The puzzle of dietary fat intake and risk of ischemic stroke: a brief review of epidemiologic data

Impact of dietary intervention on eating behavior after ischemic stroke

Objective

Ischemic stroke is a major health issue. Currently, the relationship between dietary patterns and the occurrence of cardiovascular diseases including stroke is established, but the effect of systematic dietary intervention on dietary changes in ischemic stroke patients is unknown. Our objective was to compare changes in the dietary pattern of ischemic stroke patients who received a systematic diet intervention with changes in the dietary pattern of ischemic stroke patients who did not receive a systematic dietary intervention during their hospitalization.

Methods

In this before-and-after study, two groups of patients with ischemic stroke were compared: Group 1 included 34 patients admitted with an ischemic stroke without a systematic dietray intervention; Group 2 included 34 patients admitted with an ischemic stroke with a systematic dietary intervention. Dietary patterns were assessed by a validated food frequency questionnaire of 19 questions (from a previously validated questionnaire of 14 questions), at the onset of stroke and at 6 months after stroke. This questionnaire allows the calculation of different scores as follows: global food score, saturated fatty acids score (SFA), unsaturated fatty acids score (UFA), fruit and vegetable score, and alcohol score.

Results

Score changes were more important in group 2 than in group 1 for the global food score (7.4 ± 7 vs. 1.9 ± 6.7, p = 0.0013), the fruit and vegetable score (2 ± 2.6 vs. 0.6 ± 2.2, p = 0.0047), and the UFA score (1.8 ± 2.7 vs. 0.1 ± 3.3, p = 0.0238), whereas no significant differences were observed for the SFA score (-3.9 ± 4.9 vs. -1.6 ± 6, p = 0.1779) and the alcohol score (-0.4 ± 1.5 vs. -0.3 ± 1.1, p = 0.6960).

Conclusion

This study showed that systematic dietary intervention during hospitalization improves the dietary patterns of ischemic stroke patients. The impact on the recurrence of ischemic stroke or cardiovascular events after dietary pattern changes needs to be studied.

A plasma metabonomics study on the therapeutic effects of the Si-miao-yong-an decoction in hyperlipidemic rats

ETHNOPHARMACOLOGICAL RELEVANCE

The Si-miao-yong-an decoction (SMYAD) is a famous traditional Chinese medicinal formula that has been used for centuries in ancient China for treating thromboangiitis obliterans. Because of its long history of use, it has been used to treat patients in China for thousands of years. In recent years, SMYAD has been widely used for treating cardiovascular and endocrine diseases. It was shown to significantly increase high-density lipoprotein-cholesterol levels and reduce total cholesterol and low-density lipoprotein-cholesterol levels in the serum.

AIM OF THE STUDY

Herein, a serum metabonomics approach based on the HPLC-MS/MS method was adopted to evaluate the therapeutic effect of SMYAD on high-fat diet-induced hyperlipidemia, and investigate the mechanisms for treating hyperlipidemia.

MATERIALS AND METHODS

Firstly, the change in body weight, liver histopathology, and serum biochemistry, including that in the levels of hepatotoxicity-related enzymes, oxidative stress indexes, and inflammatory factors were monitored in rats, to evaluate the therapeutic effect of SMYAD on high-fat diet-induced hyperlipidemia. Then, a serum metabolomics approach was applied, to cluster different groups using principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), as well as to screen out sensitive and reliable biomarkers. Finally, the metabolic pathways associated with specific biomarkers were analyzed, to understand the possible mechanism underlying the action of SMYAD.

RESULTS

The results indicated that SMYAD had significant anti-hyperlipidemic, anti-oxidant, and anti-inflammatory effects. Based on the results of serum metabolomics analysis, the hyperlipidemic rats showed completely different results compared to the control rats; metabolite profiles of rats from the SMYAD treatment groups showed a trend comparable to those of the normal control group in a dose-dependent manner. Besides, twelve biomarkers associated with pyruvate metabolism, taurine and hypotaurine metabolism, TCA cycle, bile acid metabolism, and glucose metabolism were identified and confirmed, to clarify the mechanism of action of SMYAD.

