Optimal dietary habits for the prevention of stroke

Diet may influence stroke risk via several mechanisms, but the optimal dietary habits for stroke prevention are not well established. We reviewed English-language MEDLINE publications from January 1979 through November 2004 for experimental, observational, and clinical studies of dietary factors (minerals, fats, cholesterol, fish, animal protein, fiber, whole grains, carbohydrate quality, fruits and vegetables, antioxidants, B vitamins, dietary patterns) and risk of stroke or hypertension, the principal modifiable stroke risk factor. A total of 121 publications were selected based on relevance and quality of design and methods. Diets low in sodium and high in potassium lower blood pressure which will likely reduce stroke risk. Consumption of fruits and vegetables, whole grains, folate, and fatty fish are each likely to reduce stroke risk. A prudent or traditional Mediterranean dietary pattern, which incorporates these individual dietary components as well as intake of legumes and olive oil, may also prevent stroke. Evidence is limited or inconsistent regarding optimal levels of dietary magnesium, calcium, antioxidants, total fat, other fat subtypes, cholesterol, carbohydrate quality, or animal protein for stroke prevention. A diet low in sodium, high in potassium, and rich in fruits, vegetables, whole grains, cereal fiber, and fatty fish will likely reduce the incidence of stroke. Further research is needed regarding the possible effects of other major dietary factors on stroke risk.     

Different risk factors for different stroke subtypes: association of blood pressure, cholesterol, and antioxidants

BACKGROUND AND PURPOSE: Blood pressure is an important risk factor for stroke, but the roles of serum total and HDL cholesterol, alpha-tocopherol, and beta-carotene are poorly established. We studied these factors in relation to stroke subtypes. METHODS: Male smokers (n=28 519) aged 50 to 69 years without a history of stroke participated in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, a controlled trial to test the effect of alpha-tocopherol and beta-carotene supplementation on cancer. From 1985 to 1993, a total of 1057 men suffered from primary stroke: 85 had subarachnoid hemorrhage; 112, intracerebral hemorrhage; 807, cerebral infarction; and 53, unspecified stroke. RESULTS: Systolic blood pressure > or = 160 mm Hg increased the risk of all stroke subtypes 2.5 to 4-fold. Serum total cholesterol was inversely associated with the risk of intracerebral hemorrhage, whereas the risk of cerebral infarction was raised at concentrations > or = 7.0 mmol/L. The risks of subarachnoid hemorrhage and cerebral infarction were lowered with serum HDL cholesterol levels > or = 0.85 mmol/L. Pretrial high serum alpha-tocopherol decreased the risk of intracerebral hemorrhage by half and cerebral infarction by one third, whereas high serum beta-carotene doubled the risk of subarachnoid hemorrhage and decreased that of cerebral infarction by one fifth. CONCLUSIONS: The risk factor profiles of stroke subtypes differ, reflecting different etiopathology. Because reducing atherosclerotic diseases, including ischemic stroke, by lowering high serum cholesterol is one of the main targets in public health care, further studies are needed to distinguish subjects with risk of hemorrhagic stroke. The performance of antioxidants needs confirmation from clinical trials.     

Homocysteine-lowering therapy: a role in stroke prevention?

On the basis of the results of several recent clinical trials, many researchers have concluded that vitamin therapy designed to lower total homocysteine concentrations is not effective in reducing the risk of cardiovascular events. However, whereas almost all myocardial infarctions are due to plaque rupture, stroke has many more pathophysiological mechanisms, and thrombosis-which is increased by raised total homocysteine concentrations-has an important role in many of these processes. Thus, stroke and myocardial infarction could respond differently to vitamin therapy. A detailed assessment of the results of the recent HOPE-2 trial and a reanalysis of the VISP trial restricted to patients capable of responding to vitamin therapy suggest that higher doses of vitamin B12 and perhaps new approaches to lowering total homocysteine besides routine vitamin therapy with folate, vitamin B6, and vitamin B12 could reduce the risk of stroke. Thus, therapy to lower homocysteine could still help to prevent stroke, if not other vascular outcomes.     

