How you think, act, and learn is affected not only by the types of food you eat, but also by how the food is prepared, how and when you eat it, and what foods you eat together.
- Care about your carbs. The brain is a sugar hog, a carbo-craver, utilizing 20 percent of the body’s carbohydrate supply. Yet it’s a smart hog, being selective about the type of sugars it craves and how it processes them. It prefers a nice steady supply. When the brain receives a steady supply of sugar for fuel, it chugs along smoothly at a steady pace. But when levels of sugar in the blood fluctuate, the brain doesn’t get its steady fuel supply and behavior and learning become more erratic. Blood sugar levels depend on what kinds of food are coming into the body. Some carbohydrates calm behavior, others excite it.
- Beware of sugar blues. Most scientists discount the relationship between sugar and behavior, especially when Attention Deficit Hyperactive Disorder (ADHD) is blamed on sugar in the child’s diet . In a paper published in the Journal of the American Medical Association, researchers analyzed the results of sixteen different studies in which children were given foods containing lots of sugar and their behavior compared with a control group. The analysis concluded that sugar had no impact on behavior. Try explaining this to a mother whose child goes wild after eating a Twinkie. Researchers tend to discount parents’ observations, believing that they have been conditioned by media reports and other parents to expect their children’s behavior to deteriorate after sugary snacks.So we’re back to the “science” of common sense – and basically physiology. Different sugars affect the brain in different ways, so it is only logical to conclude that certain sugars can adversely affect the thinking and actions of some children. The sugars at fault include glucose, dextrose, and sucrose, and the highly refined, highly processed “junk sugars” found in candy, icings, syrups, packaged baked goods, and table sugar. These sugars enter the bloodstream quickly, reaching high levels in a short time. This triggers the release of large amounts of insulin, the hormone needed to escort the sugars into the body’s cells. These sugars are used rapidly, and when they’re all used up, the blood sugar level plunges to a sugar low, or hypoglycemia . The low blood sugar triggers the release of adrenal hormones (called a “sugar high”) that squeezes stored sugar from the liver, sending blood sugar levels back up. This blood sugar roller-coaster affects moods and concentration in some children and adults, leading to “sugar highs”and “sugar blues.” The ups and downs of blood sugar and adrenal hormones can also stimulate neurotransmitter imbalance, causing the child to feel fidgety, irritable, inattentive, and even sleepy.
The best sugars for the brain are complex carbohydrates, or what grandmother termed “starches”. Starches and fruit sugars (fructose) do not cause the roller-coaster mood swings that the junk sugars do. The molecules in complex carbs are long, so it takes longer for the intestines to break them down into the simple sugars the body can use. Thus, they provide a time-release source of steady energy rather than a sudden surge followed by a sudden drop.
- Eat brain-friendly carbs. The rate at which sugar from a particular food enters brain cells and other cells of the body is called the “glycemic index” (GI) of a particular food. Foods with a high glycemic index stimulate the pancreas to secrete a lot of insulin , which causes the sugar to quickly empty from the blood into the cells; this produces the ups and downs of blood sugar and the roller coaster behavior that goes with them. Foods with a low glycemic index do not push the pancreas to secrete so much insulin, so the blood sugar tends to be steadier. Feeding your child carbohydrate foods with a low glycemic index is one way of helping him control his behavior and performance in school or at play. Foods with the best brain sugars include the following:
- Fruits: grapefruit, apples, cherries, oranges, and grapes have a low glycemic index. Fruits have a lower G.I. than fruit juices, because the fiber in the fruit slows the absorption of the fruit sugar. A whole apple will be more brain-friendly than apple juice; a whole orange better than orange juice. Freshly-made juice containing a lot of pulp is more brain-friendly than filtered juice.
- Cereals and grains: oatmeal and bran have the lowest G.I. Other foods with a favorable G.I. are spaghetti and rice. Corn flakes and sugar-coated cereals have higher G.I.s.