CONCLUSION

Using metabonomics technology, it was predicted that the therapeutic effects of SMYAD were associated with its anti-oxidation as well as anti-inflammatory activities and the adjustment of the pyruvate, taurine as well as hypotaurine metabolism pathways in the hyperlipidemic state. This study provided evidence regarding the clinical application of SMYAD and thoroughly explored the mechanism underlying the action of this traditional Chinese medicine.

Marine n-3 Polyunsaturated Fatty Acids and the Risk of Ischemic Stroke

Background and Purpose—

We hypothesized that total marine n-3 polyunsaturated fatty acids (PUFA), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the diet and in adipose tissue (biomarkers of long-term intake and endogenous exposure) were inversely associated with the risk of ischemic stroke and its subtypes.

Methods—

The Diet, Cancer and Health cohort consisted of 57 053 participants aged 50 to 65 years at enrolment. All participants filled in a food frequency questionnaire and had an adipose tissue biopsy taken at baseline. Information on ischemic stroke during follow-up was obtained from The Danish National Patient Register, and all cases were validated. Cases and a random sample of 3203 subjects from the whole cohort had their fatty acid composition of adipose tissue determined by gas chromatography.

Results—

During 13.5 years of follow-up 1879 participants developed an ischemic stroke. Adipose tissue content of EPA was inversely associated with total ischemic stroke (hazard ratio [HR], 0.74; 95% CI, 0.62–0.88) when comparing the highest with the lowest quartile. Also, lower rates of large artery atherosclerosis were seen with higher intakes of total marine n-3 PUFA (HR, 0.69; 95% CI, 0.50–0.95), EPA (HR, 0.66; 95% CI, 0.48–0.91) and DHA (HR, 0.72; 95% CI, 0.53–0.99), and higher adipose tissue content of EPA (HR, 0.52; 95% CI, 0.36–0.76). Higher rates of cardioembolism were seen with higher intakes of total marine n-3 PUFA (HR, 2.50; 95% CI, 1.38–4.53) and DHA (HR, 2.12; 95% CI, 1.21–3.69) as well as with higher adipose tissue content of total marine n-3 PUFA (HR, 2.63; 95% CI, 1.33–5.19) and DHA (HR, 2.00; 95% CI, 1.04–3.84). The EPA content in adipose tissue was inversely associated with small-vessel occlusion (HR, 0.69; 95% CI, 0.55–0.88).

Conclusions—

EPA was associated with lower risks of most types of ischemic stroke, apart from cardioembolism, while inconsistent findings were observed for total marine n-3 PUFA and DHA.

APOE and the Association of Fatty Acids With the Risk of Stroke, Coronary Heart Disease, and Mortality

Background and Purpose- The role of dietary fat on cardiovascular health and mortality remains under debate. Because the APOE is central to the transport and metabolism of lipids, we examined associations between plasma fatty acids and the risk of stroke, coronary heart disease, and mortality by APOE-ε4 genotype. Methods- We included 943 FHS (Framingham Heart Study) and 1406 3C (Three-City) Bordeaux Study participants. Plasma docosahexaenoic, linoleic, arachidonic, and palmitic fatty acids were measured at baseline by gas chromatography. All-cause stroke, ischemic stroke, coronary heart disease, and all-cause mortality events were identified prospectively using standardized protocols. Each cohort used Cox models to separately relate fatty acid levels to the risk of developing each event during ≤10 years of follow-up adjusting for potential confounders and stratifying by APOE genotype (ε4 carriers versus noncarriers). We then meta-analyzed summary statistics using random-effects models. Results- On average, participants had a mean age of 74 years, 61% were women, and 21% (n=483) were APOE-ε4 carriers. Meta-analysis results showed that, only among APOE-ε4 carriers, every SD unit increase in linoleic acid was associated with a reduced risk of all-cause stroke (hazard ratio [HR], 0.54 [95% CI, 0.38-0.78]), ischemic stroke (HR, 0.48 [95% CI, 0.33-0.71]), and all-cause mortality (HR, 0.70 [95% CI, 0.57-0.85]). In contrast, every SD unit increase in palmitic acid was related to an increased risk of all-cause stroke (HR, 1.58 [95% CI, 1.16-2.17]), ischemic stroke (HR, 1.76 [95% CI, 1.26-2.45]), and coronary heart disease (HR, 1.48 [95% CI, 1.09-2.01]), also in APOE-ε4 carriers only. Results for docosahexaenoic acid and arachidonic acid were heterogeneous between cohorts. Conclusions- These exploratory results suggest that APOE-ε4 carriers may be more susceptible to the beneficial or adverse impact of fatty acids on cardiovascular disease and mortality. In this subgroup, higher linoleic acid was protective for stroke and mortality, whereas palmitic acid was a risk factor for stroke and coronary heart disease. The mechanisms underlying these novel findings warrant further investigation.

