Position paper on vegetarian diets from the working group of the Italian Society of Human Nutrition. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Department of Health and Human Services. They can be divided into: The status of the U-shaped curve. The Cochrane Library source: There was a 3.
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Most Cited Articles The most cited articles published since , extracted from Scopus. The Plum Print next to each article shows the relative activity in each of these categories of metrics: Captures, Mentions, Social Media and Citations. The association between vegetable intake and CHD risk was heterogeneous and more marked for CV mortality 0. There are no interventional studies that specifically evaluated the influence of vegetables and fruits on CHD risk.
In interventional studies where vegetable and fruit consumption was part of the nutritional recommendations, CHD risk reduction was documented [ 10 , 11 ]. Vegetable and fruit consumption was associated with lower blood pressure [ 13 , 14 , 15 , 18 ], but the association with other CHD risk factors is not clear. Despite the lack of intervention studies, the American Heart Association AHA recommends intake of at least 8 vegetables and fruits a day [ 3 ].
The mechanism of action is not known, but it is assumed that the healthy effect of vegetables and fruits can be attributed to the dietary fiber and antioxidants in these food items [ 30 ]. Vegetables and fruits also act as a low-calorie, low-sodium, and satiating food. Nuts tree nuts and peanuts are nutrient-dense foods with complex matrices rich in unsaturated fatty acids and other bioactive compounds: By definition, tree nuts are dry fruits with one seed in which the ovary wall becomes hard at maturity.
This group includes almonds, hazelnuts, walnuts, pistachios, pine nuts, cashews, pecans, macadamias, and Brazil nuts. The consumer definition also includes peanuts, which botanically are groundnuts or legumes but are widely identified as part of the nuts food group. In addition, peanuts have a nutrient profile similar to that of tree nuts. Although chestnuts are tree nuts as well, they are different from all other common nuts because of being starchier and having a different nutrient profile [ 32 , 33 , 34 ].
Epidemiological data show a consistent negative association between nuts consumption and CHD risk [ 34 ].
Some of the studies found a dose-response pattern of association. A pooled analysis was done using data from 25 intervention nut consumption trials including walnuts, almonds, macadamias, pecans, peanuts, and pistachios conducted in seven countries among men and women with normolipidemia and hypercholesterolemia who were not taking lipid-lowering medications.
With a mean daily consumption of 67 g of nuts, LDL-C concentration was reduced by a mean of Mean TG levels were reduced by The effects of nut consumption were dose related. Different types of nuts had similar effects on blood lipid levels. However, there are no trials relating consumption to CVD endpoints. Some nuts such as walnuts also contain alpha-linolenic fatty acid. Other macronutrients include plant protein and fiber; micronutrients including potassium, calcium, magnesium, and tocopherols; and phytochemicals such as phytosterols, phenolic compounds, resveratrol, and arginine [ 35 ].
Those nutrients may have a beneficial effect on blood lipids as well as other CHD risk factors such as oxidation and inflammation. It is also possible that the substitution of high SFA, sodium, and sugar food by nuts and almonds can also explain this positive effect.
The soybean is a legume that contains no cholesterol and is low in saturated fat, and is the only vegetable food that contains all eight essential amino acids. Soybeans are also a good source of fiber, iron, calcium, zinc, and B vitamins [ 37 ]. Soy beans are the best known and most widely consumed food that contains phytoestrogen isoflavones , which are plant components that interact with mammalian endocrine systems [ 38 ].
In 22 randomized trials, isolated soy protein with isoflavones was compared with casein or milk protein, wheat protein, or mixed animal proteins. In a meta-analysis soy protein isolate, but not other soy products or components, significantly reduced diastolic blood pressure 9 studies, mean reduction 1. Although the improvement in lipoproteins and blood pressure induced by soy protein is of small and questionable clinical significance, consumption of soy protein-rich foods may indirectly reduce CVD risk if it replaces animal products that contain saturated fat and cholesterol [ 3 ].
In October , the FDA approved labeling for foods containing soy protein as protective against coronary heart disease. The FDA based this decision on clinical studies showing that at least 25 g of soy protein per day lowered total and LDL cholesterol. The FDA requires for the claim that a serving contain at least 6. The hormonal effects of dietary soy and soy extracts were extensively evaluated. A meta-analysis of studies revealed inconsistent effects on climacteric symptoms [ 40 ].
Another meta-analysis of prospective studies suggested that soy isoflavone intake is associated with a significant reduced risk of breast cancer incidence in Asian populations, but not in Western populations [ 42 ], although there was no dose-response relationship between total isoflavone intake and risk of breast cancer incidence.
Dairy products are rich in minerals calcium, potassium, and magnesium , protein casein and whey , and vitamins riboflavin and vitamin B that can exert beneficial effects on CVD. On the other hand, the presence of saturated fat in dairy products causes concern over potential adverse CV effects [ 43 ]. There is conflicting evidence on the association between dairy intake and CVD. The number of cohort studies that give evidence on individual dairy food items is very small.
