Day & Night
Children's Nutrition

Inspired by the science of mother’s milk where nutrient levels change between day and night, HAPPi is Australia’s first toddler milk system to nutritionally adapt by time of day.

The Happi Day and Night milk system is based on over 200¹ years of combined scientific research that explores the circadian rhythm.

In humans, the circadian rhythm follows a 24 hour cycle. It is like an internal clock that controls our ability to sleep at night and be alert during the day. Research shows vital nutrients in cow’s milk⁵ and human milk⁶ also have day and night cycles.

These nutrients are important for a child’s brain development, helping them learn and play by day, and turn learning into memories at night.

This research has led our experts to create our time-of-day formulas, next generation nutrition for children during their first 1000 days and beyond.

Iron: Greater levels in Night Milk

In mother’s milk, iron is an essential mineral that shows a significant concentration peak at night⁶.

Iron is crucial for brain development, cognitive function and the production of new red blood cells.

To support the rapid phases of growth, the dietary iron requirement for newborns, infants and during early childhood is high.

Tryptophan: Greater levels in Night Milk

Infants and children need tryptophan as part of a nutritionally balanced diet, and in mother’s milk, tryptophan shows a significant increase in concentration at night⁶. Tryptophan is turned into serotonin and melatonin. All three nutrients are vital for early life brain development and influencing normal appetite, sleep and mood.

Simply for children, tryptophan is a key nutrient that supports the process of cementing learning into memories, happy play and graduating from purees to finger foods.

Tryptophan isn’t produced naturally in the body, so it needs to be sourced from food.

Nucleotides: Day & Night Cycles

Nucleotides are found in mother’s milk and make up our DNA. DNA is important for energy and normal growth and development. During infancy, research shows nucleotides may also influence the immune system response.

Five types of nucleotides found in mother’s milk show day and night concentration cycles.  5’GMP, 5’AMP are highest in milk during the night. While 5′UMP does not show such a significant day and night peak, there is an increase in its levels in night milk. 5′IMP peaks during daylight hours³.


³Sánchez CL, Cubero J, S á nchez J, Chancl ó n B, Rivero M, Rodríguez A, et al. The possible role of human milk nucleotides as sleep inducers. Nutr Neurosci. 2009;12:2 – 8.

⁴Rong-Chi Huang. The discoveries of molecular mechanisms for the circadian rhythm: The 2017 Nobel Prize in Physiology or Medicine, Biomedical Journal, Volume 41, Issue 1 (2018).​​

⁵Z.W. Teng et al. Effects of the circadian rhythm on milk composition in dairy cows: Does day milk differ from night milk?, Journal of Dairy Science, Volume 104, Issue 7, 8301-8313, (2021).​

⁶Italianer, M.F et al.  Circadian Variation in Human Milk Composition, a Systematic Review. Nutrients 2020, 12, 2328. ​