36 Months Old

Happy 3rd birthday! During the first 1,000 days of life, or from birth to three years old, your toddler’s brain experiences rapid growth. By three years old, your child’s brain reaches approximately 80% of its adult size. This rapid brain development is a sign of your child’s cognitive abilities, motor skills, and communication methods. Between three and five years old, your child’s brain will continue to grow to about 90% of its intended size. During this time, your child will be ready to take on a new adventure with preschool. In this section’s Nutrient Needs and Caregiver’s Corner, you will find a few tips for building your child’s immune system and enhancing their natural defenses against widely spread germs at school.

Developmental Milestones

  • Social & Emotional: At 3 years old, your child will be able to calm down and self-soothe after about 10 minutes of spending time apart from you.
  • Language & Communication: Your toddler will start to be more inquisitive and ask questions, like “who,” “what,” “where,” or “why” something is happening. They will also be able to say their first name when asked.
  • Learning & Thinking: Your child will learn from experiences to avoid dangerous objects like touching a hot stove or closing a door too hard.
  • Movement & Physical Development: Your child will independently string items together to make art or jewelry, put on clothes by themselves, and use a fork when eating.

Nutrition Needs

Support a Healthy Immune System

Supporting your child’s immune system can look very different for each time of the year. A few ways to kick start your child’s health are at mealtime. From including a variety of whole fruits and vegetables to probiotics, here are a few ways you can help your child be ready for school this coming year.

    • Healthy Diet. A healthy and diverse diet that includes fruits, vegetables, grains, protein, and dairy, offers a variety of vitamins and minerals. The vitamins and minerals your child will get in the food they eat will support their overall health and growth. Inspire your child to explore and experience new, and exciting flavors. Each bite is one step closer to optimal health.
    • Probiotics. Probiotics are considered active organisms found in foods like yogurt, kefir, kimchi, pickles, and many other fermented foods. Including probiotics in your child’s diet can help add diversity to your child’s microbiome. The microbiome is the environment of good bacteria that play an active role in the immune system. When we include more helpful bacteria in the gut, we can strengthen our body’s natural defenses.
    • Vaccinations. Regularly taking your child to their healthcare appointments can ensure that they receive all their vaccinations at the proper time. Vaccines are needed to build your child’s immune system and prevent serious infection from viruses. If you have questions or concerns about certain vaccines, talk with your healthcare team to better understand how these vaccines work and how they protect your child against contagious diseases.

Boost Immunity

Including foods in your child’s diet that are rich in vitamins and minerals is a great way to boost their immune system before going to school. Three key vitamins and minerals that promote a healthy immune system are vitamin D, vitamin C, and Zinc.

    • Vitamin D. Adequate amounts of the “sunshine vitamin” Vitamin D protects your child from bacteria and viruses. Spending 10 to 15 minutes in the sun can help your child build their immune system and create adequate amounts of Vitamin D. Including foods like fatty fish, eggs, and vitamin D-fortified milk and juices can be another way to get adequate amounts of vitamin D in your family’s diet.
    • Vitamin C. Vitamin C is essential for the growth and repair of all the body’s cells and tissues. Taking extra amounts of vitamin C may not keep your toddler from getting sick but can limit how long or severe they are. Consider including citrus fruits, strawberries, tomatoes, bell peppers, broccoli, Brussels sprouts, and kiwifruit, which are all rich in vitamin C for an extra immune boost.
    • Zinc. Zinc is a mineral needed to promote immune functions and resist infectious diseases. It is recommended for children to start eating foods rich in zinc as early as 6 months old since the body cannot naturally make it. Animal products, like beef, pork, cheese, yogurt, and fish, are all great sources of zinc, as well as plant-based sources like zinc-fortified cereals, lentils, and legumes.

Preparing for School

When it comes time to form healthy habits, there are a few to encourage that can protect against germs. Toddlers and pre-school-aged children have as many as 8 to 12 respiratory infections, stomach bugs, or pink eyes within one year of being at school. Help your child by teaching some of these healthy habits to limit how fast germs spread.

    • Good hygiene. Encourage your child to wash their hands regularly, especially before eating and after coughing or sneezing. Teach your child how to sneeze or cough into their elbow to prevent the spread of bacteria. Always clean utensils, produce, and kitchen equipment to prevent the spread of additional germs.
    • Stay positive. Stress at home can leave your family members vulnerable to infections. Keep a positive perspective to encourage change and mitigate any stress your child may feel as they grow. Some techniques to help your child manage feelings of anxiety or depression include meditation, listening to music, or journaling to alleviate stress.
    • Encourage sleep. A good night’s sleep is a healthy behavior that promotes overall wellness. Children and early adolescents need nine to fourteen hours of sleep each night to promote their health and growth. When your child is well-rested, they are able to produce antibodies that help fight infection and keep them healthy.
    • Create a plan. Always talk with your healthcare team to devise a plan for what to do when your child gets sick. Ask what over-the-counter medications you should keep at home to alleviate symptoms as they arise. Know exactly which hospital or emergency clinic to visit if needed.

Family Engagement Activity

  • Vaccines use your body’s immune system to build resistance to specific infections. They work by exposing you to small doses of killed or weakened forms of viruses and bacteria, which causes your body to build a defense against these foreign invaders. Children who do not receive vaccines are more likely to get diseases that are extremely contagious and potentially dangerous.
  • The CDC has a recommended list of vaccinations for your child to receive from 0 to 6 years old during their regular doctor’s visits. Always ask for a copy of your child’s vaccination records to ensure they are getting all the recommended types and doses listed here.

Caregiver's Corner

Dr. Jennifer Lammers is a Doctor of Osteopathic Medicine in CHRISTUS Children’s Pediatric Emergency Medicine department. In this Caregiver’s Corner video, Dr. Lammers offers practical advice for preparing your child to go to school.

    • Promote good habits to protect your child from the germs they are exposed to in the school environment.
      • Encourage good hand hygiene to include washing their hands regularly with soap and water or using hand sanitizer when soap and water are not found.
      • Avoid sharing food and drinks that can cause the rapid spread of viruses from one child to another.
      • Stay up to date with all vaccines to build your child’s immune response when exposed to other germs.
    • Keep over-the-counter medications on hand for when your child gets sick.
      • Use pain relievers, like Tylenol or Motrin, to alleviate fevers, aches, or pain.
      • Keep antihistamines, like Benadryl or Zyrtec, easily accessible to address allergic reactions.
    • Support their immune system with regular sleep, physical activity, and healthcare provider check-ups.
      • Help your child to keep a daily routine, like waking and sleeping at the same time every day. If your child does not go to daycare, this may be new for them and may take some time to get adjusted.
      • Building physical activity every day can lower levels of stress and manage the risk of chronic diseases that weaken your immune system.
      • Take your child to their yearly wellness checks. At 3 years old, the frequency of doctor’s appointments usually changes from every 6 months to once a year. During these visits, your healthcare providers will complete a health screening to make sure your growing child is healthy.