A baby’s brain grows the fastest during infancy. This tiny bundle of smarts weighs 300 grams at birth and gradually increases to around 1,500 grams when fully grown.  Just look at a baby’s beautiful body and notice that the head occupies around 25 percent of the baby’s height. No other being enjoys such a “big head,” because our big brains are what make us smart humans. 

A baby’s brain triples in size during the first two years, and then up to about 1,300 grams, or 80 percent of its adult weight, by age four. By eight years it has reached 90 percent of its adult weight; at age sixteen the brain is full size, yet not fully developed until around age twenty-four. Since the brain is developing fastest during the first year and the second fastest between one and five years, those are the windows of opportunity when parents and caregivers can most influence how smart their child becomes.

Our brains are what make us human and above the rest of the animal kingdom. The part of the brain that makes us smartest and the most human is called the cortex, that big part in the front of our brain that occupies the most space. According to University of California neurologist Dr. Vincent Fortanasce, my main neurology consultant for this book, most of a child’s frontal cortex is formed after birth. Wow! That shows how smart it is for parents to follow the brain-building tips in this book.


To appreciate how your baby’s brain grows and how you can help it grow smarter, imagine your baby’s rapidly growing brain as the greatest little garden ever grown. A baby’s brain begins with a single cell. 

During pregnancy, it grows and multiples to 100 billion brain cells at birth. Each one of these 100 billion brain cells looks like a baby octopus, or like a tiny tree that grows many branches. 

Since every organ of the body, especially the brain, is only as healthy as each cell in it, let’s plant this first cell, like a seed, in baby’s growing brain garden and watch it grow—and then see how you can help it grow smarter.  Let’s learn about the four most important parts of a brain cell that you can help grow smarter.


The cell membrane is selective and protective. It welcomes in smart nutrients that help it grow and screens out chemicals, called neurotoxins, that are bad for the brain. The healthier the cell membrane, the healthier the whole brain. The cell membrane is composed mostly of fat, which is why, as you will read many times throughout this book, a healthy-fat diet is smartest for the brain. Also, as you will later learn, the brain cell membrane grows smarter if the child’s diet is smarter.


Inside each cell is another magnificent little structure called mitochondria, which are like energy batteries for the cell. They provide all the energy for the fast-working cell. The brain is one of the most active organs of the body, using 25 percent of all the food energy you eat and the oxygen you breathe, so the better you feed these mighty mitochondria, the better energy they make. Low mental energy is often due to these mitochondria not getting sufficient nutrients.

So, lesson #1: The better you feed each brain cell, the smarter it works.


Extending from the brain cell are branches, called axons or nerve fibers, that are like electrical wires along which nerve impulses travel.  Simply put, smartness is influenced by how fast the electrical messages travel down each nerve fiber. Like insulation on an electrical cord, the better you insulate the nerve fibers, the faster and more efficient electricity flows, which is why appliances using high energy have thick cords. The insulation on our nerve fibers is called myelin. 

Like a protective and nourishing wrap around each plant in the brain garden, myelin keeps nerve impulses flowing along their intended pathways rather than leaking out. Myelin enables the electrical message to carry its impulse a hundred times faster by increasing electrical efficiency.

Many neurodegenerative diseases are due to weakened myelin, like how frayed insulation on electrical wires weakens electrical transmission. How smart the child becomes is influenced by how efficiently and fast the messages travel across these “wires”—a process called myelination. 

Because of the high concentration of fat in the myelin and the rest of the brain cell, brain tissue is 60 percent fat. This fatty fact has two practical implications for brain health: (1) feed your child a right-fat diet, and (2) because fat is the main component that is most prone to “turning rancid” (also known as oxidation), the brain needs to be fed a diet high in antioxidants. Next, you will learn how each plant, or brain cell/nerve fiber, works in your child’s brain.


Imagine all the trillions of electrical transmissions that are going on between smartphones every day all over the world. A similar communication network occurs in your child’s growing brain. Even more important than growing more brain cells—one cell at conception to 100 billion cells at birth—each brain cell connects with others by branching out to its neighbors. 

Like making an increasing number of WeChat friends to grow your social network, brain cells form a neural network. Each brain cell may send out 10,000–15,000 branches to other branches of other brain cells. In this way, a child’s developing brain is making social connections. 

