The effects of diet on inflammation: emphasis on the metabolic syndrome

Reducing the incidence of coronary heart disease with diet is possible. The main dietary strategies include adequate omega-3 fatty acids intake, reduction of saturated and trans-fats, and consumption of a diet high in fruits, vegetables, nuts, and whole grains and low in refined grains. Each of these strategies may be associated with lower generation of inflammation. This review examines the epidemiologic and clinical evidence concerning diet and inflammation. Dietary patterns high in refined starches, sugar, and saturated and trans-fatty acids, poor in natural antioxidants and fiber from fruits, vegetables, and whole grains, and poor in omega-3 fatty acids may cause an activation of the innate immune system, most likely by an excessive production of proinflammatory cytokines associated with a reduced production of anti-inflammatory cytokines. The whole diet approach seems particularly promising to reduce the inflammation associated with the metabolic syndrome. The choice of healthy sources of carbohydrate, fat, and protein, associated with regular physical activity and avoidance of smoking, is critical to fighting the war against chronic disease. Western dietary patterns warm up inflammation, while prudent dietary patterns cool it down.     

The Role of Nutrition in Secondary Prevention of Coronary Artery Disease

Secondary prevention strategies are designed to target multiple risk factors through pharmacologic and lifestyle intervention. Therefore, diet therapy plays an important role in secondary prevention of CHD. Epidemiologic studies have identified several dietary patterns that are associated with reduced risk for CHD morbidity and mortality, such as the Mediterranean diet and a “Prudent” diet. These dietary patterns exhibit a number of similarities with current dietary recommendations for primary and secondary prevention; they are nutrient rich (from fruits, vegetables, whole grains, nuts, seeds, and plant oils, reduced-fat and fat-free milk products, seafood, and lean animal and plant proteins) and low in saturated and trans fatty acids, cholesterol, and sodium. There also is strong evidence from secondary prevention studies that long chain omega-3 fatty acids from marine sources are effective for cardiovascular disease risk reduction. In addition, there is some evidence of benefits of dietary patterns including a Mediterranean diet, a very low-fat diet, a diet high in omega-6 polyunsaturated fatty acids as well as a Mediterranean-style diet high in alpha-linolenic acid (all of which are low in saturated fatty acids). It is apparent that there are multiple dietary treatment strategies available to clinicians that enable individualized treatment plans and optimal therapeutic outcomes for patients with coronary disease.     

Nutrition and the endothelium

Growing evidence suggests that dietary factors play an important role in modulating endothelial function. Epidemiologic and clinical studies have related intake of α-linolenic acid and long-chain n-3 fatty acids to lower plasma concentrations of inflammatory cytokines and endothelial adhesion molecules, both of which are considered markers of endothelial dysfunction. In contrast, trans fatty acid intake and a higher dietary glycemic load have been associated with increased plasma concentrations of these biomarkers. Recently, several epidemiologic and intervention studies have examined the relationship between overall dietary patterns and endothelial dysfunction. In general, a "prudent diet," characterized by higher intake of fruits, vegetables, legumes, fish, poultry, and whole grains, is associated with a beneficial effect on the endothelium. Conversely, a "Western diet," characterized by higher intake of red and processed meats, sweets, desserts, French fries, and refined grains, is associated with an impairment of the endothelial function. These findings provide additional biological mechanisms through which dietary factors influence the risk of cardiovascular diseases.     

Dietary Guidelines for Americans 2010: Implications for Cardiovascular Disease

The 2010 Dietary Guidelines for Americans (DGA) provides science-based advice to promote health and reduce risk of major chronic diseases by diet and physical activity. The primary emphasis is on food-based recommendations that meet energy and nutrient needs. The DGA is made in the context of a total diet designed to reduce the incidence and prevalence of overweight and obesity. In addition, the DGA also targets cardiovascular disease (CVD) risk reduction. DGA recommends nutrient-dense foods including fruits and vegetables, whole grains, low-fat dairy, lean protein foods including seafood, and vegetable oils. This dietary pattern beneficially affects blood lipids and other CVD risk factors. Foods and nutrients to limit include solid fats (saturated fatty acids, trans-fatty acids), dietary cholesterol, added sugars, refined grains, and sodium. Healthy dietary patterns that emphasize nutrient-dense foods will significantly benefit public health, in part, by reducing CVD risk.     