However, a meta-analysis suggests a reduced risk in the subjects with the highest dairy consumption relative to those with the lowest intake: Milk intake was not associated with risk of CHD, stroke, or total mortality. When stratified into high-fat and low-fat dairy products no significant associations were found with CHD [ 45 ].
Suggested mechanisms for the blood-pressure lowering effects of dairy products include the high content of potassium, magnesium, and calcium. In the DASH diet, the combination diet rich in fruits, vegetables, and 2. An association between calcium intake and lower body weight and fat mass has been described [ 46 ]. There is some evidence that certain fermented products especially by Lactobacillus helveticus have a mildly decreasing effect on HTN, probably because of bioactive peptides [ 47 ].
The lack of effect of the high saturated fat content on LDL-C levels is attributed to the unique fatty acid composition of dairy products, consisting mostly of short-chain fatty acids and stearic acid.
Despite the contribution of dairy products to the saturated fatty acid composition of the diet, and given the diversity of dairy foods of widely differing fat composition, there is no clear evidence that dairy food consumption is consistently associated with a higher risk of CVD [ 48 ] and some evidence that low-fat products may have beneficial effects on blood pressure. The general health recommendation is to prefer low-fat products in order to reduce SFA intake.
The consumption of alcohol ethanol is widely accepted in many social situations. Most data on the association between alcohol and CVD come from short-term interventional studies on the effects of alcohol on risk factors as well as long-term observational mortality studies.
Based on cohort studies, the evidence suggests a J- or U-shaped relationship between alcohol consumption and risk of CHD [ 50 ]. In a meta-analysis of 84 prospective cohort studies, the pooled adjusted RR for moderate alcohol drinkers relative to non-drinkers was 0. Moderate intake of alcoholic beverages 1 to 2 drinks per day is associated with a reduced risk of CHD in healthy populations [ 52 ]. The findings do not implicate an advantage of one type of drink over another [ 53 ].
Among CVD patients, binge drinkers, defined as those who consumed 3 or more drinks within 1 to 2 h, had double the total and CV mortality risk of regular drinkers [ 54 ].
Episodic heavy alcohol drinking, but not moderate drinking, is reportedly associated with risk of atrial fibrillation [ 55 ]. Excessive consumption is associated with a higher risk for alcohol abuse, hypertension, overweight, various malignancies, automobile accidents, trauma, and suicide [ 57 ].
Numerous mechanisms have been proposed to explain the benefit of light-to-moderate alcohol intake on the heart, including an increase in HDL-C, reduction in plasma viscosity and fibrinogen concentration, increase in fibrinolysis, decrease in platelet aggregation, improvement in endothelial function, reduction in inflammation, and promotion of antioxidant effects [ 58 , 59 ]. However, despite the biological plausibility and observational data in this regard, these are still insufficient to prove causality.
Daily intake of more than moderate amounts of alcoholic beverages can also be a risk factor for the development of HTN, increased plasma TG levels, can serve as a source of excess calories, as well as increased risk for breast and other cancers [ 60 ].
Patients who are hypertensive have high TG levels and women at high risk of breast cancer should avoid alcoholic beverages [ 58 ]. Despite the evidence from cohort studies on the inverse association between moderate alcohol drinking and CVD, current guidelines do not recommend to begin consuming alcohol for preventing CVD. Individuals who regularly consume alcohol and who do not have a family history of cancer should do so in moderation—the equivalent of no more than one drink in women or two drinks in men per day Table 5.
Alcohol should be avoided in pregnant women [ 54 ]. People who intend to drive should avoid drinking alcohol. Energy content and ethanol in alcoholic beverages [ 61 ]. Coffee is one of the most widely consumed beverages in the world. Caffeine 1,3,7-trimethylxanthine is by far the best characterized compound in coffee.
Coffee also contains chlorogenic acid, flavonoids, melanoidins, and various lipid-soluble compounds such as furans, pyrroles, anmaltol. Many of these compounds are efficiently absorbed, have relatively high bioavailability, and have been shown to have antioxidant properties.
There is a possible bias in comparing caffeinated and decaffeinated coffee. However, most epidemiologic studies do not distinguish former users of caffeinated coffee who may have switched to decaffeinated coffee because of a health problem, and never-users who may be avoiding caffeine as part of a healthy lifestyle [ 63 ].
Energy content and ethanol in alcoholic beverages are summarized in Table 6. Based on date from: Israeli Health Ministry position paper and from [ 61 ]. Coffee consumption has long been suspected of being a contributing factor in the development of CVD, based mainly on case-control studies [ 63 , 64 ]. However, in the last few years there are accumulated data suggesting no harm [ 65 , 66 , 67 ], and even a protective association between moderate coffee drinking and CHD morbidity and CVD mortality [ 68 , 69 ].
