This is a prospective longitudinal study that will involve 200 infants enrolled at 12-13 months of age. The study will use a classic nutrition design to assess if infants' feeding practices in Canada place infants 1-2 years of age at risk for low long chain polyunsaturated fatty acid (LCPUFA), nutrients known to influence growth, and brain and immune system development. On enrollment, infants will be assigned at random to a nutrition supplement providing omega 6 and omega 3 LCPUFA or a PUFA placebo.

The objectives are to1. determine the change in dietary fat and PUFA intakes, change in biochemical measures of fatty acid status prospectively from enrollment to 24 months-of-age and 2. to use a nutritional intervention with LCPUFA to address if limiting status of these nutrients impacts growth and development to 24 months-of-age. Primary Endpoints are distributions of developmental tests scores, growth quality and parental reports of child illness. The Bayley Mental and Motor Scales (BSID-III), Peabody Picture Test, Beery Buktenica Developmental Test, Auditory Continuous Performance Test and Test of Attention and Distractibility are used. Growth is assessed as height, weight, and adipose tissue mass and distribution. Child illness is reported by the parent. Secondary endpoints are physiologic measures of blood pressure, heart rate and heart rate variability, and the genetic variables in fatty acid metabolism on fatty acid status and outcome. Blood is collected at enrolment and at 24 months-of-age. Lipids and fatty acids are assessed on plasma and blood cells. Routine, potentially confounding nutrients including iron, vitamin D, choline, folate and B12 are assessed. DNA is extracted from blood cells for genotyping. Dietary intake is assessed using a food frequency questionnaire (FFQ), 3 day food diaries and 24 hour recalls. A parent report illness dairy and questionnaire modified from the International Study of Asthma and Allergies in Childhood is used to assess illness incidence and duration. Descriptive statistics will be used to present subject characteristics, dietary intakes, growth and physiological measures and test results of total fat. Logistic regression, with multivariable-adjusted odds ratios (ORs) of a negative outcome and corresponding 95% CI will be sued to assess the effect of LCPUFA status on development, growth and health outcomes. For all multivariate models, potential confounders will be screened in stepwise fashion, and any covariate with a regression coefficient P-value < 0.05 (two-sided) will be retained. Performance on tests will be compared as LCPUFA status in the lowest quintile compared to highest quintile of outcome (i.e. the two ends of the distribution differ in LCPUFA status).

Inclusion criteria:

• term gestation (37-41 weeks gestation and 2500g or more at birth)
• single birth
• English as the primary language in the home
• non-smoking home environment
• a healthy infant not yet 13 months-of-age, who is not currently breast-fed or fed infant formula with ARA and DHA.
• primary milk source is cows' milk, cows' milk substitutes, or other milk substitutes containing no supplemental fatty acids from enrollment to 24 months-of age.
• the infant has no known food allergies, metabolic, neurological, genetic, or immune disorders that are likely, in the opinion of the investigator to impact the outcome measures in this study.
• the infant has not been fatty acid or oil, including fish oil supplements and there is no intent to provide these supplements during the study.
• the infant has no history of hospitalization, growth failure or any other event which in the opinion of the investigator is likely to impact the outcome measures in this study.

Exclusion Criteria:

• any infant that does not meet the inclusion criteria will not be included in this study.