Science in Society Archive

How to Increase the Brain Power & Health of a Nation

Abundant evidence points to the enormous potential for improving intellectual abilities (and health) through simple environmental and social interventions Dr. Mae-Wan Ho

A new report on intelligence from the American Psychological Association (APA) states [1]: “A large number of interventions have been shown to have substantial effects on IQ and academic achievement.”

The collapse of the genetic paradigm (see [2] No Genes for Intelligence, SiS 53) should convince us to redouble all efforts at appropriate interventions to improve the intellectual prowess of the nation and deliver substantial health bonuses. Let’s look at some of the options.

Education & enrichment programmes

There is clear evidence that schooling affects intelligence, as reviewed in the APA report [1]. Children deprived of school for an extended period of time show IQ deficits as much as 2 SDs (standard deviations). A child entering fifth grade approximately a year earlier than one nearly the same age (who enters fourth grade) will have a verbal IQ more than 5 points higher at the end of the school year, and as much as 9 % higher by the eighth grade.

Children lose IQ and academic skills over the summer and the loss is much greater for children of lower socioeconomic status (SES). The knowledge and skills of children in the upper fifth of family SES, however, actually increase over the summer. This effect is so marked that by late elementary school, much of the difference in academic skills between lower and higher SES children may be due to the loss of skills over the summer for lower SES children as opposed to the gains for higher SES children. Intervention over the summer months targeted at low SES children should narrow this gap. The beneficial effects of schooling apparently continue at least through junior high school.

The best prekindergarten interventions for lower SES children have substantial effects on IQ, but this typically fades by late elementary school, perhaps because the environment of the children do not remain enriched. Two examples in which early gains from prekindergarten intervention remained both placed children in average or above-average elementary schools. Children in the Milwaukee Project had an average IQ 10 points above controls at adolescence; and children in the intensive Alecedarian program had IQs 4.5 points higher than controls at 21 years of age. Regardless of whether high quality interventions have sustained IQ effects, the effects on academic achievement and life outcomes can be very substantial. The gains are particularly marked for intensive interventions such as the Perry School Project and Abecedarian program. By adulthood, individuals who had participated were about half as likely to have repeated a grade in school or to have been assigned to special education classes, and were far more likely to have completed high school, attended college, and to own their own home. This suggests that some of the effects are produced by gains in attention, self-control, and perseverance than IQ.

Self-control and discipline, along with creativity and flexibility are considered the key qualities to success in life, and can be targeted by specific interventions as described in a recent review [3]. For example, martial arts that emphasize self-control, discipline and character development such as tae-kwon-do gave children substantial gains in those cognitive functions (referred to as ‘executive functions’), much more so than standard physical education. The children participating in tae-kwon-do also improved more when tested on mental mathematics. Other effective interventions include ‘mindfulness’ practices that focus one’s complete attention on present experience, and Tools of the Mind that develop social and socializing skills through play.

The quality of teaching in kindergarten has a measurable impact on academic success and life outcomes [1]. Data from Project STAR in Tennessee showed that students randomly assigned to small kindergarten classrooms were more likely to subsequently attend college, attend a high ranked college, and have better life outcomes in a number of respects. Students who had more experienced teachers had higher earnings as adults, as did students for whom the quality of teaching - as measured by test scores - was higher.

Memory training for fluid intelligence

It is perhaps not surprising that training people in working memory skills can enhance fluid intelligence, while having no effect on crystallized intelligence [1]. This applies to both adults and children with attention deficit hyperactivity disorder (ADHD). Working memory training of low SES children using a variety of computer and non-computer games resulted in IQ gains of 10 points on a matrix reasoning task.

Similar memory training over an 8-month period was effective for elderly participants [1]. Training older adults in memory, speed in processing, and particular narrow reasoning skills produces substantial improvements that remain over a period of years. A study in the UK showed that an extra year of work was associated with a delay in the onset of Alzheimer’s disease on average by six weeks.

The overriding importance of early nutrition

The overriding importance of early nutrition for learning is highlighted in a comprehensive resource list for professionals provided by the Food and Nutrition Information Center of US Department of Agriculture’s National Agricultural Library [4]. It gives clear evidence that nutritional intervention in elementary school can improve both health and academic performance.

Retrospective analyses were conducted on school performance indicators associated with the implementation of the Healthy Kids, Smart Kids programme, a grass-roots effort to enhance school food and physical activity environment in Browns Mill Elementary School, Georgia. Data from 1995 to 2006 showed that the number of nurse, counselling and disciplinary referrals per 100 students followed a downward trend, while standardized test scores followed an upward trend beginning in the year of programme implementation.

