Nutrition Research

Summaryoverview of a heart and coronary artery showing damage (dead heart muscle) caused by a heart attack. Also shown is a cross-section of the coronary artery with plaque buildup and a blood clot.

Heart attack is the result of blocked blood flow to the heart muscle and is a major consequence of coronary heart disease (CHD). Strategies to prevent or slow the progression of endothelial dysfunction and atherosclerosis may help prevent the development of CHD and the risk of experiencing a heart attack. Additionally, consumption of nuts, tea, moderate amounts of alcoholic beverages, and food rich in vitamin E and fiber has been associated with a reduced risk of heart attack.

Disease Overview

Heart attack, also called myocardial infarction (MI), is the result of blocked blood flow to the heart muscle. Because it does not receive the oxygen and nutrients it needs, damage and death of heart tissue occurs.

Heart attacks most often result from coronary heart disease (CHD), a condition caused by atherosclerosis of the small blood vessels that supply blood to the heart. A heart attack can occur when: (1) an atherosclerotic plaque in a coronary artery is so large that it blocks blood flow to the heart, or (2) an unstable plaque ruptures and a piece of plaque or resulting blood clot blocks the flow of blood to the heart.

Following a heart attack, the heart is more prone to arrhythmias and heart failure.

See below for specific information about nutrients and dietary factors relevant to heart attack.

DEFINITIONS
Myocardial Infarction (MI) - the medical term for heart attack
Myocardial - referring to the muscular tissue of the heart
Infarct - a small localized area of dead tissue resulting from failure of blood supply
Plaque - a deposit of fat, cholesterol, immune cells, fibrin (a blood clotting protein), and other substances that forms inside arterial walls

Commonly Used Medications

Aspirin

What it does
  • Aspirin is an antiplatelet agent that interferes with the blood’s ability to clot.
  • Specifically, aspirin inhibits the production of a chemical (thromboxane) that signals blood cell fragments (platelets) to stick together at a wound site.
  • The clumping together of platelets is an early step in the sequence of events that lead to the formation of a blood clot.
What we know
  • Aspirin is often recommended to prevent recurrent heart attacks and strokes.
  • Excess bleeding is the most important harm associated with aspirin use.
  • In high-risk patients (individuals with evidence of vascular disease), the benefits of long-term aspirin use substantially exceed bleeding risks, regardless of age or gender.
  • Routine use of aspirin is not currently recommended for the primary prevention of cardiovascular disease in the general population.
  • Although available over-the-counter, aspirin is a potent medicine, can have side effects, and may interact with other medications. Consult your healthcare provider before regularly taking aspirin.
DEFINITIONS
Primary prevention - taking measures to prevent the onset of disease
Bioavailability - the fraction of ingested compound that reaches the circulation and is transported to the site of action

References

  • Cuzik J, et al. Estimates of benefits and harms of prophylactic use of aspirin in the general population. Annals of Oncology. 2015 Jan;26(1):47-57. Epub 2014 Aug 5
  • Sutcliffe P, et al. Aspirin in primary prevention of cardiovascular disease and cancer: a systematic review of the balance of evidence from reviews of randomized trials. PLoS One. 2013 Dec 5;8(12):e81970
  • Antithrombotic Trialists’ (ATT) Collaboration, Baigent C, et al. Aspirin in the primary and secondary prevention of vascular disease: collaborative meta-analysis of individual participant data from randomised trials. Lancet. 2009 May 30;373(9678):1849-60
Table 1. Potential Nutrient Interactions with Aspirin*
Supplements That May Increase Bleeding Risk Aspirin May Decrease Aspirin May Increase
Factors That May Increase Aspirin Bioavailability
Fish oil supplements Folate status Chromium absorption Caffeine
Garlic supplements Vitamin C status   Alcoholic beverages
Vitamin E supplements      
*This list is not comprehensive. Talk to your doctor or pharmacist about potential interactions between any dietary supplements and medications you are taking.

For references and more information, see the Safety sections in the vitamins, minerals, and dietary factors listed in Table 1.

