Abstract
The purpose of this study is to find the influence of foods that improve the learning abilities for a student. While studying for a day long, our brain needs to go through continuous work. Certain nutrients are necessary for proper brain functioning. Studies found that, sialic acid, folate, choline, omega-3 fatty acids, and vitamin B6 and B12 perform an important role to our sustained ability to learn. This paper will provides an overview of recent studies on the brain functions associated with certain nutrition. What Nutritional Elements Elevate Learning Abilities?
Certain foods are responsible for the proper brain functioning where as proper brain functioning is a prerequisite for efficient cognitive and learning ability. So, which foods, or at least which components of certain foods, have a more positive impact to keep our memory and learning abilities as the decades pass? Researchers have shown their interest in the potential for food and specific nutrients to influence various aspects of the psychological state, including mental performance and psychological well-being (Dye, Lluch, & Blundell 2000).
There are a number of dietary components that have been identified as influencing cognitive performance. Among them folate, vitamins B6 and B12, antioxidants, omega-3 fatty acids, amino acids, glucose, caffeine, thiamine, niacin, choline, sialic acid, zinc, and iron have a major impact on cognitive performance (Bryan, Calvaresi, & Hughes, 2002; Bryan & Calvaresi, 2003; Morris, Evans, & Bienias, 2004). Foods provided by schools also have influence on students’ performance and their learning behavior.
It was found that by providing and promoting healthier school food at lunchtime and improving the school dining room environment resulted in improvements in pupils’ learning-related behavior in the classroom after lunch (Golley, Baines, Bassett, Wood, Pearce, & Nelson, 2010). Researchers are also concerned about the excessive amount of nutrients. Some studies found that elevated amount of nutrients may interfere with brain functioning. For instance, in Bangladeshi children, Wasserman et al.
(2004, 2006) observed a negative effect of high manganese (Mn, a trace mineral which is needed for good nutrition) levels in tube well water on cognitive capacities. This paper will review existing information about nutrients that are responsible for enhancing cognitive performance. First, the type of nutrients, their source, and activity will be described. Then some recent studies related with healthy food and academic performance will be studied. Finally, impact of excess amounts of nutrients with brain functioning also will be explained.
Required nutrients at early stages of life For better brain functioning, proper nutrition should be provided from the birth of a child. Wang et al. , (2001) found that sialic acid influences the brain growth and learning abilities of human. Concentration of siallic acid in neural cell membrane is 20 times higher than the other membrane in human body. The same study also found that the human brain contains 2 to 4 times higher sialic acid than other mammals. So sufficient amount of sialic acid should be provided from the early life of a child. Their (Wang et al.
, 2001) research shows that human milk is a great source of oligosaccharide-bound sialic acid. To find the relationship between nutritional status and intellectual capacity among the six-year-old children, a study was conducted by Arija et al. , (2005) in Spain. 83 subjects (43 boys and 40 girls) participated in that study. The IQ of each subject was measured using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) (Wechsler, 1996). They also were interviewed individually and verbal and non-verbal IQ were obtained on a scale 150.
Their nutritional status was evaluated by their using a 3-day food record during non-consecutive days including one holiday (Thompson et al. , 1994). The nutritional intake was calculated by the French REGAL food composition table (Favier et al. , 1997). The findings of this paper indicate that iron and folate nutritional status is highly associated with childhood IQ. Figure 1. Relation between iron intake and non-verbal IQ (left) and folate intake and verbal IQ (right). Copied from Arija et al. , (2005). In the figure 1 there was a tendency towards higher intake of iron and folates in the group with high IQ’s.
Apart from this relationship they did not find any associations between other nutrients or metabolites associated with the metabolism of these micronutrients, such as vitamin C, riboflavin and pyridoxine. Healthier school food at lunchtime and improved dining room environment, also have an impact on students’ learning related behavior in the classroom after lunch. It was found that food provided by the school has the potential to support children’s nutrition, growth and development (School Meals Review Panel, 2005). A study by Golley et al.
