Egg yolk for memory — can eggs protect the brain from dementia?

Aim of the study: Dietary guidelines recommend eggs as an effective way to obtain DHA, yet direct evidence on the health effects and optimal dosage of egg yolk lipids for Alzheimer’s disease (AD) remains limited. This study evaluated DHA-enriched egg yolk lipids in 5 × FAD mice at doses of 1 and 2 g kg-1 day-1 for eight weeks, corresponding to human consumption of 1 or 2 eggs daily.

Results: This study evaluated DHA-enriched egg yolk lipids in 5 × FAD mice at doses of 1 and 2 g kg-1 day-1 for eight weeks, corresponding to human consumption of 1 or 2 eggs daily. The high-dose intervention (2 g kg-1) improved cognitive deficits and neuronal damage by increasing BDNF and NGF, improving synaptic plasticity (PSD95, SYN, Drebrin), increasing dendritic spine density, restoring cholinergic and glutamatergic neurons, and suppressing neuroinflammation caused by microglial activation (IL-6, IL-1β, IFN-γ). Metabolomic and gut microbiota analyses showed increased levels of neuroprotective metabolites (PC (20 : 2/22 : 6), neuroprotectin D1) and a greater abundance of genera beneficial for AD, including Muribaculaceae and Lachnospiraceae. This study provides direct experimental evidence supporting DHA-enriched egg yolk lipids as a dietary intervention for AD, with an effective dose of 2 g kg-1.

Aim of the study: The study aimed to assess the effect of the polypeptide Y complex (Yolkin), isolated from chicken egg yolk, on behavioural and cognitive functions. It also aimed to compare this activity with colostrum-derived substances (Colostrinin, Coloco), which have a confirmed impact on learning and memory.

Results: A series of behavioural tests were carried out, including an open field test, a novel object recognition test and a Morris water maze. They were used to evaluate the impact of the studied specimen on improving locomotor function and exploratory behaviour, preventing their decline and assessing episodic and spatial memory in aging rats. Yolkin administration produced effects that differed from those of colostrum-derived substances, while confirming its suggested pro-cognitive action. Therefore, it may be used to enhance cognitive functions and inhibit the progression of dementia in neurodegenerative disorders.

Aim of the study: Data on the effect of phosphatidylcholine (PCh) administration on improving memory in senile dementia of the Alzheimer type are inconsistent, probably because the studies were conducted under different conditions. Animal studies provide a good model, but data on this topic are limited.

Results: On the 2% PCh diet, Dull mice improved in memory acquisition and retention in Experiment 1 and in retention in Experiment 2. On the 8% PCh diet, Dull mice showed improved memory and retention in Experiment 1, but no effect was observed in Experiment 2 (P > 0.05). In normal mice, the 2% PCh diet did not affect memory acquisition or retention, while the 8% PCh diet had no effect or an adverse effect. These results suggest that dietary supplementation with egg yolk PCh improves memory in Dull mice, particularly when given from gestation, and that the 2% PCh diet produces a better response than the 8% PCh diet.

Aim of the study: Phosphatidylcholine (PC), the main dietary source of choline, has been shown to improve learning and memory in rodents. The anti-aging and antioxidant benefits of long-chain n-3 polyunsaturated fatty acids (PUFAs) are also widely known.

Results: In the behavioural test, the latency of the PC groups was significantly reduced, while the number of platform crossings and the time spent in the target quadrant increased compared with the M group. The improvements with SQ-PC and SC-PC were greater than with EL (P < 0.05). A similar trend was seen in physiological changes. Compared with the M group, PC groups showed effectively decreased AchE activity and increased SOD activity in the hippocampus, cortex and white matter. SQ-PC, SC-PC and EL showed decreases in brain MDA levels of 22.82, 28.80 and 11.81%, respectively, compared with the M group. MAO activity in the white matter of the SQ-PC, SC-PC and EL groups decreased by 33.05, 33.64 and 19.73%, respectively, compared with the M group. No significant differences between SQ-PC and SC-PC were found for these indicators, except for SOD activity in the hippocampus and white matter.