Brain development
Between 18-24 months, the brain continues developing nerve connections and pathways, and there is a rapid development of the cerebral cortex, which is responsible for the ability to regulate behaviour and emotions involved in self-awareness and self-consciousness[1]. The frontal and temporal lobes of the brain are developing, improving language, memory, and hand-eye coordination.
This is a time of rapid developmental milestones, and you can expect to see your toddler’s language skills improve dramatically over the next few months. Neurotransmitter synthesis is active until about 2 years of age, affecting the development of your toddler’s mood and behaviour. Nutrition during this critical time affects how your toddler’s brain develops, and a deficiency of any key nutrients involved in brain development may lead to reduced cognitive function[2-3].
At this age, it is normal for toddlers to have difficulty expressing their emotions, which often leads to temper tantrums. Feelings such as anger and frustration, guilt, shame, possessiveness, and excitement are all common at this age, and may cause outbursts in behaviour such as crying or screaming, throwing or breaking things, running away, or even holding their breath[4-5].
However, amongst the temper tantrums, your toddler is also developing a sense of empathy, and you may notice they feel sad or guilty when they have done something wrong. They also show affection by giving you lots of hugs and kisses, or by showing affection to their toys or dolls[5].
| Nutrient | Function | Dietary Sources | RDI |
| DHA | Brain development and function: structural component of grey matter, maintenance of myelin. | Breastmilk or Infant Formula. Fish: Salmon, tuna, sardines, marine algae/algal oil | AI: 10-12 mg/kg of body weight [14] |
| Choline | Needed for cell division & growth, continuing until 3-5 years of age. Provides structural integrity of membranes and neurotransmission[13]. | Breastmilk or Infant Formula. Eggs, salmon, meat, broccoli. | 200mg |
| Iron | Brain development, neurotransmitter function & red blood cells. | Breastmilk or Infant Formula Red meat, spinach, lentils, fortified cereals. | 9mg |
| Folate | Brain development, neurotransmitter function & cell division. | Breastmilk or Infant Formula. Spinach, kale, broccoli, chickpeas | 150mcg |
| Zinc | Brain development, neurotransmitter function & myelination. Behaviourally, early life zinc deficiency results in poorer learning, attention, memory, and mood [2]. | Breastmilk or Infant Formula. Meat, seafood, pumpkin seeds, and nuts. | 3mg |
| Vitamin D | Deficiency may cause behavioural, memory, and learning disorders later in life[15]. | Breastmilk or Infant Formula. (Breastmilk contains low levels of vitamin D. Sunlight exposure is needed) Sunlight exposure. Eggs, fish, and mushrooms. | 5mcg |
| Vitamin B12 | Brain development & nervous system function. | Meat, fish, eggs, and dairy. | 0.9mcg[16] |
RDI = Recommended Daily Intake
AI = Average Intake
Eye development
By now, your toddler can focus on objects both near and far, and hand-eye coordination and depth perception are well developed. Drawing and painting are likely to be favourite activities as your toddler is able to scribble with a crayon and hold a paintbrush. It is likely that your walls by now have pencil or crayon all over them, as your toddler may not be able to stay on the paper[6].
Key nutrients for eye development
| Nutrient | Function | Dietary Sources | RDI |
| Vitamin A | Required for vision and retina development. | Breastmilk or Infant Formula Retinol (active vitamin A): meat, dairy, eggs. Beta-carotene (precursor to retinol): pumpkin, sweet potato, mango, kale, broccoli. | 300mcg[16] |
| Lutein | A carotenoid that accumulates in the retina, where it prevents damage from reactive oxygen species. | Breastmilk or Infant Formula Kale, spinach, broccoli, egg yolks. | No RDI set |
| DHA | Needed for the growth and development of the brain and retina, where it accumulates[17]. | Breastmilk or Infant Formula Fish: Salmon, tuna, sardines, marine algae/algal oil | AI: 10-12 mg/kg of body weight[14] |
Intestinal and gut microbiota development
The development of the microbiome continues with the first few years of life being a crucial period. The establishment of the gut microbiota influences the maturation of the immune system, nutrient absorption, and metabolism, as well as preventing the colonization of pathogenic bacteria.
An unfavourable gut microbiota composition (typically less beneficial bacteria and diversity) has been associated with short- and long-term health conditions, such as overweight and obesity, asthma, metabolic syndromes, and chronic inflammatory diseases. The first years of life offer a unique window of opportunity for modulating the gut microbiota to promote long-term health[7].
During this time, offering a wide variety of pre- and probiotic foods will help to create a diverse colony of beneficial microbes that can influence your toddler’s lifelong health and immunity. While probiotic foods are important to introduce beneficial bacteria, of equal importance is the addition of prebiotic fibre, which helps the bacteria to colonize and reside in the gut.
If your toddler has taken a course of antibiotics, it is important to repopulate the gut with beneficial bacteria, ideally by supplementing with an infant probiotic as well as increasing pre and probiotic foods in the diet.
Immune development
Your toddler’s immune system is developing, and getting sick is a normal and frequent part of childhood. Offering your toddler a variety of nutritious foods, such as fruits, vegetables, protein, whole grains, and omega-3, will provide the immune system with the nutrients needed to mount an appropriate immune response.
High-dose vitamin C (greater than 200mg per day) has been shown to be significantly beneficial in reducing the severity and duration of the common cold virus in children[8].
