The research, using information gathered by this country’s largest longitudinal study of child development Growing Up in New Zealand, has just been published in the journal Nutrition.

University of Auckland paediatrics researcher, Dr Catherine Gilchrist, says good sleep is vital for children’s healthy development and it’s important to understand the association between diet and good sleep.

“There’s a complex relationship between toddlers’ diet and sleep and it’s one that is not especially well understood. This research gives us much greater insight into the impact certain dietary choices may have on toddlers’ length of sleep and night waking,” she says.

The research examined information from more than 6,000 mothers about their two-year-olds’ duration of sleep; night waking and diet. It found that:

• 83% of children got the recommended 11 to 14 hours sleep in a 24-hour period.
• 12% had inadequate sleep (less than 11 hours in a 24-hour period).
• 17% woke frequently at night (more than once a night).
• Children who had moderate to high vegetable intake at age two years were 20% less likely to experience frequent night waking.
• Children who had moderate intake of meat, meat alternatives and eggs were 20% less likely to experience frequent night waking.
• Children who ate more fast food, snacks and soft drinks were 30% to 40% more likely to have inadequate sleep and to wake frequently at night.
• Children who breastfed for longer than 12 months and those who ate more dairy products were more likely to wake at night.

Dr Gilchrist says other factors, outside of food choices, also impact children’s sleep. Toddlers who watched television at least once a day at age nine-months and those who had siblings were also more likely to get less than optimal sleep.

She says nutrient intake may influence sleep through the production of hormones such as serotonin and melatonin which both play a role in quality and quantity of sleep. A diet higher in vegetables and fruits may assist with hormone production and thus sleep regulation.

“Healthy dietary patterns that are characterised by higher vegetable, fruit, fish and whole grain intake and lower fast food and snack intake are associated with better sleep outcomes,” she says.

Dr Gilchrist says a greater focus on the inter-relationship between toddlers’ diets and sleep should be an important discussion during standard Well Child checks.

“Given the relationship between childhood diet and sleep, effective interventions to inform healthcare providers and parents are required. We recommend that a discussion of healthy dietary practices in relation to sleep should be a component of infant and toddler Well Child visits.

“Such an intervention could improve cognitive, behavioural and developmental outcomes in young children,” Dr Gilchrist says.

You can read the full paper here: The relationship between diet and sleep in two-year-old children: Results from Growing Up in New Zealand