Genetic and environmental factors in vascular dementia: an update of blood brain barrier dysfunction

Vascular dementia (VaD) describes a combination of both cognitive and behavioural manifestations associated with variable brain lesions of vascular origin. While vascular risk factors have been implicated in VaD, the relationship is most evident when the factors are considered together and not individually. This review will examine the significance of the integrity of blood brain barrier (BBB) tight junction (TJ) proteins - occludin and claudins in the pathophysiology of VaD. Specifically, some of the genetic contributors to VaD, namely those responsible for the integrity of the BBB, will be reviewed in detail. Moreover, environmental factors will be considered in conjunction with these genes to examine how the interaction of environmental and genetic factors contributes to one's susceptibility to VaD.

Cerebrospinal Fluid Free Fatty Acid Levels Are Associated with Stroke Subtypes and Severity in Chinese Patients with Acute Ischemic Stroke

OBJECTIVE

To assess the clinical significance of cerebrospinal fluid (CSF) free fatty acid (FFA) levels in Chinese patients with acute ischemic stroke.

METHODS

From December 2011 to October 2014, all patients with first-ever acute ischemic stroke were recruited to participate in the study. CSF levels of FFAs were assayed at 4 time points, and severity of stroke was evaluated with the National Institutes of Health Stroke Scale (NIHSS) score on admission.

RESULTS

Median CSF FFA levels were significantly (P < 0.0001) higher in patients with stroke compared with control subjects. CSF FFA levels reflected the disease severity of acute ischemic stroke. There were significant positive associations between CSF FFA levels and NIHSS scores (r = 0.424, P < 0.0001) and infarct volume (r = 0.289, P < 0.0001). CSF FFA levels in patients with cardioembolic (CE) stroke were significantly higher compared with patients with non-CE stroke (0.34 mmol/L [interquartile range, 0.26-0.42] vs. 0.14 mmol/L [interquartile range, 0.08-0.23]; P < 0.0001). Based on the receiver operating characteristic curve, the optimal cutoff value of CSF FFA levels as an indicator for the diagnosis of CE stroke was projected to be 0.22 mmol/L, which yielded a sensitivity of 83.3% and a specificity of 75.3%, and the area under the curve was 0.873 (95% confidence interval, 0.810-0.935).

CONCLUSIONS

CSF FFA levels at the time of admission were associated with stroke severity and lesion volumes. In addition, CE stroke can be distinguished from other stroke etiologies by measuring CSF FFA levels very early.

Intake of trans fat and incidence of stroke in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort

BACKGROUND

Whether elevated intakes of trans fatty acids (TFAs) increase the risk of stroke remains unclear. Except for the Women's Health Initiative-Observational Study, most studies that directly assessed the association between TFA intake and stroke yielded null results.

OBJECTIVE

The aim of this study was to investigate the association between TFA intake and stroke incidence.

DESIGN

We prospectively investigated the association between TFA intake and stroke incidence in black and white men and women (n = 17,107) from the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Participants were recruited between 2003 and 2007 from the continental United States and followed for incident stroke. Diet was assessed by using the Block 1998 food-frequency questionnaire. Cox regression was used to test whether energy-adjusted TFA intake in 1-SD increments was associated with incident stroke.