Lately, the risk for developing type 2 diabetes was found to be lower in individuals who consumed four or more cups of coffee per day compared with those who drank less than two cups per day [ 70 ].
Several mechanisms have been proposed to explain the harmful as well as protective effects that certain components of coffee may have on the development of CHD. These include the effects of coffee on blood pressure, serum cholesterol and homocysteine levels, oxidation, and inflammation [ 65 ].
Although regular consumption of moderate quantities of coffee seems to be associated with a small protection against CAD, results from randomized clinical trials about its beneficial effects are lacking. However, some groups, including people with HTN, children, adolescents, and the elderly, may be more vulnerable to the adverse effects of caffeine. Fatal or life-threatening caffeine overdoses generally involve the ingestion of caffeine-containing medications.
Symptoms of caffeine overdose may include agitation, delirium, seizures, dyspnea, cardiac arrhythmia, myoclonus, nausea, vomiting, hyperglycemia, and hypokalemia [ 72 ].
Tea has been one of the most popular beverages for years. Brewed from the plant Camellia sinensis , tea is consumed in different parts of the world as green, black, or Oolong tea. Green and black teas are processed differently during manufacturing. To produce green tea, freshly harvested leaves are steamed, yielding a dry, stable product. Most of the beneficial effects of tea are attributed to its polyphenolic flavonoids, known as catechins.
The major flavonoid is epigallocatechingallate EGCG. A population-based prospective cohort study the Ohsaki Study included 40, persons in Miyagi prefecture in northern Japan [ 74 ]. Within CVD mortality, the stronger inverse association was observed for stroke mortality. A meta-analysis of 18 studies included 13 studies on black tea and 5 studies on green tea. For black tea, no significant association was seen with the risk for developing CAD.
No randomized controlled trial studied the effects of tea consumption on CVD morbidity or mortality; however, many studies evaluated the effects of tea on CV risk factors. More than half of the randomized controlled trials have demonstrated the beneficial effects of green tea on CVD risk profiles. These results suggest a plausible mechanism for the beneficial effects of green tea [ 75 ].
In a meta-analysis of trials, black tea consumption increased systolic 5. Other suggested mediators for the association between tea consumption and reduced CVD risks include anti-inflammatory, anti-oxidant, and anti-proliferative effects, as well as favorable effects on endothelial function [ 77 ].
There do not appear to be any significant side-effects or toxicity associated with green tea consumption. In general, the stimulatory effect from green tea is considerably less than that from coffee [ 78 ]. However, tea extract may cause gastrointestinal irritation. Although there are a few case reports of liver toxicity resulting from the ingestion of large quantities of green tea or green tea extract, the incidence of this potential adverse effect appears extremely low. Since green tea may interfere with the absorption of iron supplements, iron supplements should not be ingested together with green tea components.
Possible interactions between green tea and other medications have also been reported [ 79 ]. Cocoa is rich in polyphenols, similar to those found in green tea.
Chocolate and cocoa are two different things. Fat and sugar are major components of chocolate, which has high caloric content that needs to be taken into account when assessing possible risks and benefits of recommending chocolate consumption for health purposes.
However, the major fatty acids in chocolate are oleic, palmitic, and stearic acids; oleic and stearic acids may have a neutral effect on blood lipid levels [ 81 ]. Chocolate, especially of the milk variety, contains large amounts of sugar and has possible implications for dental health and diabetes if eaten in large quantities, although carbohydrates might play a role in improving uptake of polyphenols.
Cocoa itself is much easier to recommend on a health basis as it is not high in sugar and fat. A recent meta-analysis of seven observational studies reported a beneficial association between higher levels of chocolate consumption and the risk of CVD. However, most of the studies did not adjust for socioeconomic factors, which may confound this association. Most of the existing evidence is on intermediate factors of CVD. Recent studies both experimental and observational have suggested that chocolate consumption has a positive influence on human health, with antioxidant, antihypertensive, anti-inflammatory, anti-atherogenic, and anti-thrombotic effects as well as influence on insulin sensitivity, vascular endothelial function, and activation of nitric oxide [ 82 ].
Dietary flavanols have also been shown to improve endothelial function and to lower blood pressure by causing vasodilation in the peripheral vasculature and in the brain [ 83 ]. Despite this array of benefits, there is a lack of well-designed clinical studies demonstrating a CV benefit of chocolate. The high caloric content of chocolate, particularly of some less pure forms, should be considered before recommending uncontrolled consumption [ 84 ].
The bulk of the dry weight of garlic Allium sativum contains mainly fructose-containing carbohydrates, followed by sulfur compounds, protein, fiber, and free amino acids.
It also contains high levels of saponins, a variety of minerals and vitamins A and C, and a high phenolic content. Garlic has been attributed with favorable CV effects due to its high content of thiosulfinates, including allicin, which is considered to be the active component of garlic.
