If you want to make your stay on this planet as long as possible, you'd do well to get as many of your fats as you can from olive oil, avocados and nuts. These products are the best sources of monounsaturated fatty acids. According to a 2005 epidemiological longevity study, a high intake of these fatty acids prolongs lifespan.
The study we're writing about was published in Experimental Gerontology. Researchers at the University of Bari monitored 278 healthy Italians aged between 65 and 84, from the beginning of the 1990s to the start of the 21st century. During this period they tried to work out which dietary patterns reduce the chance of mortality.
The results were sobering. Proteins, carbohydrates, fibre, 'bad' saturated fatty acids [SFA] – none of these had any effect on mortality. The researchers found only two factors that did have an effect: the intake of monounsaturated fatty acids [MUFA] and the ratio fatty acids: saturated fatty acids [UFA/SFA].
The latter meant that the Italians lived longer the more unsaturated fatty acids they consumed relative to the amount of fatty acids. It's easier to optimise your balance by cutting out ready-made products from your diet: their fatty acid composition is unhealthy. Meat fat and milk fat are less risky. Although they contain high amounts of saturated fatty acids, they also contain high amounts of monounsaturated fatty acids. But plant-based sources of fat such as nuts and seeds have the best fatty acid composition.
The Italian study confirms the conclusions of animal studies on the relationship between fatty acid composition and life expectancy. In 2011 researchers at the University of Veterinary Medicine in Austria published the results of just such a study. [J Comp Physiol B. 2011 Feb; 181(2): 289-98.] The figure reproduced below comes from this study.
The Austrian study also showed that a diet high in n-3 or n-6 polyunsaturated fatty acids had virtually no effect on the lifespan of mice. What did have an effect was the concentration of monounsaturated fatty acids in the cell membranes.
Exp Gerontol. 2005 Apr;40(4):335-43.