Eating for Thinking and Learning
Learning is fundamentally biological. It occurs when cells in the brain called neurons establish connections called synapses. Thus, learning occurs through building neural networks. The brain requires materials for building such circuitry, and particular nutrients to provide the electrical impulses and chemical reactions that power the circuits. "Nutrition and Learning Resource List for Professionals" (http://www.nal.usda.gov/fnic/service/learnpub.html) provides many studies that document the importance of diet to learning in children, but nutritional maintenance is equally important to adult thinkers. So, what foods seem particularly important?
First, water! The brain is more than 80% water. In 1995, neurophysiologist C. Hannaford noted that mild dehydration produces a common condition of poor learning performance. Dehydration is a special problem in areas typified by dry air and high altitude. Learning specialists advocate several glasses of water daily to optimize learning. Although some professors ban eating and drinking in class, one should consider the benefits of bottled water.
Our bodies are individually unique, especially in reaction to foods. A peanut butter sandwich that one person finds delicious and a great source of energy can send another individual to the emergency room. The information that follows generally serves most of us, but if your diet is special, you can search the web and likely find alternative sources for the nutrients that will not cause trouble for you.
Protein is the foremost nutrient required for brain maintenance and repair. Fish, the commonly known "brain food," is rich in taurine, an important amino acid for the brain. Although "fish oil" is better known for its role in enhanced circulatory health, research also ties lack of omega-3 oils to mental problems, including low intelligence, learning disabilities, depression and degenerative neurological diseases. Fish oil seems to enhance brain speed, memory and learning. Omega-3 fat also imparts a sense of well being, and helps thwart some types of depression. Salmon, mackerel, sardines, and herring are rich sources for omega-3 oils.
Not all "omega oils" are helpful. A Dutch study reported that older men with diets heavy in omega-6-type fat found in margarine, salad dressings, corn oil and processed foods were 75% more likely to be intellectually impaired compared to men who ate the least amount of such fat. Good amino acid sources for the brain include fish, organ meats (taurine), pork, cottage cheese, eggs, wheat germ, fowl (tryptophan) and beef (carnitine). Italian researchers found that diets with adequate carnitine promoted better memory, attention focus, and verbal skills.
Tryptophan is an important brain amino acid that is converted into useful brain chemicals such as melatonin. A deficiency of tryptophan reduces the chemicals that aid with restful sound sleep. As age reduces the body's ability to produce melatonin, tryptophan's role becomes increasingly important (see http://www.worldhealth.net/p/133,1124.html). Fowl is a source of tryptophan, so a chicken or turkey sandwich for lunch may cause drowsiness in afternoon classes. Because tryptophan is a nutrient that aids in sound sleep, sources of it are best taken at day's end. Tryptophan taken in before classes or before quiet study can cause problems for many of us.
Low-income students or those inclined not to think about long-term effects may breakfast habitually on breads or processed cereal. Such breakfasts, largely devoid of important nutrients tyrosine & choline, won't provide the boost for thinking and learning that good protein sources, such as eggs and meat provide. Creatine found in meats is known to benefit working memory and intelligence. Unless you are a strict vegetarian, it's unlikely you have a creatine deficiency.
Myelin is essential for stabilizing synaptic connections in deep learning. It acts like insulation over wire and forms a sheath over important networks when these synaptic connections are activated repeatedly. Myelin consists of 30% protein and 70% fat. One of the most common fatty acids in myelin is oleic acid, which is also the most abundant fatty acid in human milk. Oleic acid occurs in olive oils and in the oils of almonds, pecans, macadamias, peanuts, and avocados (see http://www.fi.edu/learn/brain/fats.html).
Beneficial brain nutrients in foods and supplements tend to fall into three categories: (1) those that nurture the circulatory system that nourishes the brain, (2) those that prevent free radical damage, and (3) those that promote better brain function by providing or assisting specific brain neurotransmitters. Examples of the first category include the vasodilator, niacin, and the coenzyme, CoQ10. Examples of the second are a variety of antioxidants including vitamins A, E, and C. Examples of the third are choline and pyridoxine (B-6).
Age-related breakdown of the brain involves damage by free radicals, so free radical scavengers such as vitamins C, E, A, and selenium are important to maintenance of a healthy brain. Vitamins, C, E, and A are easy to procure through a balanced diet. Studies at University of Southampton in England discovered that cognitive function was poorest among those studied with the lowest vitamin C. Those study participants who did not perform well on the administered mental exam also had an increased risk of death from stroke resulting from vascular impairment. The researchers concluded "Vitamin C status may be a determinant of cognitive function in elderly people." Selenium intake is related to mood and morale. Those tested on a diet high in selenium reported feeling more clearheaded, elated, confident and energetic. Selenium intake varies markedly with individuals. Brazil nuts are a particularly rich source of it.
