It could be said that learning begins in the stomach. When voters demand a return to the basics, they refer to reading, writing, and mathematics. From a neurobiological perspective, however, getting back to the basics pertains to fundamental building blocks of the brain and body—and those building blocks begin with nutrition and its relationship to emotions and learning.
Our Chemical Brains
Knowing how the brain functions can make a tremendous difference in how teachers address the emotional, social, cognitive, and physical learning of their students (LeDoux, 1996). Helping young people establish healthful lifetime eating habits is particularly critical, because chemicals primarily produced from substances consumed affect brain development and functioning. If parents and teachers ignore these realities and attend only to the basic facts of cognitive learning, students will fail to achieve intended academic results.
According to the theory of evolution, our earliest ancestors were single-celled organisms that developed deoxyribonucleic acid (DNA) and reproduced themselves. Gradually, cells clustered and developed their own molecular cocktails in response to environmental chemicals, especially to odors. As a result, the olfactory bulb developed as the first primitive brain, and chemicals were thereafter established as the medium of information exchange (Joseph, 1996, p. 309). Consequently, the basis of learning continues to be a delicate balance of chemicals produced mostly as a result of substances ingested.
Chemical Messengers
Chemicals released as responses to stress and food are of great concern to educators because both can effectively prevent higher-order thinking. During the evolutionary process, stress hormones developed as a rapid response to danger; thus, they are strong enough to overpower other chemicals associated with well-being, pleasure, and happiness (Joseph, 1996). For example, researchers now know that sensory input travels to the brain's relay station called the thalamus and that the thalamus passes the messages in two directions. One goes to a cluster of cell bodies in each hemisphere called the amygdala; the second goes to the thinking neocortex (LeDoux, 1996). If the amygdala's fast signals alert for self-protection, muscles tighten for fight or flight, and stress hormones (cortisol, epinephrine, and norepinephrine) increase blood flow to the muscles. Then the muscles release stored nutrients for rapid conversion to glucose, added energy, and strength.
Chronic stress causes the brain and body to deplete available nutrients, leaving nothing available for learning. Further, chronic stress inhibits the growth of message receptors (dendrites) on brain cells and limits interconnections among neurons. This results in slow thinking, depressed learning, and even mental retardation (Joseph, 1996). Similarly, ingested proteins and carbohydrates undergo lengthy processes that convert them from food to brain and body chemicals. Certain foods produce high energy, whereas other foods create a calm demeanor.
You Think What You Eat
The immune system, the endocrine system, and the brain contain many of the same types of chemicals and chemical receptors (Pert, 1997). Thus, it makes sense that when youngsters have nutritious foods available while studying, they eat as needed and consequently earn statistically higher test scores, demonstrate more positive attitudes toward school, and increase their reading speed and accuracy (Dunn & Milgram, 1993).
Because many students need to snack, chew, drink, or bite while concentrating, nutritional intake at school is worth exploring, especially if children are hyperactive, sluggish, underachieving, apathetic, or irritable (Howard, 1994; Wurtman & Stuffes, 1996/1997). Concentration and learning are more than a result of eating, they are the result of particular kinds of food intake.
Aspartame Can Be Less Than Sweet
Children usually think of eating as an enjoyable experience. However, because chemicals from foods create different reactions, this pleasant event can result in lethargy, panic, inattentiveness, or depression. This is true even though individuals may fail to associate what they eat with how they feel. C. Keith Conners (1990) and his colleagues at Children's Hospital in Washington, D.C., give us several examples. They describe an academically, athletically, and socially talented high school student who began consuming diet drinks containing aspartame shortly after it was marketed. Her doctors found no explanation for the deep depression she described as a "living hell for three years." She wrote, It got to the point where my daily routine consisted of watching TV, eating, and the consumption of at least 10 to 15 cans of diet soda. . . . When I first tried to stop use, I experienced shaking, nausea and a tremendous urge to have a diet drink. I wasn't able to stop immediately so I gradually cut down the number of cans each day until I had quit altogether. (Conners, 1990, pp. 36–37)
The teenager listed blurred vision and temporal headaches as side effects—symptoms frequently identified in children who consume beverages containing aspartame. Young children, however, may become hyperactive, tearful, and violent. One mother reported that after her child consumed aspartame, he was very quiet (did not speak) . . .he seemed to be day-dreaming. He ate a good lunch, but . . . started complaining of a headache . . . and was somewhat cranky and nasty. He slept for 3 hours. . . . He woke up crying and screaming. Proceeded to find fault with everything. Refused to eat dinner. Cried all through the meal. After dinner he . . . stood in the middle of the floor and screamed for one-half hour at the top of his lungs. I put him to bed early. . . . Next morning he was all smiles. (Conners, 1990, pp. 36–37)
None of these behaviors occurred after the boy consumed drinks with natural sugar. A few days later, the child's reaction to aspartame was even more intense. He urinated frequently, became exceedingly sleepy but never slept, ran in circles, ate nothing at dinner, and kept jumping up and talking fast before falling asleep.
