Abstract Background There are limited longitudinal data regarding nutrient intake, nutritional status and physical function in community-dwelling ethnically diverse older adults. This study explored these variables and their relationship at baseline (n = 100) and 8-months’ follow-up (n = 81) among community-dwelling ethnically diverse older adults (≥60 years) in Birmingham, United Kingdom. Methods Multiple-pass 24-h dietary recalls and the Mini Nutritional Assessment-Short Form assessed nutritional intake and status, respectively. Short Physical Performance Battery (SPPB) and handgrip strength measured physical function. Linear and multinomial regressions were used to predict relationships between physical function, nutritional status and nutrient intake. Results Complete data were collected at baseline (n = 100) and 8-months’ follow-up (n = 81). Mean (SD) age was 70 (8.1) years (60% male), with 62% being obese. Statistically significant decreases in intakes of vitamin B6, vitamin B1, iron, folate, and magnesium occurred over time. Daily intake of all micronutrients except vitamin B12, phosphorus and manganese were below the Recommended Nutrient Intakes (RNI). SPPB (Z = -4.01, p < 0.001) and nutritional status (Z = -2.37, p = 0.018) declined over time. Higher SPPB scores at baseline (OR = 0.54 95% CI 0.35, 0.81) were associated with a slower decline in nutritional status. Conclusion The observed declines and inadequate nutrient intakes in the absence of weight loss in just 8 months may pose serious challenges to healthy ageing, identifying an urgent need to re-evaluate and tailor appropriate dietary advice for this population. Additionally, the associations of nutrition and physical function observed in this study serves as an essential resource to design and implement community/faith-based interventions targeting early screening of nutritional status and physical function to ensure most older adults are assessed and treated accordingly.