Memory, alertness, visual ability, attention, and focus needed to undertake organizational tasks are also affected by the B vitamins, especially B-6, B-12, thiamine, inositol, choline, the major elements magnesium, sodium, potassium, iron, and trace elements zinc, selenium, and boron. Vegetables and especially nuts (peanuts in the case of boron) are good food sources for many antioxidants and trace nutrients (see also "Boosting Working Memory," Science v. 290 Dec. 22, 2000, pp. 2275-2276). The National Institutes of Health ascribe particular benefits to obtaining adequate folic acid (http://www.nih.gov/news/pr/mar2002/nia-01.htm). Lack of dietary folate promotes dementia and impaired short-term memory. Harvard researchers found up to 38% of adults diagnosed with depression have low blood levels of folic acid and respond less well to antidepressant drugs.
Oxford University studies found that low blood levels of folic acid triple risk of Alzheimer's disease. Good folic acid sources include green leafy vegetables, citrus fruits and juices, whole wheat bread and dry beans. Pyridoxine (B-6) is also important. In the brain, it is involved with production of an important chemical, serotonin. Low levels of serotonin also lead to irritability and even depression. USDA workers at Tufts University found elevated levels of the chemical homocysteine associated with dementia, but B-6, B-12 and folate help metabolize that chemical. They concluded in American Journal of Clinical Nutrition: "Low B vitamin and high homocysteine concentrations predict cognitive decline." (See http://www.vitacost.com/newsletter/newsletter.cfm?nl=241)
Sweeten Your Morning.
Breakfast has special importance for scholars. Students who skip breakfast to attend a morning class will not be at their potential for learning or participation. Glucose is a major nutrient used by the brain, and glucose is most depleted after awakening from a night's sleep. There's good reason to include fruit or a glass of fruit juice in the morning, along with proteins. The glucose in it can help stoke the firing of synapses. Fruits rich in antioxidants such as blueberries and black currants are good choices. These contain polyphenols and powerful anthocyanins that protect against brain damage, macular degeneration and may improve mood, energy and overall health. For more about benefits of certain fruits on the brain see http://www.lef.org/magazine/mag2002/jun2002_report_age_02.html and http://iospress.metapress.com/content/dlre39hdd3xhd10t/.
Can Coffee Help?
Coffee, chai, black tea and a number of commercial energy drinks are rich in caffeine. Caffeine is the subject of a number of studies that confirm its ability to increase alertness, learning ability, memory and reasoning.The Journal of Alzheimer's Disease recently produced a theme issue on caffeine (Volume 20, Supplement 1, 2010 "Therapeutic Opportunities for Caffeine in Alzheimer's Disease and Other Neurodegenerative Diseases") available at http://iospress.metapress.com/content/t13614762731/. Several studies also note coffee's apparent role in helping to offset the effects of sugar by decreasing susceptibility to diabetes (see http://www.physorg.com/news195300617.html and http://coffeescience.org/). Coffee is probably the least controversial mind-enhancing substance of all.
Soil depletion of micronutrients is a concern for food quality, so as depletion occurs, there may be increased need for trace element supplements. Because many students (and professors!) often are too busy to attend well to diet, supplements taken with informed awareness and in moderation consisting of a daily multivitamin compounded with trace nutrients can be worthwhile. Studies in the late 1980s showed that groups who received a multivitamin supplement outperformed control groups in reaction time, visual acuity and in measures of intelligence. No research reveals that megadoses of anything enhance cognitive function, and megadoses of some supplements (especially E, A, selenium) are harmful. The free-radical theory of aging spawned an unfortunate response through overdosing. Some free radicals are essential and used by the body. Too much of a single powerful antioxidant (such as vitamin E) can reduce these below optimal and interfere with needed cellular functions. There are several varieties of vitamin E. The common E vitamin supplement is d-alpha tocopherol, whereas the E vitamin seemingly important to cognitive function is gamma E or gamma tocopherol found in nuts and vegetable oils and in only a few supplements.
Choline supplements are helpful to some. Choline is converted into acetylcholine in the body, a chemical that is an important neurotransmitter. However, choline taken as a supplement does not easily pass into the brain to be converted, so effects may vary with individuals. The compound, phosphatidylserine (PS), found in every cell in the body but particularly concentrated in the brain, naturally declines with age. PS supplements have been proposed to combat loss of mental acuity. PS is in numerous foods, such as rice and green leafy vegetables, but in small amounts. There is currently no solid evidence to indicate that PS supplements in larger amounts boost mental function of healthy individuals, but the reader will find the compound as well as others of unproven value marketed for this purpose (see http://www.wholehealthmd.com/refshelf/substances_view/1,1525,813,00.html). A few firms compound specific supplements to maintain good brain function. Before trying any of these, study the label and research every ingredient in it on the Web to learn the effects of each and to insure the dosages you obtain, in conjunction with other supplements you maybe taking, don't add up to an overdose. Some otherwise beneficial nutrients can interfere with the effects of particular medications, so those on any prescription medication should check with a qualified professional to see if an ingredient may prove detrimental. The Memory Doctor by D. J. Mason and S. X. Smith (2005, Oakland, CA,New Harbinger Pub.) provides two good chapters about supplements and effects of common prescription medications.