Nutritional influences on inflammation and type 2 diabetes risk

There is a clear role for inflammation in the development of type 2 diabetes and its associated co-morbidities. Circulating inflammatory markers such as C-reactive protein, sialic acid, and interleukin- 6 are all significant independent predictors of disease. A number of nutritional components are hypothesized to modulate inflammation, and hence impact on disease risk. The most extensively studied nutrients are the long-chain n-3 polyunsaturated fatty acids. However, evidence is also emerging with respect to whole grain or low glycemic index foods and antioxidant vitamins. Obesity, resulting from long-term dietary energy excess, is also strongly linked to raised inflammatory status and type 2 diabetes. To date, much of the evidence for the effect of nutrients or foods on disease risk has been based on epidemiological associations. However, the links among diet, inflammation, and type 2 diabetes are supported by some data from human dietary intervention trials and/or mechanistic studies in animals. Further research is required to quantify the precise role and refine the evidence base. However, the proposed "anti-inflammatory" strategies to tackle type 2 diabetes are broadly consistent with current public health nutrition guidelines: to achieve and maintain a healthy weight, to reduce saturated fat, to increase the proportion of less refined forms of carbohydrate, and to increase intake of fruits and vegetables.     

Dietary intake and coronary heart disease: A variety of nutrients and phytochemicals are important

Opinion statement Until quite recently, the dietary focus on prevention of coronary heart disease (CHD) has been almost exclusively centered on reducing intake of cholesterol, total fat, and saturated fat. The food industry responded vigorously with low-fat products, some of which are helpful, particularly low-fat dairy products, but others that are less so, due to increases in refined carbohydrate content. Recent research shows that a variety of foods contribute to protection against CHD, including certain types of fatty acids, and a variety of components in fruit and vegetables, whole grains, and nuts. In particular, there is now an emphasis on reducing not only saturated fat, but also trans fat, whereas mono and omega-3 fatty acids have been shown to be protective. Many new studies have shown a link between intake of fruit and vegetables and whole grains and protection against CHD. This has been ascribed to their fiber, vitamin, mineral, and phytochemical content. In particular, there is accumulating evidence of protective effects for folate, vitamin B₆, vitamin B₁₂, vitamin E, vitamin C, flavonoids, and phytoestrogens. New recommendations to prevent heart disease require a greater focus on total dietary pattern with a return to the use of a variety of minimally processed foods.     

The role of dietary factors in inflammatory bowel diseases: New perspectives

The current review aimed to elucidate the role of diet in every stage of inflammatory bowel diseases, from aspects of prevention, treatment and rehabilitation. Western diet, characterized by overconsumption of refined sugar and saturated fat and low consumption of dietary fiber, may partly be blamed for its pathogenesis. Some immune‐modulated nutrients (fibers, monounsaturated fatty acids, n‐3 polyunsaturated fatty acids and vitamin D) exert their potential beneficial effects on gut microbiota and immune function, resulting in clinical remission and/or preventing relapse. However, data is limited to conclude optimal micronutrient levels and therapeutic implications. Further, diet itself is complex; therefore, it is reasonable to evaluate diet as a whole rather than a single type of food. Some specific dietary patterns are generated for the management of inflammatory bowel diseases with controversial results. Only exclusive enteral nutrition has been widely recommended for pediatric patients with non‐stricturing active Crohn's disease. Self‐monitoring, avoidance of certain types of foods, limited intake of alcohol and smoking, supplementation of minerals and vitamins if deficiency is confirmed, and adherence to the diet enriched in vegetables and fruits and low in animal food and un‐digested fiber during flares are the most common dietary recommendation. Further clinical trials with a high evidence rank are warranted.     

