Dietary Fats and Oils: Some Evolutionary and Historical Perspectives Concerning Edible Lipids for Human Consumption

Consumption of fats and oils in the ancient world was examined as a window to human nutritional needs and compared with lipid usage in the modern world, post-1900. In earlier periods, the natural and only source of edible fats and oils came from both animals and plants. These fats and oils played a vital role in the evolution of the human body structure, supporting many biochemical functions. Artifacts from prehistoric periods and the ancient world had indicated that humans were evolutionarily adapted to consume saturated lipids. They also consumed unsaturated fats and oils extracted from animals and plants, now identified as omega-3 to omega-6 in the fatty acid ratio of 1:1, commonly derived from naturally consumed unprocessed products and food sources. These fats and oils assisted in providing the ingredients for the building up of cells and maintaining their structural integrity in tissues, including the brain and other important internal organs, as well as providing energy for many biochemical processes in the body. The double bonds distributed throughout fatty acid carbon chains are a characteristic of unsaturated vegetable oils. They are more structurally diverse in polyunsaturated fats and oils with the greater preponderance for carbon-to-carbon double bonds distributed in the carbon chains. These double bonds are susceptible to generating free radicals. This article considers potential problems that proponents of the prevailing diet-heart cholesterol paradigm of the past 60 years may have neglected. It also presents the possible consequences of abandoning the evolutionarily inherited foods containing extracted natural saturated and monounsaturated fats and oils. Furthermore, the article addresses the contribution of docosahexaenoic and eicosapentaenoic acids to immunity and the possible connection of excess consumption of omega-6 fatty acid to the marked rise in obesity and other non-communicable diseases in modern civilization.

Food for Thought: Have We Been Giving the Wrong Dietary Advice?

Background: Since 1984 UK citizens have been advised to reduce total dietary fat intake to 30% of total energy and saturated fat intake to 10%. The National Institute of Clinical Excellence [NICE] suggests a further benefit for Coronary Heart Disease [CHD] prevention by reducing saturated fat [SFA] intake to 6% - 7% of total energy and that 30,000 lives could be saved by replacing SFAs with Polyunsaturated fats [PUFAs]. Methods: 20 volumes of the Seven Countries Study, the seminal work behind the 1984 nutritional guidelines, were assessed. The evidence upon which the NICE guidance was based was reviewed. Nutritional facts about fat and the UK intake of fat are presented and the impact of macronutrient confusion on public health dietary advice is discussed. Findings: The Seven Countries study classified processed foods, primarily carbohydrates, as saturated fats. The UK government and NICE do the same, listing biscuits, cakes, pastries and savoury snacks as saturated fats. Processed foods should be the target of public health advice but not natural fats, in which the UK diet is deficient. With reference to the macro and micro nutrient composition of meat, fish, eggs, and dairy foods the article demonstrates that dietary trials cannot change one type of fat for another in a controlled study. Interpretation: The evidence suggests that processed food is strongly associated with the increase in obesity, diabetes, CHD, and other modern illness in our society. The macro and micro nutrients found in meat, fish, eggs and dairy products, are vital for human health and consumption of these nutritious foods should be encouraged.