RESULTS

During a median follow-up of 7 y, 479 strokes were identified, including 401 ischemic strokes. Sex modified the association between TFA intake and stroke (P-interaction = 0.06), and thus the results were stratified by sex. In fully adjusted models, a 1-SD (2-g/d) increase in TFA intake was associated with an increased risk of any stroke in men (HR: 1.14; 95% CI: 1.02, 1.28) but not in women (HR: 0.93; 95% CI: 0.79, 1.11). Similarly, our results showed an increased risk of ischemic stroke in men (HR: 1.13; 95% CI: 1.00, 1.28) but not in women (HR: 0.93; 95% CI: 0.77, 1.12).

CONCLUSIONS

We show that sex modifies the association between TFA intake and stroke; for every 2-g/d increase in TFA intake, there was a 14% increase in the risk of stroke in men but not in women. Our findings provide further evidence to support the concerted effort to minimize TFAs in the diet.

Serum fatty acids and incidence of ischemic stroke among postmenopausal women

BACKGROUND AND PURPOSE

Although studies have linked types of fatty acids with coronary heart disease, data on individual fatty acids and risk of ischemic stroke are limited. We aimed to examine the associations between serum fatty acid concentrations and incidence of ischemic stroke and its subtypes.

METHODS

We conducted a prospective case-control study nested in the Women's Health Initiative Observational Study cohort of postmenopausal US women aged 50 to 79 years. Between 1993 and 2003, incident cases of ischemic stroke were matched 1:1 to controls on age, race, and length of follow-up (964 matched pairs). Conditional logistic regression was used to estimate odds ratios and 99.9% confidence intervals (CI) for ischemic stroke and its subtypes.

RESULTS

The multivariable-adjusted odds ratios and 99.9% CI of ischemic stroke associated with a 1-SD increment in serum fatty acid concentration were 1.38 (99.9% CI, 1.05-1.83) for linoelaidic acid (18:2tt, SD=0.04%), 1.27 (99.9% CI, 1.06-1.51) for palmitic acid (16:0, SD=2.74%), 1.20 (99.9% CI, 1.01-1.43) for oleic acid (18:1n9, SD=2.32%), 0.72 (99.9% CI, 0.59-0.87) for docosapentaenoic acid (22:5n3, SD=0.18%), 0.72 (99.9% CI, 0.59-0.87) for docosahexaenoic acid (22:6n3, SD=0.91%), and 0.81 (99.9% CI, 0.67-0.98) for arachidonic acid (20:4n6, SD=2.02%). These associations were generally consistent for atherothrombotic and lacunar stroke but not cardioembolic stroke.

CONCLUSIONS

These findings suggest that individual serum trans, saturated, and monounsaturated fatty acids are positively associated with particular ischemic stroke subtypes, whereas individual n3 and n6 polyunsaturated fatty acids are inversely associated.

Trans fat, aspirin, and ischemic stroke in postmenopausal women

OBJECTIVE

To examine the associations between dietary fat intake and ischemic stroke among postmenopausal women.

METHODS

We conducted a prospective cohort study of 87,025 generally healthy postmenopausal women (age, 50-79 years) enrolled in the Women's Health Initiative Observational Study. Repeated and validated dietary assessments were done using a self-administered food frequency questionnaire. We used Cox proportional hazards models to estimate hazard ratios (HRs) of ischemic stroke based on quintiles of the cumulative average of fat intake.

RESULTS

We documented 1,049 incident cases of ischemic stroke over 663,041 person-years of follow-up. Women in the highest quintile of trans fat intake had a significantly higher incidence of ischemic stroke (HR, 1.39; 95% confidence interval [CI], 1.08-1.79; p-trend = 0.048) compared with women in the lowest quintile, while controlling for multiple covariates. The observed association was modified by aspirin use (p-interaction = 0.02). The HR was 1.66 (95% CI, 1.21-2.36; p-trend < 0.01) among baseline non-aspirin users (n = 67,288) and 0.95 (95% CI, 0.60-1.48; p-trend = 0.43) among aspirin users (n = 19,736). No significant associations were found between intakes of saturated, monounsaturated, or polyunsaturated fat and ischemic stroke or any ischemic stroke subtypes.

