Claire Loewenfeld, born Lewisohn in Tübingen, Germany[1] (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.[2][3] She studied at Maximilian Bircher-Benner's clinic in Zurich, Switzerland,[4] 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.

In 1925 the Loewenfelds and Pincuses moved out of Berlin to adjacent rented properties which they shared on the Küssel, a peninsula jutting out into Lake Templiner in a rural district of Potsdam.

[11] Another close friend of both families, Paul Tillich, a German-American Protestant theologian wrote a dedication on the inauguration of their new home entitled, (in English), Space and Time in Dwelling.

[9][12] The Loewenfeld and Pincuses' house soon became a meeting place for Tillich and his circle of German intellectuals until Tillich, whose writings brought him into conflict with the Nazi movement, was subsequently forced into exile in the U.S.[13][14] During early 1936 the Loewenfelds travelled to Syria and Palestine where they witnessed at first-hand the initial stages of the Arab uprising against British mandate and Jewish immigration.

[8] In late 1938 Claire Loewenfeld studied at the Maximilian Bircher-Benner's clinic in Zurich, Switzerland obtaining a special diploma in nutrition.

[17] During the war, Loewenfeld wrote to The Times and the British Medical Journal about the negative impact the shortage of fresh fruit and vegetables was having on the nation's health, and advocated the collection and distribution of rose hips from the hedgerows, as they provided "our highest home-grown source of Vitamin C".

In response, the government organised a nationwide initiative to collect roadside rose hips which, with the help of the Women's Institutes, were processed into syrup for babies and children.

[13] Her experience of using dried herbs to treat sick children during the war had made her aware that the standard preparation techniques resulted in material of poor nutritional value.

Experimentation led to methods for producing dried herbs of higher quality which coincided with an increasing demand in Britain for such culinary products.