A second study demonstrated the effect of a two-year obesity prevention programme on body mass index (BMI) and academic performance in low-income elementary schoolchildren. There were 4 intervention schools and one control school totalling 4 588 school children, 48 % Hispanic. The data were presented for the subset (1 197) of the children (68 % Hispanic) who qualified for free or reduced-price school lunches. The results showed that significantly more intervention than control children stayed within normal BMI range for both years. Although not significantly so, more obese children in the intervention than in the control decreased their BMI. Overall, intervention children had significantly higher maths scores in both years, and Hispanic and White intervention children were significantly more likely to have higher maths scores. Although not significantly so, intervention children had higher reading scores in both years.

The association between intelligence and diet at 3.5 and 7 years of age was examined in more than 500 children of European descent in Auckland New Zealand, approximately half of them with low birth weight (≤10th percentile) [5].  The relationship between IQ and diet measured by food frequency was investigated using multiple regression analysis. There was no significant difference in IQ between children with low birth weight and normal birth weight at 3.5 and 7 years of age, and no differences in food frequencies.

Eating margarine at least daily was associated with significantly lower IQ scores at 3.5 years in the total sample, and at 7 years in children with low birth weight. After controlling for potential confounders, children who ate margarine daily scored 2.81 points lower than children who did not. In all children, eating the recommended daily number of breads and cereals – 4 or more times - was associated with significantly higher IQ scores at 3.5 years; the gain was 3.96 points after controlling for potential confounders.  Children who ate fish at least weekly had significantly higher IQ scores at 7 years than those who did not, a gain of 3.64 points after controlling for confounders.

Eating fish does make you smart, it appears, precisely as we have been told in the traditional folklore of many cultures. A large study was carried out in Sweden to evaluate the association between fish intake and academic grades of 9 488 adolescents using multiple linear regression models and adjusting for potential confounders such as parents’ education [6]. The results showed that grades were higher by 14.5 points in adolescents who ate fish once a week compared with those eating fish less than once a week. Adolescents who ate fish more than once a week scored even higher by 19.9 points. In the model stratified for parents’ education, there were still higher grades among children with frequent fish intake in all educational strata.

A review published in 2008 [7] summarized evidence indicating that food insecurity is a prevalent risk to the growth, health, cognitive ability, and behaviour of poor children in the United States.  Infants and toddlers in particular are at risk even at the lowest level of food insecurity. The data indicate an “Invisible epidemic” of a serious condition.

The effect of nutritional status on brain development and scholastic achievement was examined in 96 high school graduates selected from the public and private schools in the richest and poorest counties of Chile’s Metropolitan region [8]. These graduates had no history of alcoholism, or symptoms of brain damage, epilepsy or heart disease, and whose mothers had no history of smoking, alcoholism or drug intake before and during pregnancy (all known to affect foetal development). The object was to have a healthy balanced sample in terms of low and high IQ, sex, and socioeconomic status (SES). The results showed that independently of SES, high school graduates with similar IQ have similar nutritional, brain development and scholastic achievement. Multiple regression analysis revealed that maternal IQ (p < 0.0001), brain volume (p < 0.0387) and severe under-nutrition during the first year of life (p < 0. 0486), were the independent variables with the greatest explanatory power for the IQ variance, without interaction with age, sex or SES. IQ (p < 0.0001) was the only independent variable that explained both scholastic achievement variance and academic aptitude test variance, without interaction with age, sex or SES.

Studies by the Institute of Nutrition of Central America and Panama (INCAP) showed that supplementary feeding of infants and young children - with drinks that provide energy only or with added protein, both containing micronutrients - resulted in significant increases in cognitive development and school performance through to adolescence [9]. The research also suggested that the link of malnutrition to later development is not only through the neurological system, but also through changes in behaviour that affect the kinds of care the individual child receives.

A longitudinal two-year study on school children in rural Kenya found significant relationships on regression analyses between available Fe, available Zn, vitamin B12 and riboflavin with improved cognitive test scores, after controlling for confounders such as energy intake, school, socioeconomic status and illness [10].

Interventions aimed at eliminating food insecurity and micronutrient deficiencies are easily within the means of all developed nations, and should be given top priority in both developed and developing nations.

Exercise increases brain power by making more neurons

A sedentary lifestyle is associated with increased risk for cardiovascular and metabolic diseases as well as cancer, and it is well-known that exercise can reduce the incidence of diabetes, cancers and heart disease. Less well-known is the beneficial effects of exercise for the brain, described in a comprehensive review [11]. In humans and rodents, physical activity enhances cognitive functions and counteracts age-related decline of memory, delays the onset of neurodegenerative diseases enhances recovery from brain injury and depression.

