Rationale and clinical data supporting nutritional intervention in Alzheimer's disease

Adequate nutrition plays an important role in the maintenance of cognitive function, particularly during aging. Malnutrition is amongst the risk factors for developing mild cognitive impairment (MCI) and Alzheimer's disease (AD). Epidemiological studies have associated deficiencies in some nutrients with a higher risk of cognitive dysfunction and/or AD. Cognitive decline in AD is correlated with synaptic loss and many of the components required to maintain optimal synaptic function are derived from dietary sources. As synapses are part of the neuronal membrane and are continuously being remodelled, the availability of sufficient levels of nutritional precursors (mainly uridine monophosphate, choline and omega-3 fatty acids) to make the phospholipids required to build neuronal membranes may have beneficial effects on synaptic degeneration in AD. In addition, B-vitamins, phospholipids and other micronutrients act as cofactors to enhance the supply of precursors required to make neuronal membranes and synapses. Despite this, no randomized controlled trial has hitherto provided evidence that any single nutrient has a beneficial effect on cognition or lowers the risk for AD. However, a multi-target approach using combinations of (micro) nutrients might have beneficial effects on cognitive function in neurodegenerative brain disorders like AD leading to synaptic degeneration. Here we review the clinical evidence for supplementation, based on a multi-target approach with a focus on key nutrients with a proposed role in synaptic dysfunction. Based on preclinical evidence, a nutrient mixture, Souvenaid (R) (Nutricia N.V., Zoetermeer, The Netherlands) was developed. Clinical trials with Souvenaid (R) have shown improved memory performance in patients with mild AD. Further clinical trials to evaluate the effects of nutritional intervention in MCI and early dementia due to AD are on-going.