Study Title:

Adolescent Behavior and Dopamine Availability Are Omega 3 Influenced

Study Abstract

Background

Understanding the nature of environmental factors that contribute to behavioral health is critical for successful prevention strategies in individuals at risk for psychiatric disorders. These factors are typically experiential in nature, such as stress and urbanicity, but nutrition—in particular dietary deficiency of omega-3 polyunsaturated fatty acids (n-3 PUFAs)—has increasingly been implicated in the symptomatic onset of schizophrenia and mood disorders, which typically occurs during adolescence to early adulthood. Thus, adolescence might be the critical age range for the negative impact of diet as an environmental insult.

Methods

A rat model involving consecutive generations of n-3 PUFA deficiency was developed on the basis of the assumption that dietary trends toward decreased consumption of these fats began 4–5 decades ago when the parents of current adolescents were born. Behavioral performance in a wide range of tasks as well as markers of dopamine-related neurotransmission was compared in adolescents and adults fed n-3 PUFA adequate and deficient diets.

Results

In adolescents, dietary n-3 PUFA deficiency across consecutive generations produced a modality-selective and task-dependent impairment in cognitive and motivated behavior distinct from the deficits observed in adults. Although this dietary deficiency affected expression of dopamine-related proteins in both age groups in adolescents but not adults, there was an increase in tyrosine hydroxylase expression that was selective to the dorsal striatum.

Conclusions

These data support a nutritional contribution to optimal cognitive and affective functioning in adolescents. Furthermore, they suggest that n-3 PUFA deficiency disrupts adolescent behaviors through enhanced dorsal striatal dopamine availability.

From press release:

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



Published in Biological Psychiatry, the Pitt team 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 behavioral health of adolescents, not only because their diet is deficient but because their parents' diet was deficient as well. This is of particular concern because adolescence is a very vulnerable time for developing psychiatric disorders including schizophrenia and addiction."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 teens, according to a University of Pittsburgh study.

Performing experiments in rats in Moghaddam's laboratory, the research team examined a "second generation" of omega-3-deficient diets, mimicking present-day adolescents. Parents of many of today's teens 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 to grain. Since omega-3s are present in grass and algae, much of today's grain-fed cattle contain less of these essential fatty acids.

The Pitt team administered a set of behavioral tasks to study the learning and memory, decision making, anxiety, and hyperactivity of both adults and adolescents. Although subjects appeared to be in general good physical health, there were behavioral 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.

"Our study shows that, while the omega-3 deficiency influences the behavior of both adults and adolescents, the nature of this influence is different between the age groups," said Moghaddam. "We observed changes in areas of the brain responsible for decision making and habit formation."

The team is now exploring epigenetics as a potential cause. This is a process in which environmental events influence genetic information. Likewise, the team is exploring markers of inflammation in the brain since omega-3 deficiencies causes an increase of omega-6 fats, which are proinflammatory molecules in the brain and other tissues.

"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."

Other Pitt researchers involved in the study include Gonzalo Torres (ENGR '81), associate professor of neurobiology, and, from the Moghaddam laboratory: Corina Bondi, postdoctoral fellow; Jody Tock, laboratory technician; and Nelson Totah (A&S '12G), now a postdoctoral fellow at Max Planck Institute for Biological Cybernetics. The team also included, from the National Institutes of Health, Stanley Rapoport, senior investigator and chief of the brain physiology and metabolism unit; Ameer Taha, visiting fellow; and Yewon Cheon, program coordinator.

Study Information

Corina O. Bondi, Ameer Y. Taha, Jody L. Tock, Nelson K.B. Totah, Yewon Cheon, Gonzalo E. Torres, Stanley I. Rapoport, Bita Moghaddam.
Adolescent Behavior and Dopamine Availability Are Uniquely Sensitive to Dietary Omega-3 Fatty Acid Deficiency
Biological Psychiatry
2013 July
University of Pittsburgh

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