Nutritional Aspects Of Aging

Volume 2

Linda H. Chen

• Publisher: CRC Press
• Year: 2018
• ISBN:
  9781351092043
• Edition: 1
• Topic: Medicine
• Subtopic: Nutrition, Dietics & Bariatrics

In the first section of Volume 2, toxicological factors affecting nutritional status are discussed. Medications and alcohol may affect nutritional status. Section 2 provides a discussion of nutrition-related diseases which occur more frequently among the elderly. Cardiovascular diseases including coronary heart disease and cerebrovascular disease are the leading causes of death in the U.S. The relative importance of cardiovascular diseases, in terms of all deaths for the given age group, rises steadily with age. The death rate from these diseases is 28% for the middle age group (35 to 44) and is 69% for the old age group (age 75 and above. This reflects the continued progression of artherosclerosis with aging. Cancer is the second leading cause of death in the U.S. The death rate from cancer also rises steadily with age. The death rate from diabetes mellitus increases progressively with age and more rapidly after the age of 45. The incidence of diabetes mellitus is 0.23% under age 25 and 6.2% over 45.

Section II
Nutritional Basis for Diseases in Aging

Chapter 3
Cardiovascular Diseases

Kang-Jey Ho

Table of Contents

1. I. Introduction
2. II. Pathogenesis of Atherosclerosis
3. III. Lipoprotein and Cholesterol Metabolism
4. IV. Risk Factors for Atherosclerosis and Ischemic Heart Disease
   1. A. Age as a Risk Factor
   2. B. Male Predominance
   3. C. Obesity and Diabetes Mellitus
   4. D. Diet and Other Factors Affecting Plasma Lipid Levels
      1. 1. Diet
      2. 2. Chronic Renal Failure
      3. 3. Hypothyroidism
   5. E. Immunologic Senescence
   6. F. Other Factors Inducing Endothelial Injury
      1. 1. Hemodynamics
      2. 2. Chemicals
5. V. Prevention and Management
6. References

I. Introduction

Cardiovascular disease in the elderly might belong to one of the following three categories: (1) physiologic changes related to the aging process per se, (2) a specific pathologic process which is increased in frequency and severity with age, and (3) a combination of the above two. In fact, the distinction among these three categories for a particular entity of cardiovascular disease is often extremely difficult, if not impossible. Lipofucsin accumulation in the myocardium, an essential feature of so-called senile cardiomyopathy, is definitely related to the aging process.¹ The amount of lipofucsin pigment increases progressively with age at an accumulation rate of 0.3% of the total heart volume per decade.² By the time a person reaches 90 years of age, lipofucsin pigment may account for as much as 30% of the total solids of myocardial fibers. Amyloid deposit in the myocardium and basophilic degeneration of myocardial fibers are common but not universal findings in elderly persons. Endocardial fibrous thickening, valvular ring calcification, arrhythmia, cardiac enlargement, atrophy, and fibrosis cannot be considered as universal or even common results of aging. With advancing age, most vessels increase in both diameter and wall thickness, with fragmentation of elastic fibers and proliferation of collagen resulting in less extensibility of the vessel wall. The incidence and degree of hyalinization of arterioles also increase with age. However, it remains uncertain whether such changes are related to the aging process alone or its interaction with environmental factors.^1,3,4

Regardless of how much aging per se contributes to the disease process, the most common and important cardiovascular diseases in the elderly patients are coronary heart disease, cerebrovascular accident, aortic aneurysm, occlusive peripheral vascular disease, and phlebothrombosis.⁴ All of these diseases, with the exception of venous thrombosis, are based primarily upon a single common pathologic process, atherosclerosis. Hypertension and its role in cerebrovascular accidents and congestive heart failure are discussed elsewhere in this book and will not be repeated here. The discussion in this chapter is focused on the basic disease process of atherosclerosis.

Atherosclerosis is a multifactorial disease; aging is only one of the many factors attributing to such a process. First reviewed is our current understanding of the pathogenesis of atherosclerosis, followed by identification of its risk factors, particularly those pertinent to the nutritional aspects of aging.

II. Pathogenesis of Atherosclerosis

The current concept of the pathogenesis of atherosclerosis is briefly summarized in Figure 1. The primary event initiating atherosclerosis is generally believed to be endothelial injury.⁵ Since naturally occurring atherosclerosis develops slowly over a period of decades, such endothelial injury must be subtle, repetitive, and chronic. Endothelium can be damaged by excessive shear stress of hemodynamic forces, particularly those associated with hypertension.^8-15 Low-density lipoproteins (LDL) may cause functional endothelial injury as evidenced by both morphologic and physiologic alterations in the endothelium.^17-21 Other chemicals and toxins, such as homocystine and bacterial endotoxins, can produce vascular injury and arterial thrombosis.^22-24 Endothelium can also be damaged by immunologic means,^25-28 viruses,²⁹ hypoxemia,³⁰ and many other factors yet to be identified.

The damaged endothelium becomes dysfunctional, disrupted, and even desquamated.⁶ Endothelial dysfunction leads to the loss of its thromboresistant mechanisms, such as the synthesis and secretion of glycocalyx,³¹ α₂-macroglobulin,³² nonthrombotic type V surface collagen,³³ prostacyclin,^34,35 and plasminogen activator,³⁶ and also the metabolism of thrombin and vasoactive amines,^37,38 Endothelial denudation results in the direct exposure of subendothelial matrix, such as collagen (Types I and III), to the circulating blood elements. Adherence o...

Table of contents

• Cover
• Title
• Copyright
• PREFACE
• THE EDITOR
• CONTRIBUTORS
• Contents
• SECTION I: TOXICOLOGICAL FACTORS AFFECTING NUTRITIONAL STATUS
• SECTION II: NUTRITIONAL BASIS FOR DISEASES IN AGING
• Index