Allicin is formed when alliin, a sulfur-containing amino acid, comes into contact with the enzyme alliinase when raw garlic is chopped, crushed, or chewed.
Over the years, different garlic preparations have been investigated for their prevention and treatment of CV disease, including raw garlic, garlic powder tablets, oil of steam-distilled garlic, oil of oil-macerated garlic, ether-extracted oil of garlic, and aged garlic extract. All these preparations differ in their composition, which complicates comparison of studies [ 85 ]. Dried garlic preparations containing alliin and alliinase must be enteric coated to be effective because stomach acid inhibits alliinase.
Because alliinase also is deactivated by heat, cooked garlic is less powerful medicinally [ 86 ]. Long-term observation studies are missing. Intervention trials focused on CVD risk factors.
However, in a later meta-analysis of 13 trials there was no significant difference in effects on all outcome measures examined when compared with placebo [ 88 ]. A review of trials assessing the effect of garlic on thrombotic risk showed modest but significant decreases in platelet aggregation with garlic compared with placebo [ 89 ]. The antihypertensive effects of garlic have been studied but remain controversial [ 88 ].
Proven adverse effects include malodorous breath and body odor. Other unproven effects included flatulence, esophageal and abdominal pain, allergic reactions, and bleeding [ 86 ]. The effective dose of garlic has not been determined.
Dosages generally recommended in the literature for adults are 4 g one to two cloves of raw garlic per day, one mg dried garlic powder tablet standardized to 1. During the past 40 years, the public had been warned against frequent egg consumption due to the high cholesterol content in eggs and the potential association with CVD [ 90 ].
This was based on the assumption that high dietary cholesterol consumption is associated with high blood cholesterol levels and CVD. However, subsequent research suggests that, in contrast to SFA and TFA, dietary cholesterol in general and cholesterol in eggs in particular have limited effects on the blood cholesterol level and on CVD [ 91 ].
Eggs are also a source for high biological value protein, as well as vitamins and minerals such as folic acid, vitamin B12, vitamins E and D, selenium, choline, zinc, etc. Level of evidence and classes of recommendations for food items is summarized in Table 7. The epidemiologic evidence relating egg-consumption to coronary disease risk is not entirely consistent. Most large population studies did not find an association between egg consumption and CVD [ 93 , 94 , 95 ].
In several studies, consumption of at least 5 eggs per week was associated with CVD and mortality in people with diabetes [ 98 ]. In a meta-analysis of 17 intervention studies lasting at least 14 days, the addition of mg dietary cholesterol per day increased cholesterol levels by 2.
There is a great variation in the response of blood cholesterol levels to dietary cholesterol, possibly related to the large variability in intestinal absorption of cholesterol. A low-sodium diet fits all dietary strategies. Dietary sources for sodium include: On average, as dietary salt sodium chloride intake rises, so does BP. Evidence includes results from animal studies, epidemiological studies, clinical trials, and meta-analyses of trials.
Despite these results, the authors concluded that the sample size had insufficient power to exclude clinically important effects of reduced dietary salt on mortality or CV morbidity in normotensive or hypertensive populations.
Recently, the Institute of Medicine committee concluded that, although sodium restriction is recommended, evidence from studies on direct health outcomes is inconsistent and insufficient to conclude that lowering sodium intakes below mg per day either increases or decreases risk of CVD outcomes including stroke and CVD mortality or all-cause mortality in the general U.
While being supported by observational studies, randomized controlled trials have not supported a role for vitamins in the primary or secondary prevention of CVD, and have in some cases even indicated increased mortality in those with pre-existing late-stage atherosclerosis. In intervention trials including vitamins A, C, E, beta-carotene, and selenium, no beneficial effect was detected on all cause mortality in secondary prevention.
Studies have also indicated that beta-carotene mediates pro-oxidant effects. The trials that used a combination of vitamins that include beta-carotene have been disappointing. Studies also suggest that vitamins would be beneficial to individuals who are antioxidant-deficient [ ]. A recent trial reported that consumption of a multivitamin had no effect on CVD risk in men [ ]. The association between vitamin D and bone disease is well established.
However, vitamin D has many other functions and the use of vitamin D supplements to prevent and treat a wide range of illnesses has increased substantially over the last decade. Epidemiologic evidence links vitamin D deficiency to autoimmune disease, cancer, CVD, depression, dementia, infectious diseases, musculoskeletal decline, and more [ ].
A diet high in oily fish prevents vitamin D deficiency. Solar ultraviolet B radiation penetrates the skin and converts 7-dehydrocholesterol to pre-vitamin D3, which is rapidly converted to vitamin D3 [ ]. Fortified milk with vitamin D is also a source for vitamin D. In a meta-analysis of five prospective cohort studies, the RR for CV events was 1. In a meta-analysis of osteoporosis intervention trials, four trials in five articles reported the effect of vitamin D supplementation on incident CVD.
