A multi nutrient concept to enhance synapse formation and function: science behind a medical food for Alzheimer’s disease

Abstract

Alzheimer’s Disease (AD) is the leading cause of dementia. Epidemiological studies suggest that AD is linked with poor status of nutrients including DHA, B-vitamins and the vitamins E and C. Ongoing neurodegeneration, particularly synaptic loss, leads to the classical clinical features of AD namely, memory impairment, language deterioration, and executive and visuospatial dysfunction. The main constituents of neural and synaptic membranes are phospholipids. Supplemenation of animals with three dietary precursors of phospholipids namely, DHA, uridine monophosphate and choline, results in increased levels of brain phospholipids, synaptic proteins, neurite outgrowth, dendritic spines formation (i.e. the anatomical precursors of new synapses) and an improvement in learning and memory. Other nutrients act as co-factors in the synthesis pathway of neuronal membranes. For example B-vitamins are involved in methylation processes, thereby enhancing the availability of choline as a synaptic membrane precursor. A multi-nutrient concept that includes these nutrients may improve membrane integrity, thereby influencing membrane-dependent processes such as receptor function and amyloid precursor protein (APP) processing, as shown by reduced amyloid production and amyloid β plaque burden, as well as toxicity. Together, these insights provided the basis for the development of a medical food for patients with AD, Souvenaid<sup>®<sup/>, containing a specific combination of nutrients (Fortasyn™ Connect) and designed to enhance synapse formation in AD. The effect of Souvenaid on memory and cognitive performance was recently assessed in a proof-of-concept study, SOUVENIR I, with 212 drug-naïve mild AD patients (MMSE 20-26). This proof-of-concept study demonstrated that oral nutritional supplementation with Souvenaid<sup>®<sup/> for 12 weeks improves memory in patients with mild AD. To confirm and extend these findings, we have designed and initiated three additional studies. Two of these studies will be completed in 2011; Souvenir II, a 24-week European study, with 259 drug-naïve mild AD patients (MMSE≥20) and S-Connect, another 24-week study, with 527 mild-tomoderate AD patients (MMSE 14-24) using AD medication conducted in the US. The third is the EU-funded LipiDiDiet study, a 24-month study, which will enrol 300 people with prodromal AD to assess the effect on memory performance.