Conners (1990) found that aspartame affects children in different ways on the basis of factors not yet clearly understood. But the chemistry of aspartame provides some clues. Aspartame is composed of methanol (10 percent); aspartic acid (40 percent); and phenyl-alanine (50 percent), an essential amino acid (pp. 33–34). Phenylalanine is a precursor to the synthesis of the neurotransmitters dopamine and norepi-nephrine. Without the proper enzyme action in utero, phenylalanine builds up and causes phenylketonuria (PKU) at birth—a condition leading to brain damage and mental retardation. Treatment for PKU is a diet low in phenylalanine. Even when the necessary enzyme is present, phenylalanine can build up in a healthy person and cause headaches or worse (pp. 33–34).
Methanol (methyl or wood alcohol) is a toxic substance at extremely low doses that breaks down into formaldehyde (embalming fluid) and then formic acid (ant sting poison).<FOOTNOTE><NO>1</NO>See http://www.sci.ouc.bc.ca/chem/molecule/pdb/aspartam.pdb.</FOOTNOTE> Methanol can paralyze the optic nerve and cause blindness in low doses and death in larger amounts (McMurry, 1984). Aspartame has also been linked to diketopiperazine, or DKP, an agent associated with brain tumors, and to vertigo and grand mal seizures in airplane pilots. That is why 13 piloting journals and military magazines warn pilots against the use of artificial sweeteners.<FOOTNOTE><NO>2</NO>See http://www.holisticmed.com/aspartame/suffer.faq for a listing of publications.</FOOTNOTE>
Zealots and researchers exist on both sides of the controversy surrounding aspartame. Some say that it is extremely harmful; others say that the dangers have been blown out of proportion. Readers are encouraged to investigate the debate on the Internet.<FOOTNOTE><NO>3</NO>See http://www.dorway.com/asprref.html and http://www.dorway.com for a review of research studies and links to other references.</FOOTNOTE>
Eating for Energy
As a natural function of the stomach, enzymes act on protein foods, such as beans, grains, seeds, nuts, and animal products, to trigger the release of 21 amino acids, including tyrosine (Wurtman & Stuffes, 1996/1997). Tyrosine travels through the bloodstream to the brain, where it becomes L-dopa. L-dopa loses atoms to become dopamine, and dopamine, originating in the midbrain, shoots from several hundred thousand cell endings to produce a general feeling of alertness, attentiveness, quick thinking, rapid reactions, motivation, and mental energy (Pert, 1997). Tyrosine also triggers catecholamine amino acids that lead to alertness (Howard, 1994, p. 77).
When more protein is consumed than is needed, some is stored in the muscles for later use (Wurtman, 1988, p. 71). In cases of limited protein intake, people often self-administer dopamine precursors through the consumption of caffeine drinks (many with aspartame), chocolate, alcohol, marijuana, or other feel-good endorphins that range from the mildly harmful to the seriously addictive (Restak, 1993/1994).
Protein holds water in the blood, and an insufficient protein supply causes fluids from inside the cells to seep out, causing sluggishness, limited concentration, stomach bloating, and the loss of essential salts and nutrients (Spreen, Risser, & Edgett, 1995). Unfortunately, adults seldom associate these negative conditions in children with protein deficiency, even though mild malnutrition may be present.
Fear of failure, isolation, and other mild to severe psychological or physical traumas convert dopamine-produced alertness to norepinephrine-controlled agitation and aggression. This conversion takes the child from alertness to agitation and aggression in a matter of seconds. When inadequately nourished, children have great difficulty tolerating frustration and stress because they have no protein stores to draw on. Instead, they exhibit apathy, nonresponsiveness, inactivity, and irritability. When that happens, their attempts to learn are sabotaged.
Carbohydrates and Serotonin
The digestive process converts complex carbohydrates into sugars (glucose) that enter the bloodstream. Insulin also enters the bloodstream and pushes glucose and the amino acids, except tryptophan, into muscles for use as energy. Tryptophan is then free to enter the brain and synthesize into serotonin, a stress-reducing neurotransmitter (Wurtman & Stuffes, 1996/1997, pp. 21–22).
