Scientists use protein to encapsulate omega-3 oil and boost brain development
Chinese scientists show the use of nanoencapsulated suspensions not only benefit the foetal brain absorption of DHA but also in the brains of the foetus' mother and her offspring.
In subsequent behaviour assessments, the DHA Nanoencapsulation (FO) diet showed enhanced learning and memory improvement compared to the normal Fish Oil (FO) diet.
“Our team innovated the nano-encapsulation technology, which is proven to be an effective technology to protect DHA from oxidation in vivo, thus enhancing the absorption and efficacy of DHA,” said Dr Wang Yi, the study’s lead author and assistant professor at The Hong Kong Polytechnic University.
“Our findings also indicated that the technology can help overcome blood-brain barrier in DHA delivery. We therefore believe that the technology could be further applied to enhance the efficiency of drug delivery for the brain, such as those for patients with dementia or Alzheimer's disease."
Given DHA is highly unsaturated and is vulnerable to oxidation and degradation under acid conditions, the research team are uncertain that the intake of DHA through a supplementation regime would be effectively delivered and absorbed in vivo.
DHA is highly concentrated in human brain and cerebral cortex, especially as structural lipid components of biomembranes and is essential for the development and function of brain,
Extensive research has identified its role in the synaptic processes, neuronal differentiation and growth, and the regulation of neurotransmission and neuroinflammation.
Zein, an edible corn protein
Along with Dr Yi, professor Wong Man-sau, another professor based at the University and colleagues used Zein, an edible corn protein, as the encapsulation material to mimic the milk fat globule membrane and protect DHA from oxidation.
This material forms a core-shell structure to protect DHA in fish oil during gastric digestion and aid DHA absorption in the brain, intestine and placenta.
Next, they took two groups of six maternal mice each and fed them with Normal Fish Oil (Normal FO) and Nano-encapsulated Fish Oil (Nano FO) respectively.
The team found DHA concentrations in the duodenum and jejunum of the Nano FO group were significantly higher than the Normal FO group.
“The result implies that DHA, being protected by the encapsulation structure from oxidation and degradation under stomach's acidic conditions, is successfully released in the upper two parts of the small intestine of the Nano FO group,” the team said.
Additional results saw DHA levels in the brain of the Nano FO maternal mice significantly higher, suggesting DHA delivery via the Nano FO more effective in overcoming the blood-brain barrier.
Brain benefits from high DHA levels
Further experiments on the maternal mice’s offspring found notable evidence of early brain development in mice given the nanoencapsulation suspension of DHA.
Here, the researchers were divided the mice into six groups, each with 10. They were fed with either no DHA meal; Zein; normal low dose fish oil (Normal FO-low); normal high dose fish oil (Normal FO-high); Nano-encapsulated low dose fish oil (Nano FO-low); and Nano-encapsulated high dose fish oil (Nano FO-high).
Three groups, Normal FO-high, Nano FO-low and Nano FO-high were observed spending more time on new objects rather than on familiar objects, suggesting an advanced capacity to learn and memorise.
Higher amounts of Brain-Derived Neurotrophic Factor (BDNF) in the hippocampus were found in the Nano FO-high group.
BDNF, a protein ‘switched on’ by DHA, is involved in brain neuron survival and encouraging the growth of new ones.
These mice also displayed better spatial learning and memory abilities in the Y-maze experiment, an assessment of the willingness of rodents to explore new environments.
“Zein nanoencapsulation is with high potential for drug and nutrient deliveries to brain and through placenta to foetus with no toxicity concern,” the study concluded.
Source: Nanomedicine: Nanotechnology, Biology and Medicine
Published online: doi.org/10.1016/j.nano.2018.09.006
“A nanoencapsulation suspension biomimetic of milk structure for enhanced maternal and fetal absorptions of DHA to improve early brain development.”
Authors: Jie Zeng et al.