Antioxidants in Health and Disease

Antonis Zampelas, Renata Micha, Antonis Zampelas, Renata Micha

• Publisher: CRC Press
• Year: 2015
• Print ISBN: 9781032098586
• eBook ISBN: 9781000219029
• Edition: 1
• Topic: Medicine
• Subtopic: Diseases & Allergies

Antioxidant use in health promotion and disease prevention either through dietary intake or supplementation is controversial. This book reviews the latest evidence-based research in the area, principally through prospective cohort studies and randomized controlled trials. It assesses major dietary antioxidants and discusses their use in diseases such as cancer, diabetes, stroke, coronary heart disease, HIV/AIDS, and neurodegenerative and immune diseases. The use of antioxidants in health is also discussed along with common adverse effects associated with antioxidant use.

Section III

Antioxidants in Various Disease States

8 Coronary Heart Disease and Stroke

Antonis Zampelas and loannis Dimakopoulos

CONTENTS

Introduction

Risk Factors Associated with CHD and Stroke

Antioxidant Hypothesis

Antioxidants

Vitamin E

Vitamin C

Carotenoids

Selenium

Polyphenols

Resveratrol

Lycopene

Conclusion

References

INTRODUCTION

Noncommunicable diseases (NCDs) or chronic diseases generally progress slowly and have a long duration (World Health Organization [WHO] 2013a). NCDs account for 64% of all annual deaths (WHO 2013a). The four major types of NCDs are cardiovascular diseases (CVDs), cancer, chronic respiratory diseases, and diabetes. CVD is the number one cause of death globally (WHO 2011a). CVDs are a group of disorders that include coronary heart disease (CHD), cerebrovascular disease, peripheral arterial disease (PAD), rheumatic heart disease, congenital heart disease, deep vein thrombosis, and pulmonary embolism (WHO 2013b).

The majority of CVDs result from complications of atherosclerosis (Singh et al. 2005). Atherosclerosis is a disease in which plaque (fatty deposits) builds up inside the arteries and blood vessels and thus narrowing them, making it more difficult for blood to pass through and therefore limiting oxygen supply to the organs as well as other parts of the body (American Heart Association [AHA] 2013b). Heart attacks and strokes are acute events mainly caused by a blood clot that blocks the blood supply to the heart or brain, respectively (WHO 2013b). Of the 17.3 million people that have died globally due to CVD, 7.3 million died due to CHD and 6.2 million due to stroke (WHO 2011a), and it is estimated that by 2030 this number will increase to 23.3 million deaths annually (WHO 2011b).

CHD occurs when plaque builds up in the coronary arteries that supply oxygenated blood to the heart muscle, therefore limiting blood supply (National Institutes of Health 2013). This is called ischemia and can be chronic, caused by narrowing of the coronary artery, or it can be acute as a result of a plaque that suddenly ruptures (AHA 2013a).

The most common type of stroke is ischemic stroke, which occurs when a blood vessel that supplies the brain is blocked and when blood supply to a part of the brain is shut off, leading to the death of brain cells (AHA 2013b). On the other hand, a hemorrhagic stroke occurs when a blood vessel within the brain bursts (AHA 2013b). Stroke remains the second leading cause of death globally and the most common cause of disability in adults in most regions (Chen et al. 2013a). Every year, 795,000 people experience a new or recurrent stroke and, on average, every 40 s, someone in the United States has a stroke and dies of one approximately every 4 min (Go et al. 2013). In Europe, CVD is responsible for nearly half of all deaths each year, and due to its high mortality and morbidity CVD is estimated to cost the European Union €190 billion a year (Allender et al. 2008).

RISK FACTORS ASSOCIATED WITH CHD AND STROKE

There is a multitude of risk factors associated with CHD and stroke that can be differentiated to modifiable and nonmodifiable risk factors. The most important modifiable risk factors are the following: unhealthy diet, physical inactivity, smoking, and harmful use of alcohol (WHO 2013b). The effects that risk factors can exert on CVD may be shown via the so-called intermediate risk factors such as hypertension, increased levels of blood glucose and/or lipids, and increased body weight (WHO 2013b). Changes in health behavior associated with those risk factors (e.g., maintaining a healthy body weight, increasing physical activity levels, consumption of fruits and vegetables, and smoking cessation) have been shown to reduce the risk of CVD (WHO 2013b). In addition to modifiable risk factors, there are nonmodifiable risk factors, including family history, ethnicity, and being postmenopausal for women and age older than 45 years for men, that also exert an effect on CVD (AHA 2013b; World Heart Federation [WHF] 2013).

As a risk factor, diet plays an important role in the maintenance of optimal cardiovascular health, and there is consistent evidence from observational cohort studies showing that increased consumption of fruits and vegetables, as well as other plant foods, is associated with lower overall mortality rates and lower death rates from CVD (He et al. 2006, Dauchet et al. 2009, WHO 2013b). Furthermore, according to estimates, if an individual increases fruit and vegetable intake to 600 g/day, the global burden of disease could be reduced by 31% for ischemic heart disease and 19% for ischemic stroke (Lock et al. 2005). In addition, it is estimated that 74% of coronary events among nonsmokers might have been prevented by eating a healthy diet, maintaining a healthy body weight, exercising regularly for >30 min/day, and consuming a moderate amount of alcohol (Hu and Willett 2002). However, the difficulty of individuals to reduce and maintain a normal body weight, as well as make healthier food choices in the long term, made the hypothesis of counteracting this with antioxidants, among other nutrients, attractive (Traber 2007).

ANTIOXIDANT HYPOTHESIS

Evidence for the association between CVD and fruit and vegetable consumption has led to the hypothesis that specific components of fruits and vegetables are responsible for the health benefits observed, although it is not yet known which molecules found in fruits and vegetables contribute more to their cardioprotective effect (Chong-Han 2010). One very popular hypothesis is that antioxidant nutrients prevent atherosclerosis via their beneficial effect against reactive oxygen species (ROS) (Stanner et al. 2004). ROS include free radicals, oxygen ions, and peroxides, both organic and inorganic (Taverne et al. 2013). They are produced as a by-product of oxidative phosphorylation but can also be produced through physiological biochemical reactions (Taverne et al. 2013).

Physiologically, ROS are found in low levels and this enables them to function as messengers in signal transduction for vascular homeostasis and cell signaling (Taverne et al. 2013). When ROS are excessively produced, when they are not controlled, or when antioxidants are depleted, they can damage lipids, proteins, and DNA (Taverne et al. 2013). This imbalance between oxidation and reduction is called oxidative stress and can contribute to the development as well as progression of CVD (Taverne et al. 2013). In addition, common characteristics of CVD risk factors, such as obesity, dyslipidemia, insulin resistance, and hypertension are the elevated levels of oxidative stress (Griendling and FitzGerald 2003a,b). Therefore, as the majority of CVDs are a result of atheroscle...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface
• Acknowledgments
• Editors
• Contributors
• Section I Interest in Antioxidants: Why and How?
• Section II Antioxidants in Health
• Section III Antioxidants in Various Disease States
• Section IV Role of Herbs
• Index