Alzheimer's disease, amnestic mild cognitive impairment, and age-associated memory impairment: current understanding and progress toward integrative prevention

Abstract

Alzheimer's disease, AD, is the most common form of dementia. AD initially targets memory and progressively destroys the mind. The brain atrophies as the neocortex suffers neuronal, synaptic, and dendritic losses, and the hallmark amyloid plaques and neurofibrillary tangles proliferate. Pharmacological management, at best, is palliative and transiently effective, with marked adverse effects. Certain nutrients intrinsic to human biochemistry (orthomolecules) match or exceed pharmacological drug benefits in double-blind, randomized, controlled trials, with superior safety. Early intervention is feasible because its heritability is typically minimal and pathological deterioration is detectable years prior to diagnosis. The syndrome amnestic mild cognitive impairment exhibits AD pathology and to date has frustrated attempts at intervention. The condition age-associated memory impairment is a nonpathological extreme of normal brain aging, but with less severe cognitive impairment than amnestic mild cognitive impairment. Age-associated memory impairment is a feasible target for early intervention against AD, beginning with the modifiable AD risk factors - smoking, hypertension, homocysteine, type 2 diabetes, insulin resistance, and obesity. Stress reduction, avoidance of toxins, and mental and physical exercise are important aspects of prevention. The diet should emphasize omega-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid; flavonoids and other antioxidant nutrients; and B vitamins, especially folate, B6 and B12. Dietary supplementation is best focused on those proven from randomized, controlled trials: the phospholipids phosphatidylserine and glycerophosphocholine, the energy nutrient acetyl-L-carnitine, vitamins C and E, and other antioxidants. A comprehensive integrative strategy initiated early in cognitive decline is the most pragmatic approach to controlling progression to Alzheimer's disease.