As a result of years of folklore, most of us, at some point, find ourselves eating things for how we think they’ll help us — make us more energetic, smarter, or happier. Madelyn Fernstrom of the University of Pittsburgh Medical Center’s Weight Management Center was invited on the show to help us separate fact and fiction when it comes to food and our brains. While some foods may have an effect on our brains, others just play tricks on our minds. You know what you eat can affect your waistline, but can it also impact your brain? The brain is command central for our bodies and it needs fuel to function. A diet rich in fruits and vegetables, lean protein, fiber-rich carbohydrates and heart-healthy oils is ideal for our brain cells — and all our other cells, too.
A growing body of scientific evidence now shows that specific foods can also have clear effects on brain chemistry, causing changes in mood, appetite, energy, sleepiness, and other body functions. That said, while there are some connections between food and brain function, often what we believe food is going to do to our bodies trumps our bodies’ biology. So let’s take a closer look at how food affects the brain.
Food can change the brain’s chemistry
Here’s what we know from studying people in a tightly regulated lab setting, after a 12-hour overnight fast:
- When you eat a meal consisting entirely of carbohydrates, after fasting during the night, you can become sleepy and relaxed. This meal also promotes increases in serotonin, a brain chemical that’s related to mood. Antidepressants also act on serotonins. But the problem is that in real life people don’t fast for 12 hours, and when they do eat, they typically eat meals consisting of proteins, fats, and carbohydrates. Even a small amount of protein and fat in our food interferes with carbohydrate’s effect on the brain.
- When you eat a meal consisting entirely of protein after fasting during the night, you can experience an increase in norepinephrine, a brain chemical associated with mental alertness. However, again, in real life, most people don’t fast for 12 hours and don’t eat only protein as their first meal.
When changes occur in the brain’s responses, due to increases in these chemicals, they are modest and don’t happen immediately. It takes at least two hours for a change to happen in brain chemistry (we know this from animal studies), and then at least another hour or two to see changes in someone’s behavior.
Expectations can change our behaviorFood’s effect on the brain is a combination of our biology as well as our expectations. The placebo effect, or the expectation of what food can do to our mood, appetite, sex drive, and sleepiness, is great. And food affects the brain’s activities over a long period of time, not immediately. In other words, sometimes food is just food.
We can use food for many reasons relating to mood, but we do not want to confuse food with medicine. In other words, we don’t want to use food to treat diseases like depression, sleep problems, or high blood pressure. See your doctor if you think you may suffer from any of these problems.
“Brain food” myths and facts
To further clarify the biological connection to food, here’s what food does — and doesn’t do to our brains:
Myth: Eating fish makes you smarter.Fact: Fish is a perfect source of fats that are essential for normal body functions, including brain activity and other cell activities.
Myth: Warm milk and turkey put you to sleep.Fact: Both turkey and milk are good sources of lean protein, but, if anything, they make you more alert, not sleepy. They contain tryptophan, an amino acid which is a building block of protein and serotonin, the brain chemical that makes you sleepy and relaxed. However, tryptophan is just one of the amino acids found in most proteins. Other amino acids block tryptophan’s entry into the brain, so it cannot be made into serotonin. So the protein found in milk and turkey actually energizes you by boosting two other brain chemicals — dopamine and norepinephrine.
Myth: Carbohydrates are good antidepressants.
Fact: While carbohydrates can modify serotonin, the relaxing brain chemical, they only have a mild effect. This effect occurs many hours after you eat carbs — and only if you don’t eat protein or fat.
Myth: Protein improves mental focus.
Fact: Protein can increase brain chemicals related to alertness (norepinephrine and dopamine), but it has only a small effect that occurs several hours after eating.
Myth: Chocolate is calming.
Fact: Chocolate (and other palatable foods) can affect the “pleasantness” circuits in the brain. So, it not only tastes good in the mouth (we have sensors there), but certain brain circuits can be influenced by tasty choices, resulting in a temporary sense of well-being.
Myth: Carrots are good for your vision.
Fact: While we don’t usually think of our eyes as part of the brain, the retina (the part of the eye that’s essential for vision) is actually part of the nervous system. Carrots and other orange vegetables are rich in beta-carotene, a version of vitamin A. We need this vitamin for adequate vision, but even if you consume great amounts, it won’t improve your vision.
Madelyn Fernstrom’s Bottom Line: The fundamentals of a healthy diet — lean protein, lots of fruits and vegetables, fiber-rich carbohydrates, and moderate amounts of heart-healthy fat — are the same for the brain as for the whole body. While particular foods can influence brain chemistry, the biological effects are modest at best and take at least three to four hours to occur. More likely, the expectation of what the food will do to our bodies influences how we feel.
Madelyn Fernstrom, Ph.D., CNS,is the founder and director of the An associate professor of psychiatry, epidemiology, and surgery at the University of Pittsburgh School of Medicine. Fernstrom is also a board certified Nutrition Specialist from theAmerican College of Nutrition.
PLEASE NOTE: The information in this column should not be construed as providing specific medical advice, but rather to offer readers information to better understand their lives and health. It is not intended to provide an alternative to professional treatment or to replace the services of a physician.