Did you know that the brain starts to develop after the first month of pregnancy? From a tube-like structure at about 28 days, it takes on a form that resembles the adult brain within a period of 7 months. By age 2 years, the brain will achieve 80% of its adult weight and by 5 years of age, the brain is approximately 90% of adult size.
In the brain, there is an extensive network of nerve cells called neurons, which function to transmit and receive messages (nerve impulses). Neurons connect to each other through extensions from the cell body – "branches" known as dendrites bring messages to the cell body, while axons take messages away from it. Axons are often wrapped with fatty layers called myelin, which allows impulses to transmit quickly and efficiently along the neuron. Connections made between the neurons are known as synapses, and chemicals called neurotransmitters are needed to deliver nerve impulses across a synapse.
A baby's brain contains an astounding 100 billion neurons at birth, though most are not yet connected in networks. Connections among neurons are formed as the growing child experiences the surrounding world and forms attachments to his or her caregivers. By age 2 or 3, there are about 15,000 synapses per neuron, creating information superhighways. As the child grows older, the brain will eliminate connections which are seldom or never used, while active connections are kept and strengthened (this process is termed "pruning"). The child's experiences determine which connections will be strengthened and which will be pruned.
With such remarkable changes and complexity in the formation and growth of the human brain, it should come as no surprise that many nutrients are critical for healthy brain development. Energy, protein, fatty acids and various vitamins and minerals are needed to create new neurons, grow their "branches" and form synapses. Omega-3 and omega-6 fatty acids, particularly DHA and AA are key building blocks of the neuron walls and myelin. Iron is required for energy metabolism in the brain cells; choline (a type of vitamin) is needed in the production of neurotransmitters, and zinc is involved in their release to enable the transmission of nerve impulses. Researchers are also beginning to discover the potential role of other nutritional substances in the brain. For instance, lutein has recently been found to be the major carotenoid present in the infant brain. Lutein, which is naturally present in breast milk and green leafy vegetables, has powerful antioxidant properties. It has been suggested that it may serve to protect fatty acids like DHA which are prone to damage caused by free radicals.
Beyond Brain Building
Besides affecting the brain structure and functions, nutrition can also impact brain development indirectly through influencing a child's experiences. As mentioned earlier, children's experiences are crucial in the development of their cognition, motor, social and emotional abilities.
When a child is inadequately nourished, his physical growth could be affected and he might tend to be withdrawn, irritable and less energetic. Caregivers may then treat the child more negatively than they would treat a happy, healthy child. In addition, lower activity levels would limit the child's exploration of the environment and interaction with his caregivers. These situations could have adverse consequences on the child's developing brain.
Eat Right, Right Now
Clearly, good nutrition during pregnancy and the early years of life plays a crucial role in promoting healthy brain development of children, and no single nutrient is the "magic bullet". For mothers-to-be: Women who are expecting should ensure that they consume a well-balanced and varied diet to obtain the required amounts of nutrients, which are generally higher compared to the non-pregnant state (energy needs are increased during the second and third trimester of pregnancy). Appropriate weight gain during pregnancy is also important to improve health outcomes for the mother and child. The use of a maternal milk supplement which is low in fat and fortified with nutrients could help mothers to achieve their nutritional goals without excessive calorie intake.
For young children: Babies should be exclusively breastfed for the first 6 months of life, as breast milk offers the best mix of nutrients. When the child begins to consume solid foods, a wide variety of food choices should be provided to supply sufficient calories and nutrients. Milk should continue to be included as part of the child's diet, as recommended by the national dietary guidelines. Parents may consider the use of age-specific milk formulas which are specially designed to help meet the nutritional needs of growing children.
Lim Meng Thiam
Manager, Nutrition Education / Dietitian
Abbott Nutrition Singapore
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