Statins

What they do
  • Statins are a class of cholesterol-lowering medications.
  • Statins interfere with the liver enzyme HMG-CoA reductase, which is required for cholesterol synthesis.
  • As a result of this interference, less cholesterol is produced by the liver and less cholesterol ends up circulating in the blood.
What we know
  • Although there is some minor variability depending on the specific statin prescribed, statins can decrease low-density lipoprotein (LDL)-cholesterol concentration by 20 to 40 percent.
  • Statins also significantly lower the risk of heart attack, ischemic stroke, and coronary revascularization procedures in both high-risk (previous evidence of vascular disease) and low-risk (no previous evidence of vascular disease) individuals.
  • As a class, adverse events associated with statin use are not common; however, myopathy (muscle pain or weakness) and increased risk of diabetes have been observed.

References

  • Goldstein JL & Brown MS. A Century of Cholesterol and Coronaries: From Plaques to Genes to Statins. Cell. 2015;161:161-172
  • Newman CB and Tobert JA. Statin Intolerance: Reconciling Clinical Trials and Clinical Experience. JAMA. 2015;313(10):1011-12
  • Cholesterol Treatment Trialists (CTT) Collaborators. The effects of lowering LDL cholesterol with statin therapy in people at low risk of vascular disease: meta-analysis of individual data from 27 randomised trials. The Lancet. 2012;380(9841):581-90
  • Cholesterol Treatment Trialists (CTT) Collaboration. Efficacy and safety of more intensive lowering of LDL cholesterol: a meta-analysis of data from 170,000 participants in 26 randomised trials. The Lancet. 2010;376:1670-81
  • Weng T.-C, et al. A systematic review and meta-analysis on the therapeutic equivalence of statins. Journal of Clinical Pharmacy and Therapeutics. 2010;35:139-51
Table 2. Potential Interactions with Statins*
Supplements that May Increase Statin Side Effects Supplements that May Decrease Statin Activity
Niacin Antioxidant supplements (vitamin C, vitamin E, β-carotene, selenium)
  Grapefruit juice
  Phytosterols
*This list is not comprehensive. Talk to your doctor or pharmacist about potential interactions between any dietary supplements and medications you are taking.

For references and more information, see the Safety sections in the vitamins, minerals, and dietary factors listed in Table 2.

Nutrition Research

DEFINITIONS
Test tube (in vitro) experiment - a research experiment performed in a test tube, culture dish, or other artificial environment outside of a living organism; in vitro is a Latin phrase meaning in glass
Animal experiment - a research experiment performed in a laboratory animal; many different animal species are studied in the laboratory, including terrestrial (land), aquatic (water), and microscopic animals.
Observational study - a human research study in which no experimental intervention or treatment is applied, and participants are simply observed over time
Randomized controlled trial - a human research study in which participants are assigned by chance alone to receive either an experimental agent (the treatment group) or a placebo (the control group)
Placebo - a chemically inactive substance

 

Fiber

What it does

General

  • Fiber is a general term for carbohydrates that are resistant to digestion by human enzymes.
  • Fiber is considered an essential nutrient; it can be obtained from food, additives, and dietary supplements.
  • As fiber travels through the digestive tract, its physical properties (which vary depending on the type of fiber ingested) impart different health effects.
  • Beneficial health effects associated with fiber consumption include: satiety, gastrointestinal health, colonic health, and cardiovascular health.

Heart attack-specific

  • Fiber may benefit cardiovascular health by decreasing serum cholesterol or by influencing blood glucose and the insulin response.
  • Additionally, fiber-rich foods may provide other nutrients that benefit the cardiovascular system, such as magnesium and potassium, which help reduce blood pressure.
What we know
  • Observational studies consistently find that high intakes of fiber-rich foods are associated with significant reductions in coronary heart disease (CHD) risk, coronary events (such as heart attack), and CHD-related mortality.

For references and more information, see the section on cardiovascular disease in the Fiber article.

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Intravenous Magnesium

What it does

General

  • Magnesium is an essential mineral that serves as a structural component of the skeleton; assists in hundreds of enzymatic reactions involved in the synthesis of energy, DNA, and proteins; and is required for proper nerve conduction and muscle contraction.

