n-3 Polyunsaturated Fatty Acids for the Management of Patients With Chronic Kidney Disease.
THE IRISH PLAYWRIGHT George Bernard Shaw (1856-1950) once wrote: ‘‘No diet will remove all the fat from your body because the brain is entirely fat. Without a brain, you might look good, but all you could do is run for public office.’’ He was not right in one thing: the brain is just about 60% fat. And of that percentage, the biggest portion comes from n-3 polyunsaturated fatty acids (PUFAs). n-3 PUFA constitutes a family of healthy dietary fats predominantly found in fatty fish (eicosapentaenoic acid and docosahexaenoic acid) but also present, for instance, in walnuts, canola, or flax seeds (a-linolenic acid [ALA]). ALA is an essential fatty acid that cannot be synthesized endogenously by mammals and must be derived from the diet. Both eicosapentaenoic acid and docosahexaenoic acid can be synthesized from dietary ALA via elongation and desaturation endogenously, but the efficiency of this conversion is very poor and must be considered essential as well. The evidence that n-3 PUFA intake can reduce coronary heart disease mortality and to a lesser extent stroke mortality in the general population is consistent. Mechanisms behind this effect may involve the capacity of n-3 PUFA of reducing triglycerides and cholesterol levels, inhibiting platelet aggregation, as well as anti-inflammatory, antiproliferative and vasodilatory properties by reducing the availability of arachidonic acid, leukotriene, and cytokine production as well as increasing prostaglandin-I3 production. 2,3 The importance of dietary fat in a healthy and balanced diet is well recognized by current cardiovascular prevention guidelines; the American Heart Association recommends total fat not to exceed 30% of dietary energy, and the European Society of Cardiology lowers that threshold down to 10%. Both guidelines recommend progressively replacing saturated fat by PUFA, via limiting the intake of meat and fast foods and