Serum lipids in schizophrenia and other functional psychoses: a general population northern Finland 1966 birth cohort survey

OBJECTIVE: To compare fasting serum lipid concentrations of subjects with schizophrenia with a comparison group. METHOD: The study sample consists of 5654 members of the northern Finland 1966 birth cohort who participated in the field study with blood samples after overnight fasting and clinical examination in 1997-98. Total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides (TG) and glucose were analyzed. Analysis of variance were used for comparing differences in lipids means between diagnostic categories. RESULTS: Mean fasting TC in subjects with schizophrenia was 20 mg/dl higher than in the comparison group. TC and TG levels in the group of other psychoses resembled the schizophrenia group. CONCLUSION: Blood lipid levels in subjects with schizophrenia and other functional psychoses were high. As these persons are at special risk for hyperlipidemia their lipid levels should be regularly monitored, and cholesterol lowering diet, as well as medication, should be considered.     

An effect of the PAI-1 4G/5G polymorphism on cholesterol levels may explain conflicting associations with myocardial infarction and stroke

BACKGROUND AND PURPOSE:The gene-encoding plasminogen activator inhibitor type 1 (PAI-1) has a common 4G/5G 'functional' polymorphism, and people homozygous for the 4G allele have higher PAI-1 plasma concentrations. The 4G/4G genotype is associated with increased risk of myocardial infarction but paradoxically protects against stroke. We hypothesized that this paradox may be explained via an effect of the PAI-1 polymorphism on plasma lipids. METHODS: We studied 71 consecutive Italian patients referred to our Institute for first stroke or vascular cognitive impairment. PAI-1 gene 4G/5G polymorphism, total plasma cholesterol, plasma triglycerides, sex, age, smoking, oral contraceptive use, statin therapy, hypertension, diabetes, and history of myocardial infarction were examined. RESULTS:The 4G/4G genotype was significantly associated with high cholesterol (p = 0.003) but not with triglycerides (p = 0.39). Adjusted odds ratios were: 5.8 for 4G/4G vs. 4G/5G (95% CI, 3.1-23.0), and 15.9 for 4G/4G vs. 5G/5G (95% CI, 2.4-105.0). CONCLUSIONS: This finding may explain the involvement of the PAI-1 polymorphism in the clustering of atherothrombotic risk factors, and why people with the 4G/4G genotype are at increased risk for myocardial infarction. Stroke is not so clearly related to hypercholesterolemia and other effects of the 4G/4G genotype (perhaps increased PAI-1 expression) may protect against stroke.     

Diet-induced hypercholesterolemia enhances brain A beta accumulation in transgenic mice

Epidemiological data show correlations between hypercholesterolemia and Alzheimer's disease (AD). We test the hypothesis that hypercholesterolemia modulates Abeta deposition in mice overexpressing the human APP695 Swedish mutation (K670N and M671L) (TgAPPsw). Feeding mice a high fat/high cholesterol (HFHC) diet for 7-10 months increased total cholesterol levels by 4-fold. The extent of Abeta immunostained plaque-like deposits were significantly higher for mice fed the HFHC diet as compared with mice fed rodent chow. Extent of deposits correlated inversely with plasma levels of HDL and directly to apolipoprotein E. Overall, plasma lipoproteins may be an important factor in induction of AD-like plaques in mice. The lowering of plasma lipids may be therapeutic for AD patients.     

急性脑卒中与脂代谢紊乱的相关性分析

目的探讨急性脑卒中与血脂代谢紊乱的关系。方法收集2006年7月-2008年7月我科收治的符合入选条件的急性脑卒中患者1026例(出血性卒中442例,缺血性卒中584例),对其空腹血脂进行分析。结果急性脑卒中患者血脂异常发生率较高,且本组显示甘油三酯增高明显。其中脑梗死组总胆固醇、甘油三酯、低密度脂蛋白胆固醇的异常率分别达到29.79%、40.58%和28.25%;而脑出血组为30.54%38.69%和29.41%,与对照组比较均有统计学意义。结论血脂代谢紊乱是脑卒中患者发病的重要危险因素之一。     