Heart attack-specific

  • Inside our cells, magnesium can function as a calcium channel blocker. Because of this cellular activity, intravenous (IV) magnesium infusion following a heart attack might limit infarct size, prevent serious arrhythmias, and reduce the risk of death.
What we know
  • Intravenous magnesium is provided by healthcare professionals only.
  • The use of IV magnesium in the therapy of acute heart attack remains controversial. Some clinical trials have demonstrated that IV magnesium infusion given early after heart attack decreases the risk of death, some trials show no effect, and others indicate an increased risk of low blood pressure, bradycardia (slow heart beat), and flushing.
DEFINITION 
Infarct - a small localized area of dead tissue resulting from failure of blood supply

For references and more information, see the section on heart attack in the Magnesium article.  

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Selenium

What it does

General

  • Selenium is an essential trace mineral that is a structural component of certain antioxidant enzymes and influences thyroid hormone function.

Heart attack-specific

  • One family of selenium-containing antioxidant enzymes protects LDL particles from damage caused by oxidative stress. Thus, deficiency of selenium could compromise antioxidant enzyme activity and increase the oxidation of LDL particles, which makes them more atherogenic.
What we know
  • There is no clear association between selenium nutritional status and the risk of heart attack.
  • No randomized controlled trials have been conducted to date. More research is needed to determine if selenium has a role in cardiovascular disease or heart attack risk.
DEFINITIONS
Antioxidant - a compound that prevents or repairs the damage caused by reactive oxygen species
Reactive oxygen species (ROS) - highly unstable oxygen-containing compounds that react easily with nearby cellular structures, potentially causing damage
Oxidative stress - a situation in which the production of reactive oxygen species exceeds the ability of an organism to eliminate or neutralize them

For references and more information, see the section on cardiovascular disease in the Selenium article.

Selenium Flashcard. Main Functions: (1) Assists antioxidant enzymes, (2) Needed for production of thyroid hormone, which helps maintain body temperature and basal metabolic rate, and (3) Supports immune function. Good Sources: Meat, nuts, seafood, and whole grains are good sources of selenium. Meat (beef, chicken, pork), beef, 3 ounces, 30.6 micrograms; Nuts (Brazil nuts, sunflower seeds), sunflower sees, one-fourth cup, 18.6 micrograms; Seafood (tuna, clams, shrimp), tuna, 3 ounces, 92.0 micrograms. Daily Recommendation: 55 micrograms for adults. Special Notes: (1) The selenium content of plants and grains varies greatly. (a) Food selenium content is influenced by the selenium content of the soil in which it was grown. (b) Some plants accumulate selenium to a greater extent, including garlic, Brazil nuts, and Brassica vegetables (broccoli, Brussel sprouts, cabbage, cauliflower, kale). (c) A single serving of Brazil nuts (6 nuts) is above the tolerable upper intake level (UL) of 400 micrograms per day. (2) Most people in the US consume enough selenium to meet the recommendation.

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Vitamin E

What it does

General

  • Vitamin E is a fat-soluble vitamin that functions as an antioxidant in lipid (fat) environments and enhances the activity of immune cells.

Heart attack-specific

  • Vitamin E is an important antioxidant nutrient in cell membranes, where it functions to protect heart tissue and LDL particles from damage caused by oxidative stress.
What we know
  • The results of several large observational studies suggest that increased dietary consumption of vitamin E is associated with decreased risk of heart attack or death from coronary heart disease in both men and women.
  • Randomized controlled trials in healthy individuals, however, have not shown vitamin E supplements to be effective in preventing heart attacks or death.
  • There is mixed evidence that high-dose vitamin E supplementation (400 to 800 IU/day of synthetic vitamin E) influences the risk of heart attack in high-risk individuals (patients with coronary heart disease, type 2 diabetes mellitus, or renal failure
    • Some randomized controlled trials report a reduced risk, some report no effect.
    • In three of these trials, an increased risk of hemorrhagic stroke and heart failure was observed in male smokers and men with a history of cardiovascular disease, respectively.
DEFINITIONS
Antioxidant - a compound that prevents or repairs the damage caused by reactive oxygen species
Reactive oxygen species (ROS) - highly unstable oxygen-containing compounds that react easily with nearby cellular structures, potentially causing damage
Oxidative stress - a situation in which the production of reactive oxygen species exceeds the ability of an organism to eliminate or neutralize them

For references and more information, see the section on cardiovascular disease in the Vitamin E article.  