Put your hands in front of you and splay out your fingers so that they almost touch one another. This is what nerve fibers look like. The purpose of these nerve fibers, like fingers, is to connect with other nerves and form a social network, like one brain cell sending out a text message to other brain cells. 

When a child is in the womb and during early infancy, neuroscientists estimate their brain cells are making around 200,000 connections per minute. Imagine a baby’s brain cells sending over 200,000 text messages a minute. 

How do they do this? Growth and connections between brain cells are guided by biochemical cues that tell the nerves to grow this way, turn that way, connect with this neuron, and so on. These biochemical cues are called trophic factors, neurospeak for biochemicals that simply guide developing nerve cells throughout the brain in the way they should go.

Better lines of communication—pruning. You may think it would be nice to call everyone in the world with one touch on your phone, but it’s not necessary, nor would you want to. Your phone lines would be overwhelmed if these billions of lines were not correctly connected. Enter that smart gardener, Dr. Mother Nature. 

Just as you prune plants that are withering or are not necessary, your child’s growing brain goes through automatic pruning. The more active nerves become stronger because they are the most used and important. Those that are not that important are pruned away. As with muscle development, the “use it or lose it” principle applies. Pruning lets the brain circuits work more efficiently, like being left with a user-friendly phone system that contains your most commonly called numbers accessible by a one-touch dial.


The ends of the billions of baby nerve cells are tiny fingerlike feelers that attempt to branch out and connect with other nerves. There is a gap, called a synapse, between the nerves of one brain cell talking to other brain cells. Baby brains become smarter by increasing and then pruning the number of synapses. 

Cells are able to communicate across these gaps by using biochemicals called neurotransmitters. Think of neurotransmitters as biochemical emails in the brain. The smarter the emails that go back and forth between brain cells, the smarter the brain works. 

 Now that you understand your child’s growing brain garden, just imagine 100 billion plants (brain cells) growing and forming bushes. But, unlike plants in a vegetable garden, each one of these plants communicates, by email, to many other plants in the garden, and that’s how thoughts translate into actions. 

Think about when you want to move your arm.  An email is sent to the arm-movement center in your brain, which presses “reply all,” and your brain responds by moving your arm muscles—all within less than a second. What a smart design!


What you need to grow a healthy garden.

The same things you need to grow a healthy garden are what you need to grow a healthy brain: 

  1. Foods to help the garden grow. 
  2. Fertilizer to help it grow stronger.
  3. Water and irrigation.
  4. Pest control. 

This simple diagram is an overview of four ways you will learn to help your child’s little brain garden grow smarter: 

  1. Move more. Movement makes more blood vessels – like water and irrigation channels for plants – to nourish brain cells. 
  2. Eat smart foods. Smart foods help all parts of the brain grow smarter. They provide energy to the brain cell, help the brain fibers make better myelin so the brain thinks and acts quicker, help each cell better communicate with thousands of other cells, and that’s how the brain grows smarter. 
  3. Think happy thoughts. Happy thoughts grow more happy connections (a happy center) in the brain. Sad thoughts, also called toxic thoughts, if too many and dwelled on for too long, grow a sad center. 
  4. Provide smart education and experiences. Play and school help grow more nerves that connect with many more nerves and eventually grow a smarter garden.

Simply put: Growing a smarter brain garden depends on:

  • How you eat
  • How you think
  • How you move
  • How you learn

Imagine a hundred billion of these “plants” above eventually connecting with over 10,000 other plants. There is a lot going on in your child’s growing brain garden, and you will learn how to help it grow smarter. 


As discussed above, the four parts of the child’s growing brain that are most affected by food are:

  • The cell membrane
  • The mitochondria (the energy batteries inside)
  • The myelin (the fatty insulation of the nerves)
  • The connections between cells (the neurotransmitters at the synapses) 

Parents who wish a deeper understanding of how poor nutrition causes what we pediatricians in America call nutrition deficit disorder (NDD), let me take you more deeply inside your child’s brain to show how food affects brain function. 

A malnourished membrane—the root of poor brain growth. Your child grows because individual cells grow and multiply. Health 101 states that the body is only as healthy as each cell in it. Magnify that message for growing bodies and brains, when cells are dividing into new cells millions of times a minute.  

