Neurological disorders are prevalent in western society, with a global burden surpassing cardiovascular disease and cancer. Yet the causes of mental health issues are only vaguely understood.
Researchers have, however, linked the consumption of dietary fats to the development of the brain. Formed during late pregnancy and early post-natal periods, the brain relies heavily on the accumulation of Docosahexaenoic acid (DHA), a classic omega-3 fatty acid, which plays an important role in development, neuronal signaling and neural function.
“The structural component of the brain is approximately 60 per cent lipids, and about 15-30 per cent of the brain dry weight is polyunsaturated fatty acids of the omega six and omega three classes,” said Kayode Balogun, a PhD graduate student with Biochemistry professor, Dr. Sukhinder Kaur Cheema. “These two types of fatty acids are essential, but the body cannot make them. So offspring require an external supply through the mother’s diet or through breast milk.”
“Any activity that decreases the amount of omega-3, or DHA in particular, in the brain at this critical period of development would eventually lead to an improper function of the brain and, in the long run, to neurological disorders.”
In Canada, studies show there is a decline in the consumption of omega-3 during pregnancy and a simultaneous increase in the prevalence of neurological disorders. In addition, as individuals age over time, the amount of DHA in the brain declines, which has been successfully correlated to the prevalence of neurodegenerative disorders later in life, such as Alzheimer’s and Parkinson's.
“In our lab we have been working to determine whether an increase in omega-3 fed to pregnant females could lead to an accumulation of DHA in the brain of the offspring, and if prolonged postnatal feeding could lead to an even greater accumulation. If there is, could it also affect key proteins and genes involved in the regulation of brain function and actually prevent neurological diseases or disorders?”
To answer their questions, the researchers fed pregnant mice with high or low omega-3 diets throughout pregnancy and lactation so offspring would be exposed to it in utero and during breastfeeding.
“To be sure the offspring had access to omega-3, we actually quantified the amount of it in the breast milk,” said Mr. Balogun. “Interestingly, we found that mothers fed high omega-3 diets had high amounts in their breast milk.
“When the offspring were weaned, we quantified the amount of DHA in the brain and found that there was an increased accretion of DHA compared to offspring that were fed a low omega-3 diet. When we continued the offspring on a high omega-3 diet for another four months post weaning there was a further increase in the amount of DHA in the brain.”
The duo also analyzed a set of genes and proteins responsible for brain function and brain development to determine the effects of diets high in omega-3.
“Neurotrophins are a family of proteins, which are involved in the maintenance of brain function during development and are important for maintaining brain plasticity as we grow older,” said Mr. Balogun.
“We are the first group to actually show that brains with a high expression of omega-3 also had a high expression of neurotrophins.”
That is a key finding, says Dr. Cheema.
“When we exposed these mice to omega-3 for longer time periods the neurotrophin gene expression was maintained as mice aged,” said Dr. Cheema. “But the neurotrophins in those fed a low omega-3 diet went down significantly.”
“Normally as we age mental disorders start increasing,” she said. “Maintaining exposure to omega-3 seems to be beneficial in terms of protecting against the onset of Alzheimer’s Parkinson’s and other neurological disorders. In addition increased neurotrophins could lead to better cognition.
The research group will continue looking to how omega-3 regulates the expression of neurotrophins and collaborations are ongoing with physicians at the Janeway to test breast milk and cord blood samples from mothers who deliver there.
“We want to measure their omega-3 content to see where Newfoundland and Labrador women stand in terms of consuming omega-3 during pregnancy and lactation,” said Dr. Cheema. “Our long-term objective is to see whether or not this improves the health of children in the province.