Vitamin E (alpha-tocopherol) Flashcard. Main Functions: 1) Boosts antioxidant defense, 2) Protects cell membranes, and 3) Enhances immune function. Good Sources: vegetable oil, sunflower oil (1 tablespoon), 5.6 mg; nuts (hazelnuts, peanuts), almonds, 1 ounce or 23 almonds, 7.3 mg; avocado, 1 medium-sized, 2.7 mg. Daily Recommendation is 15 mg for all adults. Special Notes: 1) The term "vitamin E" actually refers to a family of eight coupounds. Alpha-tocopherol is the most active vitamin E compound. 2) More than 90% of Americans do not meet the dietary requirement for vitmain E. 3) Synthetic vitamin E (in supplements and fortified food) is less bioavailable than naturally occurring vitamin E from food.

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L-Carnitine

What it does

General

  • L-carnitine is a compound that can be made inside the body and obtained from food and dietary supplements. It is considered a conditionally essential nutrient because in some situations, the body’s demand for L-carnitine exceeds its capacity to make it.
  • L-carnitine helps the body convert fat into useable energy.

Heart attack-specific

  • Supplemental L-carnitine and propionyl-L-carnitine, administered in conjunction with standard pharmacological therapy, may improve cardiac and skeletal muscle function during ischemia.
  • Propionyl-L-carnitine in particular may benefit ischemic tissue by replenishing intermediates of energy metabolism or by increasing blood vessel dilation.
What we know
  • In animal studies, L-carnitine treatment reduces injury to heart muscle due to inadequate blood flow.
  • In people who have experienced a heart attack, L-carnitine therapy (short-term intravenous administration followed by longer-term oral administration) improved clinical outcomes in some randomized controlled trials but had no significant effect in the majority of trials.
DEFINITION
Ischemia - inadequate blood supply to an organ or part of the body

For references and more information, see the section on heart attack in the L-Carnitine article

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Coenzyme Q10

What it does

General

  • Coenzyme Q10 is a compound that can be made inside the body and obtained from food and dietary supplements.
  • Coenzyme Q10 helps the body convert food into useable energy and functions as an antioxidant in cell membranes.

Heart attack-specific

  • The antioxidant properties of coenzyme Q10 may reduce oxidative stress that occurs upon return of blood and oxygen following a heart attack.
  • Additionally, coenzyme Q10 may enhance heart muscle cell contractility (shortening) and help maintain ATP (cellular energy) production.
What we know
  • Pretreatment of animals with coenzyme Q10 has been found to decrease heart tissue damage due to ischemia-reperfusion injury.
  • In a few, small randomized controlled trials, pretreatment with coenzyme Q10 before cardiac aortic bypass surgery improved measures of heart function and oxidative stress during the post-operative recovery period.
  • However, the small number of subjects and the short duration of these trials prevent conclusive statements about the use of supplemental coenzyme Q10 in heart attack patients.
DEFINITIONS
Antioxidant -a compound that prevents or repairs the damage caused by reactive oxygen species
Oxidative stress - a situation in which the production of reactive oxygen species exceeds the ability of an organism to eliminate or neutralize them
Reactive oxygen species (ROS) - highly unstable oxygen-containing compounds that react easily with nearby cellular structures, potentially causing damage
Ischemia - inadequate blood supply to an organ or part of the body
Ischemia-reperfusion injury - The return of blood and oxygen (reperfusion) following ischemia generates reactive oxygen species which could damage surrounding heart tissue

For references and more information, see the section on heart attack in the Coenzyme Q10 article.  

