Claire Loewenfeld, born Lewisohn in Tübingen, Germany (27 September 1899 – 20 August 1974) was a nutritionist and herbalist who worked in England during and after the Second World War promoting the importance of good nutrition, most notably rosehips from Britain's hedgerows as a source of vitamin C. She studied at Maximilian Bircher-Benner's clinic in Zurich, Switzerland, and worked as a dietician at Great Ormond Street Hospital for Sick Children in London, where she developed a fruit and vegetable diet for the treatment of coeliac disease.