Teenage Boys Who Eat Fish At Least Once A Week Achieve Higher Intelligence Scores

Fifteen-year-old males 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, according to a study of nearly 4,000 teenagers published in the March issue of Acta Paediatrica.Eating fish once a week was enough to increase combined, verbal and visuospatial intelligence scores by an average of six per cent, while eating fish more than once a week increased them by just under 11 per cent.

Swedish researchers compared the responses of 3,972 males who took part in the survey with the cognitive scores recorded in their Swedish Military Conscription records three years later.

"We found a clear link between frequent fish consumption and higher scores when the teenagers ate fish at least once a week" says Professor Kjell Torén from the Sahlgrenska Academy at the University of Gothenburg, one of the senior scientists involved in the study. "When they ate fish more than once a week the improvement almost doubled.

"These findings are significant because the study was carried out between the ages of 15 and 18 when educational achievements can help to shape the rest of a young man's life."

The research team found that:

* 58 per cent of the boys who took part in the study ate fish at least once a week and a further 20 per cent ate fish more than once a week.
* When male teenagers ate fish more than once a week their combined intelligence scores were on average 12 per cent higher than those who ate fish less than once a week. Teenagers who ate fish once a week scored seven per cent higher.
* The verbal intelligence scores for teenagers who ate fish more than once a week were on average nine per cent higher than those who ate fish less than once a week. Those who ate fish once a week scored four per cent higher.
* The same pattern was seen in the visuospatial intelligence scores, with teenagers who ate fish more than once a week scoring on average 11 per cent higher than those who ate fish less than once a week. Those who ate fish once a week scored seven per cent higher.

"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" says Professor Torén.

"However we believe that this is the first large-scale study to explore the effect on adolescents."

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" explains Professor Torén.

"Fish contains both omega-3 and omega-6 fatty acids which are known to accumulate in the brain when the foetus is developing. Other theories have been put forward that highlight their vascular and anti-inflammatory properties and their role in suppressing cytokines, chemicals that can affect the immune system."

In order to isolate the effect of fish consumption on the study subjects, the research team looked at a wide range of variables, including ethnicity, where they lived, their parents' educational level, the teenagers' well-being, how frequently they exercised and their weight.

"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" concludes lead author Dr Maria Aberg from the Centre for Brain Repair and Rehabilitation at the University of Gothenburg.

"We also found the same association between fish and intelligence in the teenagers regardless of their parents' level of education."

The researchers are now keen to carry out further research to see if the kind of fish consumed - for example lean fish in fish fingers or fatty fish such as salmon - makes any difference to the results.

"But for the time being it appears that including fish in a diet can make a valuable contribution to cognitive performance in male teenagers" says Dr Aberg.

Evidence Appears To Show How And Where Brain's Frontal Lobe Works

A Brown University study of stroke victims has produced evidence that the frontal lobe of the human brain controls decision-making along a continuum from abstract to concrete, from front to back.Abstract actions can be controlled at an abstract level, such as deciding to make a sandwich, or at more concrete and specific levels, such as choosing a sequence of movements that make the sandwich.

The scientific data supports preexisting theories that abstract decisions about action take place in the front of the frontal lobe, the back portion controls the capacity for concrete decisions, and the progression from front to back forms a gradient from abstract to concrete.

The Brown researchers are among the first to show that specific areas of the frontal cortex are needed for different levels of abstract decision.

The finding, to be detailed March 1 in the journal Nature Neuroscience, represents a huge leap in comprehending how the brain supports higher level cognition and intelligent behavior. It could lead to advances in everything from the treatment of strokes to understanding how humans develop thought. Researchers from the University of California–Berkeley also participated in the study.

“It is among the strongest evidence to date for a systemic organization of the frontal cortex,” said lead author David Badre, an assistant professor of cognitive and linguistic sciences at Brown University.

The frontal cortex of brain has been long known to affect the internal control of behavior. It controls the capacity to plan, reason, conduct higher-level thinking and connect what we know about the world to how we behave.

Badre and his collaborators came to their conclusion by studying stroke victims who suffered damage to different parts of the frontal lobe. The patients all suffered a stroke at least six months prior to testing. All were screened with an MRI or CT scan to determine where any lesions existed in the brain post-stroke.

The scientists recruited 11 patients — seven men and four women, ranging from age 45 to 73. A 12th patient was recruited but could not perform any of the tests involved.

