Australian researchers have just released the results of a fascinating study which links longevity with the fatty acid composition of cell membranes. They discovered animals that have a preponderance of saturated fatty acids in their membranes have a slower metabolism and live far longer than animals that have lots of polyunsaturated fats in their membranes. The key fatty acid would seem to be the highly polyunsaturated docosahexaenoic acid (DHA), a major component of fish oils.
It turns out that cell membranes rich in DHA are a lot more fluid than membranes rich in saturated fatty acids. This results in a faster metabolism and quicker reaction times all around, especially in the brain and eyes. Unfortunately, DHA is also an easy target for free radicals that leak out of mitochondria as they produce energy. The end result is that fluid, unsaturated membranes deteriorate and age faster than more viscous, saturated ones. Free radical attacks can also damage proteins and DNA. On the other hand, a shortage of DHA in cell membranes can lead to serious problems like high blood pressure, heart disease, diabetes, and depression. So you guessed it – you can’t win! About the only proven way of increasing longevity is by restricting calorie intake which apparently removes some DHA from membranes.
Fox, Douglas. The speed of life. New Scientist, November 1, 2003, pp. 42-45