Nutrition therapy for dyslipidemia

National guidelines indicate patients with elevated low-density lipoprotein cholesterol should consume less than 7% of calories from saturated fat and less than 200 mg of cholesterol. Trans fatty acids should also be limited. Incorporation of functional foods, such as stanol-containing margarine, soy products, and soluble fiber-rich cereals and vegetables can provide further benefit. In addition to weight loss and physical activity, individuals with hypertriglyceridemia benefit from a diet moderate in fat and carbohydrate rather than a low-fat diet. Including monounsaturated or omega-3 fatty acids lowers serum triglycerides. Many of the dietary strategies to optimize serum lipids also contribute to glycemic control in patients with diabetes mellitus.     

膳食营养与慢性肾脏病

膳食结构是影响慢性非传染性疾病的重要危险因素之一。慢性肾脏病(CKD)是心血管疾病、住院及死亡事件的独立危险因素,发病率进行性增加。不同的膳食营养成分摄入及膳食模式对CKD产生不同程度的影响。多数研究表明,摄食较多的盐、动物性蛋白质、高能量但营养价值低的碳水化合物、饱和脂肪酸、含糖饮料等与CKD发生及进展风险增加相关,而植物性蛋白质、含较多谷物纤维的碳水化合物、多不饱和脂肪酸、膳食纤维、水果和蔬菜等与CKD发生及进展风险降低相关。此外,坚持得舒食、地中海饮食或素食与CKD发生及进展风险降低相关,而西方饮食和中国传统南方饮食模式与CKD发生及进展风险增加相关。因此,如何更好的选择膳食营养成分摄入及膳食模式,促进肾脏健康、预防CKD的发生及发展,有待进一步提高认识。     

Nutrition

The favorable effect of a healthy diet on the initial development and the further progression of atherosclerosis has been demonstrated. The effect is significant even in patients with adequate pharmacological treatment. Nutrition should be calorie-adjusted high in fiber, low in total fat and in saturated fats (<10% of calories) and cholesterol (<300 mg/day). Mono-unsaturated fatty acids and omega-3 fatty acids have beneficial effects. Therefore fatty fish more than once a week, nuts, fruits and vegetables (>400 g/day) have a prognostically favorable effect, whereas the supplemental use of antioxidative vitamins is of no proven benefit. These recommendations result from the experience gained over generations in millions of people in different countries (Mediterranean and Asian) with a low rate of coronary events and a high life expectancy. These dietary habits are associated with a low rate of neoplasm and of osteoporosis. The recommendation for this type of diet is a class-I recommendation.     

Physical activity and metabolic syndrome severity among older adults at cardiovascular risk: 1-Year trends

Background and aimsModifiable lifestyle factors, such as physical activity (PA) and Mediterranean diet (MD), decrease metabolic syndrome (MetS). The aim was to assess 1-year changes of leisure-time physical activity (LTPA), sedentary behavior, and diet quality according to MetS severity in older population at high cardiovascular risk.Methods and resultsProspective analysis of 55–75-year-old 4359 overweight/obese participants with MetS (PREDIMED-Plus trial) categorized in tertiles according to 1-year changes of a validated MetS severity score (MetSSS). Anthropometrics, visceral adiposity index, triglycerides and glucose index, dietary nutrient intake, biochemical marker levels, dietary inflammatory index, and depression symptoms were measured. Diet quality was assessed by 17-item MD questionnaire. PAs were self-reported using the Minnesota-REGICOR Short Physical Activity Questionnaire and 30-s chair stand test. Sedentary behaviors were measured using the Spanish version of the Nurses’ Health Study questionnaire. After 1-year follow-up, decreasing MetSSS was associated with an anti-inflammatory dietary pattern, high intake of vegetables, fruits, legumes, nuts, whole grain cereals, white fish, and bluefish and low intake of refined cereals, red and processed meat, cookies/sweets, and snacks/ready-to-eat-meals. It resulted in high intake of polyunsaturated fatty acids, omega-3 fatty acids, protein, fiber, vitamins B1, B6, B9, C, D, potassium, magnesium, and phosphorus and low glycemic index and saturated fatty acid, trans fatty acid, and carbohydrates intake. Regarding PA and sedentary behavior, decreasing MetSSS was associated with increased moderate-to-vigorous LTPA, chair stand test, and decreased sedentary and TV-viewing time.ConclusionDecreasing MetSSS was associated with an anti-inflammatory dietary pattern, high LTPA, high MD adherence, low sedentary time, and low depression risk.     

