In the developed world, breastfed babies tend to grow more slowly than bottlefed babies. Whatever the reason, it isn't the falling concentration of zinc in breast milk that occurs during lactation. In a recent trial, growth velocities were no greater in babies randomised to receive zinc supplements than in unsupplemented babies (American Journal of Clinical Nutrition 2006;84: 594-601).

Twenty four hours after admission, the urine in the catheter bag of an elderly woman taken into hospital for pelvic fracture turned an intense purple colour. Puzzlingly, urine in the collecting tube proximal to the bag stayed its usual yellow colour. The explanation is that some urinary bacteria possess an enzyme able to convert a metabolite of tryptophan into a substance that interacts with the plastic of the urine bag to produce the pigments indirubin or indigo blue. Although dramatic, purple urine bag syndrome is harmless and disappears after treatment of the infection (Age and Ageing 2006;35: 542).

Patients with motor neurone disease often seek the help of physiotherapists, speech therapists, and other health professionals in an attempt to maintain independence for as long as possible. A recent systematic review is critical that so little has been done to measure whether the interventions they provide are …