The team of US researchers used rats to model how second-generation deficiencies of omega-3 fatty acids affected long-term health, mood and cognitive functions - finding that deficiencies in the essential fatty-acid over consecutive generations can lead to cognitive and behavioural problems.
Writing in Biological Psychiatry , the team revealed that a lack of omega-3 led to elevated states of anxiety and hyperactivity in second generation adolescents and affected their memory and cognition.
"We found that this dietary deficiency can compromise the behavioural health of adolescents, not only because their diet is deficient but because their parents' diet was deficient as well," said Professor Bita Moghaddam of the University of Pittsburgh - lead author of the paper. "This is of particular concern because adolescence is a very vulnerable time for developing psychiatric disorders including schizophrenia and addiction."
"We have always assumed that stress at this age is the main environmental insult that contributes to developing these conditions in at-risk individuals but this study indicates that nutrition is a big factor, too," she suggested.
Indeed, Moghaddam noted that her team's findings show that while the omega-3 deficiency influences the behaviour of both adults and adolescents, "the nature of this influence is different between the age groups."
"We observed changes in areas of the brain responsible for decision making and habit formation."
Moghaddam and her research team examined the effects of a "second generation" of omega-3-deficient diets - which mimics the situation of many present-day adolescents.
"Given that dietary trends toward lower omega-3 PUFA consumption began in the 1960s and 1970s when most parents of current adolescents and young adults were born, the consecutive generational model might be relevant to the current state of omega-3 PUFA deficiency in humans," said the authors.
"This model therefore makes a strong case for the nutritional contribution to dopamine-related cognitive and affective functioning and vulnerability to psychiatric illness in adolescents."
The team gave both adults and adolescents rats a set of behavioural tasks to study their learning and memory, decision making, anxiety, and hyperactivity - finding that although subjects appeared to be in general good physical health, there were behavioural deficiencies in adolescents that were more pronounced in second-generation subjects with omega-3 deficiencies.
Overall, these adolescents were more anxious and hyperactive, learned at a slower rate, and had impaired problem-solving abilities, the team revealed.
"It's remarkable that a relatively common dietary change can have generational effects," said Moghaddam. "It indicates that our diet does not merely affect us in the short-term but also can affect our offspring."
"These findings bear relevance to public health, given that the second generation of deficient adolescents might mimic the current state of omega-3 PUFA deficiency in some human adolescents," the team concluded.
"In addition to compromising optimal behavioural health, this common dietary deficiency might be a critical environmental factor that contributes to illness progression in individuals at risk for developing major psychiatric disorders, including mood disorders or schizophrenia."
Source: Biological Psychiatry
Published online ahead of print, doi: 10.1016/j.biopsych.2013.06.007
"Adolescent Behavior and Dopamine Availability Are Uniquely Sensitive to Dietary Omega-3 Fatty Acid Deficiency"
Authors: Corina O. Bondi, Ameer Y. Taha, Jody L. Tock, et al