Even "Skeptical Inquirer" (2001, v. 25, n. 1, pp. 43-49), admits that a few herbs really can improve cognition, although researchers also caution against concurrent use of some herbs with certain prescription medications. Ginkgo has been the most thoroughly researched as a cognitive activator. It seems to act as a mild vasodilator and delay the decreased cognitive function otherwise imparted by normal aging. It won't boost IQ or do some of the things that charlatans may claim. It can also interfere with some anticoagulant prescriptions. Ginseng (Panax ginseng) is shown by several studies to facilitate learning and memory. Huperzine, a herbal supplement derived from Chinese clubmoss, enhances memory, focus and concentration, in those with progressed dementia. Others who take it probably won't notice any effects. All three herbs seem to work by enhancing electrical activities associated with memory formation and by increasing the production of or enhancing the activity of acetylcholine, a neurotransmitter utilized in memory and other cognitive activities.
Research in India and Australia confirms effectiveness of folk-medicine herb Bacopa monniera as a mental enhancer and reliever of anxiety. It is offered as an ingredient in a few commercial herbal supplements. Most studies to date on Bacopa involve animals. See http://www.life-enhancement.com/article_template.asp?ID=612, http://cat.inist.fr/?aModele=afficheN&cpsidt=1084024 and http://ecam.oxfordjournals.org/cgi/content/full/neq038.
Vices and Wisdom
Evidence confirms that tobacco smoke and excessive alcohol use take a severe toll on our brains. Researchers at the Cincinnati Children's Hospital Medical Center studied nearly 4,400 children exposed to secondhand smoke. The study tested blood levels of cotinine, a substance produced as the body breaks down nicotine after tobacco smoke exposure. They evaluated cotinine level against math & reading scores and found a negative correlation between cotinine and test scores.
Excessive alcohol use causes deficiency of particular B vitamins important to mental function and mood, such as folate from folic acid and thiamine. Alcohol inhibits absorption of these vitamins, and alcoholics tend to neglect diet in general. Over time, folate deficiency produces serious consequences. It's wise to follow the night party with our college friends with a morning B-supplement.
Spice It Up!
Three spices seem particularly helpful. Garlic is the traditional herb with a folk reputation for its ability to improve mental function. It is a rich source of selenium and other components known to be beneficial to cognitive function, but no study has shown a powerful link to its ability to enhance cognitive function. Not so with the two other herbs. Clinical trials with healthy, young adults revealed those who had taken sage oil capsules performed significantly better in a word recall test. Compounds in sage apparently inhibit breakdown of acetylcholine. The most exciting discovery involves curcumin, a component of turmeric that imparts the yellow color to curry spice. Populations that use curry as a common spice have unusually low levels of dementia. It may work by preventing the protein plaque, a known marker of Alzheimer's disease, which apparently causes blockages in the brain. A diet rich in curcumin could prove important in the prevention of that disease.
While the brain is a wondrous, self-repairing part of our bodies, it is nevertheless somewhat like a complex machine; when the owner neglects maintenance, complex machines sputter, malfunction, and eventually break down. It is best to begin good maintenance early in life.
One way to maintain longevity of mental performance is to use the brain. Research presented at an American Psychological Association annual meeting in Canada (http://news.wustl.edu/news/Pages/336.aspx) revealed that among adults studied (average age 75years), only one out of four had managed to avoid memory decline. The adults who maintained high frontal lobe function (the part of the brain involved in high level thinking) had memory skills "every bit as sharp as a group of college students in their early 20s." Some were retired academics. Development of high level thinking promotes development of synaptic connections, and it seems to improve chances of both a long, productive career and a much-extended quality of life—not bad perks at all!
Knowledge about nutrients and mental effects change rapidly, and the World Wide Web is a boon to getting current information. Much research on mental acuity involves an aging population, so organizations involved with longevity, memory loss, dementia, and Alzheimer's disease have particular reason to keep current and to make that information widely available. In addition to sources mentioned, useful sites include http://qualitycounts.com/fpmemory.html, and http://www.memory-key.com/.
An inexpensive E-book, The Book of Brain by Dr. Stephen Gislason, now in updated 2010 edition (http://nutramed.com/AlphaBooks/Human%20Brain.htm), devotes its Section 3 to nutrition and nutritional therapy. A fine free source on the brain in general is The Brain from Top to Bottom available at Canada's http://www.thebrain.mcgill.ca/flash/index_i.html.