- Vegetables and legumes: Legumes, such as soybeans, kidney beans, chick peas, and lentils have the lowest glycemic index of any food. Potatoes and carrots have a much higher G.I.
- Dairy products: Milk and yogurt have low glycemic indexes, slightly higher than legumes, but lower than fruits. Plain yogurt has a lower glycemic index than yogurt with fruit preserves or added sugar.
The company a food keeps and how it is prepared also affects the G.I., or how fast and steady the sugar enters the brain.
- A food with a high glycemic index, such as juice, candy, or a sweet treat is better consumed with or right after a meal because the company of other foods slows the entry of sugar into the bloodstream, and therefore the brain. Indulging in highly- sugared snacks between meals is likely to hinder learning and behavior.
- Fat can slow the absorption of sugars, which is why the sugar in ice cream would have a lower glycemic index than sugar in non-fat yogurt.
- Because salads contain mostly foods with a low glycemic index, they are an excellent school lunch, contributing to maximum mental performance. Especially good are salads containing cruciferous vegetables and beans, chickpeas, and other legumes.
- Eating foods with a low glycemic index along with highly-sugared foods lessens the effects of the fast-acting sugars on the blood sugar.
- Encourage grazing. We have noticed that children’s behavior often deteriorates in the late morning and late afternoon, or three to four hours after a meal – whether the child has ADHD or not. Children simply run out of fuel. When blood-sugar levels go down, stress hormones kick in to raise it up again, but this can cause behavioral problems and diminished concentration. To smooth out the blood-sugar mood swings, try the fine art of grazing. Let your child nibble, or graze, on nutritious foods throughout the day. Make them easily accessible in a lunch pack at school. (Smart teachers allow even upper-grade children to have a mid-morning snack.) Carry snacks with you when you are away from home. While at home, keep a supply of healthy snacks readily available in the pantry or refrigerator.Here’s a trick from the Sears’ family kitchen for the preschool child. Prepare a nibble tray. Use an ice cube tray, a muffin tin, or a compartmentalized plastic dish and fill each section with bite- size portions of colorful and nutritious foods. Give the foods fun names, such as avocado boats (a quarter of a California avocado sectioned lengthwise), banana or cooked carrot wheels, broccoli trees, cheese blocks, little O’s (O-shaped cereal), canoe eggs (hard-boiled eggs cut lengthwise in wedges), moons (peeled apple slices, thinly spread with peanut butter), or shells and worms (different shapes of pasta).
Don’t forget that children love to dip. Reserve one or two compartments in the tray for your child’s favorite dips, such as yogurt or guacamole (without the spices). Encourage the child to sit and nibble from the tray frequently throughout the day, especially late in the morning and in the mid-to-late afternoon, when the fuel from the previous meal begins to wear off. Shorten the spacing between feedings and you are less likely to have spacey children.
- Perk up your proteins. Proteins in the diet affect brain performance because they provide the amino acids from which neurotransmitters are made. Think of neurotransmitters as biochemical messengers that carry signals from one brain cell to another. The better you feed these messengers, the more efficiently they deliver the goods. Some neurotransmitters are neuron turn-ons that perk up the brain. Others have a calming or sedative effect.The two important amino acids, tryptophan and tyrosine,are precursors of neurotransmitters, the substances from which neurotransmitters are made. Tryptophan is an essential amino acid, meaning the body does not make tryptophan; it must be gotten from the diet. Tyrosine, on the other hand, is not an essential amino acid because the body can make it if there is not enough in the diet. So, it seems that dietary deficiency is more likely to affect tryptophan than tyrosine. These two amino acids influence the four top neurotransmitters – serotonin, which is made from the amino acid tryptophan, and dopamine,epinephrine,and norepinephrine,which are made from the amino acid tyrosine. Serotonin is the neurotransmitter that relaxes the brain, the other three, collectively known as catecholamines, are neurotransmitters that rev up the brain. Popular anti-depressant drugs called SRI’s (serotonin re-uptake inhibitors), Prozac, for example, work by increasing the amounts of serotonin in the brain. Since carbohydrates favor serotonin production, perhaps carbo-cravers self-medicate to increase their own serotonin.
