The acid-base balance in the body is important to bone health and is modifiable by diet. We have carried out a population study of bone health in 15,668 men and women aged 42–82 years in the Norfolk area of the UK. BUA was measured using the CUBA clinical machine. BUA was negatively related to age, smoking behaviours, previously diagnosed osteoporosis and previous fracture history and positively related to BMI, physical activity and HRT medication (in women). Those in the bottom 10% of the distribution of BUA had a 4.44-fold increased risk of incident fractures compared with those in the top 30% of the distribution. A more acidic potential renal acid load (PRAL) was associated with a 2% lower BUA (quintile 1 versus quintile 5) in women but not men both before and after adjustment for age, BMI, previously diagnosed osteoporosis, history of fractures, smoking habit, physical activity and hormone replacement therapy. No relationship was found between PRAL and a history of or incident fractures in either men or women. Comparison of the effect of PRAL on BUA with other known osteoporotic risk factors indicated that the magnitude of the relationship with PRAL was relatively small. However, longitudinal studies are required to establish whether in the long-term these small effects are important in overall fracture risk in populations.