Beta-glucan, a compound found in oats and baker’s yeast, has been shown to support immunity by improving the functioning of immune cells and the killing and clearance of pathogens. Beta-glucan has been shown to reduce the incidence of upper respiratory tract infection symptoms and improve overall well-being[9].
A clinical study of children aged 12-48 months who took a beta-glucan supplement showed a decrease in episodes of upper respiratory tract infections. Children taking a beta-glucan supplement also reported fewer sick days in a daycare setting[10].
Key nutrients for digestive and immune development
| Nutrient | Function | Source | RDI |
| Vitamin A | Formation and maintenance of mucous membranes (intestines), immune system development, and function. | Breastmilk or Infant Formula Retinol (active vitamin A): meat, dairy, eggs. Beta-carotene (precursor to retinol): pumpkin, sweet potato, mango, kale, broccoli. | 300mcg |
| Zinc | Formation and maintenance of mucous membranes (intestines), immune system development, and function. | Breastmilk or Infant Formula Meat, seafood, pumpkin seeds, and nuts. | 3mg |
| Vitamin C | Formation of collagen and connective tissue, immune system development, and function. | Breastmilk or Infant Formula Citrus fruits, kiwi fruit, mango, apple, and pear | 35mg[16] |
| DHA | Immune system development and function. | Breastmilk or Infant Formula Fish: Salmon, tuna, sardines, marine algae/algal oil | AI: 10-12 mg/kg of body weight[14] |
| Prebiotics | Prebiotics – help to feed beneficial bacteria that colonize and reside in the gut. | Breastmilk or Infant Formula Chickpeas, lentils, beans, banana, onion, asparagus, chicory, leek, berries. | No RDI set |
| Probiotics | Digestive health and immune system development and support. | Yoghurt, kefir, kim chi, sauerkraut, miso, tempeh. | No RDI set |
| Lactoferrin | Stimulates the immune system, promotes the growth of gut microbes, and has antibiotic properties. | Breastmilk or Infant Formula Dairy | No RDI set |
Bone and teeth development
From 18-24 months, your toddler is highly active. Walking has been established, and your toddler is starting to run, jump, and climb everything. The bones continue to grow rapidly, and bone-strengthening nutrients like calcium and vitamin D are essential to support normal growth and development.
By 24 months, your toddler will have almost a full set of teeth, although the second molars will not come in until about 25-33 months <sup>[11]</sup>. This makes biting and chewing much easier for your little one, and most foods can now be easily eaten.
Key nutrients for bone and tooth development
| Nutrient | Function | Dietary Sources | RDI |
| Calcium | Mineralization and growth of bones and teeth. | Breastmilk or Infant Formula Dairy, kale, broccoli, tofu. | 500mg |
| Vitamin D | Supports tooth and bone maturation (assists the absorption of calcium). | Breastmilk, Infant Formula, or infant supplement Sunlight exposure. Eggs, fish, and mushrooms. | 5mcg |
| Vitamin K | Absorption of calcium within bone during development and elongation. | Breastmilk or Infant Formula Dark green leafy vegetables such as spinach and kale. | 25mcg |
| Phosphorus | Maintain bone mineralisation. | Breastmilk or Infant Formula Meat, dairy, and wholegrains. | 460mcg |
| Manganese | Bone maturation and maintenance. | Breastmilk or Infant Formula Legumes, Nuts, seeds, wholegrains. | 80mg [16] |
Developmental milestones 18-24 months
- Gross motor skills: throw a ball, try to catch a ball, jump with a galloping motion, walk up and down stairs when holding hands with a parent.
- Fine motor skills: turn pages in a book one at a time, build towers using four or more blocks, scribble and draw lines up, down, and across a page as well as circles.
- Self-help skills: feeds self using spoon or fork, suck through a straw, assists with getting dressed (eg, pushes arms through t-shirt holes), understands common dangers such as hot or sharp objects (and stays away from).
- Cognitive skills: explore cabinets and drawers (empty entire contents of drawers!), name six body parts, sort objects by shape and colour, understand and participate in turn-taking[12].
See more: 0-6 months development| 6-12 months development| 12-18 months development
Reference
- Hodel AS. Dev Rev. 2018;48:113-144.
- Cusick et al. J Pediatr . 2016 August; 175: 16–21.
- Fox SE, et al. Child Development. 2010; 81:28 40.
- https://www.raisingchildren.net.au/toddlers/development/development-tracker-1-3-years/18-24-months
- http://www.pregnancybirthbaby.org.au/development-milestones-18-to-24-months
- http://www.stanfordchildrens.org/en/topic/default?id=age-appropriate-vision-milestones-90-P02305
- Muriel Derrien, et al. Tren Microb. 2019;27(12)997-1010.
- S Maggin Swadh. J Inter Med Res. 2010;38:386-414.
- Hong F, et al.J Immunol. 2004 Jul 15;173(2):797-806
- Meng, J Nutr Food Sci. 2016, 6:4
- http://www.betterhealth.vic.gov.au/health/conditionsandtreatments/teeth-development-in-children
- http://www.childrensmn.org /search/?q=Developmental+Milestones+18-24+Months&site=
- Derbyshire E, Obeid R. Nutrients. 2020 Jun 10;12(6):1731
- Cerdó T, et al.Curr Opin Clin Nutr Metab Care. 2019 Nov;22(6):434-441.
- https://www.nrv.gov.au/nutrients
- Huang HL, et al. Lipids Health Dis. 2013 Mar;12:27.
