Acides gras oméga-3 alimentaires et neuropsychiatrie

Omega-3 fatty acids participated in the first coherent experimental demonstration of the effect of dietary substances (nutrients) on the structure and function of the brain. Experiments were first of all carried out on ex-vivo cultured brain cells, then on in vivo brain cells, finally on physiochemical, biochemical, physiological, neurosensory, and behavioural parameters. These findings indicated that the nature of polyunsaturated fatty acids (in particular omega-3) present in formula milks for infants (both premature and term) determines the visual, cerebral, and intellectual abilities, as described in a recent review in OCL [1]. In view of the high omega-3 polyunsaturated fatty acid content of the brain, it is evident that these fats are involved in brain biochemistry, physiology and functionning; and thus in some neuropsychiatric diseases and in the cognitive decline of ageing. Though omega-3 fatty acids appear effective in the prevention of stress, their role as regulator of mood and libido is a matter for discussion pending experimental proof in animal and human models. Dietary omega-3 fatty acids could play a role in the prevention of some disorders including depression, as well as in dementia, particularly Alzheimer’s disease. Their direct role in major depression and bipolar disorder (manic-depressive disease) and schizophrenia is not yet established. Their deficiency can prevent the renewal of membranes, and thus accelerate cerebral ageing; nonetheless, the respective roles of the vascular component on one hand (where the omega-3’s are active) and the cerebral parenchyma itself on the other, have not yet been clearly resolved. The role of omega-3 in certain diseases such as dyslexia and autism is suggested. The role of omega-3 in certain diseases such as dyslexia, autism, and schizophrenia seems to suggest a problem of diet. Indeed, the insufficient dietary supply of omega-3 fatty acids in today’s French diet raises the problem of how to correct dietary habits so that the consumer will select foods that are genuinely rich in omega-3/the omega-3 family; mainly rapeseed and walnut oils on one hand and fatty fish on the other.