, (2010) in six primary schools matched in triplets and randomly assigned a 12-week intervention group or 12-week wait-listed control group. The intervention groups included promotion of healthier school food at lunchtime and changes in the school dining environment. Findings of this study indicates that a school food and dining room intervention can have a positive impact on pupils’ attentiveness. however, the authors also suggested that if raised alertness is not channeled and supervised , it may result in increased off-task behavior when pupils are working together.
Another essential nutrient, choline, plays an important role in the normal development of the brain, especially in memory center of the brain. Research shows (Zeisel , 2004) lack of choline in mother’s diet during pregnancy and lactation may have life-long effects on her child. The development of hippocampus (the memory centre of brain) in human begins after birth, and by 4 year of age it closely resembles adult structure (Dani et al. , 1997). Content of free choline in human milk is very high at the start of lactation, however, it diminishes to quantities similar to that in the commercial formulas by 30 days postpartum (Zeisel et al.
, 1986). Foods highest in total choline concentration per 100g are beef liver (418mg), chicken liver (290 mg), eggs (251 mg), wheat germ (152 mg), bacon (125 mg), dried soybeans (116 mg), and pork (103 mg) (Zeisel , 2004). For proper development of hippocampus, the Institute of Medicine (IOM) of the National Academy of Sciences set an adequate intake level for choline of 550mg/day for men and 425 mg/day for women. Effect of Nutrition on Cognition It has been suspected that cognitive processes and emotions can be affected by the relative abundance of specific nutrients.
If we can understated the molecular basis of the effects of food on the cognition, it will help us to determine how best to manipulate diet to increase the resistance of neurons to insults and promote mental fitness. This section will mainly be focused on recent evidence that shows the capacity of nutrients to affect neural pathways that are associated with synaptic plasticity. In the following table, the nutrients that affect cognition and emotion were enlisted. In addition, their food sources were also mention in the table. Table 1 Selected nutrients that affect cognitive function and emotion.
Copied from Pinilla, (2008) and Wolf et al. , (2000). Nutrient Effects on cognition and emotion Food sources Omega-3 fatty acids Amelioration of cognitive decline in the elderly; basis for treatment in patients with mood disorders; improvement of cognition in traumatic brain injury in rodents Fish (salmon), flax seeds, krill, chia, kiwi fruit, butternuts, walnuts Curcumin Amelioration of cognitive decay in mouse model of Alzheimer’s disease123; amelioration of cognitive decay in traumatic brain injury in rodents Turmeric (curry spice)
Flavonoids Cognitive enhancement in combination with exercise in rodents; improvement of cognitive function in the elderly Cocoa, green tea, Ginkgo tree, citrus fruits, wine (higher in red wine), dark chocolate Saturated fat Promotion of cognitive decline in adult rodents; aggravation of cognitive impairment after brain trauma in rodents; exacerbation of cognitive decline in aging humans Butter, ghee, suet, lard, coconut oil, cottonseed oil, palm kernel oil, dairy products (cream, cheese), meat B vitamins
Supplementation with vitamin B6, vitamin B12 or folate has positive effects on memory performance in women of various ages; vitamin B12 improves cognitive impairment in rats fed a choline-deficient diet Various natural sources. Vitamin B12 is not available from plant products Vitamin D Important for preserving cognition in the elderly Fish liver, fatty fish, mushrooms, fortified products, milk, soy milk, cereal grains Protein Provides the amino acid tyrosine needed for the release of key neurotransmitters, resulting in increased alertness and motivation, sustain energy releases, deficiencies may result in mental impairment.
Meat, food, seafood, eggs, dairy products, grain products, legumes Combination of vitamins (C, E, carotene) Antioxidant vitamin intake delays cognitive decline in the elderly Vitamin C: citrus fruits, several plants and vegetables, calf and beef liver. Vitamin E: see above Calcium, zinc, selenium High serum calcium is associated with faster cognitive decline in the elderly;reduction of zinc in diet helps to reduce cognitive decay in the elderly; lifelong low selenium level associated with lower cognitive function in humans Calcium: milk, coral. Zinc: oysters, a small amount in beans, nuts, almonds, whole grains, sunflower seeds.
