The Queen of Fats: Why Omega-3s Were Removed from the Western Diet and What We Can Do to Replace Them

Susan Allport University of California Press: 2006. 232 pp. $22.50, £14.95 0520242823

Two series of polyunsaturated fatty acids, the omega-6 and the omega-3 fatty acids, are essential dietary nutrients. Two major omega-3 fatty acids, eicosa-pentaenoic acid (EPA) and docosa-hexaenoic acid (DHA), are increasingly being seen as important modulators of biological pathways that affect growth, development and health. Consumption of these omega-3 fatty acids, which are found in fatty fish and fish oils, has been linked to the low incidence of coronary heart disease in the Inuit people of Greenland. An omega-3 fatty acid with a shorter chain, alpha-linolenic acid (ALA), found in some plant oils and sometimes converted to EPA and DHA, may also be beneficial. Omega-3 fatty acids may protect against cardiovascular disease by several mechanisms, such as lowering blood pressure; reducing plasma triglycerides; lowering the platelet aggregation response, inflammation and arrhythmias; and improving endothelial function, insulin sensitivity and atherosclerotic plaque stability.

Susan Allport discusses the history of using omega-3 fatty acids in her well-written book The Queen of Fats. She has done an excellent job in describing the events and the international collaboration involved in discovering the effects of omega-3 fatty acids. She covers almost every aspect of omega-3s, including the importance of an appropriate ratio of omega-6 and omega-3 fatty acids in the diet, which has been biased towards omega-6 fatty acids over the past 50 years, and the consequences for our health of changes in the ratio. There is considerable controversy over how much omega-6 and omega-3 fatty acids are needed in the diet, and which ones.

Many studies have shown a correlation between omega–3 fatty acids and diseases, but translating these findings into recommended amounts for individuals and populations requires careful consideration. Meta-analyses of the effects of omega–3 fatty acids are not conclusive on total mortality, combined cardiovascular events, or cancer. However, some of these meta-analyses failed to take into account many of the pitfalls that must be addressed if a clear picture of the benefits of omega-3 fatty acids is to be obtained.

Allport does not discuss recent meta-analyses of several large studies on fish oils, and fails to mention some of the possible health risks associated with a high intake of fish oils, such as increased bleeding and haemorrhagic stroke. In addition, the oxidation of omega-3 fatty acids can increase the level of low-density lipoprotein, reduce glycaemic control in diabetics, and reduce immunocompetence. She could also have elaborated on the significance of another omega-3 fatty acid, DPA, and on adverse health effects in infants and adults of lipid-soluble toxins (such as dioxins and polychlorinated biphenyl) and of heavy metals in fish oils. I also expected her to say more about the possibility of switching to new sources of omega-3 fatty acids, such as genetically modified oils, as a way of delivering more highly concentrated sources of omega-3 fatty acids. The advent of algal sources of DHA provides one of the few terrestrial sources of this fatty acid in a concentrated form. All this has been made possible by new technologies and improved processing techniques that ensure the stability and preserve the integrity of these unstable fatty acids.

Something fishy: mackerel is a good source of omega-3s. Credit: DESGRIEUX/PHOTOCUISINE /CORBIS

These omissions aside, however, Allport's book provides an interesting and comprehensive account of the history of omega-3 fatty acids. It not only provides a clearly reasoned case for the benefits of having more omega-3 fatty acids in the diet, but also offers practical advice about how to add these fats to our diet. The book is also well organized, with a clear contents list, comprehensive notes, time lines and index to enable readers to quickly locate a required topic.