Diet and coronary heart disease in diabetes

Persons with diabetes mellitus have an increased cardiovascular morbidity and mortality and therefore it is imperative to identify and treat aggressively all cardiovascular risk factors. The first line of intervention aiming to reduce the cardiovascular burden is dietary therapy along with other recommendations for lifestyle modification. Compliance with life-long dietary changes is a major issue and therefore emphasis should be placed on whole foods and dietary consumption habits. Also, dietary changes should be individualised according to patient's nutritional needs, lifestyle, cultural eating habits, taking into consideration all risk factors and existing comorbidities. Nevertheless, at least two main strategies have been proven to be effective in preventing coronary heart disease: 1). modification of fat quality through substitution of saturated fat, dietary cholesterol and trans- fatty acids with non-hydrogenated mono-and poly-unsaturated fats and increased consumption of omega-3 fatty acids; 2). modification of carbohydrate quality by choosing high-cereal fiber and low-glycaemic load intakes instead of refined grain products. Although the best diet for reducing cardiovascular risk remains uncertain, a combination of dietary interventions offers great benefits in preventing coronary events.     

Diabetogenic impact of long-chain omega-3 fatty acids on pancreatic beta-cell function and the regulation of endogenous glucose production

In healthy individuals, peripheral insulin resistance evoked by dietary saturated lipid can be accompanied by increased insulin secretion such that glucose tolerance is maintained. Substitution of long-chain omega-3 fatty acids for a small percentage of dietary saturated fat prevents insulin resistance in response to high-saturated fat feeding. We substituted a small amount (7%) of dietary lipid with long-chain omega-3 fatty acids during 4 wk of high-saturated fat feeding to investigate the relationship between amelioration of insulin resistance and glucose-stimulated insulin secretion (GSIS). We demonstrate that, despite dietary delivery of saturated fat throughout, this manipulation prevents high-saturated fat feeding-induced insulin resistance with respect to peripheral glucose disposal and reverses insulin hypersecretion in response to glucose in vivo. Effects of long-chain omega-3 fatty acid enrichment to lower GSIS were also observed in perifused islets suggesting a direct effect on islet function. However, long-chain omega-3 fatty acid enrichment led to hepatic insulin resistance with respect to suppression of glucose output and impaired glucose tolerance in vivo. Our data demonstrate that the insulin response to glucose is suppressed to a greater extent than whole-body insulin sensitivity is enhanced by enrichment of a high-saturated fat diet with long-chain omega-3 fatty acids. Additionally, reduced GSIS despite glucose intolerance suggests that either long-chain omega-3 fatty acids directly impair the beta-cell response to saturated fat such that insulin secretion cannot be augmented to normalize glucose tolerance or beta-cell compensatory hypersecretion represents a response to insulin resistance at the level of peripheral glucose disposal but not endogenous glucose production.     

Dietary patterns and the risk of coronary heart disease in women

BACKGROUND: Although substantial information on individual nutrients or foods and risk of coronary heart disease (CHD) is available, little is known about the role of overall eating pattern. METHODS: Using dietary information from a food frequency questionnaire in 1984 from the Nurses' Health Study, we conducted factor analysis and identified 2 major dietary patterns-"prudent" and "Western"-and calculated factor scores of each pattern for individuals in the cohort. We used logistic regression to examine prospectively the associations between dietary patterns and CHD risk among 69 017 women aged 38 to 63 years in 1984 without history of major chronic diseases. RESULTS: The prudent pattern was characterized by higher intakes of fruits, vegetables, legumes, fish, poultry, and whole grains, while the Western pattern was characterized by higher intakes of red and processed meats, sweets and desserts, french fries, and refined grains. Between 1984 and 1996, we documented 821 CHD cases. After adjusting for coronary risk factors, the prudent diet score was associated with a relative risk (RR) of 0.76 (95% confidence interval (CI), 0.60-0.98; P for trend test,.03) comparing the highest with lowest quintile. Extreme quintile comparison yielded an RR of 1.46 (95% CI, 1.07-1.99; P for trend test,.02) for the Western pattern. Those who were jointly in the highest prudent diet quintile and lowest Western diet quintile had an RR of 0.64 (95% CI, 0.44-0.92) compared with those with the opposite pattern profile. CONCLUSION: A diet high in fruits, vegetables, whole grains, legumes, poultry, and fish and low in refined grains, potatoes, and red and processed meats may lower risk of CHD.     