Selenium: nuts, cereals, meat, fish, eggs Copper Cognitive decline in patients with Alzheimer’s disease correlates with low plasma concentrations of copper Oysters, beef/lamb liver, Brazil nuts, blackstrap molasses, cocoa, black pepper Iron Iron treatment normalizes cognitive function in young women Red meat, fish, poultry, lentils, beans Fat In combination with protein, sustains glucose breakdown longer, carrier of fat-soluble vitamins A, D, E and K and essential fatty acids, which nerve cell membranes, Over- or under consumption can trigger a neurotransmitter imbalance Oils, salad dressings, butter, margarine, lard layers on meat.
Most fats are hidden because they are added during food preparation. Vitamin B12, folic acid, and iron are also associated with impairment of memory, concentration and learning ability. A study (Masalha et al. , 2008) was conducted to determine the impact of the deficiency of vitamin B12 and folic acid on the academic achievement of elementary school children from a low socio-economic population, living in southern Israel. The amount of nutrients were determined from the 67 blood sample (30 boys and 37 girls) of Rahat Public Elementary School in Southern Israel.
Each samples’ Academic Achievement Index ( Carruyo-Vizacaino et at. , 1995) was calculated by averaging final grades in all courses studied during the previous two semesters, for each subject in this study. To determine the number of meat meals consumed weekly, the number of family members living in the same house and whether the father was employed or not, an independent interviewer did administer a personal questionnaire. The linear probability model of grade good was shown in the following table. These results show that probability of good grades increases if the vitamin B12 > 200pg/mL and the father has a job.
Table 2 Association of vitamin B12 deficiency and low serum hemoglobin levels with academic achievement. Copied from Masalha et al. , (2008) Effect of toxic metal on learning ability The presence of some toxic metals in the human body impairs the learning ability and behavior. In recent studies, it was suggested that excess Manganese (Mn, toxic metal) may interfere with developing brain functions. For instance, a study by Wasserman et al. (2004, 2006) about Bangladeshi children, found a negative effect of high Mn levels in tube well water on cognitive capacities.
Another recent study by Filho et al (2011) was conducted to find the impact of elevated level of Mn and Cognitive performance in school aged children. This study was done at the village of Cotegipe, a small community of 620 people in the municipality of Simoes Filho, State of Bahia, Brazil. A total of 83 children participated to this study. Mn sample were collected from their blood samples and also from their hair. The Wechsler Intelligence Scale for Children, version III-WISC was used by a psychologist over a period of four weeks to measure children’s cognition. Figure 2.
Scatter plot of children’s verbal (left), full-scale (right), IQ scores Vs Mn hair levels, adjusted for maternal education and nutrition status. Copied from Filho et al (2011). The findings of their research (Fig 1) shows that there is linear relationship between manganese in hair and their verbal IQ which indicates that for those children who lives in the vicinity of a Mn alloy production, there is a negative association between manganese intake and full-scale and verbal IQ. Along with manganese, researchers also found that mercury, cadmium, lead, and tin also affect learning ability.
These metals affect the chemical synaptic transmission in the brain and the peripheral. They also harm our central nervous system (Lopez-oratol et al, 1999). There is evidence that toxic metals are associated with developmental delays, learning disabilities, depression, and behavioral abnormality. These symptoms were normally appeared to the children (Windham, 2007). According to Lopez-oratol et al, (1999) over 20% of the children in the United States have had their learning significantly affected by toxic metals such as mercury, lead, and cadmium. Summary
Diet, enough sleep, exercise, and other aspects of our daily interaction with the environment, control our brain health and mental functions. A number of recent well-designed studies suggested that presence of certain nutrients can influence cognition by acting on molecular system, which is vital for maintaining cognitive function. They concluded that, maintaining diet is a viable strategy for enhancing cognitive abilities and protecting the brain for damage. For all the students to be successful in their academic environment, educators cannot disregard the importance of establishing and supporting healthy lifestyle habits.
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