The contents of a brain cell are held together by the cell membrane, a flexible bag magnificently constructed to protect all the structures inside the cell, such as where the energy is produced and the genes replicate themselves, and where all the biochemical action occurs. The cell membrane is designed to communicate with the small branches of the bloodstream that flow next to it. 

Nutrients from the food you eat seep out of tiny capillaries through the cell membrane and into the cell, thereby feeding the genes and the microscopic energy machines called mitochondria.

The most important thing you need to know about the cell membrane is that it’s selective. This biochemical perk is called permeability, which means that it lets in only the nutrients that the cell needs and keeps out the harmful stuff it doesn’t need.  

But a malnourished cell membrane becomes stiff and stubborn and doesn’t let the good nutrients in, nor keep the bad stuff out. When cell membranes don’t behave properly, the whole body misbehaves—or gets sick. 

The two most relevant facts you should know about cell membranes are: 

  • They are composed mostly of fat.
  • Built into the surface of these membranes are millions of microscopic parking places, biochemically known as receptor sites. The membrane can tell if a nutrient or a chemical in the blood is good or bad for the cell by whether or not the nutrient fits into these receptor sites. 

Another way of looking at this cerebral communication system is that these receptor sites are like locks and keys. The receptor sites are the locks, and chemical messengers, called neurotransmitters, are the keys. Real food feeds these messengers, fake food doesn’t. Fit the right keys in the right locks and you have really smart brain health. 

Jam the wrong keys into these locks and you have brain illnesses. Remember this analogy about the cell membrane because it is vitally important to understanding how real food makes the cell grow healthy and prevents NDD (nutrition deficit disorder), and fake food causes NDD. 

The neurotransmitters, the keys, are made mostly of proteins, while the receptors, the locks, are made mostly of omega fats. Yet the standard American diet (SAD), especially breakfast, is sadly deficient in these two nutrients. 

One day I was counseling parents on how to help their children learn and behave better at school. After “checking the oils” in this child’s diet, I felt like saying, “Your child’s brain is full of molecular misfits.” 

Are you with me so far? Okay, suppose you are a cell builder and you want to make the healthiest cell membrane. Naturally, you choose the best building materials, and that’s what the body in its wisdom wants to do. Since the number one structural component of cell membranes is fat, the healthier the fats, the healthier the cell membrane, and the healthier the child. It’s really that simple!  

Suppose your child doesn’t eat enough smart omega-3 fats. Here are three things that could happen in the child’s growing brain: 

  1. In the wall of the cell membrane, the locks and the keys don’t fit, so the membrane becomes less selective. It may not let enough of the right nutrients in nor keep the toxins out. When the brain cell membrane is less healthy, the cell is less healthy and the whole brain is less healthy. 
  2. The nerves don’t fire as fast. Extending from each brain cell is a long filament like a tentacle on an octopus. This is how brain cells communicate with one another, and how nerve messages travel, store memories, and communicate with the rest of the body. For example, telling the child to quickly raise her hand when she knows the answer to a teacher’s question in class. 
  3. The omegas don’t make as much myelin. A substance called myelin makes nerves fire faster and communicate better. Myelin, which is like insulation on an electrical wire, is composed mostly of fat, mainly omega-3 fats. Just like the electrical wiring in your home, the better the insulation, the safer and more efficiently the electrical currents travel. If the myelin doesn’t get enough omega-3s, it becomes like frayed insulation on electrical wires. The child’s brain gets fuzzy, forgetful, and quirky because the cell membranes and the myelin are quirky.


One of the most scientifically researched natural “medicines” for mood disorders—at all ages—is “go fish!”  Because research has shown that eating more omega-3 fish oils helps people be less sad and depressed, neuroscientists call omega-3s “happy fats.”  

Your baby’s brain develops quickly during infancy, which is essential to provide them with the foundation for optimal health later in life. These insights from Dr. Sears can help you create the ideal diet for your growing child!

While this is only a brief introduction to children’s nutrition and the role omegas have in your child’s development, it’s an essential foundation for optimizing your child’s health. To learn more about how Omega-3 DHA can support your child’s development, click here

This is an excerpt from Dr. Bill Sears’ book, Raising a Smarter Child. (Used with permission.)