[Heart and nutrition: which fatty acids for which cardiac function?]

Cardiovascular risk factors are often related to diet and the dietary fatty acids play a leading role quantitatively and qualitatively. In addition to the demonstration of the beneficial properties of n-3 PUFA on the development of atherosclerosis, there is a growing body of experimental evidence on the implication of n-3 PUFA in the regulation of cardiac function because of cardiac enrichment with n-3 PUFA to the detriment of arachidonic acid. The antiarrhythmic effect of these PUFA has been demonstrated in several animal species, the positive results of the GISSI-prevenzione study being partially associated with this property. This effect is related to the presence of DHA in cardiac phospholipids but the molecular mechanism is poorly understood. Moreover, the presence of DHA in the membranes decreases the production of cAMP induced by a b-adrenergic stimulation. This characteristic related to the interaction between the protein receptor complex and its environment provokes effects similar to those of a betablocker specifically due to the presence of DHA and not to the decrease in arachidonic acid. Finally, n-3 PUFA induce a reduction of cardiac b-oxidation and oxygen consumption in the animal. This effect, mild undr physiological conditions, manifests itself during post-ischaemic reperfusions as an improvement of metabolic recovery and ventricular function. In conclusion, the relationship between the heart and fatty acids will change because of the increasing incidence of cardiac failure associated with a chronic catabolic state. Daily dietary PUFA, in particular the n-3 forms, is insufficient, especially when a hypertrophic heart has to increase its membrane mass. In view of the positive effects of a high BMI on morbi-mortality of cardiac failure, nutrition and cardiology may have to reinforce their relationship in the short-term.