A meta-analysis of a large number of studies on older adults has shown that aerobic exercise, at least for the elderly, is very important for maintaining IQ, especially for executive functions such as planning, inhibition, and scheduling of mental procedures [12]. The effect of aerobic exercise is more than o.5 SD for the elderly, more for those past age 65 than those younger. It is possible to begin cardiovascular exercise as late as the seventh decade of life and substantially reduce the likelihood of Alzheimer’s disease.

But exactly how does exercise work to increase brain power and help prevent degeneration? The most likely answer appears to be through neurogenesis, the ability of the brain to repair and renew itself by making new neurons [11].

Not long ago, neurobiologists and the general public believed that we were born with the neurons we would have in life, and no new neurons would ever be generated in the brain. That dogma was overturned in the 1990s. New neurons are continually generated throughout adulthood, mainly in two regions of the brain: the dentate gyrus in the hippocampus, a paired brain structure involved in memory, learning and emotion, and the subventricular zone, a layer of cells found along the brain’s lateral ventricles. The newly generated neurons form synapses and integrate into existing neuronal circuits.

Laboratory experiments have revealed that exercise not only significantly increases the number of new neurons in rats and mice, it also influences the morphology of individual newly generated cells and enhances their maturation, and is associated with increased plasticity in the hippocampus in forming synapses, thereby influencing learning and memory. In rodents, both voluntary wheel running and forced treadmill training have been shown to improve spatial learning with different types of mazes and training.

In rodents as well as non-human primates, aging is associated with decline in neurogenesis and cognitive functions. The age-dependent reduction in neurogenesis can be partially prevented when animals are housed with a running wheel over a 6-month period. Furthermore, the decline in neurogenesis and cognitive functions associated with normal aging can be reversed in part by wheel-running. Mice that had been sedentary for 18 months were started on the running wheel for one month, after which they showed significant improvements in spatial memory in learning the water maize, and the survival of newly generated neurons was also increased to the level of young sedentary controls.

Correlation between neurogenesis and exercise was first established in mice through MRI measurements of angiogenesis (blood volume) [13]. Among all hippocampus subregions, exercise was found to have a primary effect on the dentate gyrus cerebral blood volume (CBV), the dentate gyrus was only subregion known to support adult neurogenesis. Moreover, exercise-induced increases in dentate gyrus CBV were found to correlate with postmortem measurements of neurogenesis. Using similar MRI technologies, CBV maps were generated over time in the hippocampus of exercising humans. As in mice, exercise was found to have a primary effect on dentate gyrus CBV, and the CBV changes were found to selectively correlate with cardiopulmonary and cognitive function.

Another significant effect of exercise is an increase of brain-derived neurotropic factor (BDNF) in the hippocampus, which supports the survival of existing neurons and encourages the growth and differentiation of new neurons and synapses ([14, 15]). The levels of hippocampal BDNF are significantly higher in wheel-running as opposed to sedentary rodents after 5 days, and correlates with the level of activity. There is also 3.1 fold as many new neurons in the dentate gyrus of running compared to sedentary mice.

Most intriguingly, running also increases retrotransposon activity, reflected in the number of new insertions of long interspersed nucleotide elements (LINEs-1, of L1) in the hippocampus, and also activates silenced L1 insertions in other non-neurogenic brain regions [16]. Such regulated ‘natural genetic engineering’ processes are now found to be particularly active in the brain, and are strongly associated with normal brain function [15] (see also [17] Rewriting the Genetic Text in Human Brain Development, SiS 41).

The correlations between BDNF, neurogenesis, and L1 insertions are presented in Figure 1 [15].   

Description: Excercise increases brain power

Figure 1   Correlations between physical exercise and increase in BDNF neuronal growth factor (A, B), number of new neurons generated (C), and retrotransposon insertions (D) (Redrawn after Charney, 2011 [15])

Article first published 01/02/12



To conclude

There is now overwhelming evidence that perinatal nutrition, education and enrichment programmes, and physical exercise are all highly effective in improving brain function, as well as health and well-being, and for all age groups. For far too long, our policy-makers have been misled and misinformed into believing that intellectual ability and health are largely determined by the genes, and hence social and environmental interventions would have little or no effect. This pernicious genetic determinist ideology has now been definitively and thoroughly refuted by a convergence of findings in molecular genomics and biometrical genetics (see [2, 18] Mystery of Missing Heritability Solved? SiS 53). It is our responsibility to take immediate action in all the appropriate remedial and proactive interventions to safeguard the physical and mental health and well-being of the nation for the present and future generations.