Effects of dietary fats versus carbohydrates on coronary heart disease: A review of the evidence

Recommendations arising from the traditional diet-coronary heart disease (CHD) paradigm, which focuses on effects of total and saturated fat on serum total and low-density lipoprotein cholesterol, may have failed to reduce CHD risk and inadvertently exacerbated dyslipidemia, insulin resistance, and weight gain, particularly among individuals who are older, female, sedentary, or obese. A suitable dietary paradigm must consider types and qualities of fats and carbohydrates consumed, their effects on a range of intermediary risk factors, and characteristics that may modify individual susceptibility. Based on current evidence, replacement of total, unsaturated, and even possibly saturated fats with refined, high-glycemic index carbohydrates is unlikely to reduce CHD risk and may increase risk in persons predisposed to insulin resistance. In contrast, a diet that is 1) rich in whole grains and other minimally processed carbohydrates; 2) includes moderate amounts of fats (approximately 30%–40% of total energy), particularly unsaturated fats and omega-3 polyunsaturated fats from seafood and plant sources; 3) is lower in refined grains and carbohydrates; and 4) eliminates packaged foods, baked goods, and fast foods containing trans fatty acids, will likely reduce the risk of CHD.     

Japanese dietary lifestyle and cardiovascular disease

To demonstrate the reasons for low morbidity and mortality from coronary artery disease (CAD) and reconfirm the effectiveness of the Japanese dietary lifestyle for preventing CAD, we herein review the CAD risk transition, and post-war changes in Japanese food and nutrient intake. Large-scale cohort studies in Japan were selectively reviewed. Low serum total cholesterol contributed to preventing CAD, and decreased blood pressure was the major factor favoring stroke reduction. Japanese consumed more plant and marine origin foods, but fewer animal foods with saturated fatty acids (SFA) during the 1960-70s than in recent decades. Adequate control of total energy with restriction of saturated fatty acids from animal foods, increased intake of n-3 polyunsaturated fatty acids, including fish, soybean products, fruits and vegetables together with low salt intake are responsible for promoting CAD and stroke prevention. A diet with adequate total calories and increased intake of fish and plant foods, but decreased intake of refined carbohydrates and animal fat, a so-called Japan diet, appears to be quite effective for prevention of CAD risk factors and is recommended as dietary therapy for preventing CAD.     

The changing roles of dietary carbohydrates: from simple to complex

The dietary recommendations made for carbohydrate intake by many organizations/agencies have changed over time. Early recommendations were based on the need to ensure dietary sufficiency and focused on meeting micronutrient intake requirements. Because carbohydrate-containing foods are a rich source of micronutrients, starches, grains, fruits, and vegetables became the foundation of dietary guidance, including the base of the US Department of Agriculture's Food Guide Pyramid. Dietary sufficiency recommendations were followed by recommendations to reduce cholesterol levels and the risk for cardiovascular disease; reduction in total fat (and hence saturated fat) predominated. Beginning in the 1970s, carbohydrates were recommended as the preferred substitute for fat by the American Heart Association and others to achieve the recommended successive reductions in total fat and low-density lipoprotein cholesterol (LDL-C). Additional research on fats and fatty acids found that monounsaturated fatty acids could serve as an alternative substitution for saturated fats, providing equivalent lowering of LDL-C without concomitant reductions in high-density lipoprotein cholesterol and increases in triglycerides witnessed when carbohydrates replace saturated fat. This research led to a sharper focus in the guidelines in the 1990s toward restricting saturated fat and liberalizing a range of intake of total fat. Higher-fat diets, still low in saturated fatty acids, became alternative strategies to lower-fat diets. As the population has become increasingly overweight and obese, the emergence of the metabolic syndrome and its associated disruptions in glucose and lipid metabolism has led to reconsiderations of the role of carbohydrate-containing foods in the American diet. Consequently, a review of the evidence for and against high-carbohydrate diets is important to put this controversy into perspective. The current dietary recommendations for carbohydrate intake are supported by the evidence.     