None reported a statistically significant effect of vitamin D supplementation with or without calcium on myocardial infarction, stroke, and other cardiac and cerebrovascular outcomes.
Study participants were followed for 1, 5, or 7 years. In summary, at this time no recommendations can be made for vitamin D screening or treatment in populations without risk for bone fractures, for the sake of preventing CVD. Further investigation is needed to find whether treatment for vitamin D deficiency can reduce CVD morbidity and mortality. Coenzyme Q10 CoQ10 is a naturally occurring, fat-soluble quinone that is localized in hydrophobic portions of cellular membranes and acts as an electron carrier in the mitochondrial respiratory chain [ ].
It also functions as an antioxidant, scavenging free radicals and inhibiting lipid peroxidation [ ]. Clinical studies have focused on three potential effects of CoQ10 supplementation: In different CVDs, including cardiomyopathy, relatively low levels of CoQ10 in myocardial tissue have been reported.
However, in a sub-analysis of patients with ischemic systolic heart failure enrolled in the CORONA study, rosuvastatin reduced CoQ10, but even in patients with a low baseline CoQ10, rosuvastatin treatment was not associated with a significantly worse outcome [ ].
Favorable short-term clinical and hemodynamic effects of oral CoQ10 supplementation have been observed in double-blind trials, especially in people with HTN and chronic heart failure.
There have been no important adverse effects reported from experiments using daily supplements of up to mg CoQ10 for 6—12 months and mg daily for up to 6 years [ ]. There was a 3. However, the long-term effect of this supplementation on clinical outcome is unknown. In a meta-analysis of five trials including patients, treatment with coenzyme Q10 significantly improved endothelial function as assessed peripherally by flow-mediated dilatation SMD 1.
However, the endothelial function assessed peripherally by nitrate-mediated arterial dilatation was not significantly improved [ ]. However, the authors conclude that due to the possible unreliability of some of the included studies, it is uncertain whether or not CoQ10 reduces blood pressure in the long-term management of primary HTN [ ].
Statins inhibit 3-hydroxymethylglutaryl coenzyme A HMG-CoA reductase, blocking cholesterol synthesis at a step that not only reduces cholesterol synthesis but also the production of other metabolites, including ubiquinone CoQ The effects of statins on skeletal muscle with CoQ10 supplementation were inconsistent. Supplementation of CoQ10 increases these levels [ ]. However, the effect of CoQ10 supplementation on patients with statin myopathy is inconsistent, and recent randomized trials of coenzyme Q10 supplementation have shown conflicting results [ ].
Magnesium Mg is an abundant intracellular mineral in the body. Therefore, Mg status is difficult to determine from serum Mg measurements [ ]. Dietary sources of Mg are green leafy vegetables particularly spinach , nuts, avocados, whole grains, legumes beans and peas , soy beans, chocolate, and some seafood [ ]. Observational epidemiological studies have shown that the Mg content of drinking water and food is inversely related to morbidity and mortality from heart disease and stroke [ , , ].
Relatively small studies have shown a distinct advantage in providing Mg versus placebo on reducing mortality in patients with acute MI; however, two major studies published in recent years have failed to prove this [ ]. Intervention studies have indicated that Mg supplementation was effective in patients with heart failure receiving diuretic therapy that reduces both Mg and potassium levels [ ]. The effect of Mg on the primary and secondary prevention of CV morbidity and mortality as well as all-cause mortality remains unclear, and therefore it is not yet possible to give conclusive recommendations in this respect.
Homocysteine is an amino acid that contains sulfur and is produced in the body during the breakdown of the amino acid methionine.
Part of the homocysteine formed in this process is recycled back to build methionine, while the rest is excreted in the urine. Folic acid, vitamin B12, and vitamin B6 regulate the metabolism of homocysteine. Deficiencies of one of these vitamins can lead to high blood homocysteine level. Major food sources of folic acid are: Food sources for vitamin B12 include animal products: The effectiveness of folic acid and B vitamin supplementation was examined mainly in secondary prevention intervention studies.
These studies failed to prove that reducing homocysteine level by folic acid and vitamin B supplements improves CVD incidence [ ]. The effect in primary and secondary prevention of stroke was minimal, as shown in a meta-analysis of 13 trials and 39, participants. A meta-analysis of folic acid supplementation in patients with chronic kidney disease also failed to show a beneficial effect in cardiovascular outcome [ ]. Polyunsaturated fatty acids are characterized according to the position of the first double bond.
Humans cannot synthesize short-chain fatty acids and therefore need to consume them in their diet. They include the plant-derived alpha-linolenic acid ALA, ALA is found in seeds, vegetable oils especially canola and flaxseed , green leafy vegetables, walnuts, and beans. Although some ALA can be transformed in the human body to EPA and DHA, such conversion appears to be inefficient [ ], and the majority of these fatty acids are consumed from cold water oily fish, such as salmon, herring, mackerel, anchovies, tuna, and sardines.