References

  1. Nisbett RE, Aronson J, Blair C, Dickens W, Glynn H, Halpern DF and Turkheimer E. Intelligence: New findings and theoretical developments. American Psychologist, Advance online publication. doi: 10.1037/a0026699
  2. Ho MW. No genes for intelligence. Science in Society 53 (to appear) 2012.
  3. Diamond A and Lee K. Interventions shown to aid executive function development in children 4 to 12 years old. Science 2011, 133, 959-64.
  4. Role of Nutrition in Learning and Behavior: A Resource List for Professionals August 2011, Food and Nutrition Information Center, National Agricultural Library, USDA, http://www.nal.usda.gov/fnic/pubs/learning.pdf
  5. Theodore RF, Thompson JMD, Waldie KE, Wall C, Becroft DMO, Robinson E, Wild CJ, Clark PM and Mitchell EA. Dietary patterns and intelligence in early and middle childhood. Intelligence 2009, 37, 506-13.
  6. Kim J-L, Winkvist A, Åberg MA, Åberg N, Sundberg R, Torén K and Brisman J. Fish consumption and school grades in Swedish adolescents: a study of the large general population. Acta Paediatrica 2010, 99, 72-77.
  7. Cook JT and Frank DA. Annals of the New York Academy of Sciences 2008, 1136, 193-209.
  8. Ivanovic DM, Leiva BP, Pérez HT, Almagià AF. Toro TD, Soledad M, Urrutia C, Inzunza NB and Bosch EO. Nutritional status, brain development and scholastic achievement of Chilean high-school graduates from high and low intellectual quotient and socio-economic status. British Journal of Nutrition 2002, 87, 81-92.
  9. Engle PL and Fernández PD. INCAP studies of malnutrition and cognitive behavior. Food & Nutrition Bulletin 2010, 31, 83-94.
  10. Gewa CA, Weiss RE, Bwibo NO, et al. Dietary micronutrients are associated with higher cognitive function gains among primary school children in rural Kenya. British Journal of Nutrition 2009, 101, 1378-87.
  11. Van Praag H. Neurogenesis and Exercise: past and future directions. Neuromol Med DOI 10.1007/s12017-008-8028-z
  12. Colcombe S and Kramer AF. Fitness effects on the cognitive function of older adults: a meta-analytic study. Psychological Science 2003, 14, 125-30.
  13. Pereira AC, Huddleston DE, Brickman AD, Sosunov AA, Hen R, McKhann GM, Sloan R, Gage FH, Brown, TR and Small SA. An in vivo correlate of exercise-induced neurogenesis in the adult dentate gyrus. PNAS 2007, 104, 5638-43
  14. Cotman CW and Berchtold NC. Exercise: a behavioural intervention to enhance brain health and plasticity. Trends in Neuroscience 2002, 25, 295-301.
  15. Charney E. Behaviour genetics and post genomics. Behavioral and Brain Sciences (in press), 2011.
  16. Muotri AR, Marchetto MCN, Zhao C and Gage FH. Environmental influence on L1 retrotransposons in the adult hippocampus. Hippocampus 2009, 19, 1002-7.
  17. Ho MW. Rewriting the genetic text in human brain development and evolution. Science in Society 41, 16-19, 2009.
  18. Ho MW. Mystery of missing heritability solved? Science in Society 53 (to appear) 2012.

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Todd Millions Comment left 2nd February 2012 22:10:11
Some of the more mage observers when I was a child had noticed that-infants copy parents too the extent that the most important determnite for a childs literacy was;The kid seeing their parents reading.The unstated follow through of course would be a supply of good picture based books,with simple clear text for them to copy this behaviour with. I'm unsure how the "smart"phones change this-social media is particularly alarming too me on this point-amoung all the others. Before it was the inexplicable -"read too your child approach"in vogue,rather than a read with child. One thing,on the variable test score point-The basic game theory for any timed exan(work it or multiple choice)-is (as I worked it out,age 9.),do the questions you get FIRST,star the ones you can get,with some figuring;and check mark the ones that you may or may not be able too work out.Awnser in that priority. You would be suprised how much this can bump up an IQ too those who haven't figured it out.A raised in cold war peace divident I suppose. Now-after my must do in strict sequence steam engineer training(heat content),if I try too use this approach-I have an small attack that I'm NOT doing it step by step.So my score suffers.But my actual ability is the same.

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