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First 1000 days

The basis of “the first 1000 days” is that essentially the time between conception and around a child’s second birthday is a crucial window of opportunity to optimise health1. This concept is grounded in the Developmental Origins of Health and Disease framework and continues to be reinforced by Australasian and international research.

Its importance can be summarised in four key elements: early prevention is more effective than later treatment; early-life nutrition influences long-term health; the early environment shapes metabolic, immune and neurodevelopmental trajectories; and the framework provides a structure to guide clinical care and policy.1-3

Before conception and throughout fetal and early postnatal development, nutritional status, metabolic health and environmental exposures can induce biological adaptations that influence later disease risk. Maternal pre-pregnancy BMI and excessive gestational weight gain are consistently associated with higher childhood adiposity and cardiometabolic risk.2,3 In addition to nutrition, early exposure to environmental factors – including tobacco smoke, endocrine-disrupting chemicals and dietary pesticide residues – has been associated with altered immune and metabolic outcomes4. Observational evidence suggests organic dietary patterns reduce pesticide exposure, though direct long-term clinical outcome data remain limited5.

Breastfeeding confers important short- and long-term benefits. Large epidemiological analyses demonstrate reduced infectious morbidity, lower risk of overweight and type 2 diabetes, and maternal cardiometabolic protection6.

Introduction of solids around six months (not before four months), while continuing breastfeeding, aligns with developmental readiness and allergy-prevention evidence. The Australasian Society of Clinical Immunology and Allergy recommends introducing common allergenic foods in age-appropriate forms within the first year to reduce allergy risk7.

Overall, nutritional, metabolic and environmental exposures across the first 1000 days exert lasting biological effects, reinforcing this period as a critical opportunity for long-term health optimisation.

References

  1. Davies PSW, et al. Early life nutrition and the opportunity to influence long-term health: an Australasian perspective. J Dev Orig Health Dis. 2016;7:440-448. doi:10.1017/S2040174415007989
  2. Godfrey KM, Reynolds RM, Prescott SL, Nyirenda M, Jaddoe VWV, Eriksson JG, et al. Influence of maternal obesity on the long-term health of offspring. Lancet Diabetes Endocrinol. 2017;5(1):53–64. doi:10.1016/S2213-8587(16)30107-3
  3. Woo Baidal JA, Locks LM, Cheng ER, Blake-Lamb TL, Perkins ME, Taveras EM. Risk factors for childhood obesity in the first 1000 days: a systematic review. Am J Prev Med. 2016;50(6):761–779. doi:10.1016/j.amepre.2015.11.012
  4. Heindel JJ, Balbus J, Birnbaum L, Brune-Drisse MN, Grandjean P, Gray K, et al. Developmental origins of health and disease: integrating environmental influences. Endocrinology. 2015;156(10):3416–3421. doi:10.1210/en.2015-1394
  5. Vigar V, Myers S, Oliver C, Arellano J, Robinson S, Leifert C. A systematic review of organic versus conventional food consumption: is there a measurable benefit on human health? Nutrients. 2019;12(1):7. doi:10.3390/nu12010007
  6. Victora CG, Bahl R, Barros AJD, França GVA, Horton S, Krasevec J, et al. Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. Lancet. 2016;387(10017):475–490. doi:10.1016/S0140-6736(15)01024-7
  7. Australasian Society of Clinical Immunology and Allergy (ASCIA). ASCIA guidelines for infant feeding and allergy prevention. Sydney: ASCIA; updated 2022. Available from: https://www.allergy.org.au/hp/papers/infant-feeding-and-allergy-prevention
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