Ern?hrung bei rheumatischen Erkrankungen

The goals of dietary therapy in rheumatic diseases are alleviation of under- and malnutrition, inhibition of inflammation, prophylaxis of osteoporosis, as well as recognition and treatment of nutrient sensitivities or intolerances. Inflammation inhibition in these patients is improved by manipulating the omega-3/omega-6 fatty acids ratio in the diet. Reduction of dietary arachidonic acid is recommended. This polyunsaturated fatty acid is the main precursor of pro-inflammatory mediators which interact with chemokines und cytokines. Simultaneously, intake of anti-inflammatory omega-3 fatty acids is increased. Studies have shown that this dietary regimen results in an amelioration of symptoms in patients with inflammatory rheumatic diseases. Dietary therapy in rheumatic diseases is often complicated by concomitant diseases and physical handicaps necessitating interdisciplinary patient care, consisting of rheumatologists, nutritionists, physiotherapists and ergotherapists. Dietary therapy of rheumatic diseases is an adjuvant therapy that should be initiated after a patient is properly diagnosed.     

Prevention of strokes

Stroke is a major cause of morbidity and mortality. Risk factors for stroke have been determined through prospective epidemiologic study. Control of risk factors has been demonstrated to reduce stroke incidence, either through controlled trials or inferred from observational studies. In the past few years, new approaches to the treatment of established risk factors have been discovered. These include aggressive control of hypertension in diabetes patients, prevention of type 2 diabetes through lifestyle modification, carotid endarterectomy for moderate symptomatic carotid stenosis, encouragement of a high level of physical activity, and control of abdominal obesity and elevated body mass index. In addition, new strategies for stroke prevention have been identified, including encouragement of a diet high in fruits, vegetables, whole grains, and omega-3 fatty acids, the use of vitamins B12, B6, and folic acid in hyperhomocysteinemia, and moderate alcohol consumption. Clinical trial data support the use of hydroxymethyl-coenzyme A inhibitors in patients with coronary artery disease, and ramipril in high-risk patients with coronary artery disease and diabetes, for the primary prevention of stroke. New risk factors for stroke are being investigated, including the role of chronic inflammation and infection, and these may provide future strategies for stroke prevention.     

Diet and the metabolic syndrome

Lifestyle and diet play important roles in the development of cardiovascular disease (CVD), which is the leading cause of death in Western countries. Metabolic syndrome, which is characterized by a group of metabolic risk factors, is associated with the subsequent development of type 2 diabetes and CVD. Epidemiological studies have documented that nutritional factors may affect the prevalence of the metabolic syndrome. Beyond weight control and reduction of total calories, the diet should be low in saturated fats, trans fats, cholesterol, sodium, and simple sugars. In addition, there should be ample intake of fruits, vegetables, whole grains, and monounsaturated fat; fish intake should be encouraged. These features are very reminiscent of the nutritional principles currently used to define the Mediterranean-style diet. This diet's high fiber content, n-3 fatty acids, and antioxidants, as well as phytochemicals from olive oil, legumes, whole grains, fruits, and vegetables, might be responsible for its beneficial effect on the health of metabolic syndrome patients. This may occur through the reduction of systemic vascular inflammation and endothelium dysfunction without having a drastic effect on body weight. The choice of healthy sources of carbohydrates, fat, and proteins, associated with regular physical activity and avoidance of smoking, is critical to fighting the war against chronic disease.