The Discovery of Vitamins
Even in the nineteenth century little was known about nutrition. Sailors on long sea voyages still suffered from scurvy, and rickets was common among the over-crowded and poorly-fed inhabitants of Britain’s Victorian industrial cities. During the early 1900s, in a series of ingeniously-designed feeding experiments, Hopkins solved the riddle of these devastating conditions. He fed young rats on a strictly controlled synthetic diet of purified carbohydrates, fats and proteins with mineral salts and water. The rats failed to grow, and even lost weight, unlessthey were given small amounts of milk daily. Hopkins reasonedthat milk contained 'accessory food factors' that are requiredonly in trace amounts but are indispensable for normal growth andhealth.
These factors soon became known as vitamins. Within a few years, lack of vitamin D was shown to be responsible for the development of rickets, and scurvy was shown to occur when vitamin C was lacking in the diet. Gradually, during the inter-war years, the different vitamins were chemically isolated and characterised, and shown to be necessary for the prevention of different disorders in humans or animals.
Hopkins' experiments transformed nutritioninto a clearly recognized branchof biochemistry founded upon scientific principles. The ability to synthesize products in the laboratory that were identical in properties and physiologicaleffect with the natural vitamins spawned a new industry of nutritional supplements.
James Lind’s 'A treatise of the scurvy’ (reprint).
Naval surgeon James Lind (1716-94) conducted the first modern clinical trial and showed that citrus fruits cured scurvy. His 1753 treatise recommended that sailors eat a wide range of fresh fruit and vegetables to prevent scurvy. However it was largely ignored.
Specimen of scurvy grass Cochlearia officinalis, collected in 1869
Scurvy grass has a high vitamin C content and was a critical ingredient in various eighteenth century cures for scurvy. Mrs Ebot Mitchell’s 1707 ‘Receipt for the Scurvy’ involved ‘3 handful of water cresses with like quantity of Scurvy Grass and like quantity of brooklime, one handful of betony and half handful of wormwood. The mix should further be added to a quart of wine, covered and allowed to stand for 12 hours before pouring liquid into a bottle. The mixture should be added with juices from eight oranges and casualty must take eight spoons of it every day with a draught of ale’.
(On loan from Oxford University Herbaria)
‘A Plan for rendering salted meat more nutritious thereby preventing scurvy’ by Robert Galloway (1877)
Following the aborting in 1876 of the British Arctic Expedition due to a high incidence of scurvy among the naval crews, attention was focused again on cures for scurvy. Robert Galloway believed the critical antiscorbutic component of lime juice was ‘phosphate of potash’ which could be better supplied by adding it to sailors’ salted meat. The lime juice on this expedition was ineffective as the distillation method of preparation destroyed most of the vitamin C.
'De rhachitide' by John Mayow (1674)
Rickets emerged as a serious medical condition in London in the mid 1600s, and John Mayow's tract summarises what little was known about it at the time. Retrospectively, rickets’ sudden appearance is attributed to the increased frequency of smogs, blocking the vitamin D-inducing UV rays.
Child with rickets
Edward Mellanby, one of Hopkins’ students, discovered the dietary cause of rickets. While lecturing at King's College for Women in London from 1913 to 1920, he conducted a series of Hopkins-style feeding experiments. He found that feeding caged dogs on a diet of porridge induced rickets, which could then be cured with cod liver oil.
Weight Curves of adolescent rats with and without dietary supplement
These graphs heralded the discovery of vitamins and the explanations for many devastating human diseases. They are reproduced from Hopkins’ seminal 1912 paper "Feeding Experiments Illustrating the Importanceof Accessory Factors In Normal Dietaries”. This significant nutritional study conclusively showed that some hitherto unidentified components were needed to achieve a physiologically complete diet.
Sample of the first crystals of vitamin C (1928)
These were isolated by Albert Szent-Gyorgyi (1893–1986) while engaged in enzyme research in Hopkins' department. On returning to his native Hungary, Szent-Gyorgyi discovered that paprika gave a high vitamin C yield. This enabled him to fully characterise the cellular function of vitamin C. He received the 1937 Nobel Prize forPhysiology or Medicine for this work.
Hopkins’ Nobel Prize Medal
In 1929 the Nobel Prize in Physiology or Medicine was divided equally between Frederick Gowland Hopkins 'for his discovery of the growth-stimulating vitamins' and Christiaan Eijkman 'for his discovery of the antineuritic vitamin' (ie. vitamin B1 which prevents the neurological disease beriberi).
Scales used by Hopkins
To commemorate being awarded the Nobel Prize, Hopkins gave this highly accurate pair of scales to the department. Hopkins' colleague Malcolm Dixon remembered ‘you could not buy biochemicals then – you had to make them’; so the accurate weighing of reagents was of paramount importance.