Diets lacking omega-3 fatty acids – found in foods like wild fish, eggs, and grass-fed livestock – can have worsened effects over consecutive generations, especially affecting anxiety levels and hyperactivity in teens, according to a University of Pittsburgh study.

The research, published in Biological Psychiatry, found that in a rodent model second-generation deficiencies of omega-3s caused elevated states of anxiety and hyperactivity in adolescents and affected the teens’ memory and cognition.

“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,” said Bita Moghaddam, lead author of the paper and Professor of Neuroscience in the Kenneth P. Dietrich School of Arts and Sciences.

“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,” Professor Moghaddam said. “This is of particular concern because adolescence is a very vulnerable time for developing psychiatric disorders including schizophrenia and addiction,” she said.

Study details

The research team examined a “second generation” of omega-3 deficient diets, mimicking human adolescents. Researchers said the parents of many of today’s teenagers were born in the 1960s and 1970s, a time period in which omega-3-deficient oils like corn and soy oil became prevalent, and farm animals moved from eating grass, which is typically higher in omega-3s, to grain.

A series of behavioural tasks were administered to study learning and memory, decision making, anxiety, and hyperactivity of both adults and adolescents. Although subjects appeared to be in general good physical health, the study found that there were behavioural deficiencies 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, according to researchers.

“Our study shows 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,” Professor Moghaddam said. “We observed changes in the areas of the brain responsible for decision making and habit formation,” she said.

Epigenetics may be cause

Researchers said they were now exploring epigenetics as a potential cause. Epigenetics is a process in which environmental events influence genetic information. The research team said it will also explore the markers of inflammation in the brain, since omega-3 deficiences cause an increase of omega-6 fats, which are pro-inflammatory molecules in the brain and other tissues.

“It’s remarkable that a relatively common dietary change can have generational effects,” said Professor Moghaddam. “It indicates that our diet does not merely affect us in the short-term but also can affect our offspring,” she said.

The research was supported by grants from the US National Institute of Health and the National Institute on Ageing Intramural Research Program.

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