Beta-blockers reduce the risk of early death in ischemic stroke

OBJECTIVES: Beta-blockers reduce mortality in patients after myocardial infarction. Experimental studies suggest that beta-blockers have also neuroprotective properties. The aim of this study was to assess if use of beta-blockers is associated with reduced risk of early death in ischemic stroke patients. MATERIALS AND METHODS: Retrospective data analysis of 841 consecutive patients with acute ischemic stroke admitted to the stroke unit within 24 h after stroke onset. RESULTS: 10.6% of patients received beta-blockers during hospitalization. Thirty-day case fatality was significantly lower in patients treated with beta-blockers than in those not treated with beta-blockers (6.8% versus 19.0%, P < 0.01). After adjustment for other prognostic factors, the use of beta-blockers was associated with reduced risk of early death (relative hazard 0.37, 95% confidence interval 0.16-0.84) independently of age, stroke severity, fasting glucose, total cholesterol level and pneumonia. When patients who died of cardiovascular causes were excluded from the analysis, the use of beta-blocker was no longer significantly associated with risk of death (P = 0.12). CONCLUSION: In a retrospective series the use of beta-blockers was associated with reduced risk of early death in patients with ischemic stroke.     

Plasma lipoproteins in cortical versus lacunar infarction

We investigated the relation of plasma lipids to the risk for ischemic stroke by comparing clinical and biochemical characteristics of survivors of cortical (n = 48) and lacunar (n = 36) brain infarction. By analysis of variance, no differences were observed in the concentrations of total cholesterol, triglycerides, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, or apoproteins A1 and B. Patients with lacunar infarction, however, had higher concentrations of high density lipoprotein (HDL)-cholesterol than patients with cortical stroke. This HDL-cholesterol difference was due primarily to a strikingly low HDL-cholesterol content in white patients with cortical stroke. These data suggest that previously demonstrated differences in HDL-cholesterol concentrations between patients with ischemic stroke and control subjects without stroke may apply to patients with cortical but not lacunar infarction. Separation of cerebral infarction into subtypes based on mechanism may help clarify lipid-related risk factors in cerebrovascular disease.     

The absorption and transport of lipids by the small intestine

Dietary lipid provides as much as 40% of the caloric intake in the Western diet. Triacylglycerol is the main dietary fat. The human small intestine is also presented daily with 11-12 g of phospholipid, predominantly phosphatidylcholine. The predominant sterol in the Western diet is cholesterol, which is derived from animal fat. Plant sterols account for up to 20-25% of total dietary sterol. This paper reviews our current understanding of the process and the factors that regulate the absorption and transport of different dietary lipids by the human small intestine.     

Vitamin K-dependent and vitamin K-independent hypocoagulant effects of dietary fish oil in rats.

In rats, dietary fish oil causes a plasma triglyceride-lowering as well as hypocoagulant effect. The latter is apparent from reduced levels of vitamin K-dependent coagulation factors and a decreased thrombin-forming potential of the coagulating plasma. Here, we describe that intervention with low levels of n-3 polyunsaturated fatty acids (n-3 PUFAs, about 2.5% of digestible energy, en%) resulted in no more than a small reduction in coagulation factors, when supplied as part of a high-fat diet relatively rich in vitamin K. Plasma triglycerides also remained unchanged. On the other hand, when feeding rats with low- or high-fat diets restricted in vitamin K, intervention with 3 en% of n-3 PUFAs acids (fish oil) caused only a lowering in triglycerides in combination with high fat. The fish caused a reduction in coagulation potential and levels vitamin K-dependent coagulation factors (prothrombin and factor VII) that was most prominent with the low-fat diet. Fish oil, in combination with low fat but not with high fat, reduced the vitamin K levels in the liver of the animals. In addition, regardless of the fat content, the vitamin K-independent coagulation factor V was decreased in the fish oil groups. Taken together, these results indicate that, in the rat, the hypocoagulant effect of a low dose of n-3 PUFAs is most apparent at low intakes of both vitamin K and fat, is not linked to the triglyceride plasma level, but involves modulation of both vitamin K-dependent and -independent coagulation factors.     

