Robert G Ackman Contents

I. Introduction 155

II. Why There Are So Many Fish Fatty Acid Compositions 155

A. Coldwater Fish 156

B. Freshwater Fish 161

C. Shellfish and Crustacea 162

D. Australasia and the Tropics 163

III. Oily Fish and Health Considerations 164

IV. Fish as Food 172

A. Omega-3 Fatty Acids and Health 173

B. New Market Exploitation 175

C. Short-Chain or Long-Chain 177

a. Alternate Sources and Delivery Systems 177

D. The Safety Factor 178

References 180

I. INTRODUCTION

"Fish is a brain food" is an old admonition given to children who decline to eat fish. It originated in the roughly similar appearance of white fish muscle lipids and those extracted from the human brain, and even the chemists of the nineteenth century found similarities in the phosphorus content, not realizing that this indicated that both tissues were rich in phospholipids. The fatty acids of fish were even more mysterious and the polyunsaturated ones were easily destroyed in the inexact analyses of the time. Fish was usually sold just as fish, a food to be eaten because it was Friday in Catholic countries, or because it was cheap. At about the turn of the century, a few organic chemists began to sort out the structures of two highly unsaturated fatty acids, known as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). By the 1950-1960 era, much patient work in Germany, Japan, Britain, and the United States had identified most of the fish fatty acids and Stansby (1967) could write an excellent book on fish oils, including early work on their hypercholesterol-emic effects. However, the nutritional and biochemical aspects of these two particular fatty acids had to wait nearly two more decades for proper documentation of the role of "omega-3" fatty acids (Holman, 1998).

II. WHY THERE ARE SO MANY FISH FATTY ACID COMPOSITIONS

The author realised rather late in his career that he had developed one table of fatty acids of fish and fish oils and just kept changing the numbers (Ackman et al., 1988). This was almost independent of whether the analysis was of edible muscle, or the whole fish or bodies of molluscs, or whether of freshwater or marine species. The qualitative uniformity of the tables was a consequence of the

Was this article helpful?

0 0

Post a comment