The Barker hypothesis suggests an adverse environment in utero predisposes offspring to greater risk of metabolic syndrome in later life. Therefore, it is important to optimise maternal health in terms of diet and well-being, to facilitate better health outcomes for mother and child. We aimed to determine associations between dietary intakes and well-being in a pregnant cohort. This is retrospective cohort analysis of a combination of 3 studies; The ROLO Study (a Randomised cOntrol trial of a LOw glycaemic index diet in pregnancy), the PEARS study (Pregnancy Exercise And nutrition Research Study with smartphone app support) and an RCT of a probiotic study. All data were collected prior to intervention (approx. 16 weeks). 3 day food diaries were used to determine dietary intakes. The WHO-5 item Well-Being Index was used to determine mental well-being. Initial associations were determined using Pearson correlations, and further defined using multiple regression analysis adjusted for age, BMI, HP index and METs. There were 1521 women included in the analysis; mean age 32 years and BMI 27kg/m2. 96% were Caucasian and 60% had 3rd level education. Average HP index was 5.78 (moderate income level). Average activity level was 440 METs. 27% had low well-being, with 59% being the average score. Results of the regression analysis showed the following to have significant effect on well-being; fibre (B = 0.074, p=0.018), Magnesium (B=0.084, p=0.009), Niacin (B=0.092, p=0.004), thiamine (B=0.073, p=0.018) and folate (b=0.077, p=0.024). Nutrition and well-being appear to be related in early pregnancy, and may play a key role in creating a favourable in utero environment. The findings support research on the gut-brain axis demonstrating fibre can modulate gut microbial health, a determinant of well-being. Fibre and Magnesium are principle nutrients in both the DASH and Mediterranean diets, which have can improve mental health. These data suggest nutritional intervention strategies may improve mental and physical health in mothers which may in turn benefit offspring.