Various sources of omega-3 fatty acids are used as supplements for commercial use, including fish oil, flaxseed oil, and walnut oil. Most fish oil supplements undergo purification processes and do not appear to contain these substances in appreciable quantities.
Commonly used doses of omega-3 supplements up to 1 g daily do not appear to have significant side effects. However, larger doses may cause minor gastrointestinal upsets, worsening of glycemia control, and a rise in LDL-C levels [ ]. Most observational studies show an inverse correlation between fish consumption and cardiovascular CVD.
A review of 11 cohort studies involving , individuals suggested that fish consumption at 40—60 g daily is associated with markedly reduced CHD mortality in high-risk, but not in low-risk populations [ ]. A meta-analysis of intervention trials including individuals treated with omega-3 compared to controls found a significant decrease in mortality from MI but not in non-lethal MI [ ].
Recent meta-analyses of randomized controlled trials found little evidence of a protective effect of omega-3 supplementation on the incidence of CVD [ ], cerebrovascular disease [ ], or atrial fibrillation [ ].
In a meta-analysis of 20 studies of 68, patients 13 on secondary prevention , omega-3 PUFA supplementation was not associated with a lower risk of all-cause mortality, cardiac death, sudden death, myocardial infarction, or stroke based on relative and absolute measures of association. The long-chain omega-3 fatty acids EPA and DHA compete with arachidonic acid a long chain omega-6 fatty acid in the synthesis of prostaglandins and leukotrienes involved in inflammation and thrombogenesis.
Omega-3 fatty acids have been shown to increase arrhythmic thresholds, reduce blood pressure, improve endothelial function, reduce inflammation and platelet aggregation, enhance plaque stabilization, and favorably affect autonomic tone [ ]. At high doses 2—6 g daily they can significantly reduce the serum triglyceride levels, but the long-term clinical outcome of such treatment in hypertriglyceridemic individuals has not been evaluated [ ].
Sterols constitute an important constituent of plant cellular membranes, in a manner similar to the role of cholesterol in human cells [ ].
They are found at low concentrations in most plant-derived nutrients but at somewhat higher concentrations in some grains. Despite their structural similarities to cholesterol, plant sterols are not synthesized in the human body and are only minimally absorbed from the human intestinal tract. The average western diet contains approximately — mg of cholesterol, approximately — mg of plant sterols, and 20—50 mg of plant stanols.
Amongst the best known plant sterols are sitosterol, campesterol, and stigmasterol. Those that are incorporated in food are usually esterified. Hydrogenation converts sterols into stanols e. The optimal dose appears to be 1. Due to their biochemical similarity, plant sterols and stanols can displace cholesterol from mixed micelles in the intestine, thus reducing the absorption of dietary cholesterol [ ].
Although they have significant atherogenic potential, the intestinal absorption of sterols and stanols is poor, resulting in very low serum concentrations. An exception to this rule is patients with sitosterolemia, a rare genetic disorder in which the absorption of sterols is enhanced, resulting in significant damage to various organs. Level of evidence and classes of recommendations for nutritional supplements is summarized in Table 8.
Sterol supplementation at the recommended doses is generally considered safe [ ]. However, several potential risks need to be considered. In addition to inhibiting cholesterol absorption, some though not all studies suggest that sterols and stanols can reduce the blood levels of antioxidants such as lycopene and beta-carotene. This can be counteracted, at least partly, by the ingestion of a diet reach in vegetables and fruits [ ].
Despite the low serum concentration of sterols and stanols, some concern has been raised that even the slight increase associated with dietary supplementation of sterols might increase the risk for atherosclerosis [ ]. A healthy diet should include diversity of foods and to maintain a healthy weight. It is preferable to eat fresh or frozen food without additional sugar, salt or high-calorie gravies, using cooking methods that retain the original nutrients undestroyed. It should contain a variety of vegetables and fruits, legumes, whole grains, whole wheat bread and high-fiber low-salt food items.
Vegetable oils, especially olive and canola oils, excluding palm and coconut oils , should be preferred over animal fat. Additional elements that may confer health benefits include avocado, nuts, almonds and tahini, low-fat dairy products, green tea and 2 to 3 servings of fatty fish per week. It is recommended to minimize consumption of high-fat meat especially processed meats that are high in fat and sodium , hard margarines and pastries with hydrogenated fat, and foods that are high in sodium and sugar.
It is recommended to drink a lot of water, and reduce consumption of sweetened beverages as well as fresh juices.