INTERPRETATION

In this large cohort of postmenopausal women, higher intake of trans fat was associated with incident ischemic stroke independent of major lifestyle/dietary factors. Aspirin use may attenuate the potential adverse effect of trans fat intake on ischemic stroke.

Associations between types of dietary fat and fish intake and risk of stroke in the Caerphilly Prospective Study (CaPS)

BACKGROUND

Few population-based longitudinal studies on diet and stroke have been conducted, and associations between dietary fat and fish intake and risk of stroke are unclear.

OBJECTIVES

To prospectively examine relationships between intakes of total fat, saturated fat, unsaturated fat, white fish and oily fish and risk of stroke in a well-defined population of 2710 middle-aged men.

STUDY DESIGN

Prospective cohort study.

METHODS

Detailed information on health and lifestyle factors was collected via interview, and diet was assessed on three occasions using a food frequency questionnaire. Stroke ascertainment was by self-report and inspection of clinical records. Extracted data were assessed by two independent experts.

RESULTS

During a median follow-up of 18 years, 225 strokes (209 ischaemic and 19 haemorrhagic) were eligible for inclusion in the analyses. For most recent diet (i.e. food frequency questionnaire data collected immediately prior to the stroke event), there was a slightly lower risk of stroke with higher intakes of unsaturated fat and oily fish. Multiple adjusted hazard ratios (HRs) for the lowest vs highest quintiles of unsaturated fat and oily fish intakes were 0.66 [95% confidence interval (CI) 0.41-1.05, P trend = 0.13] and 0.66 (95% CI 0.41-1.05, P trend = 0.09), respectively. Baseline and cumulative diets showed a slightly higher risk of stroke with higher intake of white fish; HRs for the lowest vs highest quintiles were 1.16 (95% CI 0.76-1.77, P trend = 0.22) and 1.28 (95% CI 0.77-2.13, P trend = 0.48), respectively.

CONCLUSIONS

Overall, strong associations were not found between intakes of different types of fat and fish and risk of stroke in middle-aged men. The inverse associations between unsaturated fat and oily fish intakes and risk of stroke were weak, but the direction of association was broadly consistent with other studies; however, these relatively weak associations were not conventionally statistically significant.

Surveying food and beverage liking: a tool for epidemiological studies to connect chemosensation with health outcomes

Genetics, environmental exposures, and aging interact to produce variations in the perception or liking of taste, olfaction, and somatosensory sensations (i.e., chemosensation). Chemosensory variation can affect disease risk by influencing what people like and choose to eat from abundant supplies of desirable high-fat, sweet, and salty foods and alcoholic beverages at the expense of less-available or less-liked vegetables. We contend that assessing dietary preference via liking-disliking surveys holds promise for linking chemosensation with dietary intake and health outcomes in population-based studies. Typical intake measures (e.g., frequency surveys, dietary records) are difficult to complete and interpret. Because of memory issues and dietary restraint, individuals under- or overreport intakes, leading to inaccurate conclusions about diet-disease relationships. Surveying food and beverage liking is a time-efficient, simple task that minimizes the cognitive limitations of intake measures. In the present study, women in a worksite health risk appraisal completed brief food frequency and liking surveys and reported their height and weight, and blood pressure was measured. While liking and intake measures for high-fat and high-fiber foods were correlated, only liking was associated with disease risk. In multiple regression models, women reporting greater liking for high-fat foods and less liking for spicy foods had greater adiposity and/or blood pressure, controlling for age. These data, along with previous laboratory and community-based studies, support that reported liking of high-fat foods explains variability in adiposity and adiposity-related outcomes. Hedonic measures appear to capture habitual intake of foods and beverages, are easy to implement in the field, and thus may increase understanding of how chemosensory variation modifies disease risk.

Midlife serum cholesterol and increased risk of Alzheimer's and vascular dementia three decades later

AIMS

To investigate midlife cholesterol in relation to Alzheimer's disease (AD) and vascular dementia (VaD) in a large multiethnic cohort of women and men.

