing systematic reviews and meta-analyses of prospective studies was conducted to provide an overview of the range and validity of the reported associations of food groups with stroke risk.

DESIGN

The PubMed, EMBASE and Cochrane Library databases were searched for articles published up to September 2015 to identify systematic reviews of prospective studies.

RESULTS

A total of eighteen studies published from 2008 to 2015 were eligible for analysis. Overall, thirteen specific foods were studied for an association with stroke outcome, including nuts, legumes, fruits and vegetables, refined grains, whole grains, dairy products, eggs, chocolate, red and/or processed meat, fish, tea, sugar-sweetened beverages and coffee. Whereas a high consumption of nuts, fruits, vegetables, dairy foods, fish and tea, and moderate consumption of coffee and chocolate demonstrated a protective effect, a high consumption of red and/or processed meat was associated with increased stroke risk. Refined grain, sugar-sweetened beverage, legume, egg and whole grain intake showed no effect on stroke outcome.

CONCLUSIONS

The current overview provided a high level of evidence to support the beneficial effect of specific foods on stroke outcome. Clinicians and policy makers could inform clinical practice and policy based on this overview.