Researchers gave the patients four different tests that ultimately required selecting a finger-press response. For example, the first test would show a color such as red, which required an index finger push. Blue would trigger the middle finger. The test would then become more difficult by adding more alternate finger presses.

Patients faced greater challenges in selecting a response as subsequent, progressive tests became more complex, with more abstract options.

Badre and colleagues found that damage at a given location affected more abstract decisions but left intact the capacity for more concrete decisions. “If there is damage in a given spot, it will affect all higher (decision-making) functions but not lower functions,” Badre said.

The National Institutes of Health, Veterans Administration Research Service and a National Research Service Award supported the research.

HIV Is Evolving To Evade Human Immune Responses

HIV is evolving rapidly to escape the human immune system, an international study led by Oxford University has shown. The findings, published in Nature, demonstrate the challenge involved in developing a vaccine for HIV that keeps pace with the changing nature of the virus.The extent of the global HIV epidemic gives us a unique opportunity to examine in detail the evolutionary struggle being played out in front of us between an important virus and humans,’ says lead researcher Professor Philip Goulder of the Peter Medawar Building for Pathogen Research at Oxford University.

‘Even in the short time that HIV has been in the human population, it is doing an effective job of evading our best efforts at natural immune control of the virus. This is high-speed evolution that we’re seeing in the space of just a couple of decades.’

The study better describes HIV's ability to adapt by spelling out at least 14 different "escape mutations" that help keep the virus alive after it interacts genetically with immunity molecules that normally attack HIV.

"Key genetic regions of HIV introduced into individuals of different ancestry in different places have been evolving to a greater or lesser degree according to inherited factors controlling immune response," said Richard Kaslow, M.D., a professor in the UAB School of Public Health and a co-author of the study. "If HIV adapts differently in genetically distinct hosts, the challenge ahead in vaccine design is formidable," he said.

HIV has already killed 25 million people, and an estimated 33 million are currently infected. However, HIV does not kill all people at the same rate. On average, an adult with HIV will survive for ten years without anti-HIV drugs before developing AIDS. But some people will progress to AIDS within 12 months while others can make effective immune responses to the virus and survive without any anti-HIV therapy for over 20 years.

Genes encoding a key set of molecules in the human immune system called the human leucocyte antigens (HLA) are critically important. HLA determine the progress of many infectious diseases including HIV, and enable the recognition and killing of HIV-infected cells. Humans differ from each other in the exact HLA genes they have, and small differences can make the difference in how long it takes to progress to AIDS.

The research team set out to determine whether HIV is adapting to human immune responses. They looked at HIV genetic sequences in different countries around the world, including the UK, South Africa, Botswana, Australia, Canada, and Japan, wanting to see whether the HIV sequences could be related to the different HLA genes present in the different populations.

The collaboration between Oxford University, the Ragon Institute at Massachusetts General Hospital, Kumamoto University in Japan, the Royal Perth Hospital and Murdoch University in Australia and others analysed the genetic sequences of the HIV virus and human leucocyte antigen (HLA) genes in over 2,800 people.

Mutations that allow HIV to get round immune responses directed by a particular HLA gene were found more frequently in populations with a high prevalence of that HLA gene. This is strong evidence for HIV adaptation to the human immune system at the level of populations.

‘Where a favourable HLA gene is present at high levels in a given population, we see high levels of the mutations that enable HIV to resist this particular gene effect,’ says author Professor Rodney Phillips, co-director of the James Martin Institute for Emerging Infections at Oxford University. ‘The virus is outrunning human variation, you might say.’

‘The temptation is to see this as bad news, that these results mean the virus is winning the battle,’ says Professor Goulder. ‘That’s not necessarily the case. It could equally be that as the virus changes, different immune responses come into play and are actually more effective.’

The results are important because it is our most effective immune responses that vaccines against HIV would try and boost to a level that would protect against the virus.

‘The implication is that once we have found an effective vaccine, it would need to be changed on a frequent basis to catch up with the evolving virus, much like we do today with the flu vaccine,’ explains Professor Goulder.

‘In this anniversary year of Darwin’s birth, we are accustomed to think of evolution happening over thousands, tens of thousands and even millions of years,’ says Professor Goulder. ‘But we are seeing changes in HIV, and our immune response to the virus, in just a couple of decades.’

The work was funded by a number of organisations including the Wellcome Trust, the Medical Research Council, the US National Institutes of Health, and Oxford’s James Martin 21st Century School.