维生素E对脑梗死患者低密度脂蛋白氧化延迟时间的影响

目的 探讨维生素E治疗对脑梗死患者血液中低密度脂蛋白体外氧化延迟时间的影响.方法 选取22例脑梗死患者作为治疗组.给予维生素E(300mg/d)治疗;选取22例年龄、性别、血压、病灶部位及程度与治疗组相当的腩梗死患者作为对照组,小给予维生素E治疗.收集患者发病24 h以内和发病2周时血清,测定血样中低密度脂蛋白体外氧化延迟时间,同时测定血清中维牛素E浓度,低密度脂蛋白中的总胆固醇、三酰甘油、游离胆固醇.结果 治疗组患者2周时血样中低密度脂蛋白体外氧化延迟时间明显长于对照组[(71.84±9.75)min vs(60.95±9.33)min],差异有统计学意义(P<0.05).血清中维牛素E的浓度明显高于对照组[(17.41±5.24)ìmol/L vs(12.90±6.27)ìmol/L],差异有统计学意义(P<0.05),且与卒中症候呈现负相关趋势.治疗组与对照组静脉血中低密度脂蛋白中的总胆固醇、三酰甘油、游离胆固醇差异无统计学意义[分别为(5.08±0.61)vs(4.72±0.61)mmol/L;(0.88±0.06)mmol/Lvs (0.84±0.03)mmol/L;(1.62±0.41)vs(1.65±0.92)mmol/L].结论给予维生素E治疗可以增加急性期脑梗死患者血液中低密度脂蛋白体外氧化延迟时间,增强患者体内的抗氧化能力.     

Long-term prognosis of infratentorial transient ischemic attacks and minor strokes.

BACKGROUND AND PURPOSE: This study was performed to gather information about long-term prognosis after infratentorial transient ischemic attacks and minor strokes and about the factors influencing it. METHODS: We included 226 patients with transient ischemia and 169 patients with a minor stroke of the brain stem/cerebellum consecutively admitted to a neurological department. Medical records and the findings of computed tomography, Doppler ultrasonography, and angiography were evaluated retrospectively. Follow-up information was gathered from the patients and their physicians by questionnaires. Complete follow-up information was available for 381 patients. RESULTS: During a mean follow-up of 3.9 years, 15.7% of the 381 patients suffered a stroke and 6.8% a myocardial infarction; 15% died. Kaplan-Meier estimates revealed a cumulative stroke rate of 5.1% within the first year and a risk of stroke, myocardial infarction, or death of any cause of 9.8%. In a proportional hazards model, the time-dependent risk of stroke was significantly increased by increasing age (p = 0.018), minor stroke (p = 0.0005), hypertension (p = 0.022), previous stroke (p = 0.0006), and carotid artery occlusive disease (p = 0.0065). The probability of stroke, myocardial infarction, or death was influenced by age (p = 0.0001), minor stroke (p = 0.006), diabetes (p = 0.015), previous stroke (p = 0.002), infarct on a computed tomogram (p = 0.041), and carotid artery disease (p = 0.032). CONCLUSIONS: Long-term prognosis after brain stem/cerebellar transient ischemic attacks and minor strokes is significantly influenced by age, diabetes, hypertension, previous stroke, and concomitant carotid artery disease. Patients with transient ischemic attacks have a better prognosis than those with minor stroke.     

Blood Lipids and other Related Risk Factors of stroke

Abstract To assess the ralationship between incidence of stroke and blood lipids, apolipoprolcin (apo) , 219 patients with stroke(cerebral hemorrhage 87, cerebral infarction 132) , diagnosed with the aid of CT, were examined. The levels of serum total cholesterol, triglycerioes, apo-A, apo-B were calculatea. 160 cases with no disorder in metabolism of blood lipids or other disease of meurologic system were taken as centrol group. The results zhowed that the ratio of high density lipoprotein cholesterol and low clensity lipoprotein cholesterol was iower than.that of control group(p＜0. 05) . In the patients group, cases with diabetes, hypentension coronary heart disease or onesity, the levels of blood liprds. triglyceride and cholesterol were higher than those vithout above mentioned disease The condusion is, that there is certain reletionship between the contents of bliid lipids. lipoprotein and it sulqraction HDL2, HDL3 and cerebrovasculor cisease. The radis of high density lipoprotein and low density lipoprolein is the important factor in predicting of stroke     

Long-term effects of high lipid and high energy diet on serum lipid,brain fatty acid composition,and memory and learning ability in mice

Objective

It is well known that high lipid and high energy diet is harmful to health. But the different effects of high lipid diet composed of either saturated fatty acids or unsaturated fatty acids have not been distinguished.