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Alcoholic Beverages

What they do

General

  • Alcoholic beverages contain ethanol and other ingredients with bioactive properties that may benefit health.
  • When consumed in moderation (no more than two drinks/day for men and one drink/day for women), alcoholic beverages have been associated with beneficial effects in the cardiovascular system.

Heart attack-specific

  • Moderate alcohol consumption appears to:
    • inhibit blood clot formation
    • increase HDL-cholesterol concentration
    • improve insulin sensitivity
    • exert anti-inflammatory effects
What we know
  • Moderate alcohol consumption is consistently associated with a reduced risk of coronary heart disease (CHD).
  • Long-term observational studies report that men and women who consumed moderate amounts of alcohol have a risk of heart attack or dying from CHD approximately 30 percent lower than those who do not drink alcohol.

For references and more information, see the section on Potential Health Benefits of Moderate Alcohol Consumption in the Alcoholic Beverages article

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Nuts

What they do

General

  • Nuts are a good source of soluble fiber, phytosterols, mono- and polyunsaturated fatty acids, protein, certain vitamins (folate, vitamin E), and minerals (calcium, magnesium, potassium).
  • Examples of tree nuts include: almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pistachios, and walnuts.
  • Peanuts are not nuts; they are legumes. However, peanuts are nutritionally similar to tree nuts and have some of the same beneficial properties.

Heart attack-specific

  • The soluble fibers and phytosterols present in nuts and peanuts inhibit intestinal absorption of dietary cholesterol, which can lead to reductions in serum total- and LDL-cholesterol.
  • Alpha-linolenic acid, an omega-3 fatty acid present in nuts and peanuts, may exert anti-arrhythmic effects.
  • Substituting dietary saturated fat with unsaturated fat lowers LDL-cholesterol and decreases cardiovascular disease risk.
What we know
  • Regular nut consumption (one ounce at least five times per week) is associated with a significantly lower risk of developing or dying from coronary heart disease.
  • A large randomized controlled trial conducted in Spain, the PREDIMED Trial, tested the effect of supplementation with olive oil or nuts on the prevention of cardiovascular events in high-risk individuals eating a Mediterranean diet.
    • Supplementation with olive oil (four tablespoons per day) or mixed nuts (approximately one ounce of walnuts, hazelnuts, and almonds per day) for about five years resulted in a significant 30 percent reduction in the risk of major cardiovascular events (heart attack, stroke, and cardiovascular death).
HIGHLIGHT: NUTS
  • Nuts are packed with healthy fats and, therefore, calories.
  • One ounce of nuts contains approximately 160 calories and 14 to 19 grams of fat (mainly mono- and polyunsaturated fatty acids).
  • One ounce of nuts equals approximately: 24 almonds, 8 medium Brazil nuts*, 18 medium cashews, 12 hazelnuts, 12 macadamia nuts, 15 pecan halves, 47 pistachios, 14 walnut halves, and 35 peanuts.
  • It is recommended to substitute nuts for sources of saturated fat and junk food.

*Depending on growth conditions, a single Brazil nut could contain exceedingly high levels of selenium. 

DEFINITION

The traditional Mediterranean diet is characterized by:

  • high intake of olive oil, fruit, nuts, vegetables, and cereals
  • moderate intake of fish and poultry
  • low intake of dairy products, red meat, processed meats, and sweets
  • wine in moderation, consumed with meals

For references and more information, see the section on cardiovascular disease in the Nuts article.  

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Tea

What it does

General

  • Tea is an infusion of the leaves of the Camellia sinensis plant and includes white, green, oolong, and black teas. This summary does not discuss herbal teas, which are infusions of herbs or plants other than Camellia sinensis.
  • Tea contains a number of bioactive substances, including caffeine, fluoride, and flavonoids, which may exert beneficial health effects.

Heart attack-specific

  • Tea is particularly rich in catechins, a type of flavonoid that has been shown to improve endothelial function and promote relaxation of arterial walls.
What we know
  • Overall, the available research suggests that consumption of at least three cups/day of black tea may be associated with a modest decrease in the risk of heart attack.

For references and more information, see the section on cardiovascular disease in the Tea article

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