Swedish study links fishy diets to superior mental scores among adolescent males
by Craig Weatherby
The results of a new study from Northern Europe adds to the substantial body of evidence suggesting that fishy diets benefit brains at all ages.
These findings are especially significant because they affect males in mid-adolescence… a time when the brain is still developing, and academic achievement becomes most critical to future prospects.
A while back, we covered U.S. research that revealed the surprising malleability of teenagers’ brains, in “Omega-3s Seen Boosting Performance of Healthy Young Brains”.
The new findings suggest that the impacts of fish diets may be especially strong at this stage of life.
The intelligence scores of boys who ate fish more than once a week were 12 percent higher than those of boys who ate fish less than once a week.
And there were other positive outcomes for the fish lovers, as we'll relate.
First study to link fish to brain benefits in teenagers
Swedish researchers compared the responses of 3,972 males who took part in the survey at age 15 with the cognitive scores recorded in their Swedish Military Conscription records three years later (age 18).
Among these 15-year-old males, those who ate fish at least once a week displayed higher cognitive skills at the age of 18 than those who it ate it less frequently.
“We found a clear link between frequent fish consumption and higher scores when the teenagers ate fish at least once a week” said Professor Kjell Torén from the Sahlgrenska Academy at the University of Gothenburg. “When they ate fish more than once a week the improvement almost doubled.”
More than half (58 percent) of the boys who took part in the study ate fish at least once a week and a further one-fifth (20 percent) ate fish more than once a week.
The research team reported these key outcomes:
A number of studies have already shown that fish can help neurodevelopment in infants, reduce the risk of impaired cognitive function from middle age onwards and benefit babies born to women who ate fish during pregnancy.
- When male teenagers ate fish more than once a week their combined intelligence scores were on average 12 percent higher than those who ate fish less than once a week. Teenagers who ate fish once a week scored seven percent higher.
- The verbal intelligence scores for teenagers who ate fish more than once a week were on average nine percent higher than those who ate fish less than once a week. Those who ate fish once a week scored four percent higher.
- Teenagers who ate fish more than once a week posted visuo-spatial intelligence scores 11 percent higher than those who ate fish less than once a week. Those who ate fish once a week scored seven percent higher.
However, the Swedish study is the first large-scale study to explore the effect that eating fish exerts on adolescents’ mental performance.
In order to isolate the effect of fish consumption on the teenage boys, the research team looked at a wide range of variables, including their ethnicity, where they lived, their parents’ educational level, the teenagers’ well-being, how frequently they exercised, and their weight.
Lead author Dr. Maria Aberg made two key points:
“Having looked very carefully at the wide range of variables explored by this study it was very clear that there was a significant association between regular fish consumption at 15 and improved cognitive performance at 18.”
“We also found the same association between fish and intelligence in the teenagers regardless of their parents' level of education.”
The researchers plan further research to see if the kind of fish consumed—for example, lean fried fish, or fatty fish such as salmon—makes any difference to the results.
“But,” as Dr. Aberg said, “for the time being it appears that including fish in a diet can make a valuable contribution to cognitive performance in male teenagers.”
Omega-3s remain the likely brain-boosting factor
The exact mechanism that links fish consumption to improved cognitive performance is still not clear.
“The most widely held theory is that it is the long-chain polyunsaturated fatty acids found in fish that have positive effects on cognitive performance,” explained Professor Torén.
"Fish contains both omega-3 and omega-6 fatty acids which are known to accumulate in the brain when the fetus is developing. Other theories have been put forward that highlight their vascular and anti-inflammatory properties and their role in suppressing pro-inflammatory immune system chemicals [e.g., cytokines].”
- Aberg MA, Aberg N, Brisman J, Sundberg R, Winkvist A, Torén K. Fish intake of Swedish male adolescents is a predictor of cognitive performance. Acta Paediatr. 2009 Mar;98(3):555-60. Epub 2008 Oct 29.
- University of Gothenburg (UG). Teenage boys who eat fish at least once a week achieve higher intelligence scores. Accessed online at http://www.sahlgrenska.gu.se/english/news_and_events/news/News_Detail/?contentId=872716