METHODS

The Kaiser Permanente Northern California Medical Group (healthcare delivery organization) formed the database for this study. The 9,844 participants underwent detailed health evaluations during 1964-1973 at ages 40-45 years; they were still members of the health plan in 1994. AD and VaD were ascertained by medical records between 1 January 1994 and 1 June 2007. Cox proportional hazards models - adjusted for age, education, race/ethnic group, sex, midlife diabetes, hypertension, BMI and late-life stroke - were conducted.

RESULTS

In total, 469 participants had AD and 127 had VaD. With desirable cholesterol levels (<200 mg/dl) as a reference, hazard ratios (HR) and 95% CI for AD were 1.23 (0.97-1.55) and 1.57 (1.23-2.01) for borderline (200-239 mg/dl) and high cholesterol (>or=240 mg/dl), respectively. HR and 95% CI for VaD were 1.50 (1.01-2.23) for borderline and 1.26 (0.82-1.96) for high cholesterol. Further analyses for AD (cholesterol quartiles, 1st quartile reference) indicated that cholesterol levels >220 mg/dl were a significant risk factor: HR were 1.31 (1.01-1.71; 3rd quartile, 221-248 mg/dl) and 1.58 (1.22-2.06; 4th quartile, 249-500 mg/dl).

CONCLUSION

Midlife serum total cholesterol was associated with an increased risk of AD and VaD. Even moderately elevated cholesterol increased dementia risk. Dementia risk factors need to be addressed as early as midlife, before underlying disease(s) or symptoms appear.

Stroke and plasma markers of milk fat intake--a prospective nested case-control study

Background

Dairy products are high in saturated fat and are traditionally a risk factor for vascular diseases. The fatty acids 15:0 and 17:0 of plasma lipids are biomarkers of milk fat intake. The aim of the present study was to evaluate the risk of a first-ever stroke in relation to the plasma milk fat biomarkers.

Methods

A prospective case-control study was nested within two population based health surveys in Northern Sweden. Among 129 stroke cases and 257 matched controls, plasma samples for fatty acid analyses were available in 108 cases and 216 control subjects. Proportions of 15:0 and 17:0 of plasma lipids, weight, height, blood lipids, blood pressures, and lifestyle data were employed in conditional logistic regression modelling.

Results

The proportions of fatty acids 17:0 and 15:0+17:0 of total plasma phospholipids were significantly higher in female controls than cases, but not in men. 17:0 and 15:0+17:0 were significantly and inversely related to stroke in the whole study sample as well as in women. The standardised odds ratio (95% CI) in women to have a stroke was 0.41 (0.24–0.69) for 17:0 in plasma phospholipids. Adjustment for traditional cardiovascular risk factors, physical activity and diet had marginal effects on the odds ratios. A similar, but non-significant, trend was seen in men.

Conclusion

It is hypothesised that dairy or milk fat intake may be inversely related to the risk of a first event of stroke. The intriguing results of this study should be interpreted with caution. Follow up studies with greater power, and where intakes are monitored both by dietary recordings and fatty acid markers are needed.

Lifestyle and Risk of Cardiovascular Disease and Type 2 Diabetes in Women: A Review of the Epidemiologic Evidence

Cardiovascular disease is the leading cause of death among both women and men in the United States, accounting for nearly half of all deaths and considerable morbidity. Type 2 diabetes is a major risk factor for cardiovascular disease and one that is particularly potent in women; its prevalence has increased dramatically in recent years. Epidemiologic data indicate that cardiovascular disease and type 2 diabetes share common risk factors and are largely preventable; indeed, findings from the Nurses' Health Study suggest that 74% of cardiovascular disease cases, 82% of coronary heart disease cases, and 91% of diabetes cases in women could be prevented by not smoking, engaging in regular physical activity, maintaining a healthy weight, eating healthier food, and drinking moderate amounts of alcohol. This article reviews lifestyle risk factors and preventive strategies for cardiovascular disease and type 2 diabetes among women.