Method

Eighteen pregnant C57BL/6j (22–25 g) mice were randomly divided into three groups of six each and fed with chow or high lipid diet composed of either flaxseed oil (chow diet 84%, cholesterol 0.2%, flaxseed oil 15.8%) or lard fat (chow diet 84%, cholesterol 0.2%, lard fat 15.8%). After weaning, the offspring were fed the same diet as their mothers were fed during the experiment, and their spatial memory and learning ability were evaluated by Morris water maze when they were 8 weeks old. Next, the blood and tissues were sampled when they were 9 weeks old. Serum lipids were determined using kits, and brain fatty acids were measured using a gas chromatograph.

Results

Compared to chow diet (control), high flaxseed oil diet (HFO) increased high density lipoprotein cholesterol level (HDL-C) in the mothers but not in offspring; high lard fat diet (HLF) increased serum total cholesterol level (TC) and low density lipoprotein cholesterol level (LDL-C) both in mothers and offspring. Brain fatty acids profile was altered by HLF compared with chow diet. Polyunsaturated fatty acids and long-chain polyunsaturated fatty acids content were significantly lower in the HLF group than in the control group, but saturated fatty acids content were significantly higher in HLF group than those in control group. The changed fatty acids composition affected the spatial memory and learning ability of adult offspring.

Conclusions

A long-term high lard diet increased offspring serum TC and LDL-C levels and affected the brain's fatty acid composition, and memory and learning ability. The polyunsaturated fatty acid content of the brain may be correlated with serum cholesterol levels.     

Gender differences in blood lipids and the risk of ischemic stroke among the hypertensive adults in rural China

Background: Though large epidemiological studies have not established associations between blood lipids and ischemic stroke, increasing evidences have suggested that lipid-modifying agents may reduce cerebrovascular events. Aims: To determine whether blood lipids are risk factors for ischemic stroke among hypertensive rural adults in China. Settings and Design: A cross-sectional survey was conducted during 2004-2006, which underwent cluster multistage sampling to a hypertensive resident group in the countryside of China. Materials and Methods: A total of 6,412 individuals (2,805 men, 3,607 women) with age >/= 35 years were included. At baseline, lifestyle and other factors were obtained and blood lipids were assessed at a central study laboratory. Ischemic stroke was defined according to the criteria established by the National Survey of Stroke and all cases were further classified into lacunar infarction and other ischemic strokes. Statistical Analysis: Univariable and multivariable logistic regression were used. Results: In the univariable logistic regression model, LDL cholesterol (LDLc) in men and total cholesterol (TC), LDLc and TC-to-HDL cholesterol (TC: HDLc ratio) in women were risk factors for other ischemic strokes, with OR 1.42 (95% CI, 1.16-1.75), 1.31 (95% CI, 1.11-1.55), 1.47 (95% CI, 1.16-1.88) and 1.67 (95% CI, 1.28-2.14), respectively. After adjusting for independent variables, an increase in non-HDL cholesterol (non-HDLc) was associated with a significant increased risk of other ischemic strokes in women, with adjusted OR 1.45 (95% CI, 1.08-1.93). Conclusions: LDLc was the common risk factor for ischemic stroke in men and women, whereas Non-HDLc, TC and TC: HDLc ratio levels were related to ischemic stroke as risk factors only in women.     

Clinical efficacy of the ketogenic diet

The ketogenic diet is an effective alternative therapy used to control intractable seizures. It was originally described in 1921 as a way to duplicate and prolong the beneficial effects that fasting appeared to have on seizure control. It involves consuming a calorie-restricted diet in which the fat:carbohydrate + protein ratio ranges from 2:1 to 5:1. Recent prospective studies in children demonstrate that about 50% of children will continue on the diet for at least a year, with 40-50% of those starting the diet having a >50% reduction in seizures after 12 months. When the diet is discontinued it is usually due to lack of efficacy. The diet is a radical medical therapy and nutritional well-being is a constant concern. Renal stones have occurred in 5-8% of children on the diet; lipids are elevated, but the significance of this is not known. The mechanism of action of the diet remains unknown, and it is difficult to assess which biochemical parameters should be monitored as adjustments are made to the diet.     