Two factors influence whether the brain perks up or slows down following a meal: the ratio of protein to carbohydrate, and the ratio of the amino acids tryptophan and tyrosine. High protein, low carbohydrate, high tyrosine foods that are likely to jumpstart the brain are seafood, soy, meat, eggs, and dairy. High carbohydrate, low protein, high tryptophan foods that are likely to relax the brain include: chocolate, pastries and desserts, bean burritos, nuts and seeds (e.g., almonds, filberts, sunflower and sesame seeds), and legumes. (For a detailed discussion of how different amino acids in food perk up or slow down the brain, see Food for Sleep).
- Pick the right carb-protein partnership. Brain performance following a meal is also affected by the carbohydrates consumed with the protein. Carbohydrates stimulate the release of insulin, which helps more tryptophan to enter the brain where it makes more serotonin. The more simple sugars in the meal, the more serotonin is produced, and the more the brain is sedated. Complex carbohydrates – slower insulin-release sugars – on the other hand, will cause less drastic serotonin production. A high calorie meal will contribute even more to serotonin production, leading to “serotonin slump.” (See related section, Lethargic After Lunch). Eating too much at any meal, regardless of the carbohydrate or protein content, seems to diminish mental performance. So, to perk up the brain, eat a meal that is:
- High in tyrosine-containing proteins.
- Moderate in the amount of sugars, containing mainly complex carbohydrates.
- Relatively low in calories.
To relax, or even sedate the brain, eat a meal that is:
- High in tryptophan-containing proteins.
- High in carbohydrates.
- High in calories.
You can plan your meals according to how you use your brain during the day. A low-calorie, high-protein meal that also contains complex carbohydrates makes you more alert and would be perfect for breakfast and lunch. A higher calorie, higher carbohydrate, lower protein meal could help you relax and fall asleep in the evening.
Skip the dessert at lunchtime if you have a lot of work or learning to do in the afternoon. If you want to be alert after the evening meal, save dessert for a before-bedtime snack.
The balance between calories, carbohydrates, and protein in a meal affects different people in different ways. This is not an exact science. You need to figure out what combinations work the best for you, giving you energy and alertness when you need it. Keeping a diary of what you eat and how you feel can help you make corrections. For parents, careful observation of your school-age child is important when you’re trying to figure out what foods enhance behavior and school performance, and which foods make it worse. This is a challenging game, but one that every home nutritionist can play.
- Feed your brain the right fats. There are two windows of time in which the brain is especially sensitive to nutrition: the first two years of life for a growing baby and the last couple decades of life for a senior citizen. Both growing and aging brains need nutritious fats.
- Feeding baby brains. The most rapid brain growth occurs during the first year of life, with the infant’s brain tripling in size by the first birthday. During this stage of rapid central nervous system growth, the brain uses sixty percent of the total energy consumed by the infant, and the brain itself is sixty percent fat. Fats are major components of the brain cell membrane and the myelin sheath around each nerve. So, it makes sense that getting enough fat and the right kinds of fat can greatly affect brain development and performance. In fact, during the first year, around fifty percent of an infant’s daily calories come from fat. Mother Nature knows how important fat is for babies; she provides around fifty percent of the calories in mother’s milk as fat.
- Best fats for growing brains. It’s not only the amount of fat that’s important for growing brains, it’s the type of fat. Different species provide different types of fat in their milk, fine-tuned to the needs of that particular animal. For example, mother cows provide milk that is high in saturated fats and low in brain-building fats, such as DHA. This helps their calves grow rapidly, though it may not do much for their brains. In adult cows, the brain is small compared with the body. Cows don’t have to do a lot of thinking to survive. In human infants, the brain grows faster than the body. Highly developed brains are important to human beings, so human milk is low in body-building saturated fats and rich in brain-building fats, such as DHA (docosahexaenoic acid),an omega 3 fatty acid.