The Mediterranean diet has been shown to reduce cardiovascular morbidity and mortality in both primary and secondary prevention. Other dietary patterns that have been shown to confer advantage in specific medical situations include low-fat diet for individuals at high cardiovascular risk, DASH diet for people with hypertension, and low-carbohydrate diets for overweight people and for the metabolic syndrome.
Sigal Eilat-Adar serves as a scientific consultant for the dairy industry and has given lectures on behalf of a number of companies in the food and pharmaceutical industry, including some on cereals, milk and milk products, tea, nuts, and nutritional supplements. Yaakov Henkin serves as a scientific consultant, and has given lectures on behalf of a number of companies in the food and pharmaceutical industry, including some that are involved in the distribution of cereals, milk products, tea, chocolate, wine, and nutritional supplements.
National Center for Biotechnology Information , U. Journal List Nutrients v. Published online Sep This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license http: This article has been cited by other articles in PMC. Abstract Lifestyle factors, including nutrition, play an important role in the etiology of Cardiovascular Disease CVD.
Introduction Lifestyle factors, including nutrition, play an important role in the etiology of Cardiovascular Disease CVD. Table 1 Levels of evidence. Open in a separate window. Low-Fat Diets The consumption of a lower fat diet is generally accepted in all clinical guidelines on CV prevention, and will therefore not be discussed in detail in this manuscript.
Table 4 Level of evidence and classes of recommendations for food patterns. Food pattern Recommendations Strength Level of evidence Low-fat diet Low-fat diet with restricted calories may present a healthy alternative to the typical Western diet. It may improve quality and life expectancy in healthy people, as well as in patients with overweight, diabetes, and CVD. II a A Low-carbohydrate Diet In the short-run, low-carbohydrate diets lead to a greater weight loss compared to low-fat diets.
Some studies have shown that this advantage is retained at 2 years but not at longer follow-up periods II b A Low-carbohydrate diets are preferable to a low-fat diet in reducing TG levels and increasing HDL-C blood levels. It should be emphasized that carbohydrates should preferably be replaced by unsaturated vegetable fats.
I A The diet should be accompanied by lifestyle changes such as: Conclusions All four dietary patterns described above are useful for reducing CVD risk factors, and some have also shown a favorable effect on plaque regression [ 19 ] and CVD mortality [ 16 ].
Individual Food Items 3. Whole Grains and Dietary Fiber Whole grains represent unprocessed grains that contain the endosperm; the bran the outer layer of the whole grain and the germ are in the same relative proportions as they exist in the intact grain.
Nuts Nuts tree nuts and peanuts are nutrient-dense foods with complex matrices rich in unsaturated fatty acids and other bioactive compounds: Intervention Studies In 22 randomized trials, isolated soy protein with isoflavones was compared with casein or milk protein, wheat protein, or mixed animal proteins. Dairy Products Dairy products are rich in minerals calcium, potassium, and magnesium , protein casein and whey , and vitamins riboflavin and vitamin B that can exert beneficial effects on CVD.
Possible Mechanisms Suggested mechanisms for the blood-pressure lowering effects of dairy products include the high content of potassium, magnesium, and calcium. Conclusions Despite the contribution of dairy products to the saturated fatty acid composition of the diet, and given the diversity of dairy foods of widely differing fat composition, there is no clear evidence that dairy food consumption is consistently associated with a higher risk of CVD [ 48 ] and some evidence that low-fat products may have beneficial effects on blood pressure.
Alcoholic Drinks The consumption of alcohol ethanol is widely accepted in many social situations. Possible Mechanisms Numerous mechanisms have been proposed to explain the benefit of light-to-moderate alcohol intake on the heart, including an increase in HDL-C, reduction in plasma viscosity and fibrinogen concentration, increase in fibrinolysis, decrease in platelet aggregation, improvement in endothelial function, reduction in inflammation, and promotion of antioxidant effects [ 58 , 59 ].
Conclusions Despite the evidence from cohort studies on the inverse association between moderate alcohol drinking and CVD, current guidelines do not recommend to begin consuming alcohol for preventing CVD. Table 5 Energy content and ethanol in alcoholic beverages [ 61 ].
Coffee and Caffeine Coffee is one of the most widely consumed beverages in the world. Table 6 Caffeine content in selected food and drink products. Product Quantity Caffeine content mg Coffee, instant 1 glass, mL 75 Roasted, ground, perculated or filter, or espresso 1 glass, mL — Coffee, decaffeinated 1 glass, mL 4 Tea, green 1 glass, mL 24 Tea, black 1 glass, mL 15—24 Tea, leaf or bag 1 glass, mL 40— Cocoa drink 1 glass, mL 1.
Possible Mechanisms Several mechanisms have been proposed to explain the harmful as well as protective effects that certain components of coffee may have on the development of CHD.