Hypertension as an important factor for cerebrovascular atherogenesis in rats.

A new model for studies on atherogenesis in the cerebrovascular system was obtained by using recently established stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP on a hypercholesterolemic diet (20% suet, 5% cholesterol, and 2% cholic acid) had ring-like fat deposits in the circle of Willis, which were detected within a few weeks by new techniques for the macroscopical demonstration of fat deposits "as a whole" and were proved to be good quantitative indices for the initiation of atherogenesis. Experimental studies using more than 200 rats including SHRSP, experimental hypertensive rats (renal infarction hypertension) and WK rats, fed a hypercholesterolemic diet with 1% salt in the drinking water for 1 week, 2 weeks, 10 weeks and more than 10 weeks, revealed that the arterial fat deposition in the brain was affected by BP, serum cholesterol level, strain difference and age. High BP was confirmed to be more important than the other factors by the quantitative analysis of sudanophilic rings in relation to BP.     

Dietary supplementation with vitamin E in hyperlipoproteinemias: effects on plasma lipid peroxides, antioxidant activity, prostacyclin generation and platelet aggregability

In a placebo-controlled trial healthy volunteers and patients with hyperlipoproteinemias types II and IV received orally vitamin E at doses of 300 mg and 600 mg daily for 2 weeks. Serum tocopherol levels increased two-fold, but serum concentrations of total lipids, cholesterol, triglycerides, ceruloplasmin and transferrin remained unchanged. Dietary supplementation with vitamin E suppressed elevated concentrations of plasma lipid peroxides and this effect was correlated with an increase in serum antioxidant activity. In patients a mild platelet suppressant effect of vitamin E (600 mg daily) was observed. Feeding an atherogenic diet to rabbits for a week resulted in elevation of plasma lipid peroxides and a 90% decrease in arterial generation of prostacyclin. Enrichment of the atherogenic diet with 100 mg vitamin E daily prevented the increase in plasma lipid peroxides and protected the prostacyclin generating system in arteries. Thus, in hyperlipoproteinemias vitamin E corrects certain abnormalities of lipid metabolism which might predispose to atherosclerosis.     

Dietary diacylglycerol extenuates arterial thrombosis in apoE and LDLR deficient mice

INTRODUCTION: Prevention of arterial thrombotic diseases has high priority in developed countries. An appropriate diet is thought to be the best way to prevent or reduce the risk of mortality from such diseases. The aim of the present study was to evaluate the effect of diacylglycerol (DAG)-rich diets on arterial thrombosis. MATERIAL AND METHODS: Diet-sensitive congenital apolipoprotein E (ApoE) and LDL receptor (LDLR) double deficient mice were used. Thrombosis was assessed by the rate and extent of thrombus formation in the carotid artery of mice after laser irradiation. Plasma total cholesterol and triglyceride levels were measured by enzymatic assays. Four kinds of diets were used: high fat (Western-style) diet contained 20% fat (w/w) and 0.05% cholesterol (w/w); the TAG-rich and the DAG-rich high fat diet contained 20% TAG or DAG oil (w/w) with very similar fatty acid composition and 0.05% cholesterol ; Low fat (Japanese-style) diet contained 7% fat, without cholesterol. These diets were on the basis of AIN93G and were given to mice for 8 weeks from 6 weeks of age. RESULTS: Western-style high fat and TAG-rich high fat diets significantly increased thrombogenicity compared with low fat diet. DAG-rich high fat diet showed the lowest value, and the extent of thrombogenicity was equivalent to the low fat diet group. Fasting plasma total cholesterol level of DAG-rich high fat and low fat diet groups were significantly lower than that of TAG-rich high fat and high fat diet groups. Fasting plasma triglyceride levels in DAG-rich high fat diet group were significantly lower than in the TAG-rich high fat diet group. CONCLUSIONS: Dietary DAG but not TAG oil extenuates arterial thrombus formation. The mechanism of this effect is unclear and further investigated.