Abstract: Brain neurons form synapses throughout the life span. This process is initiated by neuronal depolarization, however the numbers of synapses thus formed depend on brain levels of three key nutrients—uridine, the omega-3 fatty acid DHA, and choline. Given together, these nutrients accelerate formation of synaptic membrane, the major component of synapses. In infants, when synaptogenesis is maximal, relatively large amounts of all three nutrients are provided in bioavailable forms (e.g., uridine in the UMP of mothers’ milk and infant formulas). However, in adults the uridine in foods, mostly present at RNA, is not bioavailable, and no food has ever been compelling demonstrated to elevate plasma uridine levels. Moreover, the quantities of DHA and choline in regular foods can be insufficient for raising their blood levels enough to promote optimal synaptogenesis. In Alzheimer’s disease (AD) the need for extra quantities of the three nutrients is enhanced, both because their basal plasma levels may be subnormal (reflecting impaired hepatic synthesis), and because especially high brain levels are needed for correcting the disease-related deficiencies in synaptic membrane and synapses.
Alex's notes: Most of us are familiar with DHA and its importance in health, and I would assume the same of choline. Uridine is a basic nucleic acid that is a crucial component of RNA, and unlike DHA and choline which are prevalent in fatty-fish and eggs, respectively, dietary uridine is not bioavailable and rapidly destroyed within the liver and GI tract. Interestingly, the ability of the brain to create phosphatidylcholine (PC) and other related cognitive compounds requires concentrations of DHA, choline, and uridine that are well above what is normally present. Increasing the concentrations through supplementation increases PC formation.
This review briefly discusses the control of synaptogenesis, concluding that there are many available enzymes and the limiting factor is indeed nutrient availability. It then goes on to discuss the biosynthesis of membrane components and how uridine, DHA, and choline play a role. Overall this review just supports the notion that you should eat your salmon and eggs. Uridine is interesting and may be worth looking into supplementing if you suffer from cognitive issues.