Conclusions Although regular consumption of moderate quantities of coffee seems to be associated with a small protection against CAD, results from randomized clinical trials about its beneficial effects are lacking. Tea Tea has been one of the most popular beverages for years. Possible Mechanisms Most of the beneficial effects of tea are attributed to its polyphenolic flavonoids, known as catechins. Observational Studies A population-based prospective cohort study the Ohsaki Study included 40, persons in Miyagi prefecture in northern Japan [ 74 ].
Intervention Studies No randomized controlled trial studied the effects of tea consumption on CVD morbidity or mortality; however, many studies evaluated the effects of tea on CV risk factors. Adverse Effects There do not appear to be any significant side-effects or toxicity associated with green tea consumption.
Chocolate Cocoa is rich in polyphenols, similar to those found in green tea. Observation Studies A recent meta-analysis of seven observational studies reported a beneficial association between higher levels of chocolate consumption and the risk of CVD.
Garlic The bulk of the dry weight of garlic Allium sativum contains mainly fructose-containing carbohydrates, followed by sulfur compounds, protein, fiber, and free amino acids. Adverse Effects Proven adverse effects include malodorous breath and body odor. Dosage The effective dose of garlic has not been determined. Eggs During the past 40 years, the public had been warned against frequent egg consumption due to the high cholesterol content in eggs and the potential association with CVD [ 90 ].
Table 7 Level of evidence and classes of recommendations for food items. Food item Recommendations Strength Level of evidence Whole grains and dietary fiber The recommended dietary fiber intake is 14 g per kcal, or 25 g for adult women and 38 g for adult men.
I A Vegetables and fruits It is recommended to consume at least 8 portions of vegetables and fruits a day. Preferably root vegetables and deep-colored fruits such as spinach, carrot, peach, and blueberries since they usually contain more micronutrients compared to other vegetables and fruits. II a B It is recommended to eat the whole fruit rather than fruit juice because of the fiber content and the satiation.
II a A It is recommended to use cooking techniques such as sautéing or simmering that preserve the micronutrients in the vegetables and fruits without additional calories, SFA, TFA, salt or sugar. II a A In cases of disease influenced by dietary carbohydrates, sodium, or potassium diabetes, kidney, coagulation , vegetables and fruits quantity should be personally adjusted.
II a B Milk and dairy products It is recommended to include dairy products preferably low-fat and without added sugar as part of a balanced diet. II a B Low-fat milk and dairy products lower blood pressure. I A There is epidemiologic data to suggest an association between dairy product consumption and reduced CVD. III C Alcohol Due to the absence of interventional controlled studies of moderate alcohol consumption with clinical endpoints, there is no recommendation to start drinking alcohol for health benefits.
III C In individuals who regularly drink a moderate amount of alcohol 1 drink a day in women and 2 drinks per day in men with meals, there is an associated reduced CVD incidence. Larger amounts should be discouraged. Healthy adults without caffeine sensitivity: However, the causal effect and the dose needed for this effect is unknown.
III C Dark chocolate, with a high cocoa percent, has abundant antioxidants and therefore preferable over milk chocolate. II a B Garlic Eating 2 garlic cloves a day may marginally reduce blood cholesterol levels. It is recommended to limit egg consumption to 3—4 per week, including eggs contained in other foods.
Observational Studies The epidemiologic evidence relating egg-consumption to coronary disease risk is not entirely consistent. Intervention Studies In a meta-analysis of 17 intervention studies lasting at least 14 days, the addition of mg dietary cholesterol per day increased cholesterol levels by 2. Biological Mechanisms There is a great variation in the response of blood cholesterol levels to dietary cholesterol, possibly related to the large variability in intestinal absorption of cholesterol.
Salt and Sodium A low-sodium diet fits all dietary strategies. Antioxidant Vitamins E and C While being supported by observational studies, randomized controlled trials have not supported a role for vitamins in the primary or secondary prevention of CVD, and have in some cases even indicated increased mortality in those with pre-existing late-stage atherosclerosis.
Vitamin D The association between vitamin D and bone disease is well established. Randomized Trials In a meta-analysis of osteoporosis intervention trials, four trials in five articles reported the effect of vitamin D supplementation on incident CVD. Coenzyme Q10 Coenzyme Q10 CoQ10 is a naturally occurring, fat-soluble quinone that is localized in hydrophobic portions of cellular membranes and acts as an electron carrier in the mitochondrial respiratory chain [ ].
Intervention Studies Favorable short-term clinical and hemodynamic effects of oral CoQ10 supplementation have been observed in double-blind trials, especially in people with HTN and chronic heart failure. Magnesium Magnesium Mg is an abundant intracellular mineral in the body. Observational Studies Observational epidemiological studies have shown that the Mg content of drinking water and food is inversely related to morbidity and mortality from heart disease and stroke [ , , ].
Intervention Studies Relatively small studies have shown a distinct advantage in providing Mg versus placebo on reducing mortality in patients with acute MI; however, two major studies published in recent years have failed to prove this [ ].