When studying adults, Wurtman found that the consumption of "any carbohydrate food will induce your brain to make more serotonin" (Wurtman, 1988, pp. 142–143). High serotonin levels are found in leaders and in people with a positive sense of self, whereas low levels are associated with depression, low self-esteem, and a desire for sweets (Wurtman & Stuffes, 1996/1997, p. 27). When a person enjoys high positive self-esteem, successful problem solving, and authentic accomplishments, the brain manufactures its own serotonin. Thus, successful leadership opportunities in school settings build serotonin for students. Teachers, therefore, are encouraged to devise ways for each child to shine at something personally meaningful.
Breakfast and Snacks Feed the Mind
Students who eat a nutritious breakfast make fewer errors throughout the morning than those who skip breakfast. Young people who skip breakfast are inclined to eat heartily at lunch and then feel sluggish during the afternoon (Pollitt, Leibel, & Greenfield, 1981, p. 77). One 11th grader habitually consumed a grape soda and a pack of doughnuts or cookies before school—high quanities of simple and complex carbohydrates. For an hour, his sugar high kept him fairly amiable, but as the sugar wore off, he began hitting others. When given choices, he consumed a hamburger and a glass of milk for breakfast, foods high in protein, and he became "reasonably likeable" after two weeks (Howard, 1994, p. 78).
With his team at Children's Hospital, Conners (1990) monitored sugar intake with different combinations of food consumed by "severely disturbed" children admitted to a psychiatric ward. They write, it became apparent that the behavior was quieter on days in which the breakfast was relatively high in protein but more active on days with relatively high carbohydrate intake. [Emphasis his.] Carbohydrate-containing foods, such as bread, waffles, and doughnuts eaten at breakfast, produced a worsening of behavior (more activity) in conjunction with the sugar drink. If the children ate eggs, meat, fish, or cheese, the sugar was beneficial. (p. 91)
Although the availability of appropriate foods could have a positive impact on student learning and behavior, schools rarely provide snacks or encourage parents to do so. Without question, many students could profit from having access to healthful snacks throughout the school day, or at least at midmorning. Teachers and parents may wish to experiment by comparing how children behave when provided with bagels, graham crackers, popcorn, bread sticks, granola bars, vanilla wafers, melba toast, raw vegetables, or other carbohydrates with their reactions to snacks of peanuts, peanut butter and crackers, beef jerky, or trail mix high in peanut composition.
Students, parents, and teachers could use a checklist to monitor their emotional and behavioral reactions to food. This self-monitoring is one way to help students understand the relationship between food and learning. Clearly, children require a breakfast with high levels of protein for alertness and a balanced diet that includes complex carbohydrates throughout the day. Of course, including food in the classroom may require more than a teacher's interest in experimentation.
Better School Food, Better Learning
Melva Matkin, principal of the award-winning Gregoric Esparza Accelerated Elementary School in San Antonio, Texas, laments, In efforts to improve our school, we analyzed, scrutinized, and restructured every aspect except food service. That was off limits to us. We met with strong resistance to make changes, because the a la carte junk foods children buy bring in revenues that support personnel positions. (Personal communication, January 15, 1998)
Child nutrition directors from the 50 states gave similar testimony before Congress in 1994. At those hearings, Ellen Hass, assistant secretary for Food and Consumer Services, U.S. Depart-ment of Agriculture, reported on a USDA study that revealed "government-sponsored school meals served to kids today do not meet the government's own nutritional standards for a healthful diet" (Subcommittee on Elementary, Secondary, and Vocational Education, 1994, p. 23). Hass emphasized how essential it is for these programs to refocus on their nutritional mission because the programs "touch the lives of more than one in six Americans every day" (Subcommittee on Elementary, Secondary, and Vocational Education, 1994, pp. 6–7).
Making Nutrition a School Issue
Although drastic changes in children's behaviors are often blamed on violent television programming and lack of parental guidance, nutrition is rarely mentioned. There are no single answers to why children behave—or at least appear to behave—more negatively than in years past. One thing is certain: The challenges are to investigate numerous factors that influence brain development and to incorporate emerging knowledge about those relationships into schooling practices. The relationship between food substances and learning has received considerable general attention, but little specific research. Perhaps now is the time to change that.
Teachers instinctively know that genuine school reform comes from within. They change their own attitudes and priorities as they push forward to make a difference in the lives of their students. Teachers expect other educational decision makers to take emerging knowledge about the brain and body seriously, too. Teachers can create exciting lesson plans about nutrition, and they can work with parents to provide appropriate classroom snacks, but school administrators must do their part to ensure the availability of nutritious foods in the lunchroom, the vending machines, and the classrooms. If administrators ignore this responsibility, teachers may as well be whistling in the wind because children's eating habits are caught more than taught. Teaching children about foods and their relationships to behavior and achievement is important, but action by parents, school boards, administrators, and politicians is equally critical.
