La dieta occidentale e la demenza di Alzheimer.

Alzheimer Disease, characterised by a global impairment of cognitive functions, is more and more common in Western societies, both because of longer life expectancy and, probably, because of increasing incidence. Several hints suggest that this degenerative disease is linked to western diet, characterised by excessive dietary intake of sugar, refined carbohydrates (with high glycaemic index), and animal product (with high content of saturated fats), and decreased intake of unrefined seeds--cereals, legumes, and oleaginous seeds--and other vegetables (with high content of fibres, vitamins, polyphenols and other antioxidant substances, phytoestrogens) and, in several populations, of sea food (rich in n-3 fatty acids). It has been hypothesised, in fact, that AD, may be promoted by insulin resistance, decreased endothelial production of nitric oxide, free radical excess, inflammatory metabolites, homocysteine, and oestrogen deficiency. AD, therefore, could theoretically be prevented (or delayed) by relatively simple dietary measures aimed at increasing insulin sensitivity (trough reduction of refined sugars and saturated fats from meat and dairy products), the ratio between n-3 and n-6 fatty acids (e.g. from fish and respectively seed oils), antioxidant vitamins, folic acid, vitamin B6, phytoestrogens (vegetables, whole cereals, and legumes, including soy products), vitamin B12 (bivalve molluscs, liver), and Cr, K, Mg, and Si salts. This comprehensive improvement of diet would fit with all the mechanistic hypotheses cited above. Several studies, on the contrary, are presently exploring monofactorial preventive strategies with specific vitamin supplementation or hormonal drugs, without, however, appreciable results.