The Fats of Life: Essential Fatty Acids in Health and Disease

Preface

I had the good fortune to collaborate with several scientists on a wide range of research topics in the early 1980s, when I worked in the laboratory of Gerald Cohen at Mount Sinai School of Medicine in New York. My research focus was lipid peroxidation and the oxidative destruction of polyunsaturated fatty acids in cell membranes and its effects on aging, cancer, and inflammation. Free radicals are believed to be responsible for many cancers, and lipid peroxidation is thought to be one of the ways that free radicals are mediating carcinogenesis, as well as promoting various diseases of aging. There was evidence that dietary polyunsaturated oils were promoting some cancers. Polyunsaturated fatty acids are considered to be essential dietary constituents because we are unable to make them from other nutrients and they have vital functions in numerous physiological systems in the human body. Sune Bergström, Bengt Samuelsson, and John Vane shared the Nobel Prize for Physiology or Medicine in 1982 for their discoveries related to metabolism of polyunsaturated fatty acids to powerful bioactive substances known collectively as eicosanoids. The scientific community was constantly discovering new lipid messengers and new roles for those that were already known. Eicosanoids were affecting nearly every system in the body, often in ways that were beneficial, but sometimes their actions were detrimental. The distinctions between omega-3 polyunsaturated fatty acids found in fish oils and omega-6 polyunsaturated fatty acids found in vegetable oils were beginning to unfold, and eicosanoids formed from them accounted for many observed differences in physiological responses to dietary fats from these disparate sources. As I got involved in research projects related to inflammation, cancer, and epilepsy, I began to see that eicosanoids derived from essential fatty acids had powerful effects, and that manipulation of dietary fats that are metabolized to eicosanoids or not involved in their production could have profound influences on the course of several diseases. The polyunsaturated fatty acids nurtured a fascination and wonder for me, perhaps because of the complex ways in which they were affecting so many aspects of health and disease. There was also considerable interest in saturated fats and cholesterol at that time. The results from two large-scale studies of the effects of dietary PREFACE xi intervention and behavior modification on serum cholesterol and heart disease were emerging by 1985. The Multiple-Risk Factor Intervention Trial (MRFIT) and the Lipid Research Clinics Coronary Primary Prevention Trial each involved several thousand participants and hundreds of physicians and researchers. An aim of each study was to get people to reduce their consumption of saturated fats and cholesterol, which had been associated with heart disease. Michael Brown and Joseph Goldstein received the Nobel Prize in Physiology or Medicine in 1985 for their work on genetic causes for high levels of cholesterol in the blood that can lead to heart disease at a young age. Genetic factors were emerging as a major contributor to the risk of heart disease. Indeed, genetic factors seemed more important than dietary fats and cholesterol. There was widespread belief that unsaturated vegetable oils were much healthier in the diet than saturated fats, particularly fats from animals that also contained cholesterol. I was involved in research that was showing that saturated fats were generally benign, whereas dietary polyunsaturated vegetable oils were susceptible to lipid peroxidation, which was associated with many of the common maladies of modern civilization. By the 1990s lipid peroxidation in low-density lipoprotein (LDL) was found to promote atherosclerosis and consequent heart disease, yet the doctrine of saturated fats and cholesterol causing heart disease persisted. Certainly very high levels of cholesterol in the blood were cause for serious concern. However, blanket recommendations for less saturated fat in the diet and implications that polyunsaturated oils were acceptable baffled me. I was also astonished to see the popular health and nutrition literature condemning tropical oils, such as palm and coconut oils, because they contained high levels of saturated fats. I had never seen any studies that indicated consumption of these oils increased the incidence of any disease. However, significant pressure was placed on the food industry to remove tropical oils from their products, which resulted in their replacement with partially hydrogenated vegetable oils. The latter contained levels of saturated fats as high as those in palm oil but also had high levels of trans fats, which were known to be at least as bad as saturated fats with respect to serum cholesterol. The recommendations to...